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Inclusion morphology and fracture : toughness of pipeline steels Maiti, Ranen 1983

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INCLUSION MORPHOLOGY AND FRACTURE TOUGHNESS OF PIPELINE STEELS by RANEN MAITI B.E. (Met.), R.E. College, Durgapur, India, 1967 D.I.I.T. (Foundry Engg.), I.I.T., Kharagpur, India, 1969 M. Tech. (Phy. Met.), I.I.T., Kharagpur, India, 1971 M.A.Sc., The University of B r i t i s h Columbia, 1978 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES Department of Metallurgical Engineering We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA February, 1983 (c) Ranen M a i t i , 1983 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Metallurgical Engineering The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date: ABSTRACT The effect of increasing hot deformation on inclusion parameters such as area fraction (AF), the average inclusion length (Co), the inter-inclusion distance (D), the aspect ratio (FF) and the density of distribu-tions (N);bas been quantitatively analysed by use of Quantimet 720, an image analysing computer and direct microstructural measurements. Two types of X-70 pipeline steel, one a semi-killed conventional (CON) steel, the other a fully killed and calcium treated for inclusion shape control (CAT) steel were examined in this research. Four stages of hot reduction of the CON steel viz. S2 (38% reduced), S3 (70% reduced), S4 (88% reduced) and S6 (97% reduced) and two stages of the CAT steel viz. CI (63% reduced) and C2 (95% reduced) were used in the investigation. The effect of inclusion parameters on the yield strength, total ductility and elastic and elastic-plastic fracture toughness of these materials were investigated to establish the role of inclusions in the ductile, ductile-brittle transition and brittle fracture processes. The elastic and elastic-plastic fracture toughness of the specimens were measured by K J C testing as per ASTM standard E-399-78a method and unloading compliance J-integral technique as per ASTM standard respectively. It was observed that the semi-killed CON steel containing elongated inclusions shows anisotropy in elastic-plastic fracture toughness; whereas the CAT steels with globular inclusions exhibited isotropic elastic-plastic fracture toughness. The inclusion parameters shape, size and distribution do not affect the yield strength of the X-70 steel. n The inclusion parameters markedly affect the elastic-plastic fracture toughness properties of the X-70 CON steel, particularly in the ductile and transition temperature region where failure occurs by the mechanism of microvoid coalescence. The effect of inclusions on the elastic fracture toughness in the brittle temperature region, where fracture occurs by cleavage mechanism, is insignificant. The most significent inclusion parameters which affect the elastic-plastic fracture tough-ness in the ductile fracture regime are the area fraction AF and the inter-inclusion spacing (D). The elastic-plastic fracture toughness of the CON and CAT X-70 pipeline steel at RT has been correlated (i) with AF by the following relation: KIC " JIC = 1 6 8 - 0 9 " 116.28AF + 45.04 (AF)2 in Ksi/Tn (ii) with D by the following relation: K T r -= J T r = 85.569 + 0.041 D - 0.631xlO'5D2 in KSi/Tn" i i i TABLE OF CONTENTS Page Abstract 1 1 Table of Contents • 1 V List of Tables 1 X • . . . x i-• xv List of Figures List of Symbols X X 1 X Acknowledgements X X X 1 1 Chapter 1 INTENT OF THE THESIS 1 2 MATERIALS AND MICROSTRUCTURE 4 2.1 Test Materials 4 2.2 Laboratory Techniques Involved in Microstructure Analysis 4 2.3 Heat Treatment Details 6 2.4 Microstructural Analysis 8 2.4.1 As Received Condition 8 2.4.2 Heat-Treated Condition 1 6 3 INCLUSIONS 2 2 3.1 Type of Inclusions 3.2 Formation of Oxide and Sulphide Inclusions in a Semi-Killed Steel 2 4 27 3.3 Inclusion Analysis 3.3.1 Optical Metallography 2 7 IV Chapter 3.3.2 SEM EDS Analysis 3.3.3 Electron Microprobe Analysis 3.4 Inclusion Morphology of a Semi-Killed Steel 3.5 SEM Analysis of Inclusions of Semi-Killed Steel 3.6 EPM Examination of Inclusions of Semi-Killed Steel ... 3.6.1 S3 (70% reduction) Stage 3.6.2 S6 (97% reduction) Stage 3.7 Discussion of Plasticity of Inclusions 3.8 Inclusion Shape Control 3.8.1 Modification of Inclusions by Calcium Addition. 3.8.2 Inclusion Morphology of Calcium Treated Steels. 3.8.3 " SEM Analysis of C2 (95% reduction) Inclusion .. 3.8.4 EPM Analysis of C2 (95% reduction) Inclusion .. 3.9 Inclusion Rating on a Quantimet 720 3.9.1 Area Fraction (AF) 3.9.2 Average Inclusion Length (Co) 3.9.3 Form Factor (FF) 3.9.4 Inter-Inclusion Distance (D) 3.9.6 Extended Inclusion Length (L) 3.9.7 Experimental Details of Inclusion Rating 3.9.8 Analysis of Inclusion Parameters from Quantimet Data Page 28 28 28 34 34 37 37 42 48 49 53 55 57 60 60 61 62 62 2 62 3.9.5 Number of Inclusions per mm (N) 62 63 63 v Chapter Page 3.9.9 Analysis of Inclusions by Optical Metallography 6 6 3.9.10 Comparison of Microstructural Analysis with Quantimet Analysis 6 9 3.9.11 Distribution of Inclusions 7 3 3.9.12 Analysis of Inclusion Data for 97% Reduced CON Steel and 63% and 95% Reduced CAT Steel .. 78 4 MECHANICAL PROPERTIES 80 4.1 Introduction 80 4.2 Tensile Specimen and Testing 80 4.3 Tensile Properties 83 4.3.1 Correlation of Yield Strength With Percent Deformation for As Received Materials 83 4.3.2 Correlation of Yield Strength With Micro-Structure 83 4.3.3 Correlation of Yield Strength With Percent Deformation for HT Material 87 4.3.4 Correlation of True Strain to Fracture With Percentage Deformation 89 4.4 Fracture Toughness 93 4.4.1 Specimen Preparation and Configuration 93 4.4.2 Fracture Toughness Testing 95 4.4.2.1 Analysis of the Experimental Data to Obtain K Q / K J C Toughness 9 8 vi 4.4.2.2 J-Integral Test Details 4.4.2.3 Validity of Single Specimen Technique. 4.4.2.4 Correlation of Fracture Toughness of AR Material With Percentage Reduction 4.5 Justification for Heat-Treatment 4.6 Effect of Heat-Treatment on Fracture Toughness 4.7 Fracture Toughness of Heat-Treated Materials 4.7.1 38% Reduced Material (S2) 4.7.2 70% Reduced Material (S3) 4.7.3 88% and 97% Reduced Material (S4 and S6) 4.7.4 63% and 95% Reduced CAT Material (CI and C2).. 4.8 Correlation of Fracture Toughness of CON and CAT Steels in HT Condition With Percentage Reduction 4.9 Anisotropy 4.9.1 Anisotropy in Yield Strength 4.9.2 Anisotropy in True Strain to Fracture 4.9.3 Anisotropy in Fracture Toughness RELATIONSHIP BETWEEN FRACTURE TOUGHNESS AND INCLUSION PARAMETERS 5.1 Correlation of Fracture Toughness With Inclusion Parameters 5.1.1 Correlation of Fracture Toughness With Area Fraction (AF) . . . v i i Chapter Page 5.1.2 Correlation of Fracture Toughness With Average Inclusion Length (Co) 159 5.1.3 Correlation of Fracture Toughness With Inter-Inclusion Distance (D) 162 5.1.4 Correlation of Fracture Toughness With Aspect Ratio (FF) 166 5.1.5 Correlation of Fracture Toughness With Number of Inclusions per mm (N) 168 5.2 Analysis of the Inclusion Parameters 168 5.3 Regression Analysis 170 6 SUMMARY OF OBSERVED EFFECTS OF INCLUSION PARAMETERS ON DUCTILITY AND FRACTURE TOUGHNESS 172a 6.1 Effect of Hot Rolling on the Inclusion Shape Change . . 172a 6.2 The Effect of Inclusion Shape on Tensile Ductility . . . 172a 6.3 Effect of Inclusion Shape on Ductile Fracture Toughness 172e 6.4 Brittle Fracture 172j 7 CONCLUSIONS 173 7.1 Conclusions 173 7.2 Suggestions for Future Work 176 BIBLIOGRAPHY 1 7 8 APPENDICES 1 8 9 I A FORTRAN Program, Modified Inclusion Rating (MIR) for Inclusion Analysis from Quantimet Data I89 II Experimental Data A, P H , P y , N f f From Quantimet 1 9 0 III Analysed Inclusion Parameters From Quantimet Data 2 0 8 IV Inclusion Parameters From Microstructural Analysis 2 2 6 V Fracture Toughness Results 2 3 3 VI Inclusion Parameters With Fracture Toughness 2 4 5 v i i i LIST QF TABLES Table Page 2.1 Chemical Compositions of Different Stages of Reduction of an X-70 Pipeline Steel 5 2.2 Heat-treatment Details for S2, S3, S4 and S6 Stages of CON Steel and CI and C2 Stages of CAT Steel 8 2.3 Grain Size of Polygonal Ferrite and Percentage of Second Phase in S2, S3, S4, S6 Stages of CON Steel in the as Received Condition 1 4 2.4 Structural Details of Heat-treated Samples 1 7 3.1 Electron Probe Microanalysis (EPMA) of an Inclusion from the S3 (70% reduction) Stage (a) Elongated Matrix Phase 3 9 (b) Globular Second Phase 3 9 3.2(a) Ca/S Ratio in CAT Steels 5 3 (b) Melting Temperature of CaS and Ca-Aluminate 5 5 3.3 Chemical Analyses to Two Inclusions From the C2 (95% reduced) CAT Steel by EPMA 5 9 3.4 Inclusion Parameters (as analysed from Quantimet data) on LS and TS Plane 6 5 3.5 Inclusion Parameters viz. Length, Width and FF on LS and TS Plane of Ingot, S2, S3, S4 Stage of CON Steel as Obtained from Microstructural Analyses 6 7 3.6 Comparison of Inclusion Parameters from Quantimet Analysis with Microstructural Analysis 7 * ix Table 3.7 Corrected Inclusion Parameters of S2, S3, S4 Stages of CON Steel on LS and TS Planes 4.1 Inclusion Parameters of S2, S3, S4, S6 Stages of CON Steel and CI and C2 Stages of CAT Steel on LS and TS Plane ; 4.2 Kj;f \ and Stress Ratio Used for Fatigue Precracking f(max) of AR and HT Specimens 4.3 Inclusion Parameters in LS and TS Plane and e f Values at Various Temperatures for Longitudinal and Transverse Specimens of Heat-treated S4 (88% reduced) CON Pipeline Steel 4.4 Inclusion Parameters in LS and TS Plane and e f Values at Various Temperatures for Longitudinal and Transverse Specimens of Heat-treated C2 (95% reduced) CAT Pipeline Steel 4.5 Comparison of Inclusion Parameters in LS and TS Plane of S2, S3, S4, S6 Stages of CON steels and CI and C2 Stages of CAT Steel Appendix II 2.21 Quantimet Data for S2 LT Plane 2.22 Quantimet Data for S2 TS Plane 2.23 Quantimet Data for S2 LS Plane 2.31 Quantimet Data for S2 LT Plane Page 74 93 97 142 143 153 190 191 192 193 x Table Page 2.32 Quantimet Data for S3 TS Plane 194 2.33 Quantimet Data for S3 LS Plane 1 9 5 2.41 Quantimet Data for S3 LT Plane 1 9 6 2.42 Quantimet Data for S4 TS Plane 1 9 7 2.43 Quantimet Data for S4 LS Plane 1 9 8 2.61 Quantimet Data for S6 LT Plane 1 9 9 2.62 Quantimet Data for S6 TS Plane 2 0 0 2.63 Quantimet Data for S6 LS Plane 2 0 1 2.71 Quantimet Data for CI LT Plane 2 0 2 2.72 Quantimet Data for CI TS Plane 2 0 ~ 2.73 Quantimet Data for CI LS Plane 2 ° £ 2.81 Quantimet Data for C2 LT Plane c u " 2.82 Quantimet Data for C2 TS Plane m ?n" 2.83 Quantimet Data for C2 LS Plane Appendix III 3.21 Inclusion Parameters of S2 LT Plane as Analysed from Quantimet Data 20! 3.22 ' Inclusion Parameters of S2 TS Plane as Analysed from Quantimet Data 20 3.23 Inclusion Parameters of S2 LS Plane as Analysed from Quantimet Data 21 3.31 Inclusion Parameters of S2 LT Plane as Analysed from Quantimet Data 21 xi Table Page 3.32 Inclusion Parameters of S3 TS Plane as Analysed ?i ? from Quantimet Data 3.33 Inclusion Parameters of S3 LS Plane as Analysed from Quantimet Data 2 1 3 3.41 Inclusion Parameters of S3 LT Plane as Analysed from Quantimet Data 2 1 4 3.42 Inclusion Parameters of S4 TS Plane as Analysed from Quantimet Data 2 1 5 3.43 Inclusion Parameters of S4 LS Plane as Analysed from Quantimet Data 2 1 6 3.61 Inclusion Parameters of S6 LT Plane as Analysed ?17 from Quantimet Data 3.62 Inclusion Parameters of S6 TS Plane as Analysed 218 from Quantimet Data 3.63 Inclusion Parameters of S6 LS Plane as Analysed 219 from Quantimet Data 3.71 Inclusion Parameters of CI LT Plane as Analysed 220 from Quantimet Data 3.72 Inclusion Parameters of CI TS Plane as Analysed 221 from Quantimet Data 3.73 Inclusion Parameters of CI LS Plane as Analysed 222 from Quantimet Data 3.81 Inclusion Parameters of C2 LT Plane as Analysed 223 from Quantimet Data xii Table Page 3.82 Inclusion Parameters of C2 TS Plane as Analysed 22^  from Quantimet Data 3.83 Inclusion Parameters of C2 LS Plane as Analysed from Quantimet Data 225 Appendix IV 4.1 Microstructural Analysis of Ingot Stage Inclusions 226 4.2 Microstructural Analysis of S2 LS Plane Inclusions 227 4.3 Microstructural Analysis of S2 TS Plane Inclusions 228 4.4 Microstructural Analysis of S3 LS Plane Inclusions 229 4.5 Microstructural Analysis of S3 TS Plane Inclusions 230 4.6 Microstructural Analysis of S4 LS Plane Inclusions 231 4.7 Microstructural Analysis of S4 TS Plane Inclusions 232 Appendix V 5.1 KQ / KIC~ JIC R e s u l t s o f S 2 ( 3 8 % educed) Stage with Crack Transverse to the Rolling Direction 2 3 3 5.2 KQ / KIC" JIC R e s u l t s o f s 2 ( 3 8 % educed) s t a 9 e w i t n Crack Parallel to the Rolling Direction 2 3 4 5.3 KQ / K IC" J IC R e s u 1 t s o f S 3 (70% reduced) Stage with Crack Transverse to the Rolling Direction 2 3 5 5.4 KQ / KIC~ JIC R e s u l t s o f S 3 ( 7 0 % r e d u c e d ) s t a 9 e with Crack Parallel to the Rolling Direction 2 3 6 5.5 KQ / KIC~ JIC R e s u 1 t s o f S 4 ( 8 8 % educed) Stage with Crack Transverse to the Rolling Direction 2 3 7 xi i i Table Page 5.6 KQ / K IC " J i e R e s u l t s o f s 4 ( 8 8 % reduced) Stage with Crack Parallel to the Rolling Direction 2 3 8 5.7 V K IC" J IC R e s u l t s o f S 6 ( 9 7 % reduced) Stage with Crack Transverse to the Rolling Direction 2 3 9 5.8 KQ / KIC" JIC R e s u l t s o f S 6 ( 9 7 % reduced) S T A 9 E W I T N Crack Parallel to the Rolling Direction 2 4 0 5.9 K Q / K I C " J I C R e s u l t s o f c 1 ( 6 3 % reduced) Stage with 241 Crack Transverse to the Rolling Direction 5.10 K Q / K I C " J I C R e s u l t s o f c l ( 6 3 % educed) Stage with Crack Parallel to the Rolling Direction 5.11 V K IC" J IC R e s u l t s o f C 2 ( 9 5 % reduced) Stage with 243 Crack Transverse to the Rolling Direction 5.12 K Q / K I C " ° I C R e s u l t s o f C 2 ( 9 5 % reduced) Stage with Crack Parallel to the Rolling Direction 2 4 4 Appendix VI 6.1 Inclusion Parameters of TS Plane with K I C ~ J j C in 245 LT Orientation 6.2 Inclusion Parameters of LS Plane with K I C ~ J j C in 246 TL Orientation xiv. LIST OF FIGURES Figure Page 2.1 Brick enclosure for the heat-treatment of blanks 7 ' 2.2(a) Microstructure of S2 (38% reduced) CON pipeline steel in as received condition X 150 9 (b) Microstructure of S3 (70% reduced) CON pipeline steel in as received condition X 150 9 (c) Microstructure of S4 (88% reduced) CON pipeline steel in as received condition X 150 10 (d) Microstructure of S6 (97% reduced) CON pipeline steel in as received condition X 150 10 (e) Microstructure of CI (63% reduced).CAT pipeline steel in as received condition X 150 11 (f) Microstructure of C2 (95% reduced) CAT pipeline steel in as received condition X 150 11 2.3(a) Scanning Electron Microstructure ; of aci'cular phase in S3 (70% reduced) CON pipeline steel X 8000 13 (b) Scanning Electron Microstructure of acicular phase in CI (63% reduced) CAT pipeline steel X 8000 13 2.4(a) Microstructure of S2 (38% reduced) CON pipeline steel in heat-treated condition X 150 18 (b) Microstructure of S3 (70% reduced) CON pipeline steel in heat-treated condition X 150 (c) Microstructure of S4 (88% reduced) CON pipeline steel in heat-treated condition X 150 xv 18 19 20 20 21 Figure Page (d) Microstructure of S6 (97% reduced) CON pipeline steel in heat-treated condition X 150 19 (e) Microstructure of CI (63% reduced) CAT pipeline steel in heat-treated condition X 150 (f) Microstructure of C2 (95% reduced) CAT pipeline steel in heat-treated condition X 150 (g) Scanning Electron Microstructure of acicular phase of C2 (95% reduced) CAT pipeline steel in heat-treated condition X 8000 3.1(a) 3D composite of the inclusion morphologies present in the ingot (0% reducted) stage of CON pipeline steel X 880 (b) 3D composite of the inclusion morphologies present in the S2 (38% reduced) stage of CON pipeline steel X 930 . . (c) 3D composite of the inclusion morphologies present in the S3 (70% reduced) stage of CON pipeline steel X 900 (d) 3D composite of the inclusion morphologies present in the S4 (88% reduced) stage of CON pipeline steel X 900 . . (e) 3D composite of the inclusion morphologies present in the S6 (97% reduced) stage of CON pipeline steel X 900.. 3.2(a) Inclusion morphology of S6 (97% reduced) CON pipeline steel on LT plane in heat-treated condition X 550 (b) Inclusion morphology of S6 (97% reduced) CON Ipipeline steel on LS plane in heat-treated condition X 550 29 30 30 31 31 33 33 xvi Figure 3.3(a) SEM back scattered electron image of a S3 (70% reduced) stage inclusion X 2000 (b) Central region of the electron image of the inclusion in Fig. 3.3(a) X 6000 . (c) SEM x-ray EDS of region (1) of inclusion in Fig. 3.3(b) showing elemental analyses (d) XEM x-ray EDS of region 2 of inclusion in Fig. 3.3(b) showing elemental ananlyses (e) SEM x-ray EDS of region 3 of inclusion in Fig. 3.3(b) showing the elemental analyses (f) X-ray image of Mn in inclusion in Fig. 3.3(b) (g) X-ray image of S in inclusion in Fig. 3.3(b) (h) X-ray image of Si in inclusion in Fig. 3.3(b) 3.4(a) Secondary electron image at X 2000 of an inclusion in S3 (70% reduced) stage on EPMA (b) X-ray image of Mn in the inclusion X 2000 (c) X-ray image of S in the inclusion X 2000 (d) X-ray image of Si in the inclusion X 2000 (e) X-ray image of Fe in the inclusion X 2000 (f) X-ray image of Al in the inclusion X 2000 3.5 EPM analyses of a: S6 (97% reduced) stage inclusion showing: (a) Absorbed electron image X 2150 (b) Mn x-ray image X 2150 Page 35 35 35 35 35 36 36 36 38 38 38 38 38 38 40 40 XV11 Figure (c) S x-ray image X 2150 (d) Si x-ray image X 2150 (e) Fe x-ray image X 2150 (f) Al x-ray image X 2150 3.6 EPM Analyses of an S6 (97% reduced) stage inclusion showing: (a) Absorbed electron image X 2150 (b) Mn x-ray image X 2150 (c) Si x-ray image X 2150 (d) S x-ray image X 2150 (e) Fe x-ray image X 2150 3.7 Influence of Ca in steel on composition of indigenous oxides 3.8 Cap - A1 20 3 phase diagram 3.9 3D composite of inclusion morphologies of (a) CI (63% reduced) CAT pipeline steel X 550 (b) C2 (95% reduced) CAT pipeline steel X 550 3.10 SEM x-ray EDS showing the elemental analyses of an inclusion from the C2 (95% reduced) CAT steel (a) Dark region (b) Light (transparent) region 3.11 EPM analyses of a C2 (95% reduced) CAT pipeline steel inclusion showing: (a) Absorbed electron image X 4000 xviii Figure (b) X-ray image of Ca X 4000 (c) X-ray image of Al X 4000 (d) X-ray image of S X 4000 (e) X-ray image of Mn X 4000 3.12 Schematic of quantimet Pu measurement 3.13 Schematic of plate and inclusion geometry 3.14 Schematic of Py measurement in quantimet . . (a) While inclusion is 0° to the horizontal scan lines (b) While inclusion is at an angle to the horizontal scan lines 3.15 Inclusion distribution (a) In LT plane in ingot (0% reduced) material (b) In LS plane in SE (38% reduced) material (c) In TS plane in S2 (38% reduced) material 3.16 Variation of maximum inclusion size (a) In LT plane of ingot (0% reduced) material (b) In LS plane in S2 (38% reduced) material 4.1 (a) Orientation of tensile and compact tension specimens with respect to rolling direction of the plate (b) Dimesnions of tensile specimen 4.2 Correlation of yield strength with percentage deformation for as received materials (a) At RT in longitudinal direction (b) At RT in transverse direction Page 58 58 58 58 61 69 72 72 75 75 75 77 77 82 82 84 84 xix (c) at - 80°C in longitudinal direction (d) at - 80°C in transverse direction (e) at -196°C in longitudinal direction (f) at -196°C in transverse direction 3 Dependence of yield strength with second phase in AR material (a) at RT in longitudinal direction (b) at RT in transverse direction (c) at - 80°C in longitudinal direction (d) at - 80°C in transverse direction (e) at - 196°C in longitudinal direction (f) at -196°C in transverse direction .4 Correlation of yield strength with percentage deforma-tion of heat-treated material (a) at RT in longitudinal direction (b) at RT in transverse direction (c) at - 80°C in longitudinal direction (d) at - 80°C in transverse direction (e) at - 196°C in longitudinal direction (f) at - 196°C in transverse direction .5 Correlation : of true strain to fracture, e^, with percentage deformation for AR materials (a) at RT in longitudinal direction (b) at RT in transverse direction xx Figure (c) at -:80°C in longitudinal direction (d) at - 80°C in transverse direction (e) at - 196°C in longitudinal direction (f) at - 196°C in transverse direction 4.6 Correlation of true strain to fracture, E f , with percentage deformation for heat-treated materials (a) at RT in the longitudinal direction (b) at RT in the transverse direction (c) at - 80°C in the longitudinal direction (d) at - 80°C in the transverse direction (e) at - 196°C in longitudinal direction (f) at - 196°C in transverse direction 4.7 Geometry and dimensions of a half inch thick compact tension (% TCT) specimen 4.8 J-integral test records (a) at RT for heat-treated S3 (70% reduced) specimen HTS3LT09 with crack transverse to rolling direction (b) at -196°C for heat-treated CI (63% reduced) CAT specimen HTC1LT07 with crack transverse to the rolling direction . 4.9 J-Aa resistance plot (a) for heat-treated S6 (97% reduced) CON steel as obtained by single specimen technique(s) as well as by multiple specimen technique (M) Page 90 90 90 90 92 92 92 92 92 92 96 101 101 104 xxi Figure Page (b) for heat-treated S6 (97% reduced) CON steel HTS6LT05 specimen as obtained by single specimen technique 104 4.10 Correlation of K J C - J J C fracture toughness with percentage deformation of AR materials (a) at RT with crack parallel to rolling direction (TL) 1 ° 6 (b) at RT with crack transverse to rolling direction (LT) . . . 1 0 6 (c) at -80°C with crack parallel to rolling direction (TL).. 1 0 6 (d) at - 80°C with crack transverse to rolling direction (LT) 1 0 6 (e) at -196°C with crack parallel to rolling direction (TL).. 1 ° 6 (f) at -196°C with crack transverse to rolling direction (LT) 1 ° 6 4.11 Temperature dependence and effect of heat treatment on KIC " JIC f r a c t u r e toughness of S3 (70% reduced) CON pipeline steel (a) for LT specimens (b) for TL specimens ^ 9 4.12 Fractographs of J-integral/K I C specimens of AR S3 (70% reduced) CON pipeline in TL orientation tested at (a) RT (b) -40°C (c) -80°C (d) -120°C (e) -150°C and (f) -196°C X 400 1 1 1 4.13(a) Temperature dependence of the J j C fracture toughness of HT S2 (38% reduced) CON pipeline steel in LT and TL orientation 113 (b) Temperature dependence of the K J C - J J C fracture tough-ness of HT S2 (38% reduced) CON pipeline steel in LT and TL orientation 113 xx i i Figure Page 4.14 Temperature dependence of KQ/KJ C - J j C fracture tough-i ness of HT S2 (38% reduced) CON pipeline steel (a) in LT orientation H 4 (b) in TL orientation 1 1 4 4.15 Temperature dependence of K Q / K i c - J J C fracture tough-ness of HT S3 (70% reduced) CON pipeline steel (a) in LT orientation (b) in TL orientation 1 1 7 4.16 Fractographs of J-integral/Kj C specimens of HT S3 (70% reduced) CON pipeline steel in TL orientation tested at (a) RT (b) -40°C (c) -80°C (d) -180°C and (e) -196°C X 400 118 4.17 Temperature dependence of k Q/ KJC~ J I C f r a c t u r e toughness of HT S4 (88% reduced) CON pipeline steel (a) in LT orientation 120 (b) in TL orientation 12° 4.18 Temperature dependence of Kg/K I C - J J C fracture tough-ness of HT S6 (97% reduced) CON steel (a) in LT orientation (b) in TL orientation: 121 4.19 Fractographs of d-integral/K I C specimens of HT S6 (97% reduced) CON steel in TL orientation tested at (a) RT (b) -40°C (c) -80°C (d) -120°C and (e) -196°CX400 122 4.20 Temperature dependence of K Q/ K i c - J I C fracture tough-ness of HT CI (63% reduced) CAT steel (a) in LT orientation (b) in TL orientation I2 4 xxiii Figure Page 4.21 Temperature dependence of KQ/KIC - J J C fracture tough-ness of HT C2 (95% reduced) CAT steel (a) in LT orientation (b) in TL orientation 1 2 5 4.22 Fractographs of J-integral/Kj C specimens of HT C2 (95% reduced) CAT steel in TL orientation tested at (a) RT (b) -40°C (c) -80°C (d) -120°C and (e) -196°C X 400 1 2 6 4.23 Correlation of Kj C - J j C fracture toughness of heat-treated materials with percentage deformation (a) at RT in TL orientation 1 2 8 (b) at RT in LT orientation 1 2 8 (c) at -80°C in TL orientation 1 2 8 (d) at -80°C in LT orientation 1 2 8 (e) at -196°C in TL orientation 1 2 8 (f) at -196°C in LT orientation 1 2 8 4.24 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated 52 (38% reduced) CON pipeline steel 1 3 2 4.25 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated 53 (70% reduced) CON pipeline steel 1 3 3 4.26 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated 134 54 (88% reduced) CON pipeline steel xxiv Figure Page 4.27 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated S6 (97% reduced) CON pipeline steel 1 3 5 4.28 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated CI (63% reduced) CAT pipeline steel 1 3 6 4.29 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated C2 (95% reduced) CAT pipeline steel 1 3 7 4.30 Schematic representation of the orientation of elongated inclusions in longitudinal and transverse tensile specimens of a hot rolled plate ^ 4.31(a) Temperature dependence of J j C fracture toughness of HT S3 (70% reduced) CON pipeline steel in LT and TL ids orientation (b) Temperature dependence of K J C - J j C fracture toughness of HT S3 (70% reduced) CON pipeline steel in LT and TL 145 orientation 4.32(a) Temperature dependence of J J C fracture toughness of HT S4 (88% reduced) CON pipeline steel in LT and TL 146 orientation (b) Temperature dependence of K J C - J j C fracture toughness of HT S4 (88% reduced) CON pipeline steel in LT and TL . . . . . 146 orientation xxv Figure Page 4.33(a) Temperature dependence of J j C fracture toughness of HT S6 (97% reduced) CON pipeline steel in LT and TL orientation 1 4 7 (b) Temperature dependence of Kj C - J J C fracture toughness of HT S6 (97% reduced) CON pipeline steel in LT and TL orientation 4.34(a) Temperature dependence of J j C fracture toughness of HT CI (63% reduced) CAT pipeline steel in LT and TL orientation (b) Temperature dependence of Kj C - J J C fracture toughness of HT CI (63% reduced) CAT pipeline steel in LT and TL • a. ... 148 orientation 4.35(a) Temperature dependence of J j C fracture toughness of HT C2 (95% reduced) CAT pipeline steel in LT and TL 149 orientation (b) Temperature dependence of K J C - J J C fracture toughness of HT C2 (95% reduced) CAT pipeline steel in LT and TL 149 orientation 4.36 Schematic representation of the inclusion morphology 152 with respect to LT and TL CT specimen 5.1 (a) Correlation of HT RT Kj C - J j C fracture toughness data 155 with area fraction of inclusions (b) Correlation of Ht -80°C Kj C - J j C fracture toughness 155 data with area fraction of inclusions xxvi Figure 5.1 (c) Correlation of HT -196°C K I C - J j C fracture toughness data with area fraction of inclusions (AF) 5.2 (a) Correlation of HT RT K J C - J j C fracture toughness data with average length of inclusions (Co) (b) Correlation of HT -80°C K J C - J J C fracture toughness data with average length of inclusions (Co) (c) Correlation of HT -196°C Kj C - J J C fracture toughness data with average length of inclusions (Co) 5.3(a & b) Correlation of Ht RT K J C - J J C fracture toughness data with inter-inclusion spacing (D) (c) Correlation of HT -80°C K J C - J j C fracture toughness data with inter-inclusion spacing (D) (d) Correlation of HT -196°C K I C - J J C fracture toughness data with.interr.inclusion spacing. (D) 5.4 (a) Correlation of HT RT K J C - J J C fracture toughness data with aspect ratio (FF) (b) Correlation of HT -80°C K J C - J J C fracture toughness data with aspect ratio (FF) (c) Correlation of HT -196°C K J C - J J C fracture toughness data with aspect ratio (FF) 5.5 (a) Correlation of HT RT K J C - J j C fracture toughness 2 data with the number of inclusions per mm (N) (b) Correlation of HT -80°C K j C - J J C fracture toughness 2 data with the number of inclusions per mm (N) (c) Correlation of HT -1966C k J C ~ J i c f r a c t u r e toughness 2 data with the number of inclusions per mm (N) xxvii Figure specimen 6.3 Schematic illustration of micro-mechanical model for inclusion initiated fracture in a transverse tensile specimen Page 6.1 Inclusion shape change with increasing hot reduction 172b 6.2 Schematic illustration of micro-mechanical model for inclusion initiated fracture in a longitudinal tensile 172f 172g xxviii \ LIST OF SYMBOLS AR As received Ao 2 2 Initial cross-sectional area, inch (mm ) Af 2 2 Final cross-sectional area, inch (mm ) a o Crack length, inch(mm) Aa Crack extension, inch(mm) A i Area under P-A curve at the ith unloading point, in- lb(KJ) AF Area fraction(%) A Area of the detected features in number of picture points A L Area of the live frame in number of picture points b Uncracked ligament W-aQ, inch(mm) B Thickness of compact tension specimen, inch(mm) CAT Calcium treated CI 63% reduced stage of CAT X-70 pipeline steel C2 95% reduced stage of CAT X-70 pipeline steel • CON Conventional CT Compact tension specimen c o Initial compliance, inch/lb(mm/N) AC. Increment in compliance at the i unloading point, in/lb(mm/N) Co Average inclusion length, micron D Inter-inclusion distance, micron E Young's Modulus, PSi(MPa) FF Form Factor or aspect ratio of inclusion GIC Crack extension force under plane strain condition, lbf/in(N/m) xxix HT Heat-treated IP Inclusion parameters 2 J T r Critical J-integral plane strain fracture toughness, in-lb/in (KJ/m2) 2 2 J.. J-value at the ith unloading point, in-lb/in (KJ/m ) 2 2 JQ Calculated J-value, in-lb/in (KJ/m ) Kg Calculated plane stress fracture toughness, Ksiv^n (MPa»^ m) Kj£ Plane strain fracture toughness under static loading, Ksi/in" (MPa/m) K^ (max) Maximum stress intensity factor for fatigue precracking, Ksi/in" (MPa^J) KJ Kilo-jdule : ^IC'^IC ^l a s t "i c "Plast ic fracture toughness (K^ calculated from JJQ) Ksi/Tn (MPav'm) L Extended inclusion length, micron M Magnification factor in picture points per micron 2 N Inclusion density i.e. number of inclusions per mm Total number of inclusions counted in the field of view P Load, lb(N) Pp Load at 5% secant off set, lb(N) pps Picture points p H Horizontal intercept, pps Py Vertical intercept, pps P Maximum load, lb(N) max Pm_. Minimum load, lb(N) r Cyclic stress ratio RD Rolling direction . xxx 52 38% reduced stage of CON X-70 pipeline steel 53 70% reduced stage of CON X-70 pipeline steel 54 88% reduced stage of CON X-70 pipeline steel S6 97% reduced stage of CON X-70 pipeline steel %TCT Half inch thick compact tension specimen w Depth of CT specimen, inch(mm) e f True strain to fracture a 0.2% offset yield strength, Psi(MPa) y-* a*i~ Flow stress, PSi(MPa) flow A Load-point displacement, inch(mm) a Correction factor for bending and rotation of CT specimen during testing v Poisson's ratio u Micron Y Austenite xxxi ACKNOWLEDGEMENT I wish to express my appreciation and feeling of indebtedness to Dr. E. B. Hawbolt, for introducing me to this problem and his guidance, keen interest, constructive criticism, immense encouragement and ever available help throughout the course of this investigation. I am also thankful to Dr. J . S. Nadeau for his guidance, helpful suggestions and invaluable advice during the init ial phase of the present investigation. Thanks are also due to Asst. Prof. R. G. Butters, Dr. I.V. Samarasekera and fellow graduate students for their assistance and help-ful discussions during the research work. I very much appreciate the assistance of the technical staff, in particular, H. Tump and R. Mcleod throughout the experimental programme and R. Bennett and P. Musil during the preparation of the thesis. I am grateful to the Canadian Commonwealth Scholarship and Fellowship Committee, Ottawa and the Department of Metallurgical Engg., University of British Columbia, Vancouver, Canada for giving me this opportunity and faci l i t ies to work towards a Ph.D degree. The financial support provided by CCSFC in form of common wealth scholarship and also by the Department of Metallurgical Engg., University of British Columbia, in the form of graduate student research assistantship are gratefully acknowledged. I will not be doing justice to myself i f I do not acknowledge the hard times and sacrifices which my wife, Bibha, and my daughter, Munmun, had to make during the course of the present study. This thesis would not have seen this day without their whole-hearted support and their love xxxi i for me. I will also remain indebted to my mother, sisters and brothers for their good wishes and continued moral support in completing this work. In the end, I am feeling very sad that my father and my elder brother could not live this long to see me ful f i l l ing their dream. It was due to their blessings and endless affection for me that I have completed this work. I dedicate the present work to their imperishable memory. xxxi i i 1 Chapter 1 INTENT OF THE THESIS The most important design parameters for HSLA steels are high strength and high fracture toughness; the latter includes a high ductility requirement. The fracture toughness property reflects the capacity of the material to resist crack propagation; this parameter is important in terms of fracture safety of a pipeline. The toughness and ductility are greatly affected by STEEL CLEANLINESS; steel cleanliness is a measure of the non-metallic inclusion content of the steel; particularly the distribution and morphology of oxides and sulphides. The presence of elongated inclusions in hot rolled plates leads to a considerable aniso-tropy in fracture toughness. In particular, a very poor toughness for fracture parallel to the inclusion path is observed. In order to improve these poor toughness properties, the non-metallic contents of the steels have been reduced by introducing new and innovative deoxidation, desulphurisation and inclusion shape control practices. This is accom-plished primarily by calcium or rare earth addition to the molten metal. The rare earth or calcium inclusions replace the MnS stringers and planar arrays of A1 20 3 clusters; they possess limited plasticity at hot rolling temperatures. The modified inclusions retain their globular shape and thereby improve the toughness and ductility of the rolled material. An examination of the literature clearly establishes: a) that the volume fraction of non-metallic inclusions in steel, a 2 measure of the cleanliness of the steel, plays an important role in deter-1-19 mining the strength and ductility of the steel. b) that the morphology of the non-metallic inclusions is important in establishing the degree of anisotropy of the mechanical properties of the s t e e l . 2 0 " 3 1 However, very l i t t le work is reported that examines the effect of non-metallic inclusions on the elastic and elastic-plastic fracture toughness of a HSLA X-70 steel. This study has been initiated to examine: a) The relative significance of specific inclusion parameters e.g. volume fraction, shape, size, density of distribution and inter-particle spacing on the fracture toughness in the elastic and elastic-plastic fracture regime. b) The relative significance of the inclusion parameters on the aniso-tropy of the elastic and elastic-plastic fracture toughness. c) The relative effect on mechanical properties of inclusions present in a conventionally processed steel vs a Ca-treated steel of the same chemical composition. The variation in inclusion parameters in a single grade X-70 steel were obtained by the following: i) Gradual stringering out of the inclusions in a conventional semi-killed (CON) X-70 pipeline steel due to increasing percentage of control-led hot deformation. i i ) Inclusion shape control with calcium treatment (CAT). In addition, i t should be realized that both the CON and the CAT steel contain an inhomogeneous distribution of inclusions in the as-cast ingot. 3 The relative effect of inclusion parameters on the fracture toughness properties of the steel at different hot reduction stages were assessed for a temperature range RT down to -196°C. The fracture toughness results were determined using both the K I C plane strain fracture toughness test-ing 3 2 and the J-integral elastic-plastic fracture toughness procedures , j 33-35 as per ASTM standard. This information is then used to examine the role of inclusions dur-ing fracture in the elastic and in the elastic-plastic failure condition. It is hoped that this study will give a more fundamental understanding of the role of the non-metallic inclusions on the fracture processes taking place under ductile, brittle and mixed mode fracture conditions. Chapter 2 4 MATERIALS AND MICROSTRUCTURES 2.1 Test Materials Materials in the form of slab sections and plate sections represent-ing different percentages of hot rolling reductions from production heats were supplied by IPSCO Steel, Regina, a Canadian pipeline steel manu-facturer. These slabs and plates were to be used to produce an X-70 grade steel. The original thickness of the ingots from which the slabs and plates were obtained was 760 mm. The chemical composition of these slabs and plates with and without calcium treatment are contained in Table 2.1. All of the steel samples show a similar chemical composition except for the S-content. The chemical composition of S2(38%), S3(70%), S4(88%) and S6(97%) indicate that these are conventional semi-killed steel and will be designated CON steel. Their deoxidation was accomplished by Fe-Mn and Fe-Si additions only. These steels contain a higher sulphur concentration ^ 0.027 to 0.032 Wt 1. The CI and C2 steels are fully killed steels obtained by using Al-deoxidation practice and calcium treated for inclusion shape control and will be designated CAT steel. These steels contain much less sulphur, ^ 0.005 to 0.009 wt 1. The 0/S ratio varies from 0.331 to 0.892 in case of CON steels. The CAT steels con-tain higher Si and Al . 2.2 Laboratory Techniques Involved in Microstructural Analysis The microstructure associated with the different stages of deformation Table 2.1 Chemical Compo^Hon^ nf Steel Representing Different Stages of Reduction of an X-70 Pi p e l i Designation Chemical Composit ion Slab/Plate Reduction C Mn S P Si Cu Ni Cr Nb Mo Sn Al 0 470 mm Slab Stage 2 (S2) 38 0.06 1.88 0.027 0.008 0.05 0.26 0.14 0.06 0.068 0.27 0.028 - 0.0127 230 mm Slab Stage 3 (S3) 70 0.06 1.91 0.032 0.009 0.09 0.24 0.12 0.10 0.067 0.25 0.027 0.0106 90 mm Crop Stage 4 (S4) 88 0.07 1.95 0.026 0.009 0.09 0.27 0.11 0.05 0.068 0.19 0.024 0.0142 20 mm Plate Stage 6 (S6) 97 0.07 2.03 0.028 0.011 0.09 0.28 0.11 0.08 0.066 0.20 0.033 0.O25O 11 inch Slab CAT 63 (CI) 63 0.08 1.67 0.009 0.010 0.20 0.23 0.21 0.08 0.065 0.24 0.016 0.033 0.0028 lis inch Plate CAT 95 (C2) 95 0.06 1.62 0.005 0.008 0.16 0.17 0.14 0.10 0.062. 0.215 0.012 0.02 0.0044 6 of the CON and CAT steel was examined in the as received (AR) and in the heat-treated (HT) condition. This examination was accomplished by using the following three different test techniques: a) Optical Metallography b) Electron Metallography by Scanning Electron Microscopy (SEM) c) Grain Size Determination. Optical Metallography: The specimens were polished to 0.06 u and then etched with a 2-4% nital solution. Using a Carl Zeiss Ultraphot micro-scope, optical microstructures were obtained at different magnifications. Quantitative analysis of the phases present was accomplished using a 36 linear intercept method. Electron Metallography: Electron metallographic studies were carried out using the SEM to analyse the second phase present in the micro-structure. The specimen preparation was the same as that described for the optical metallographic examination. Grain Size Determination: The ASTM grain sizes of the structure present at the S2, S3, S4, S6, CI and C2 stages of reduction of the pipeline steel in the AR and HT conditions were determined using the Hilliard 37 38 single circle intercept procedure. * This is the ASTM standard method for estimating the average grain size of metals. 2.3 Heat Treatment Details The microstructural analysis of the AR material showed a wide range of grain sizes with varying percentages of polygonal ferrite and a second phase. A structure normalising heat treatment was used to obtain a uniform grain structure with each stage of reduction having the same amount of polygonal ferrite and second phase. The blanks to be machined for compact tension (CT) specimens and tensile specimens were wrapped inside a stainless steel bag to protect against high temperature oxidation during the austenitizing treatment. The closed packets were placed inside a rectangular cavity made of high temperature bricks as shown in Fig. 2.1 The brick enclosure was fastened with nichrome wire and placed inside a muffle furnace for the austenitizing Fig. 2.1 Brick enclosure for heat-treatment of blanks. treatment. After a predetermined time of soaking in the Y - region, the bagged samples were cooled slowly inside the furnace down to a temperature of 780°C in the a-y region. After soaking for a given time the whole assembly was removed from the furnace and allowed to air cool to ambient temperature. The following heat-treatment cycles (Table 2.2) were employed for each of the steel samples. The precise heat treatment for each steel was established by trial and error to yield a uniform grain size and microstructure for all of the stages of deformation. This heat treatment cycle may be designated as a controlled structure treatment. 8 Table 2.2 Heat Treatment Details for S2. S3. S4, and S6 Stages of CON Steel and CI and C2 Stages of CAT Steel. HT Steel Samples 1. Y - temp - 950°C Soaking time - 2 hrs. followed by furnace cooling down to 780°C, soaking time - 3 hrs., followed by slow cool to RT in air S2, S3, S4 and CI 2. Y - temp - 1000°C Soaking time - 2 hrs. followed by furnace cooling down to 780°C, soaking time - 3 hrs. , followed by slow cool to RT in air S6 and C2 2.4 Microstructural Analysis 2.4.1 As Received (AR) Condition Figures 2.2(a) to (f) show the microstructures of the S2(38%), S3(70%), S4(88%), S6(97%), CI(63%) and C2(95%) stages of pipeline steel in the AR condition. These figures reveal the following microstructural details: a) Each microstructure consists of two phases. One phase is polygonal ferrite; the other phase is an acicular ' structure composed of mainly acicular ferrite and some upper bainite. This structure confirms the 39 definition of acicular ferrite given by Leslie. He refers that acicular ferrite is a structure in which the ferrite grains are highly 1 0 - 2 irregular in shape with a high dislocation density, about 10 cm , and forms Figure 2.2(a): Microstructure of S2 (38% reduced) CON pipeline steel in AR condition X 150 Figure 2.2(b): Microstructure of S3 (70% reduced) CON pipeline steel in AR condition X 150 Figure 2.2(c): Microstructure of S4 (88% reduced) CON pipeline steel in AR condition X 150 Figure 2.2(d): Microstructure of S6 (97% reduced) CON pipeline steel in AR condition X150 Figure 2.2(e): Microstructure of CI (63% reduced) CAT pipeline steel in AR condition X150 Figure 2.2(f): Microstructure of C2 (95% reduced) CAT pipeline steel in AR condition X150 12 either by a bainitic or massive transformation of austenite to ferrite. The only exception is S4(88% reduced) material; this structure consists of 100% of the ;.acicular structure. The second phase mostly comprises acicular ferrite because inside the second phases, no prior austenitic grain boundary is visible. Acicular ferrite is different from bainitic ferrite with respect to the prior y-austenite grain boundary network; the prior boundary network is retained in bainitic structures, but not in 40 acicular ferrite structures. In addition, the bainite forms a con-stituent in the second phase structure in Mn-Mo-Nb pipleline steels as 41 reported by Brownrigg and Boelen. b) For samples S2(38%), S3(70%), S6(97%), CI(63%), and C2(95%), the percentage of the two phases viz the polygonal ferrite and the acicular structure in the AR condition vary to a considerable extent from one stage to another. c) Each stage possesses a different polygonal ferrite grain size. The microstructure of the second phase as revealed on the SEM is shown in Fig. 2.3(a) and (b) at higher magnification. The microstructures show the white regions. These are acicular ferrite regions having a common grain orientation and thus, possess same reflectivity due to similar higher secondary electron emission in the SEM. The acicular ferrite regions in the structure look alike the Widmansfatten ferrite regions that are also white. The grain size of the polygonal ferrite in the AR structure and the percentage of the polygonal ferrite and the second phase are shown in Table 2.3. It may be noted that the S6(97% reduced) material possesses the finest grain size. It is well established * that to achieve a 13 Figure 2.3(b): Scanning electron microstructure of acicular phase in CI (63% reduced) CAT pipeline steel in AR condition X8000 14 Table 2.3 Grain Size of Polygonal Ferrite and Percentage of Second Phase in S2, S3, S4, S6 Stages of CON Steel and CI and C2 Stages of CAT Steel in the AR Condition. Stages ASTM Gr. Size Polygonal Ferrite % Second Phase % S2 5.27 60 40 S3 4.60 40 60 S4 <v 11 - 12.00 NIL 100 S6 11.24 80 20 CI 5.74 60 40 C2 10.58 60 40 100% acicular ferrite structure in HSLA steels, apart from stringent composition requirements viz C-0.06%, Mo - 0.25-0.50%, Mn - 1.50-2.25%, Nb ^ 0.05 wt%, the material has to undergo controlled rolling processes which include a) A low slab reheat temperature of the order of 1050°C - 1 1 5 0 o C ^ ^ ° ' H D H 0 b) A high percentage of deformation (74 to 83%) below 9 0 0 ° C 4 3 ' 4 4 c) A low finish rolling temperature (780°C) 4 5 Sometimes, instead of 100% acicular ferrite, the matrix structure consists of significant amounts of polygonal ferrite. The factors which are responsible for this change in microstructural appearance of polygonal ferrite a r e : 4 0 ' 4 4 ' 4 9 a) Improper chemical composition b) Large amounts of strain energy imparted to the austenite during controlled rolling 15 c) Too slow a cooling rate; the rate at which the steel slab is cooled following controlled r o l l i n g . 4 3 ' 4 4 ' 5 ^ 49 51 A.P. Coldren et al. and R.L. Cryderman et a l . reported that the polygonal morphology becomes predominant when the finish rolling temperature is 760°C or lower. The reason is that the polygonal ferrite transformation is strongly accelerated when the austenite is severely deformed. They also indicated that for Mn-Mo-Nb steels that are not controlled rolled, the most common cause for the formation of coarse polygonal ferrite is a major defi-ciency in the Mn, Mo or Nb content or minor deficiencies in all three. D.B. 43 50 McCutcheon et a l . and M. Falco et a l . reported that an alternative means to increase acicularity in the structure is accelerated cooling of 43 the plate after the finish rolling operation. D.B. McCutcheon et a l . suggested that spray cooling is suitable to develop highly acicular micro-52 structures as a replacement for alloying. H.N. Lander et a l . reported that processing schedules during hot rolling practice do produce a wide variety of structures in the final product, although the chemical com-position of the Mn-Mo-Nb steel plates remain the same. They indicated that a product with 100% acicular ferrite or predominantly acicular fer-rite with a small amount of fine grained polygonal ferrite or even a microstructure close to that of a pearlite reduced steel could result depending upon the rolling schedule. The Mn-Mo-Nb steels having a carbon content of approximately = 0.06% that contain a reduced pearlite microstructure will have a limited amount of pearlite because of the relatively low carbon content. Several CO CC workers have demonstrated that for producing a pearlite reduced line pipe steel, the carbon content should be greater than 0.08% (normally 16 around = 0.1% with lower Mn, Mo and Nb content e.g. Mn - 1.4%, Mo =0.17%, Nb - 0.03 to 0.055%. A typical microstructure of a pearlite reduced steel consists of a polygonal ferrite matrix with small regions of non-lameller pearlite and upper bainite. The increased carbon content is required to give the higher strength i.e. more pearlite is required when the Mn-content is reduced. Although the samples in this study possess adequate alloying addi-tions of Mn > 1.62%, Nb > 0.062%, Mo > 0.19% and C < 0.08% for obtaining 100% acicular ferrite in the fully controlled rolled structure, theyexhibit instead, a structure made up of polygonal ferrite and acicular ferrite with some upper bainite. This structure arises due to a combination of the following reasons: a) The thicker AR materials do not undergo adequate controlled rolling processes at low temperatures. b) The greater thickness of the slab gives rise to slower cooling rates, permitting the continuous cooling curve to pass mainly through the ferrite region and finally through the upper bainitic region in the CCT curve. The major reason, is that these slab samples have not received the complete processing treatment. Instead, these samples have been removed at various stages of the hot reduction and have been cooled to room temperature using whatever cooling capacity was available at that stage of the reduction. 2.4.2 Heat Treated (HT) Condition To examine the effect of inclusion parameters on mechanical 17 properties, i t was necessary to obtain a common microstructure for each of the steel specimens. This was accomplished by subjecting each steel to a controlled structure heat treatment as detailed in section 2.3. Fig. 2.4(a) to (f) show the resulting microstructures of the S2(38%), S3(70%), S4(88%), S6(97%), CI(63%) and C2(95%) stages of the pipeline steel in the heat-treated condition. It can be seen that the structure con-sists mainly of fine grained polygonal ferrite and small regions of acicular ferrite and upper bainite. The detailed microstructure of the second phase in the heat treated specimen is shown in Fig. 2.4(g). The microstructure is similar to those in Figs. 2.3(a) and (b) and are typical of acicular ferrite structure as described in section 2.4. The structural details of each stage of the material are listed in Table 2.4. The data in Table 2.4 and the microstructures Fig. 2.4(a) to (f) do demonstrate the fact that the controlled heat treatment has produced essentially the same microstructure for each stage of the steel samples. Table 2.4 Structural Details of Heat-Treated Samples Stages Polygonal Ferrite ASTM Gr. Size % Polygonal Ferrite % Second Phase S2 9.46 90-95% 10-5% S3 9.64 90-95% 10-5% S4 9.70 90-95% 10-5% S6 9.52 90-95% 10-5% CI 10.08 90-95% 10-5% C2 10.14 90-95% 10-5% 18 Figure 2.4(a): Microstructure of S2 (38% reduced) CON pipeline steel in HT condition X150 Figure 2.4(b): Microstructure of S3 (70% reduced) CON pipeline steel in HT condition X 150 19 Figure 2.4(c): Microstructure of S4 (88% reduced) CON pipeline steel in HT condition XI50 Figure 2.4(d): Microstructure of S6 (97% reduced) CON pipeline steel in HT condition X150 20 Figure 2.4(f): Microstructure of C2 (95% reduced) CAT pipeline steel in HT condition X150 21 Figure 2.4(g): Scanning electron microstructure of acicular phase of C2 (95% reduced) CAT pipeline steel in HT condition X8000 22 Chapter 3 INCLUSIONS Non-metallic inclusions in steels have long been a serious concern to metallurgists mainly because of their harmful effect on mechanical properties. Considerable research and development time has been expended in attempts to reduce their volume fraction and thereby to produce a cleaner steel having improved mechanical properties. In fact, steels should be considered as a composite material, containing asmall volume fraction of inclusions in a metallic matrix. Independent of the process controls applied during melting, refining or casting operations, a small volume fraction of inclusions is always present in the finished steel. These non-metallic inclusions must be regarded as an integral part of the steel. Thus, the microstructure of the inclusions and their effect on the mechanical properties of the steel must be examined in the same detail as has been the microstructure and the mechanical properties of the s t e e l . 5 6 3.1 Type of Inclusions In general, non-metallic inclusions in steel fall into two groups according to their origin: exogenous inclusions and endogenous . , . 56-59 inclusions. a) The exogenous inclusions are mechanically entrapped inclusions; 58 their source is external to the melt. Usually these are oxides originating from the slags dr ladle refractories. 23 57 b) The endogenous inclusions according to Sim are those that form by precipitation as a result of homogeneous chemical reactions in the steel. These are mainly oxides and s u l f i d e s 1 6 ' 5 5 " 6 0 and are fil intrinsic to the composition of the steel. Endogenous inclusions are of two types viz. primary inclusions and secondary inclusions. The primary inclusions are oxides and form mainly due to deoxida-tion processes i.e. a chemical reaction of the deoxidizer with dis-solved oxygen in the liquid steel: x A + y 0 = AxGy (solid or liquid) These oxides precipitate directly as solids or liquids from the melt before 59 the solidification of metallic phases. The secondary inclusions are those that precipitate from the steel melt during cooling and solidification due to a decrease in the solubility of oxygen and sulphur in liquid steel with decreasing temperature. The 57 58 secondary inclusions are mainly sulfide and oxide inclusions. ' The sulphide inclusions in steel generally consist of FeS and/or MnS depend-ing upon the Mn:S ratio. Iron sulfide, FeS, occurs in steels deficient in Mn. It forms as an eutectic having a melting point of 988°C; in the presence of oxygen, the melting point further decreases to 940°C. This constituent tends to form at grain boundaries and melts during hot ro l l -ing, giving rise to the well known hot shortness e f f e c t s . 5 6 , 5 8 ' 6 2 " 6 4 In order to avoid FeS formation, the steel composition should possess a high Mn:S ratio; however, i t has been reported that even with Mn:S = 40:l, the sulphide inclusions contain some F.<* 6 « . 6 5 During the solidification and subsequent.cooling, MnS precipitates in three different morphologies16' 5^-61, 65-72 ^pg^ing u p o n the degree of deoxidation of the melt. 24 a) Type I are randomly dispersed globular sulfides. They form by a monotectic reaction in a liquid rich in oxygen and low in sulphur and occur in interdendritic regions. Because of their formation via an oxygen rich l iquid, Type I MnS is frequently associated with oxide inclusions. These occur in rimmed or semi-killed steels "I C C O CC where the oxygen content is more than 0.01 wt %. ' ' These are precipitated as liquid in a liquid metal; due to surface tension 6 9 forces, they originate in the form of spherical particles. In 5 7 6 6 a semi-killed steel they precipitate along with MnO and SiO^. ' b) Type II appear in the form of a branched rod or a fan-like structure; they precipitate as a liquid by a co-operative monotectic r e a c t i o n 5 6 ' 6 7 ' 6 8 in the interdendritic regions. Type II MnS in-clusions are found in fully-kil led steels thoroughly deoxidized with Al containing less than 0.01 wt % o x y g e n . 5 7 ' 6 5 , 6 6 c) Type III appears in the angular or octahedral form; the morphology indicates that they precipitate as solid particles from the melt. CC CC CO Many authors ° » D D ' D O suggest that they form as a consequence of a divorced eutectic reaction. They are found in steels which have been thoroughly deoxidized with Al and contain an excess of C, Si and Al . 3.2 Formation of Oxide and Sulphide Inclusions in a Semi-Killed Steel It has already been mentioned that oxide inclusions originate in the molten steel as a consequence of the chemical reaction of the deoxidiser with dissolved oxygen and also due to the decrease in solubility of oxygen associated with the freezing process. It is a common observation that the deoxidation reaction becomes more complete as the liquid steel cools; the 25 solubility product of the oxide component decreases with decrease in 61,73 temperature. ' The deoxidising potentials of different elements used as deoxidisers can be ascertained from their relative deoxidation constant value. For example, at 1600°C for liquid iron, the solubility product of Ce, A l , Si and Mn is : KQe = 8.1 x IO"2 2, K f t l =4.3 x 10" 1 4 , K $ i = 2.2 x 10~5, _2 = 5.1 x 10 . These figures demonstrate that Al is a much stronger deoxidiser than Si and Mn, whereas, the rare earth element Ce is an extremely strong deoxidiser with respect to A l , Si and Mn. In semi-killed steels where deoxidation is carried out by the addition of FeMn and Fe-Si, Turkdogen 7 4 ' 7 5 has demonstrated that there is a c r i t i -cal ratio [% Si]/[% Mn] for a given temperature; for values higher than this ratio i.e. for a higher Si-content in the steel, solid s i l ica forms as the deoxidation product and for a ratio lower than the crit ical value, which is the case for a higher Mn content, molten Mn-silicate inclusions 57-59 73-76 result. A considerable amount of work has been reported ' on the rate controlling phenomena in deoxidation processes. 59 Flemings postulated that there are six steps in the formation of primary inclusions. Forward et a l . 7 6 concluded that homogeneous nuclea-tion of oxides occurs during solidification and that a significant super-saturation is achieved in the liquid steel during solidification. Sulphide inclusions are secondary inclusions. During deoxidation processes and init ial stages of solidification, the oxygen content in the liquid metal is high; this restricts the solubility of sulphur in 57 the liquid metal, thereby limiting the formation of sulphide inclusions as a primary inclusion product. During the freezing of steel, alloy or impurity elements such as 0 and S are rejected to the interdendritic 26 liquid. Since sulphides form eutectics with oxides in Fe-base alloys and thereby lower the melting point in the system, the secondary inclusions will be located in those regions where the liquid metal is last to solidify, namely the primary grain boundaries or interdendritic regions. The degree of deoxidation has a profound effect on the type of sulphide inclusions formed during the solidification processes. In understanding and predicting the chemistry and morphology of inclusions during solidification processes, the ternary or quaternary phase diagram has become an important tool. HiIty and Crafts 7 7 examined the Fe-S-0 system and located a ternary eutectic of 67% Fe, 24% S and 9% 0 at 920°C and a miscibility gap extending over part of the metal f ie ld. They also studied the modification of the Fe-S-0 system with Mn, Al and Si a d d i t i o n 7 8 ' 7 9 and observed the associated variation of the miscibility gap. The sequence and progress of the formation of both sulphides and oxides was also predicted during the freezing of Fe-base alloys. They outlined that the chemistry and morphology of the oxide and sulphide in-clusions during the solidification process depends on the 0/S ratio. on Yarwood et a l . extended the ideas of Crafts and Hilty and proposed an isolation model for the formation of oxysulpiride inclusions. Their model delineates the fact that oxysulph'ide inclusions form as discrete liquid droplets in the growing dendrite by a monotectic reaction L = Fe(S) + 59 oxy sulphide (1). This model which is also supported by M.C. Flemings, proposes that at higher 0/S ratios <= 0.125, inclusions rich in Wtistite, FeO, tend to form as a spherical particle within the dendrites, while at 0/S ratios less than 0.08, wustite rich spherical inclusions disappear 27 and suTpfride-rich inclusions form as interdendritic sheet or rods at or near the dendrite arm boundaries. Baker and Charles 6 6 clearly demon-strated the sequence of reactions occurring in the formation of Type I, Type II, and Type III sulphides along with oxide inclusions with the help of the Fe-MnS-MnO pseudo-ternary diagram. In our semi-killed CON steels, the 0/S ratio varies from 0.331 to 0.892. Therefore, oxysulphide inclusions rich in oxygen formed as liquid droplets and give rise to Type I MnS in the ingot product. 3.3 Inclusion Analysis Inclusions in the AR and HT CON and CAT steels used in this study were analysed in si tu, using the following procedures: a) Optical Metallography b) Scanning Electron Microscopy (SEM) x-ray Energy Dispersive Spectrum (EDS) analysis c) Electron Probe Microanalysis (EPMA) d) Inclusion rating on a Quantimet 720. 3.3.1 Optical Metallography Specimens were polished to 0.06um. micron. A Carl Zeiss ultra-phot metallograph was used to examine the optical microstructure of the inclusions; photomicrographs were taken at several different magnifica-tions. The inclusion morphology was examined for each of the stages of deformation on each of the three planes viz LT, TS and LS for the AR, HT CON and CAT steel samples. 28 3.3.2 SEM-EDS Analysis The specimens were polished to 0.06 urn and examined using an ETEC Autoscan No. 26 to determine qualitatively the elements present and their distribution in the optically visible inclusions. To obtain a sharp EDS, an operating voltage of 20 KV was employed and approximately 100,000 counts were used. 3.3.3 Electron Probe Microanalysis Electron probe microanalysis was performed using a JE0L Micro Probe Analyser, Model 150 for two purposes: a) To obtain the chemical composition of the inclusions. b) To determine the elemental distribution in an inclusion. From the above information, the probable inclusion stoichiometry could be obtained; at the same time, the mechanism of formation of the inclusions was ascertained. 3.4 Inclusion Morphology of a Semi-Ki11ed Steel Figures 3.1(a) to (e) show the inclusion morphology and the structure of the inclusions present in the AR samples ingot (0% reduction), S2 (38% reduction), S3 (70% reduction), S4 (88% reduction) and S6 (97% reduction) respectively. These figures illustrate the microstructures of inclusions in the LT, TS and LS plane of the hot rolled materials; Figures 3.1(a) to (e) are representative of the structures of the inclusions in the semi-killed conventional steel. These microstructures show that the inclusions are multiphase; one phase is light, the other dark. These phases may consist of Type I MnS with (Fe , Mn)0, Si0 2 sil icates. 29 Figure 3.1(a): 3D composite of the inclusion morphologies present in the ingot (0% reduced) stage of CON pipeline steel X880 the S3 (70% reduced) stage of CON pipeline steel Figure 3.1(e): 3D composite of the inclusion morphologies present in S6 (97% reduced) stage of CON pipeline steel X900 32 The effect of hot rolling on the gradual stringering out of these inclusions may be best observed by examining the change in inclusion length on the LS plane from Figures ;3.1(b) to (e) (from 38% reduction to 97% reduction). The inclusions in the LT plane undergo both flattening and elongation due to the compression and the resulting unidirectional elongation of the material due to rolling stresses. The change in cross-section of inclusions due to rolling can be seen by examining the size variation of the inclusions on the TS plane. The inclusions present in the S6 stage Figure 3.1(e) exhibit a fractured or shattered appearance indicating that the inclusions at the S6 (97% reduction) are fragmented at the low rolling temperatures, characteristic of the final stages of reduction. The effect of the heat-treatment used to obtain the same steel structure at each stage of reduction viz a) austenitizing at 1000°C for 2 hours, b) controlled cooling inside the furnace to 780°C, c) soaking at 780°C for 3 hours and d) controlled cooling in air to RT, on the morphology of the inclusions of the S6 (97% reduction) stage are shown in the Figures 3.2(a) and (b) for the LT and LS planes. A comparison of the HT inclusion morphology shown in Figures 3.2(a) and (b) with that of the AR product shown in Figure 3.1(e) for the S6 (97% reduction) material, shows that there is no change in the morphology of the inclusions due to 81 the heat treatment. The work of Mcfarland and Cronn suggests that Type II MnS stringers might undergo some spheroidization when annealed at980°Cfor 2 hours; but no spheroidization of either phase is evident in our samples. The low controlled rolling temperature experienced at the final stages of reduction as shown in Figures 3.1(e), 3.2(a) and (b) 33 Inclusion morphology of S6 (97% reduced) CON pipeline steel on LS plane in HT condition X 550 34 has fragmented the inclusions; any spheroidization of the irregular inclusions due to the heat treatment would be readily apparent. 3.5 SEM Analysis of Inclusions of Semi-Killed Steel Figure 3.3. shows the structure, x-ray energy dispersive spectra (EDS) analysis and the distribution of elements in an inclusion present in the semi-killed CON pipeline steel. This inclusion is present in the S3 (70% reduction) material. Figure 3.3(a) shows the back scattered electron image of the inclusion at X2000, with Figure 3.3(b) showing the central region at a higher magnification, X6000. The x-ray EDS analysis taken at the three different regions designated 1, 2 and 3 are shown in Figures 3.3(c), (d) and (e) respectively. Region 1 contains mainly MnS, whereas, regions 2 and 3 contain both silicates and sulphides; the Fe peak common to all of the locations may be due to Fe present as FeO in the silicates as well as Fe from the adjacent steel matrix. The Nb peak present in region 2 is thought to have originated from the Nb(C,N) pre-cipitate present in the matrix. An SEM x-ray mapping of the spatial distribution of Mn, S and Si for the same inclusion is shown in Figures 3.3(f), (g) and (h) respectively. Mn is distributed throughout the inclusion, whereas Si shows an enhanced concentration in all areas except region 1; S is localized in region 1. The distribuiton of Mn, S and Si suggests that the inclusion consists of an elongated Fe, Mn silicate matrix containing spherical pockets of MnS. 3.6 EPM Examination of Inclusions in the Semi-Killed Steel EPMA studies were carried out to further investigate the distr i -bution of elements in the inclusions and to obtain an approximate chemical composition of the inclusions. 35 x-ray energy (Kev) Figure 3.3 (a) SEM back scattered electron image of a S3 (70% reduced) stage inclusion X2000 (b) Central region of the inclusion X6000 SEM x-ray EDS of inclusion in Figure 3.3(b) showing the elemental analyses (c) Region 1., (d) Region 2., (e) Region 3. Figure 3.3 X-ray images of (f) Mn, .(g) S and (h) Si in inclusion in Figure 3.3(b) X6000 3.6.1 S3 (70% reduction) Stage Figure 3.4 shows the distribution of Mn, S, S i , Al and Fe in a typical inclusion present in the semi-killed steel. The x-ray images confirm that the light globular regions are high in Mn and S, containing mainly MnS; Mn is distributed uniformly throughout the inclusion; whereas Si is concentrated in the matrix phase and S is localized in the globular phase. Figure 3.4(f) shows that Al is almost absent in the inclusion whereas Figure 3.4(e) shows a uniform low concentration of Fe throughout the inclusion. These x-ray images show that the inclusion probably consists of an (Fe, Mn)0, S i ^ silicate and a MnS sulphide. It should be noted that the silicates constitute the matrix of the elongated inclusions, whereas the spherical second phase is probably MnS. The average chemical composition of the elongated matrix region and the globular second phase region as obtained by EPMA is shown in Tables 3.1(a) and (b) respectively. The chemical analysis suggests that the elongated matrix phase consists of primarily silicate (Fe, Mn)0. S ^ whereas the spherical region contains mostly Mn and S. 3.6.2 S6 (97% reduction) Stage Figures 3.5 and 3.6 represent two typical inclusions in the S6 (97% reduced) semi-killed steel. The figures show the absorbed electron image and the distribution of Mn, S, S i , Fe and Al in the in-clusions. The x-ray images in Figure 3.5 show that Mn is distributed throughout the body of the inclusion; a small concentration of Fe is also present throughout the inclusion Figure 3.5(e). S is distributed throughout the inclusion but is concentrated in the central section; Si 38 (e) (0 Figure 3.4 (a) Secondary electron image of an inclusion in S3(70% reduced) CON steel on EPMA x-ray images of (b) Mn, (c) S, (d) S i , (e) Fe and (f) Al X2000 Table 3.1 Electron Probe Microanalysis (EPMA) of an Inclusion in a CON Steel From the S3 (70% Reduction) Stage: Element Weight Percent Atomic Percent K-Ratio UNKN Intensi t ies STD UNKN Backgrounds STD Si KA 11.77 13.25 0.1373 2912 21204 65 65 Mn KA 39.73 22.88 0.3709 53149 143284 156 156 S KA 3.05 3.01 0.1069 942 8816 142 142 Al KA 0.54 0.63 0.0045 44 9862 35 35 Fe KA 20.25 11.47 0.1941 25881 133369 154 154 0 * 24.66 48.75 (b) Globular Second Phase Element Weight Percent Atomi c Percent K-Ratio UNKN Intensi t ies STD UNKN Backgrounds STD Si KA 0.02 0.02 0.0002 5 21204 65 65 Mn KA 58.29 38.63 0.5307 76047 143284 156 156 S KA 26.52 30.12 1.1445 10090 8816 142 142 Al KA 0.06 0.08 0.0005 5 9862 35 35 Fe KA 1.99 1.30 0.0188 2514 133369 154 154 0 * 13.12 29.85 *At % oxygen i s the d i f f e r e n c e between the sum o f the At ' o f t he elpment.s ,mrt i n n . (e) (f) 3.5 EPM analysis of a S6 (97% reduced) inclusion showing (a) Absorbed electron image, x-ray images of (b) Mn, (c) S, (d) S i , (e) Fe and (f) Al X2150. Vertical lines are a result of the malfunction of the scan generator. 41 (e) Figure 3.6 EPM analysis of a S6 (97% reduced) inclusion showing (a) Absorbed electron image, x-ray images of (b) Mn, (c) S i , (d) S and (e) Fe X2150. Vertical lines are a result of the malfunction of the scan generator. 42 is absent in the central section, but may be present at either ends; Al is neither apparent in the inclusion nor in the matrix. Therefore, the composition of the inclusion in Figure 3.5 is consistent with the analysis of the light phase shown in Figures 3.3 and 3.4; this phase is an elongated MnS inclusion although some silicates may be present at either end. The absorbed electron image of the inclusion in Figure 3.5 is part of an elongated inclusion as is seen in Figure 3.1(d) LS plane. Figure 3.6 shows the x-ray images of a shattered inclusion. Mn is distributed in all fragments; Si is also present, whereas Fe is present only to a small concentration and localized in patches; S is not apparent in the fragments. Therefore, the shattered inclusion is primarily composed of (Fe, Mn)0 . Si0 2 si l icate. 3.7 Discussion of Plasticity of Inclusions The deformation associated with hot rolling is primarily elongation of the* str ip; this gives rise to elongation of the inclusions along the rolling direction. The plasticity of the inclusion, that i s , the rela-tive reduction of an inclusion with respect to a steel matrix, was f i rst 82 defined by Malkiewicz and Rudnik. They defined a Deformation Index (v) which is the ratio of the true strain for the inclusion and that for the matrix i.e. v = -— m where e. = true strain of the inclusion m = true strain of the steel matrix. For the plain strain condition which is being encountered during hot roll-, . . • 83-86 ing operations, the reduction index is 43 In a/b v = — 21n ho/h where a and b are the major and minor axes of the ellipsoid respectively which is taken to approximate the shape of inclusion and ho and h are the thicknesses before and after rolling respectively. Subsequently, T .J . 87 Baker et a l . developed a linear relationship between v and the hardness of the inclusion and that of the matrix: where = hardness of inclusion Hm = hardness of matrix. Thus, inclusions which have very low hardness (e.g. f luids), have v - 2.00 and are highly plastic; on the other hand for = Hm, v = 1 and the resulting inclusion plasticity is comparable to that of the matrix. For H.j = 2 ^ , the inclusion is rigid giving rise to v = 0 and no plastic strain in the inclusion. Depending upon the index of deformability, 65 the following situations may arise: a) The inclusions may fracture b) The inclusion may deform plastically and maintain continuity with the steel c) The inclusion may partially tear away from the steel producing a cavity. It has been suggested that voids form with less deformable inclusions, those having an index of deformation less than 0.5. Klevebring and 88 Mahrs developed a model showing the formation of microcracks at the interface between non-deformable hard inclusions and the steel matrix during hot deformation. 44 The deformability of inclusions is mainly dependent on their chemical composition and the hot rolling temperature. The composition of the inclusion determines its liquidus temperature, while the rolling tempera-86 ture affects the relative flow stress of the inclusion and the steel. 58 Kiessling has summarized the effects of temperature and composition on the deformability of oxide type inclusions. The deformability index of FeO type inclusions (e.g. MnO) decreases with increasing rolling temperature e.g. v = 0.50 at 800°C to v = 0.20 at 1200°C. The plasticity of complex inclusions like (Fe, Mn)0 further decreases with an increase in temperature. Inclusions like A1 2 0 3 , calcium aluminates Ca0.6Al203 and pure SiO^ are hard at all possible temperatures of steel deformation with v = o. However, sil icate inclusions containing varying amounts of FeO, MnO and Si0 2 are extremely plastic at temperatures above oo 0 7 85 1000°C and brittle below 1000°C. According to Maunder and Charles, above 1100°C all silicates are fluid or partly fluid and deform with l i t t l e reduction of the steel giving continuous flat stringers. When rolled below 1000°C, all silicate inclusions shatter and draw out into 83 discontinuous stringers. Sven Ekerot observed with a series of in-clusions containing varying amounts of FeO, MnO and Si0 2 that v varied from approximately zero to 1000°C temperature to between 1.4 to 1.6 at about 1000-1100°C temperature. A deformation index as high as 2.0 has been observed with inclusions containing * 80% SiO^, = 15% A1 20 3 the remainder being FeO and MnO. These inclusions have a transition temperature as low as 800°C. Although the deformation characteristics of silicate inclusions is well established, this is not the case with sulphide inclusions. 45 Unlike silicate inclusions, the deformability index v of sulphide in-T • A • • 11 • , . 65,87-87,89-91 elusions decreases with increasing rolling temperature. The plasticity of sulfide inclusions also depends on the oxygen content; as the oxygen content increases and the MnS inclusions change from Type III to Type I, the plasticity decreases with increasing rolling temperature. The deformability of the single phase Type I MnS increases from a mean value of v = 0.40 to 0.55 at 1200°C to v = 0.65 to 0.82 at 89 900°C. This is because of the fact that Type I MnS in steel can dissolve considerable amounts of oxygen. This increases the hardness 84 of the sulfide inclusions, thus decreasing the deformation index. Accord-91 ing to Waudby the plasticity of Type I MnS increases from 1200°C to 900°C. As mentioned in the previous section, Type I MnS is associated with oxy-sulphide eutectic and silicate inclusions in a semi-killed steel. The deformation characteristics of this duplex Type I MnS is different from single phase Type I MnS. At high oxygen contents, the characteristic sulfide behaviour becomes dominated by that of the MnO-MnS eutectic phase and the inclusion behaves like a fluid with a sharp increase in v at high 89 91 temperature 1200°C) rolling operations. ' This is because the rolling temperature 1100°C) of the eutectic MnO-MnS inclusion is very close to the eutectic temperature.87 However, Maunder and Charles 8 5 reported that in the presence of silicate inclusions, the sulphide phase was prevented from deforming at all temperatures. At high temperatures, the fluid silicate deformed preferentially and the sulphide was dispersed down the inclusion. At low temperatures, the sulphide was supported by the hard silicate matrix and remained undeformed. 46 The deformation of inclusions in a semi-killed pipeline steel with increasing percentages of reduction in hot rolling processes is clearly shown in Figure 3.1. The analysis of the phases present in the inclusion now makes i t possible to describe the effect of hot rolling on each of the phases. At 38% reduction the sil icate phase in the inclusions underwent elongation whereas the lighter sulphide phase remained essentially spherical Figure 3.1(a). At 70% reduction, essentially spherical sulphides are also observed, refer to Figures 3.1(b), 3.3 and 3.4; however, some sulphide inclusions show small amounts of elongation. At 88% reduction, some elongation of the sulphides did occur (Figure 3.1(c)). Therefore, the presence of near spherical MnS inclusions at the 38%, 70% and 88% reduction stages indicates that the matrix phase (Fe, Mn)0. SiOg has undergone the primary elongation of the inclusion; there may be some reduction of the MnS present after 88% reduction, but very l i t t le compared to that exhibited by the silicate matrix. It is well established that the silicate inclusions are hard, brittle and non deformable below a rolling temperature of 1100°C and are fluid and highly plastic above oo pc q-] oo this temperature range. Ekerot has reported that the plasticity index of sil icate inclusions at 1100°C is above 1.4. On the other hand, Type I MnS, which usually occurs in a semi-killed steel, is less plastic at the high rolling temperature; its plasticity increases with a decrease oc pn ni pq in rolling temperature. ' ' Baker and Charles reported that the reduction index or relative plasticity of Type I MnS at the 1200°C ro l l -ing temperature is below 0.4. Therefore, rolling temperature of 1100°C or above, silicate inclusions undergo considerable reduction, whereas Type I 47 MnS inclusions undergo very l i t t le plastic reduction. As a consequence the silicates form the major body of the stringers and the sulphides retain their equiaxed shape as a second phase in the silicate inclusion. The behaviour of inclusions at 38%, 70% and 88% reduction of the semi-85 killed steel agrees with the hypothesis presented by Maunder and Charles. Examination of Figure 3.1(d) which is representative of the inclusions in the semi-killed steel after 97% hot reduction shows that: a) the MnS phase does not retain its globular shape as was observed in the 38%, 77% and 88% reduced material and instead undergoes heavy reduction, forming elongated stringers, Figures 3.5(b) and (c). b) The silicate portion of the inclusion is no longer a continuous stringer; the silicate matrix has broken down into small fragments viz Figures 3.1(e), 3.2(a) and (b), 3.6(a), (b), and (c) during the rolling process. The behaviour of in-clusions at the later stages of rolling clearly indicates that the material underwent controlled rolling operations below a temperature of 900°C. At temperatures below 900°C, the plasticity of the MnS inclusions cc pc pq ol is a maximum and approaches to 1.0, J 0 3 * 0 * ' 3 whereas the silicate in-clusions become britt le and their plasticity index approaches to 83 85 91 zero. ' ' Therefore, the MnS phases undergo stringering and the silicate portions of the inclusions undergo fracture forming discontinuous s t r i n g e r s . 8 5 ' 9 1 Waudby91 mentioned that when the finish rolling tempera-ture is low, as in the controlled rolling of pipeline steels, elongated continuous stringers of silicate inclusions begin to crack transverse to the deformation direction. The observed behaviour of silicate inclusions at 97% deformation agrees with the findings reported in the literature. 48 3.8 Inclusion Shape Control In most tonnage steels the major inclusion forming component is sulphur, and since the amount of sulphur may be as much as 2.5 times greater than that of the oxygen contents, sulphide inclusions constitute 31 the greater volume fraction of the total inclusion content. During hot rolling operations, MnS inclusion form elongated stringers. Although the major contributor to the elongated inclusions is MnS, clusters of A l ^ particles in a killed steel or silicate inclusions in a semi-killed steel may be present in the stringers. The solution to the problem of the anisotropy of mechanical properties is to eliminate the elongated sulphide, oxide or sil icate inclusions from the steel matrix or to modify the inclusions to a rigid type of inclusion having negligible plasticity at the hot rolling temperatures. To reduce the adverse effects of inclusions, the steel industries attempt to reduce the sulphur content of the steel; in addition to maintain the equiaxed inclusion shape during rol l ing, the composition of inclusions is altered. These modifications involve the adoption of highly sophisti-cated melting procedures which incorporate efficient deoxidising and de-sulphurisation techniques to obtain a very low oxygen level (less than 10 ppm) and a maximum sulphur level of 0.005 wt %. Even i f the sulphur or oxygen level is low, the inclusions in the steel matrix will be primarily MnS which will be elongated, forming stringers or planar arrays during rolling. In order to alter the plasticity of the inclusions, it is therefore necessary to add alloying elements which are strong sulphide formers and replace Mn in the sulphide and at the same time produce a 49 non-deformable inclusion at the high rolling temperature. Major research e f f o r t s 9 ' 2 2 ' 2 4 , 3 1 , 5 6 , 6 1 ' 6 9 ' 9 2 " 1 4 7 have resulted in the use of simultaneous deoxidation, desulphurization and inclusion shape control. These are being accomplished by the addition of Z r 2 4 ' 1 2 2 ' 1 2 3 , T i 1 2 4 , R E 2 2 » 3 1 ,69,100, 1 2 5 " 1 3 3 and c a 1 0 1 " 1 2 1 ' 1 3 4 " 1 4 7 . 3.8.1 Modification of Inclusions by Calcium Addition The use of calcium for inclusion shape control has increased rapidly during the last half of the 1970's. It globularizes A1 20 3 type oxides by forming calcium aluminates and causes sulfides, mainly CaS, to encompass the oxides. Calcium is a highly reactive metal; i t has a high affinity for oxygen and sulphur. Its deoxidising and desulphuriz-ing potential at steel melting temperatures is matched only by that of the rare earth elements.61 Despite its excellent thermodynamic proper-t ies, calcium has not been used extensively because of the highly reac-tive nature and its high vapor pressure at ;steelmaking temperatures. Sponseller and F l i n n 1 0 1 reported that at 1607°C, the solubility of Ca in pure iron is 0.032 wt %. The solubility can be further enhanced by A l , C, Ni and Si addit ions. 1 0 1 Hilty and Popp 1 0 3 reported that S i , Al and Ba reduce the thermodynamic activity of Ca and thus its vapor pressure in an alloy form. The authors also reported on the addition of Ca as a Ca-Si-Ba-Al alloy. Several w o r k s 1 0 4 " 1 0 6 have reported the addi-tion of Ca as complex compounds like CaSi, CaSiMn, CaSiBa, CaSiMnAL: etc. S. K. Saxena and his c o - w o r k e r s 1 0 8 ' 1 1 3 ' 1 1 7 ' 1 2 1 ' 1 4 7 reported the addition of Ca in the form of CaO-containing slag powders for deoxida-tion, desulphurization and inclusion morphology control of AT-killed 50 steels. Their laboratory and in-plant trials on Al-killed steels using slag powder injection treatment through a carrier gas have resulted in a final oxygen level of 6-10 ppm and a sulphur content of 0.006 - 0.009%. As a consequence of this process, the A1 20 3 cluster type inclusions changed into globular C a O - A l ^ inclusions having a larger sulphur capa-city. During the treatment, Type II sulphide inclusions gradually dis-appeared giving rise to a round and complex inclusion containing C a O . A l ^ and (Ca,Mn)S. Hilty and F a r r e l l 1 0 7 ' 1 1 0 ' 1 1 1 investigated the modification of in-clusions in an Al-kil led steel by increasing amounts of Ca-addition. Their results (Figure 3.7) show that the starting inclusion in an Al -killed steel consists of 100% A1 20 3 clusters and Type II or III MnS. As the Ca-content of the molton steel increases, the Ca0/Al 20 3 ratio in-creases in the inclusion; the composition of the Ca-aluminate varied from Ca0.6Al203 to Ca0.2Al203 to C a O . A l ^ and finally to 12Ca0.7Al203 with increasing Ca-content. This proposed reaction sequence does con-form to the expected phase changes as depicted in the CaO.Al,,03 equili-brium phase diagram shown in Figure 3.8. The suggested reactions for the formation of Ca-aluminate and CaS inclusions are: mCaO(slag) + nAl 20 3(s) ^ mCaO.nAl^ . 3Ca0(slag) + 2 /U ^ A1203 (s) + 3 Ca The above reactions hold good for additions of CaO as CaO - containing slag powder 51 CALCIUM CONTENT OF STEEL - ppm Figure 3.7 Influence of Ca in steel on composition of indigenous oxides :3oo 1300 0 CaO 10 20 30 40 50 60 WEIGHT. PER CENT 70 80 90 100 A l 2 0 3 Figure 3.8 CaO - A190_ phase diagram 52 3 Ca + A1 20 3 ts) = 3 CaQ (S) + 2 Al_ nCaO (S) + mAl203 (S) = nCaO.jnAV^d) 3 Ca •+ S. = 3 CaS 115 H. Nashiwa et a l . postulated the following mechanism for the formation of complex inclusions in a Ca-treated Al-ki11ed steel: First, oxides precipitate as the solidification of steel continues. Simultan-eously, Ca and Al combine with oxygen to make a globular mCa0.nAl203 inclusion. Successively Ca whose affinity for S is stronger than Mn, together with Mn, combines with sulphur and precipitates as (Ca,Mn)S around the surface of already formed mCa0.nAl203 inclusions which has the capacity of desulphurization especially when the CaO content is high. 102 13 The work of Salter and Pickering, Saxena and Engh support the above sequence of reactions taking place in Ca-treated Al-killed steels. Hilty and F a r r e l 1 0 7 ' 1 1 0 ' 1 1 1 observed that for a 0.005% S containing steel, at low Ca concentrations, the sulphide phases complexed with CaO.Al 20 3 consists of (Ca.Mn) S; at higher Ca concentration (=88 ppm) only CaS formed. In a 0.015% S steel, even with 102 ppm Ca, the sulphide consisted of (Ca,Mn)S. They also observed that at Ca concentrations in excess of 15 ppm, A1 20 3 galaxy type oxides and Type II sulphides were replaced by round globular aluminate and sulphide complex inclusions. 115 H. Nashiwa et a l . reported that the inclusions change to globular 114 type when the Ca/S ratio becomes greater than 0.3. Farrel and Hilty 53 demonstrated that in Al-killed X-65 HSLA steels, MnS stringers and planar cluster of A^C^ inclusions could be eliminated once a threshold concentration of Ca is attained in the steel. This threshold value depends upon the init ial sulphur content of the steel. For a steel of sulphur level 0.005%, this threshold value is reported to be in the range of 20-40 ppm or Ca/S ratio of 0.4 - 0.8. 3.8.2 Inclusion Morphology of Calcium Treated Steels Figures 3.9(a) and (b) show the inclusion morphology and the structure of inclusions present in the heat-treated samples of the 63% (CI) and 95% (C2) reduced fully-kil led calcium-treated steel. These inclusions consist of two phases, a lighter phase and a darker phase. Since these steels are fully killed using Al deoxidation practice and also calcium treated, the inclusions are thought to consist of tnCaO-nAlgO^ and (Ca,Mn)S. The most important characteristic of these inclusions is their globular shape on all three planes. The Table 3.2(a) shows the Ca/S ratio present with CAT 63% and CAT 95% steel samples. Table 3.2(a) Ca/S Ratio in CAT Steels S wt % Ca wt % Ca/S CAT 63% . 0.009 0.004 0.44 CAT 95% 0.006 0.004 0.66 It may be noted that the inclusions changes its shape to globular type when Ca/S ratio is «\. 0.44, compared to a Ca/S value of 0.3 as reported by Nashiwa et a l . 1 1 5 and 0.4 - 0.8 as reported by Hilty and F a r r e l . 1 1 4 (b) t s Figure 3.9 3D composite of inclusion morphologies of (a) CI (63% reduced) CAT pipeline steel X550 and (b) C2 (95% reduced) CAT pipeline steel X550 55 In addition, the inclusion size does not appear to depend upon the per-centage of deformation as is the case of the semi-killed steel. The size and shape of the inclusions remain more or less unaffected as the sample is rolled down from 63% to 95% as shown in Figures 3.9(a) and (b). There-fore, i t is apparent that these inclusions do not undergo any plastic deformation during the hot rolling operations. The non-deformability of the Ca-treated inclusions during rolling operation has been reported by several r e s e a r c h e r s . 1 1 5 ' 1 3 4 " 1 4 7 H. Nashiwa et a l . 1 1 5 have stated that the complex Ca-aluminate, CaS inclusions are not deformed by hot rolling because their melting temperatures are quite high with respect to ro l l -ing temperature. This is shown in Table 3.2(b). Table 3.2(b) Melting Temperature of CaS and Ca-Aluminate Inclusion Layer Composition Melting Point °C L CaO. 6A1203 1820 2 CaO. 2A1293 1745 3 CaO. A1 20 3 1600 4 CaS 2400 The melting temperature of MnS is 1610°C. So depending upon the concentra-tion of CaS in the outer sulphide layer, the melting temperature of (Ca,Mn)S inclusions become higher than 1610°C. 3.8.3 SEM Analysis of C2 (95% reduction) Inclusion Figure 3.10 shows the x-ray EDS of a typical inclusion in the Ca-treated steel after 95% deformation (C2). The dark peripheral s Ca Fe X-ray energy (Kev) Figure 3.10 SEM x-ray EDS showing the elemental analyses of an inclusion from C2 (95% reduced) CAT steel (a) dark region (b) light (transparent) region 57 region contains a high concentration of Ca and S, but only a small amount of Al and Mn. The light central region contains very l i t t le S and Mg, but does contain a significant amount of Al and Ca; the Mg pick-up may be from a refractory. The x-ray EDS data supports the reported composition of the inclusion in a Ca-treated steel; i t is primarily composed of CaS-Al^O^ at the periphery with Ca-aluminate in the core. 3.8.4 EPM Analysis of C2 (95% reduction) Inclusion Figures 3.11(a), (b), (c), (d) and (e) show the absorbed electron image and x-ray distributions of Ca, A l , S, Mn, in a Ca-treated inclusion (C2). The x-ray mapping reveals that Ca is present throughout the inclusion; S is concentrated around the lower periphery of the in-clusion; Al is present to a large extent in the central region; Mn is present mainly where S is present. The x-ray mappings suggest that the inclusion is mainly composed of mCaO. nAlgOg phase in the centre with (Ca,Mn)S and to some extent A l ^ i n the periphery. On the basis of 115 EPMA observations, H. Nashiwa et a l . reported that a typical inclusion consisted of two phases: the inner-phase is Al^O^ - CaO and the outer phase is CaS - MnS - A^O-j. In the outer phase, the concentration of CaS increases with the increase in Ca-content of the steel; MnS disappears at Ca-level of 30 ppm. However, our CAT 63% and CAT 95% steel contain 40 ppm Ca, and MnS is s t i l l present in the outer periphery of the inclu-sion along with CaS. S a x e n a 1 2 1 , 1 4 7 and co-workers 1 1 3 reported two phase inclusions with CaO . A^O^ in the core surrounded by (Ca,Mn)S in the periphery. 58 (e) Figure 3.11 EPM analysis of a C2 (95% reduced) CAT pipeline steel inclusion showing (a) Absorbed electron image, x-ray images of (b) Ca, (c) A l , (d) S and (e) Mn X400. Vertical lines are a result of the malfunction of the scan generator. Chemical Analyses of Two Inclusions From the C2 (95% reduced) CAT Steel by EPMA Inclusion (1) Element Weight Percent Atomic Percent K-Ratio Intensities UNKN STD Backgrounds UNKN STD Al KA 15.44 12.26 0.2304 3100 13457 138 138 Ca KA 18.13 9.70 0.3736 18928 50658 45 45 S KA 16.20 10.83 0.7210 6523 9047 540 540 Mn KA 0.08 0.03 0.0007 100 147730 2803 2803 0 * 50.15 67.18 Inclusion (2) Element Weight Percent Atomic Percent K-Ratio Intensities UNKN STD Backgrounds UNKN STD Al KA 15.56 10.54 0.2115 2847 13457 138 138 Ca KA 8.78 4.01 0.2005 10157 50658 45 45 S KA 1.69 0.96 0.0716 647 9047 540 540 Mn KA 0.10 0.03 0.0008 122 147730 2803 2803 0 * 73.87 84.45 60 The chemical composition of two inclusions as obtained by EPMA is shown in Table 3.3. The Al/Ca ratio for inclusion (1) is 1.26 and that of inclusion (2) is 2.627. These ratios are very close to the Al/Ca ratio = 2:1 of inclusions having the chemical composition C a O . A l ^ . Therefore the Ca-modified inclusions in this study is thought to have compositions very close to CaO . A l ^ . This phase is present in the central region of the inclusion whereas CaS is present in the outer rim with some MnS and Al^O^. 3.9 Inclusion Rating on a Quantimet 720 The quantitative inclusion analysis was obtained using a Quantimet 720, an image analysing computer of IMANCO, Metals Research Group Corporation, New York, U.S.A. The following parameters were determined: a) Area Fraction (AF) % b) Average Inclusion Length (Co), Micron c) Inter-inclusion Distance (D), Micron d) Aspect Ratio or Form Factor (FF) 2 e) Number of Inclusions per mm (N). In this study, an average of 50 fields of view were taken to obtain a representative inclusion parameter. A Fortran program, Modified Inclusion Rating MIR (Appendix I), has been developed and utilized to analyse the raw data obtained from the Quantimet 720 to give the average and standard deviation of the inclusion parameters. 3.9.1 Area Fraction (AF) % ] 4 8 If A L = Area of the live frame under consideration in number of picture points (pps), 61 and A = Area of the detected features in number of picture points, then, the area fraction of the feature, in % AF = - i r - x 100 3.9.2 Average Inclusion Length The average particle length in one direction is the ratio of the total area to the number of horizontal intercepts. The 720 reads the number of intercepts between the horizontal scan lines and the r v P H t— WIDTH C Figure 3.12 Schematic of Quantimet PH Measurement. V detected features; each intercept is a picture point. The intercept measurement which is the sum of the horizontal inter-cepts is then the vertical height of all detected features in the frame. Therefore, the average width of all inclusions in a field of view is C = PHXM where P^  = Horizontal intercept M = Magnification factor in pps per micron The image in the TV screen can be rotated with the help of the scanner head. After rotating the image on the screen by 90°, the intercept measurement gives rise to Py. Therefore, the average inclusion length Co is given by: 62 3.9.3 Form Factor (FF ) 1 4 8 given by: The form factor is a measure of the aspect ratio and is pp = Average inclusion 1ength Average inclusion width A / P V X H P H Co = T A/PHXM pv 1 AQ 3.9.4 Inter-Inclusion Distance (D) The inter-inclusion distance, D, is a measure of the mean free path between inclusions. The mean free path of an infinitely small point travelling horizontally in a two phase system is given by: A -A _ Area of the matrix _ _L D ~ Horizontal Intercept PuXM H Here the area parameters are considered as a linear parameter one picture point wide. 3.9.5 Number of Inclusions per mm (N) The inclusion density is given by the following relationship: N - - . M 2 N = T T A L where N.^ = Total number of inclusions counted in the field of view. 3.9.6 Extended Inclusion Length (L) In case of a ductile fracture, i t could be assumed that in-clusions in the fracture plane participate in the fracture process. The extended inclusion length is then considered to be the fracture path and is given by the following relationship: 63 L = N f f x Co 2 where = Inclusion density i.e. no. of inclusions per mm of the fracture plane Co = Average inclusion length 3.9.7 Experimental Details of Inclusion Rating; The specimens were polished to a 0.06 um finish. With the help of a calibration block, the magnification of the inclusion image on the TV screen was determined prior to any experimentation. For each particular f ield of view, four readings were taken, namely A, P^, P v and N f f . Care was taken to select the threshold setting and to eliminate the presence of background noise. This was accomplished by shifting the frame position, keeping the live frame size constant. In most of the cases, a frame size of 750 x 600 pps was used; however, in a few cases 600 x 600 pps and 400 x 600 pps were used. For each stage of reduction of the steel the inclusion rating was measured for each of the three mutually perpendicular planes i.e. LT, TL and LS plane on samples that were used for fracture toughness testing. The data were analysed using a computer program, MIR. 3.9.8 Analysis of Inclusion Parameters from Quantimet Data The experimental data as obtained from the Quantimet are shown in Appendix II. From the determinations of the area of inclusions (A), the horizontal intercept of inclusions (P^), the vertical intercept of inclusions (Py) and the number of inclusions in the field of view (N f f ) , the inclusion parameters viz, the area fraction (AF), the average 64 inclusion length (Co), the inter-inclusion spacing (D), the form factor (FF) and the number of inclusions per mm (N) were calculated with the help of a computer program MIR; the results are shown in Tables 3.21 to 3.83(Appendix III). The standard deviation of each inclusion parameter was calculated and the results are included in each table. The average value of the inclusion parameters for each stage of deformation for the LS and the TS planes are shown in Table 3.4 The data indicate the following inclusion characteristics: a) In the semi-killed CON steel, as the deformation increases from 0% to 38%, the AF increases; however on further reduction, the area fraction (AF) of inclusions decreases; the number of particles per unit area (N) increases. This is true for both the LS and the TS planes. The decrease in the AF parameter with increasing deformation on the TS plane may be due to the reduction of C, the average width, with the length remaining more or less constant. The reason for the decrease of AF with increasing deformation on the LS plane is due to the gradual thinning effect and the statistical distribution of inclusions. b) Quantimet data on average inclusion length in the rolling direction indicates that on deformation from 0% to 38%, Co increases consider-ably. However, i t decreases gradually from 38% deformation to 97% deformation. Although the form factor FF shows an increase from 38% reduction to 70% reduction, it decreases from.70% reduction to 88% reduction. Therefore, the quantimet data on the average 65 Table 3.4 Inclusion Parameters (as Analysed from Quantimet Data) on LS and TS Planes TS Plane: Percent Deformation AF Co D FF N SI 0% 0.510 4.986 1181 1.015 337 S2 38% 1.595 15.001 536 2.226 131 S3 70% 1.086 11.621 351 3.724 119 S4 88% 0.929 9.216 365 3.076 199 S6 97% 0.431 3.958 825 2.531 759 CI 63% 0.178 4.492 4305 1.167 70 C2 95% 0.211 5.447 4489 1.187 48 Percent Deformation AF Co D FF N SI 0% 0.510 4.986 1181 1.015 337 S2 38% 0.938 7.960 698 1.509 280 S3 70% 0.737 6.519 559 1.817 348 S4 88% 0.408 6.429 906 2.117 205 S6 97% 0.318 3.472 793 1.718 412 CI 63% 0.228 5.046 2755 1.137 82 C2 95% 0.204 5.570 3863 1.150 52 66 inclusion length Co and the form factor FF are totally misleading in terms of structure observations (Figures 3.1(b), (c), (d) and IT 87 in terms of reported literature. * The literature on the change in inclusion length during hot rolling suggests that with the in-creasing percentage of deformation, inclusions stringer out on the rolling plane and the projected inclusion length gradually in-creases. Additional tests were performed to examine the discre-pancy between the observed and the Quantimet data and to analyse the validity of the Quantimet readings viz A, P H , Py and N^. 3.9.9 Analysis of Inclusions by Optical Metallography Inclusions of the semi-killed pipeline steel at 0% reduction (ingot stage), 38% reduction (S2), 70% reduction (S3) and 88% reduction (S4) were analysed using the optical microstructures of the inclusions at various magnifications. The maximum diameter of the essentially spherical inclusions at the ingot stage were measured; in the case of S2 to S4, the inclusions were considered to be ellipsoids and the major axis, as maximum length, and the minor axis as maximum width were measured. For the ingot stage, 40 inclusions were considered and for the S4 (88% reduction) LS plane, 41 inclusions were measured; in all other cases 50 inclusions were measured. The measured data are included in Appendix IV. The important inclusion parameters viz maximum length, average length, maximum width, average width, maximum for factor and average form factor for the LS as well as TS planes for 0% through to 88% reduction are also shown in Table 3.5. The data indicates that with increasing percentage of hot deformation in the LS plane Footnote: 40,41 and 50 inclusions - mean the average of the largest inclus-ions obtained in each of 40, 41 and 50 fields of view. Table 3.5 Inclusion Parameters viz Length, Width and FF on LS and TS Planes of Ingot, S2, S3, S4 Stages of CON Steel as Obtained From Microstructural Analyses %R Length Co(u) Width C (y) FF Co C Maximum Average Maximum Average Maximum Average 0% 27.99 10.11 27.99 10.11 1.00 1.00 38% 107.51 27.98 22.00 6.55 22.00 4.13 70% 233.57 64.39 15.09 5.38 33.08 11.83 88% 170.76 60.29 11.22 4.15 71.63 25.00 TS Plane: 0% 27.99 10.11 27.99 10.11 1.00 1.00 38% 20.83 10.26 17.02 5.56 3.75 1.86 70% 42.26 13.88 12.74 4.18 7.04 3.30 88% 25.64 1-1.93 12.46 3.82 14.32 4.05 68 a) The maximum length and average length of inclusions increase markedly from 0% to 70% reduction; then decrease slightly at 88% reduction. This later reduction due to extensive deformation is thought to be due to inhomogeneous nature of the inclusion distribution. b) The maximum and the average width of the inclusions decrease with increasing percentage of deformation. c) The maximum and the average value of form factor increase with increasing percentage of hot deformation. Thus obvious stringering out of the inclusions as a consequence of hot rolling is a characteristic feature of wrought semi-killed steel products and has been reported in the literature by various research workers . 1 1 , 8 7 In the TS plane a) The maximum length and the average length do not indicate any increase with increasing percentage of hot deformation; the length remains more or less unaffected. b) However, the maximum width and the average width decrease with increasing: percentage of deformation. c) The form factor, the maximum and the average, show an increasing trend with increasing percentage of hot deformation. The data in Table 3.5 also shows that the width parameters in the LS plane are comparable to the width values obtained for the TS plane. Figure 3.13 also shows that the width of the inclusions in the LS plane and in the TS plane should be similar. Therefore, the direct measurement 69 a= length bs width Figure 3.13 Schematic of plate and inclusion geometry. of the inclusions from the microstructure establishes the stringering effect and the expected change in the inclusion dimensions as a con-sequence of hot roll ing. 3.9.10 Comparison of Microstructural Analysis with Quantimet  Analysis The average inclusion length, the average inclusion width and the form factor for inclusions in the LS plane and also in the TS plane of the 38%, 70% and 88% reduced semi-killed material, as obtained by microstructural analysis and by Quantimet analysis, are compared in Table 3.6. a) Considering the average inclusion length data, the microstructural analysis yields much higher Co values than those of the Quantimet analysis. 70 i) For the LS plane data, the Quantimet analysis shows a decrease in inclusion length with increasing percentage of hot deformation; however, the microstructural analysis indicates an increase in the inclusion length with increasing percentage of deformation upto 70%. i i ) For the TS plane the microstructural analysis indicates that the length of inclusions is not markedly affected by in-creasing percentage of deformation and the Quantimet analysis shows a similar trend although the absolute numbers are much lower for the Quantimet analysis. The average inclusion width data shows that with an increasing percentage of deformation, the average inclusion width decreases. This trend is the same for both the Quantimet and the micro-structural analysis. It should also be noted that the average width values as determined by both the procedures are comparable. The width measurements were obtained using the following Quantimet relationship: c . J L -P HXM The fact that the measured and the Quantimet width values are comparable shows that the P^  measurements are correct and hence acceptable. The data in Table 3.6 also shows that the width of the inclusions in the LS plane is very close to the width of the inclusions in the TS plane. Therefore, the Quantimet width measurements are considered to be reliable. The microstructural analysis of the form factor in the LS and the TS plane shows a definite stringering effect of inclusions; the Table 3.6 Comparison of Inclusion Parameters From Quantimet Analysis With Microstructural Analysis LS Plane: TS Plane: %Red Average Inc. Length (y) Average Inc. Width (y ) F F Microstructural Quantimet Microstructural Quantimet Microstructural Quantimet 38% 27.98 15.00 6.55 6.57 4.13 2.22 70% 64.39 11.62 5.38 3.16 11.83 3.72 88% 60.29 9.21 4.15 3.16 25.00 3.07 38% 10.26 7.96 5.56 5.14 1.86 1.50 70% 13.88 6.51 4.18 3.54 3.30 1.81 88% 11.93 6.42 3.82 3.39 4.05 2.11 72 FF on the LS plane increases from a value 4.13 at 38% deformation to a value 25.00 at 88% deformation. However, the Quantimet data on the LS plane gives a poor indication of the stringering of the inclusions. The Quantimet analysis of the average inclusion length and the form factor do not represent the actual elongation of the inclusions during rolling. It is apparent that the Quanti-met gives an erroneous value to the average length of the inclu-sions. Since this value is calculated from the relation using a measured, i t is this measurement that is suspected. Pv is the total width of all detected features as determined by summing the number of horizontal intercepts, each intercept representing one picture point as shown in Figure 3.14 (a) and (b) schematically. Co = A Ave.Height Figure 3.14 Schematic of P y measurement in Quantimet a) while inclusion is 0° te the horizontal scan lines b) while inclusion is at an angle to the horizontal scan lines 73 It can be seen that Py is a poor representation of the average height of the shape i f the inclusion width is not uniform. The Quantimet measured width, Py, would consistently be too high and therefore the calculated average length measurement would consistently be too low as is observed in Table 3.6. Again, the Quantimet analysis uses the relation A. - A D = — PHXM for calculating the inter-inclusion distance; since the readings of A, P^  are reliable for elongated inclusions, the inter-inclusions distance measurement by Quantimet are, therefore, acceptable. Therefore, the inclusion parameters AF, D, N from the Quantimet data and Co and FF from the metallographic observations represent the valid inclusion parameters for the S2 (38%), S3 (70%) and S4 (88%) material and are indicated in the Table 3.7. These parameters will be used for the mechanical property-inclusion parameter correlations later on. 3.9.11 Distribution of Inclusions The number of inclusions in each field of view obtained by Quantimet measurements is plotted in Figures 3.15(a), (b) and (c) to show the distribution of inclusions. Figure 3.15(a) illustrates the inclusion distribution in the ingot stage, (b) the inclusion distribution on the LS plane of the 38% deformed material and (c) the inclusion distribution on the TS plane of 38% deformed semi-killed steel. All three figures indicate that the inclusion distribution is quite random and Table 3.7 Corrected Inclusion Parameters of S2, S3, S4 Stages of CON Steel on LS and TS Planes LS Plane: TS Plane: Percent Deformation AF Co (y) D (y) FF N S2 038%) 1.595 27.98 536 4.13 131 S3 (70%) 1.086 64.39 351 11.83 119 S4 (88%) 0.929 60.29 365 25.00 199 S2 (38%) 0.938 10.26 698 1.86 280 S3 (70%) 0.737 13.88 559 3.30 348 S4 (88%) 0.408 11.93 906 4.05 205 10 20 30 40 50 FRAME No. (a) tO 20 30 40 50 FRAME No. (b) 10 20 30 FRAME No. Figure 3.15 Inclusion distribution (a) in LT plane in ingot (0% reduced) material (b) in LS plane in S2 (38% reduced) material (c) in TS plane in Sw (38% reduced) material 76 heterogeneous; the number, of inclusions vary abruptly from one frame to another. A similar inhomogeneous inclusion distribution is expected at other stages of reduction since each stage in this study is obtained from a different heat, although the compositions of all the samples are approximately constant. Figure 3.16 illustrates the variation of maximum inclusion size observed in each frame for the ingot stage and the S2 stage for the CON steel. The size measurements were taken from the microstructure examina-tion data. It may be noted that there exists a wide variation of maximum inclusion sizes. However, the variation of maximum size should be a valid description of true inclusion size; i t assumes that the maximum size is equal to true inclusion size and therefore, i t removes the 3D to 2D problem. It is also apparent that for a single condition, e.g. the as cast material» there is a wide true size variation of the inclusions. This init ial size distribution, of course, affects the sizes obtained at the later stages of hot roll ing. These figures emphasize the heterogeneous size distribution of inclusions. Another point to be noted is that the composition of inclusions and their distribution vary from the bottom end to the top end and from the surface to the centre of the original ingot. In this study, the slab samples were taken at random. Therefore, the correlation of mechanical properties with inclusion parameters which has been performed in this study, may not hold good for slab samples obtained from other locations in the ingot. Since the composition of each of the selected slab samples used in this study are similar, i t is likely that the 77 Figure 3.16 Variation of maximum inclusion size (a) In LT plane of ingot (0% reduced) material (b) In LS plane of S2 (38% reduced) material 78 inclusion chemistry will also be similar (if not identical) for each slab. 3.9.12 Analysis of Inclusion Data for 97% Reduced CON (S6) Steel  and 63% and 95% Reduced CAT Steel For the fragmented inclusions and the spherical inclusions, PyValues are close to P^  values; hence are reliable. Therefore the Quantimet analysis for the S6 CON material and for the CAT steels are acceptable. In this case of the S6 material, the AF, Co, FF, N are comparatively lower and the D value is comparatively greater than those of the 88%, 70% and 38% deformed material. This is due to the fact that at 97% reduction, the elongated inclusions have fractured into small pieces separated by intervening steel matrix (Figures 3.1(d), 3.2(a), (b) and 3.6). Therefore, although the optical microstructure of the S6 (97% reduction) inclusions show that these are present as the longest stringers, the actual inclusion parameters become smaller due to break-down of the stringers. In the case of the CAT steel, with increasing percentage of deforma-tion: a) The inclusion parameters do not experience appreciable shape change. This supports the fact that the CAT steel inclusions do not undergo plastic deformation during the hot rolling processes. b) The magnitude of the FF parameter is approximately 1.1 for CAT steel and greater than 4.13 for the CON steels. These values sup-port the fact that CAT steel inclusions remain spherical in shape whereas the CON steel inclusions become elongated with increased hot rolling. 79 The CAT steel possesses very low values of area fraction of inclusions (AF), inclusion density (Ii) and inclusion length and very high inter-inclusion spacing compared to the CON steel. This reaffirms the fact that the CAT steel is a cleaner steel than the semi-killed CON grade having a wt % S CAT = 0.005 to 0.009 % whereas the CON steel has a wt % S CON - 0.027 to 0.032 %. The inclusion parameters for the LS plane and the TS plane in the CAT steel do not differ significantly with increasing degree of hot reduction. This characteristic confirms the spherical nature of the CAT steel inclusions. 80 Chapter 4 MECHANICAL PROPERTIES 4.1 Introduction It is well recognized that non-metallic inclusions markedly influence the mechanical properties of wrought steel, in particular, those properties which involve ductile fracture processes i.e. the opening up or growth and 93 149 coalescence of voids within the metal with increasing strain. * Such properties include: a) Tensile ductility (measured as true strain to fracture, = In Ao/Af where Ao = init ial cross-sectional area, Af = final cross-sectional area. b) Ductile upper shelf energy in the Charpy v-notch test, and c) Fracture toughness. 149 T. GIadman pointed out that the required transverse upper shelf energy in transverse Cy specimens to ensure adequate resistance to fracture in pipeline material is significantly affected by inclusions; an increase in the inclusion content causes a decrease in the impact energy of the material. 4.2 Tensile Specimen and Testing Small rectangular samples 0.4 inch x 0.4 inch x 2.5 inch were cut along the rolling direction and transverse to the rolling direction for the fabrication of tensile specimens. All samples were obtained at least 81 50 mm from the flame cut edge. Some of these sections were heat treated to obtain a similar grain structure and microstructure for each stage of the hot reduction of the CON and CAT steel. Cylindrical specimens were fabricated from the as received (AR) as well as the heat-treated (HT) material. The orientation of the tensile and the compact tension specimens with respect to the rolling direction is shown schematically in Fig. 4.1(a). Fig. 4.1(b) shows the dimensions of the tensile specimens used throughout the experimental programme. Substandard sized tensile specimens having 150 151 dimensions proportional to the standard ' were used to enable testing at sub-zero temperatures; i t was essential to immerse the specimen and the testing fixtures into a temperature controlled bath and to complete the test in this environment. As shown in the Fig. 4.1(a), specimen (i) is a longitudinal tensile specimen and specimen (i i) is a transverse tensile specimen. The tensile testing was carried out using an Instron machine. The tests were conducted at RT, -40°C, -80°C, -120°C and -196°C at a crosshead speed of 0.02"/min and load vs. displacement was recorded . using a chart speed of 0.5"/min with a load scale of 0-2000 lbs. At least two specimens were used for each test temperature. After the test was completed, the fractured specimen halves were dried and the diameter at the fractured end was measured to an accuracy of 0.001 mm using a travelling microscope. This measurement was used to obtain the percent reduction in area and the total ductility at fracture i.e. the true strain to fracture, which is determined by using: 82 Figure 4.1 (a) Orientation of tensile and compact tension specimens with respect to rolling direction of the plate (b) Dimensions of the tensile specimen where Ao Af 4.3 Tensile Properties 4.3.1 Correlation of Yield Strength with Percent Deformation for As Received Materials Figures 4.2(a) to (f) show the variation of yield strength of theS2(38% reduction), S3 (70% reduction) S4 (88% reduction) and S6 (97% reduction) stages of reduction of the semi-killed CON steel and the CI (65% reduction) stage of the CAT steel with percentages of hot deforma-tion; both steels are in the AR condition. The Figures 4.2(a) and (b) for the RT and Figures 4.2(c) and (d) for the -80°C data show a random distribution of points; there is no obvious trend or dependence of yield strength on the percentages of hot deformation. Since the steel is being hot worked, the effect of strain hardening is annealed out. However, each stage possesses a different microstructure and grain size. The yield strength data obtained at -196°C Figures 4.2(e) and (f) shows a trend in that the yield strength increases with increasing per-centages of hot deformation. An increase of 20 KSi (138 MPa) results from an increase in the percent deformation from 40% to 97%. 4.3.2 Correlation of Yield Strength with Microstructure The structure of the AR CON steel was examined to explain the wide scatter in the tensile data. The structure of the conventional semi killed steel after the following stages of reduction 38% (S2), 70% (S3), 83 = In Ao/Af . . . (4 . i ; = init ial cross-sectional area = average cross-sectional area at the fractured surface 84 80 ci 70r 60 h 50 AR RT IIRD 1 1 r A - C A T O - CON RT i R D 140 I30r-CO ci 20 4 0 60 80 100 20 (a) % D E F (b ) AR - 8 0 ° C . IIRD 500 o Q. z H 4 0 0 100 AR - 8 0 ° C . i R D AR - / 9 6 ° C . IIRD AR - J 9 6 ° C . J.RD H900 8 0 0 100 Figure 4.2 Correlation of yield strength with percentage deformation of as received materials (a) at RT in longitudinal direction (b) at RT in transverse direction (c) at -80°C in longitudinal direction (d) at -80°C in transverse direction (e)at-196°C in longitudinal direction (f) at-196°Cin transverse direction 85 88% (S4) and 97% (S6) and of the calcium-treated steel with 63% reduction (CI) and 95% reduction (C2) consists.of varying percentages of polygonal ferrite and an acicular second phase *(refer to Table 2.3). The average yield strength of the AR CON and CAT steel at different stages of hot deformation are plotted in Fig. 4.3 as a function of percent second phase to explain the observed wide variation in the tensile data. The Figures 4.3(a) to (d) indicate that in the as received condition, for tests conducted at RT through -80°C, there is a positive trend of the dependence of the yield strength on the percent of second phase present; the yield strength increases with increase in percentage of the second phase. This is due to the fact that the polygonal ferrite is a much weaker phase than the acicular second phase; the latter contains many low angle boundaries and some fine carbide precipitates. The AR S4 (88% reduction) sample contains 100% acicular structure and is much stronger than the other samples. It is interesting to note that at -196°C the Figures 4.3(e) and (f), there is no apparent dependence of yield strength on the microstructure of the CON and CAT steel. Thus, at -196°C where the clevage mechanism is operative, the microstructure becomes less important and the lack of ductility of the bcc polygonal ferrite controls the yield strength. Therefore, as expected, the tensile yield strength data shows that for tests conducted at RT through -80°C, the yield strength of the CON steel pipeline steels is structure sensitive. *The second phase contains mainly acicular ferrite and some upper baini 86 50 20 (a) 20 (40 •* 1509-120 h 20 (e) X 40 60 80 % SECOND PHASE AR -80°C. I/RD __fc) 100 20 X X X 40 60 80 % SECOND PHASE AR -80°C. iRD 40 60 60 % SECOND PHASE AR -/96°C. //RO T 100 20 40 60 60 (d) % SECOND PHASE AR -/96°C. XRD 40 60 80 % SECOND PHASE 100 20 (f) 40 60 80 % SECOND PHASE 500 400 o a. 5 100 too 900 -1800 o Q. S 100 Figure 4.3 Dependence of yield strength with second phase in AR material (a) at RT in longitudinal direction (b)atRT in transverse direction (c) at -80°C in longitudinal direction (d) at -80°C in transverse direction (e) at -196°Cin logitudinal direction (f) at -196°C in transverse direction 87 4.3.3 Correlation of Yield Strength with Percent Deformation for  Heat-treated Material To remove the structure sensitivity without affecting the in-clusion morphology, the steel samples were heat treated. The effect of heat treatment on the yield strength values of the S2 (38% reduction) S3 (70% reduction), S4 (88% reduction) and S6 (97% reduction) semi-killed conventional steels and the CI (63% reduction) and C2 (95% reduction) CAT steels are shown in Fig. 4.4(a) to (f). The figures show that after the heat treatment, the yield strength is no longer sensitive to the percen-tages of hot deformation. It has been established in section 2.4 that the structure resulting from the heat treatment is comparable for each sample independent of the degree of reduction. Therefore, the elimination of the structure variation has resulted in uniform yield strength values. For example, at RT, for the longitudinal samples, the average yield strength is 40.25 KSi (277.56 MPa); the standard deviation over the entire deformation range is ± 2.21 KSi (15.24 MPa). The yield strength of the heat-treated samples is appreciably lower than that of the as received samples. The data also shows the effect of inclusion morphology on the yield strength of the material. In the case of the AR material, Fig. 4.3(a) to (f) reveal: that the yield strength values of the CI (63% deformation) CAT steel is comparable to that of the S2 (38% deformation) CON steel, both possessing 60% second phase and similar grain structure. In the case of the HT material, Fig. 4.4(a) to (f) also show that the yield strength values of the CAT steels are comparable to those of the CON steels. This data indicate that the inclusion morphology has 88 60 90 40 HT RT tl RD 30 1 1 T O - CON A -CAT (c) (30 * IZOr 100 20 40 60 60 (a) HT -80°C. f/RD 100 20 % DEF HT -/96°C. //RD HT RT 1 R 0 H400 HT - 8 0 C 1RD - 400 o a A- 300 _L a. Z 40 60 * DEF 60 too HT -»96°C. J.RD H 7 0 0 40 60 80 %DEF Figure 4.4 Correlation of yield strength with percentage deformation of heat-treated material (a) at RT in longitudinal direction (b) at RT in transverse direction (c) a t -80°Cin longitudinal direction (d) at-80°C in transverse direction (e) at -196°Cin longitudinal direction (f) at-196°Cin transverse direction 89 l i t t le effect on the yield strength properties of the material. This is thought to be due to the fact that in the elastic region or in the initial region of the plastic deformation, the inclusions do not play a major 149 role in the yielding processes. T. Gladman pointed out that inclusions have l i t t le effect on yield strength because this property is dependent upon the initiation of plastic deformation. Similar results have been reported by A. D. W i l s o n 1 2 ' 1 4 6 and H. Nashiwa et a l . 1 1 5 4.3.4 Correlation of True Strain to Fracture with Percentage  Deformation In the AR condition, the S2 (38% deformation), S3 (70% deforma-tion), S4 (80% deformation) and S6 (97% deformation) stages of reduction of the CON steel and the CI (63% deformation) and C2 (95% deformation) stages of the CAT steel individually possess variable grain sizes and microstructures. Figures 4.5(a) to (f) show the correlation of e f on the percentage of hot reduction for the AR condition for S2 (38%), S3 (70%), S4 (80%), S6 (97%), CI (63%) and C2 (95%) steels. These figures show that: a) There is no simple dependence of on the percentage of hot deformation; b) The Ca-treated CI steel possesses enhanced ductility in the transverse direction; c) At-196°iC the ductility of steel at all stages of reduction is very low. Therefore, i t is apparent that i t is essential to remove the effect of variable grain size and microstructure for each stage of the material in order to examine the effect of inclusion morphology on the true strain 90 AR RT II RD 12 10 OB 0 6 2 0 (C ) Vi; O B\-0 4 h 0 0 h AR RT ±RD i 1 r x 2 0 40 6 0 80 (0) %DEF. AR -80°C. // X X 100 20 40 60 60 100 (b) %DEF AR -80°C. 1 R D i 1 r x J L 40 6 0 60 %DEF AR -»96°C. IIRD 40 60 %DEF. AR -»96°C_1_RD too 40 60 %DEF. 100 Figure 4.5 Correlation of true strain to fracture (ef) with percentage deformation for AR materials (a) at RT in longitudinal direction (b) at RT in transverse direction (c) at -80°C in longitudinal direction (d) at -80°C in transverse direction (e) at -196°C in longitudinal direction (f) at -196°C in transverse direction 91 to fracture. Hence, the samples obtained at each stage of deformation were subjected to a controlled heat-treatment to achieve a similar structure and grain size without changing the inclusion morphology. The Figures 4.6(a) to (f) show the correlation of e f with percent deformation for the heat-treated condition. The following points may be noted: a) At RT and -80°C, 38% deformed material possesses higher e f than 70% (S3), 88% (S4) and 97% (S6) deformed material. b) With specimens transverse to the rolling direction the decreases from 38% deformed material to 88% deformed material, and then i t increases. The data indicates that depends upon the inclusion morphology. This trend is not apparent with specimens parallel to rolling direction. c) The Ca-treated steel possesses much higher ductility in the transverse direction as compared to that of the conventional semi-killed material. d) At -196°C, there is no simple dependence of on percentage deformation. In the case of the heat-treated materials, the effects of the micro-structure and grain size on the have been eliminated by heat treating to produce in both the CON and the CAT steels a comparable microstructure and grain size. Therefore, the observed variation in the vs % hot reduction for the heat-treated material can be related to the change in inclusion morphology. The Table 4.1 summarises the inclusion para-meters for the different stages of hot deformation in the longitudinal and transverse planes for the CON (S2, S3, S4, S6) and the CAT (CI, C2) 92 HT RT XRD 20 40 60 60 100 20 (a) %DEF. (b) HT -80°C. IRD 0 8 h 0 4 h 60 80 %DEF. 100 HT -80°C. XRD 100 HT -/96°C IIRD HT -196 °C. J.RD Ho 8 HO 4 1 o 1 - CON -CAT - o O A" o ° l 1 1 20 40 60 80 100 20 (e) % D E F (f> 40 60 80 %DEF. 100 Figure 4.6 Correlation of true strain to fracture (e f) with percentage deformation for heat-treated materials (a) at RT in longitudinal direction (b) at RT in transverse direction (c) at -80°C in longitudinal direction (d) at -80°C in transverse direction (e) at -196°C in longitudinal direction (f) at -196°C in transverse direction 93 steels. The variation of with % deformation can be well explained in terms of the inclusion parameters cited in Table 4.1: a) The higher e f values observed for the CAT steel compared to those of the CON steel particularly in the transverse specimen are due to the smaller AF, Co,N and FF values and the higher inclusion spacing (D); b) 38% deformed material possesses higher e f than 70%, 88% deformed material because of smaller average inclusion length, FF and inclusion density and higher inter-inclusion spacing. c) At -196°C where brittle fracture occurs, e f does not depend on the percent deformation i.e. on inclusion morphology; this may be due to the fact that where the clevage failure mechanism is operative, inclusions do not play a major role in the fracture process. 4.4 Fracture Toughness 4.4.1 Specimen Preparation and Configuration Small test coupons 0.60 ± 0.05 inch thick, 1.30 ± 0.05 inch wide with varying lengths to 5.00 inch were cut from the rolled plates and slabs with their major axis along the rolling direction or transverse to the rolling direction. These sections were used to fabricate the compact tension (CT) specimens with a crack orientation: a) Parallel to the rolling direction (T-L orientation) b) Transverse to the rolling direction (L-T orientation). The orientation-of the CT specimens with respect to the rolling direction of a plate is shown schematically in Figure 4.1(a). Half inch thick compact tension (h TCT) specimens were used for both Table 4.1 Inclusion Parameters of S2, S3, S4, S6 Stages of CON Steel and C l , C2 Stages of CAT Steel LS Plane: TS Plane: Steel Area Average Inclusion Form Density Stage ,Fraction Length Spacing Factor No./rnm^ Fracture Path (% DEF) AF(%) Co(p) D(g) FF N N X Co (p) S2 (38%) 1.595 27.98 536 4.13 131.54 3,680 CON S3 (70%) 1.086 64.39 351 11.83 119.70 7,662 S4 (88%) 0.929 60.29 365 25.00 199.98 12,056 S6 (97%) 0.431 3.95 825 2.53 759.32 3,004 CAT Cl (63%) 0.178 4.44 4305 1.16 70.30 314 C2 (95%) 0.211 5.44 4489 1.18 47.98 261 S2 (38%) 0.938 10.26 698 1.86 280.86 2,872 CON S3 (70%) 0.737 13.88 559 3.30 348.56 4,830 S4 (88%) 0.408 11.93 906 4.05 205.32 2,445 S6 (97%) 0.318 3.47 793 1.71 412.48 1,430 CAT Cl (63%) 0.228 5.04 2755 1.13 82.04 413 C2 (95%) 0.204 5.57 3863 1.15 52.32 281 4^ 95 fracture toughness tests, the plane strain fracture toughness Kj C test, and the elastic-plastic fracture toughness J-integral test. Figure 4.7 shows the geometry and the dimensions of the compact tension specimens used in this study. The specimen dimensions conform to the specimen requirements as per ASTM E399-78a standard for plane strain fracture 32 toughness testing. The geometry has been modified to facilitate the measurement of crack opening displacement at the loading line. This configuration has been approved by the ASTM Committee for J-integral . + . 33-35 testing. 4.4.2 Fracture Toughness Testing The Kj C test and J-integral tests were utilized to characterize the fracture toughness of the material. From a single test specimen both Kg/KjC elastic and J J C elastic-plastic fracture toughness could be obtained. The %TCT specimens were fatigue precracked using a Sonntag Fatigue Testing machine model SF-l-U, operated with a manual preload. This equipment introduces a cyclic tensile load which is symmetrical across the notch of the specimen. The stress intensity used for precracking, K ^ m a x j , never ; exceeded 60% of the measured Kg value. In fact, K f ( m a x ) started from 18.00 KSi/Tn" to a maximum of 25.59 KSi/in" throughout the precracking operation, whereas the lowest Kg value obtained for these materials was 59 KSi/Tn. Thus, the maximum K ^ m a x j was only 43.37% of the measured Kg value. In all specimens, the minimum fatigue precrack length, 0.05 inch 32 (1.3 mm) was employed. This also satisfies the J J C test procedure 33-35 requirement of a fatigue crack length of not less than 0.76 mm (0.03 inch). Table 4.2 shows the K f ( m a x ) and cyclic stress ratio (r) 96 DIMENSIONS IN INCHES. SCALE - 2 s I Figure 4.7 Geometry and dimensionsof a half inch thick compact tension (% TCT) specimen. 97 Table 4 2 IC, N and Stress Ratio (r) used for Fatigue Precracking I a u i c f(max) __ • -— of AR and HT Specimens Specimen Kf(max) (KSi/irT) P • r ' _: min Pmax AR S2 21.79 to 25.59 0.041 AR S3 20.38 to 23.96 0.014 AR S4 21.79 to 25.59 0.041 AR S6 - do - - d o -HT S2 - do - - do -HT S3 - do - - do -HT S4 - do - - do -HT S6 18.01 to 21.18 0.033 HT CAT 63 - do - - d o -HT CAT 95 - do - - d o -employed to fatigue precrack the specimens in the AR and HT condition. The fracture toughness test generates a record of axial load vs dis-placement. In this test programme, a special COD gauge was used to record continuously the load-point displacement. An MTS model 632-02B-21 clip-on displacement gauge conforming to the ASTM standard E399-78a was attached to the specimen to provide a simultaneous measure of load point displace-ment in these experiments. This device could be used for the temperature range -268°C to +66°C. 98 The fracture toughness tests were carried out using an Instron machine operated at a constant strain rate; tests were conducted using a full scale load range of 0-5000 lbs. (22.25 KN) with the COD gauge preamplifier setting at the 10X range and a cross head speed of 0.02 inch/minute. Using these settings, 10 inches of chart movement was equivalent to a displacement of 0.05 inch. The fracture toughness tests were conducted at RT, -40°C, -80°C, -120°C and -196°C to establish the full ductile-brittle transition behaviour. Low temperature tests were accomplished using an ethanol-methanol bath; the bath temperature was controlled to an accuracy of ± 2°C. All low temperature experiments were carried out keeping the speci-men, COD gauge and fixture inside the bath; a minimum soaking time of 20 minutes was employed to equilibrate the temperature of the sample prior to initiating the tests. Using this procedure, a single test specimen yielded Kg and Jg fracture toughness data. 4.4.2.1 Analysis of the Experimental Data to Obtain K Q ^ K I C  Toughness In almost all of the test specimens, the fatigue pre-crack was slightly longer in the center, representing a thumbnail appear-ance on the fracture surface. The crack length, a Q , was measured using a travelling microscope; nine readings were taken across the specimen thick-ness at equal intervals. The average of the 9 readings was used as the crack length of the specimen. That is a = 1 L ^ ...(4.2) 0 9 a 0 In all test samples, a crack length of the order of 0.50< -jj-<0.55 was 99 obtained; the ASTM standard requirement for crack length is 0.45 < < 0.55. In all cases, the 5% Secant offset procedure was adopted to measure the P P n load value. The -P^- ratio was observed to be greater than 1.10 for RT, -40°C, -80°C tests and less than 1.10 for tests conducted at lower 32 152 temperatures. Then Kn was calculated using the relationship * a./W\ ...(4.3) K = X f(Vw) D\.ri where Pg = 5% Secant offset load B = thickness of the specimen W = width of the specimen a Q = crack length of the specimen Finally, the validity criterion for obtaining Kj^ was examined using the relationship: B > 2 . 5 ^ ^ ° - ^ ...(4.4) where a = 0.2% offset yield strength at the respective test ys temperature. 4.4.2.2 J-Integral Test Details A single specimen test technique was used to evaluate 32-35 153-156 the Jj^ fracture toughness as per standard method. • ' This method has the following advantage over the multiple specimen method: a) A single specimen provides the J-integral data instead of the 4 to 6 specimens normally required. b) A J-Aa resistance curve can be properly established. 100 The single specimen J-integral test technique required that after the applied load exceeded the init ial elastic region, the specimen was unloaded upto approximately 10 percent of the load and then reloaded. This unloading and reloading procedure was repeated at least 15 times after small increments of plastic deformation. The test was then dis-continued and the specimen was broken apart into two halves for crack length measurement purposes and to allow examination of the fracture sur-faces. The single specimen method monitors crack advance by comparison of the compliance obtained at specific load levels with a calibrated compli-33 ance-crack length curve; this was f i rst demonstrated by Clark et a l . It has been shown that small amounts of unloading (in the order of 10 percent of load) will not disturb the fracture process; but will provide a small portion of a linear elastic curve whose slope can be compared with a calibrated compliance-crack length to give an instantaneous measure of crack length. Typical test records are shown in Figures 4.8(a) and (b). At each temperature, a minimum of two specimens were tested. At tempera-tures -120°C and -196°C, the unloading and reloading compliance method could not be employed, as the specimens broke into two halves before any appreciable plastic deformation occurred. For tests carried out at RT, -40°C and -80°C, the energy expended to extend the crack by Aa was calcula-ted at each unloading point. Since Y - axis, load P = 525.32 lb/inch of chart X - axis, A = 0.005 inch/inch of chart, one square inch in the record denotes an equivalent energy of 2.627 in-lb. 101 Figure 4.8 J-integral test records (a) at RT for heat treated S3 (70% reduced) specimen (HTS3LT09) with crack transverse to rolling direction and (b) at -196°C for heat-treated CI (63% reduced) CAT specimen (HTC1LT07) with crack transverse to the rolling direction. 102 Therefore, for each unloading, the amount of energy expended for crack extension was msasured by the area A, under the P-A curve' in in-lb. The 34 35 J-value at the ith unloading point was calculated using the relationship ' A. J i = B5" f (aQ/W) ...(4.5) where A. = Area under P-A record at the ith unloading I b = W - a Q = uncracked ligament f (a0/W) = . where a = V(2 a Q /b) 2 + 2(2aQ/b) + 2 - (2ao/b + 1) The crack growth, Aa.., at each unloading point was determined using the relat ionship: 3 3 , 1 5 5 W-a Ac. Aa. = °- x — L ...(4.6) 2 where c Q = init ial elastic compliance of the specimen Ac. _ i = c, - c change in compliance of the specimen i "o at the ith unloading As per recommended pract ice , 3 4 , 3 5 a J.. - Aa.. resistance line was obtained for each specimen using a linear regression analysis; this data is termed the R-plot. A line representing the onset of gross plastic flow, defined by J = 2a^ Aa where = a y s + ^ was constructed on each R-plot J flow flow v 2 and the intersection of the R-line with the blunting line was taken as the Jq fracture toughness value. For the measured JQ to be a valid J J C the following size requirement must be satisfied by an elastic-plastic fracture 34 35 154 toughness specimen: ' ' 103 B > 25 3Q ...(4.7) °flow In this study, all samples met this requirement and therefore the Jg values obtained were considered as valid Jj^ measurements. From the value, a corresponding K J C value was calculated using the relationship between elastic-plastic and linear elastic fracture mechanics p a r a m e t e r s : 1 5 2 ' 1 5 4 ' 1 5 7 K 2 °IC = GIC = Y ~ ( 1 _ v ? , ) ...(4.8) where v = Poisson's ratio E = Elastic modulus of steel specimens / J I C • E which gives an equivalent K— = V 2~ ...(4.9) » 1-v 4.4.2.3 Validity of Single Specimen Technique Figure 4.9(a) illustrates the J-resistance curve obtained by using a single specimen technique as well as by using a multi-ple specimen technique. The heat treated S6 (97% deformation) specimens with crack transverse to the rolling direction were used to generate these graphs. The tests were performed at RT. Figure 4.9(b) also shows the J-resistance curve generated by using a single specimen technique. It should be noted that the HTS6LT04 specimen gives a value of J J C as 580.00 in - lb / in 2 (101.61 KJ/m2) and the HTS6LT05 specimen yields a 2 2 value of J I C equal to 560.00 in-lb/in (98.11 KJ/m ) - both by single 2 2 specimen technique. A J j C value of 550.00 in-lb/in (96.36 KJ/m ) was obtained using the multiple specimen technique. The J J Q values obtained CRACK J . TO RD AT RT. HTS6LT04 CRACK EXTENSION , mm. 0-5 10 104 400 1200 N C \ 1000 T 800 o 600 400 200 0 (a) O - SINGLE SPECIMEN H. J , e '58000in-lb/in* A - MULTIPLE SPECIMEN J,E •SSO-OOin-lb/in8 J L •01 -02 03 04 05 CRACK EXTENSION .INCHES.Ad0 CRACK 1 TO RD. AT RT. HTS6 LT 05 CRACK EXTENSION. mm. 0 5 10 120 80 40 06 1200 L. (b) •01 -02 03 04 - 05 -06 CRACK EXTENSION, INCHES, A a o Figure 4.9 J - Aa, resistance plot (a) for heat-treated S6 (97% reduced) CON steel as obtained by single specimen technique and by multiple specimen technique (b) for heat-treated Se (97% reduced) CON steel HTS6LT05 specimen as obtained by single specimen technique. 105 by using the single specimen technique are slightly higher (4.5%) than those obtained by using a multiple specimen technique. A similar trend is 156 reported in the existing literature. The single specimen test technique was adopted as a valid testing technique for computing the JJQ fracture toughness of the pipeline materia' 4.4.2.4 Correlation of Fracture Toughness of AR Materials  With Percentage Reduction Preliminary fracture toughness tests were carried out with the AR material. The Figures 4.10(a) to (f) show the correlation of fracture toughness of S2 (38% reduction), S3 (70% reduction), S4 (88% reduction) and S6 (97% reduction) stages of semi-killed CON steel with percentage deformation. The Figures 4.10(a) to (d) which stand for the ductile fracture regime show that: a) There is an appreciable amount of scatter of the data b) No simple dependence of Kj C - J j C fracture toughness on percentage deformation is apparent. It may be noted that the variables which affect the fracture toughness properties for any stage of CON steel in AR condition are: a) The relative percentage of second phase b) The grain size, c) The inclusion morphology. Hence, to draw a correlation between fracture toughness properties with inclusion morphology, the effect of those other variables must be eliminated. It should be noted that at -196°C i .e. in the brittle temperature 106 AR RT T L 20 40 60 80 (a) % REDUCTION - 8 0 ° C . TL > 40 -100 20 (b) 40 60 80 % REDUCTION - 8 0 °C. LT 20 40 60 80 100 20 ( C ) % REDUCTION (d) -196 °C. T L 40 60 80 % REDUCTION 20 40 60 80 ( e ) % REDUCTION 100 20 (f) 40 60 80 % REDUCTION 80 ° o QL 2 100 100 Figure 4.10 Correlation of K J Q - J J Q fracture toughness with percentage deformation of AR materials (a) at RT with crack parallel to rolling direction (TL) (b) at RT with crack transverse to rolling direction (LT) (c) at -80°C with crack parallel to rolling direction (TL) (d) at -80°C with crack transverse to rolling direction (LT) (e) at -196°C with crack parallel to rolling direction (TL) (f) at -196°C with crack transverse to rolling direction (LT) 107 region, the fracture toughness properties of the different stages of hot reduction are comparable and therefore are not sensitive to changes in grain size and microstructure in this fracture mode. 4.5 Justification for Heat-Treatment Since the aim of this thesis is to delineate the effect of inclusion morphology on the total ductil ity, strength and fracture toughness of a X-70 pipeline steel, the influence of other variables, like microstructure and grain size had to be eliminated. Table 2.3 describes the microstructure and grain size of the different stages of reduction S2(38% reduction), S3 (70% reduction), S4 (88% reduction), S6 (97% reduction) stage of semi-killed steel and Cl (63% reduction) and C2 (95% reduction) stage of Ca-treated steel in the AR condition. The true effect of inclusion morphology on the mechanical properties would be masked by the structure and grain size differences between the as-received samples as shown in previous figures viz Figures 4.2(a) to (d), Figures 4.5(a) to (d) and Figures 4.10(a) to (d). Therefore, in order to eliminate the effect of microstructure and grain size variation on the mechanical properties, the samples repre-senting each stage of deformation were subjected to a controlled heat treatment procedure as detailed in section 2.3; this produced a similar microstructure and grain size for all stages as appended in Table 2.4. This heat treatment cycle removed the microstructural sensitivity without affecting the inclusion morphology as described in section 2.4, Figures 2.4(a) to (f). The comparable yield strength data of the heat-treated samples for all stages of hot reduction Figures 4.4.(a) to (f) support the 108 fact that the heat-treatment operation has produced a uniform structure for all stages of deformation of the CON and CAT steel. 4.6 Effect of Heat-Treatment on Fracture Toughness The effect of the heat-treatment on the fracture toughness properties of the 70% hot rolled CON steel (S3) is shown in Figure 4.11(a) for the crack orientation transverse to the rolling direction and in Figure 4.11(b) for the crack orientation parallel to the rolling direction. These figures show: a) At -120°C and above, that is in the transitional ductile fracture regime, the HT material possesses a higher toughness than the AR : material in both the LT and TL orientation. b) At -196°C, in the brittle fracture range, both the HT and the AR fracture toughness values are identical in both the LT and TL orientations indicating the lack of sensitivity of brittle fracture to microstructure. The improvement of the fracture toughness properties as a consequence of the heat-treatment in the transition and ductile fracture region is due to a) The reduction of the second phase b) The development of an equilibrium structure of fine grained polygonal ferrite with a small percentage of acicular second phase. c) Elimination of lattice strains •••< d) Grain size refinement. Since the heat-treatment does not alter the inclusion morphology, the improvement in fracture toughness of the HT material over the AR material is due to these microstructural refinement effects. 109 S3 CRACK J L RD(LT) 1 2 0 - 2 0 0 -150 -100 -50 (a) TEMPERATURE, °C. 120 Kt 6 50 o S 1 2 0 S3 CRACK II RD (TL) T r - 2 0 0 - 1 5 0 - 1 0 0 - 5 0 (b) TEMPERATURE , C. H I 2 0 •> 6 o S figure 4:11 Temperature dependence and effect of heat-treatment on KIC " JIC f r a c t u r e toughness of S3 (70% reduced) CON pipe-line steel (a) for LT specimens (b) for TL specimens The following is a comparison of the fractographs of 70% reduced CON steel in the AR condition (Figure 4.12) with that in the HT condition (Figure 4.16). It may be noted that: a) At RT, the fracture surface(Figure 4.16(a))consists of 100% dimpled structure in case of the HT condition showing 100% ductile failure, whereas the fracture surface of AR material (Figure 4.12(a)) shows approximately 20% fibrous and 80% faceted surface. This shows that the heat-treated material possesses considerably higher ductility and toughness as compared to the AR material. b) The fractograph in Figure 4.16(d) which is obtained at -120°C for heat-treated condition could be compared with fractograph in Figure 4.12(a) that stands for AR material at RT. Therefore, upto -120°C, the heat-treated material possesses greater ducti-l i ty and hence toughness than the as received material. c) At -196°C, the fractographs of the heat-treated material (Figure 4.16(e))and the as received material (Figure 4.12(f)) are comparable. This elucidates the fact that at -196°C where the material fai ls by the brittle fracture process and where cleavage fracture mechanism is operational, the microstructure of the material does not play a dominant role in the fracture process. 4.7 Fracture Toughness of Heat-Treated Materi als 4.7.1 38% Reduced Material (S2) The fracture toughness results obtained from testing and I l l (e) (0 Figure 4.12 Fractographs of J-integral/K T C specimens of AR S3 (70% reduced) CON steel in TL orientation tested at (a) RT, (b) -40°C, (c) -80°C, (d) -120°C, (e) -150°C anf (f) -196°C X400 112 J-integral testing for 38% hot reduced CON steel (S2) in the heat-treated condition are included in Appendix V (in Tables 5.1 and 5.2); the table includes data from specimens with crack parallel (TL) and transverse to the rolling (LT) direction. Figure 4.13(a) shows the temperature dependence of the Jj^ fracture toughness of the S2 stage in the heat-treated condition for both the LT and TL orientation. It should be noted that all of the J-integral (Jn) fracture toughness values from RT down to -196°C are valid J ^ ; they satisfied the validity criterion viz B > 25 and the same may be CTflow noted from B2 values in Tables 5.1 and 5.2 (Appendix V). This graph shows the following: a) The J j C toughness depends on the temperature of testing; it decreases gradually from RT to -196°C. This temperature dependence of Jj£ values is apparent for both crack orientations. b) At temperatures -120°C and above, the elastic-plastic fracture toughness is much higher in the LT direction than in the TL direction; below -120°C, the LT and TL data are comparable. c) In the transition and the ductile temperature regime, the material in the heat-treated condition possesses anisotropic fracture toughness properties. Figure 4.14(a) and (b) show the comparison of k Q / K J Q toughness data with equivalent Kj C calculated from J J C toughness data (KjC - JJQ)'» both are plotted as a function of temperature for the LT and the TL orienta-tion respectively. The data shows: a) At temperature -196°C, where Kg data becomes valid K j C , the K J C toughness values from K J C testing are equivalent to Kj C toughness 113 600 en C \ 5 4 0 0 I c I 2 2001-HTS2 1 r-A - LT(XRD) O - TL(I/ RD) A -' o - ° X - 2 0 0 -150 -100 - 5 0 (a) TEMPERATURE , °C. 90 60 30 N E 50 T 120 A w 80 o I 4 0 o H T S 2 1 1 h A - L T ( l R D ) O - T U l / R D ) „ A -A ^ A 0 1120 » 6 E 180 o 0. 40 _L X - 2 0 0 - / 5 0 -100 - 5 0 50 (b) TEMPERATURE , °C. Figure 4.13 Temperature dependence of (a) J I C fracture toughness and (b) K I C - J J C fracture toughness of HT S2 (38% reduced) CON pipeline steel in LT and TL orientation. 114 H T S 2 CRACK 1 RD 120 (f) V) NE 8 0 I o r- 40 h-O < or u_ - - A A / / / (a) ~ ° - - - o ° 120 80 40 o QL - 2 0 0 -150 - 1 0 0 - 5 0 50 T E M P E R A T U R E , C. A — K. CALCULATED IC FROM J | c -gTCT O " K Q / K ( C ^ T CT H T S 2 CRACK II RD (b) T E M P E R A T U R E , °C. Figure 4 . 1 4 Temperature dependence of k Q / K I C ~ J I C f r a c t u r e toughness of HT S2 (38% reduced) CON pipeline steel (a) in LT orientation (b) in TL orientation 115 values calculated from the toughness (K^ - J^) data. This equivalence of K J C with Kj C - J ^ c at temperature -196°C, where the plane strain condition prevails (i.e. at the tip of the crack a triaxial state of stress exists), means the strain energy release dictated by plane-strain fracture mechanics as well as that defined by the elastic-plastic fracture mechanics are the same, b) At temperatures -120°C and above, the - values are higher than the Kg values. It should be recalled that at -120°C and above, Kg values are not valid K J C values. Therefore, in this temperature range the Jj^ data represents a valid fracture tough-ness value for the material. It should be noted that there are two transitions in fracture behaviour with temperature, namely: a) A plane strain (KJQ ) transition b) A plane strain to plane stress transition commonly called the 'Elastic-plastic Transition'. •J CO Although Wessel suggested that the failure mechanism in test was cleavage over the whole temperature range, Barsom and Rolfe's fracto-15Q graphic analyses established that the K J C transition is associated with the onset of a change in the microscopic fracture mode. At low temperatures, the fracture is 100% cleavage or quasi-cleavage. In the transition region or at intermediate temperature, the fracture surface exhibits a combination of quasi-clevage and tear dimples. At higher temperatures above the transition region, the fracture surface consists of 100% tear dimples. In the case of the KjrVKg test speci-mens, the elastic-plastic transition takes place with increasing test 116 temperature; whereas for J-integral test specimen, a plane strain transi-tion takes place. In the brittle temperature region, the presence of a higher yield stress allows a higher level of tensile stress to be present in the plastic zone ahead of the crack and ensures crack tip tr iaxial i ty; hence a plane strain condition is encountered. As a result, cleavage failure occurs. Since J is a measure of the characteristic crack tip elastic-plastic f ie ld , similar to K in linear elastic-fracture mechanics, the equivalence of K J Q data with - toughness value is an obvious consequence. 4.7.2 70% Reduced Material (S3) The fracture toughness properties of the 70% hot rolled CON steel (S3) as obtained by testing and J-integral testing are included in Appendix V (Tables 5.3 and 5.4) for HT condition and are plotted in Figures 4.15(a) and (b). These figures depict the temperature dependence of KQ/ KJQ toughness and K J C - J J C toughness and their correlations in LT and TL orientations respectively. The toughness results are comparable to those obtained for the 38% hot rolled steel. In this case also, in the brittle temperature region, KJ (, and Kj^ - J j C toughness values are comparable in both the crack orientations. At the transition and ductile fracture temperature regime, the Kj C - J j C toughness data are much higher than the Kg toughness values. Figure 4.16 shows the fractographs of K I C /J-integral heat-treated specimens tested at RT, -40°C, -80°C, -120°C and -196°C. The RT specimen failed completely by ductile fracture processes and the specimen at -196°C failed by brittle fracture processes; whereas, the specimens at -40°C, 117 HTS3 CRACK J - RD ^ - 2 0 0 -150 -100 -50 0 TEMPERATURE ,°c. (a) -H20 n 6 o a . 2 A - K,C CALCULATED FROM J , E J TCT ® - » < o / K . c i T C T HTS3 CRACK II RD T 6 o Q. s - 2 0 0 -150 -100 -50 0 TEMPERATURE ,°c (b) Figure 4 . 1 5 Temperature dependence of k Q / K I C * * J I C f r a c t u r e toughness of HT S3 (70% reduced) CON pipeline steel (a) in LT orientation (b) in TL orientation 118 CON pipeline steel in TL orientation tested at (a) RT, (b) -40°C, (c) -80°C, (d) -120°C and (e) -196°C X400 119 -80°C and -120°C failed by a combination of fracture processes leaving evidence of ductile and brittle behaviour. With the decrease in test temperature, the percentages of faceted fracture surface increases and at -196°C temperature, the fracture surface consists of 100% faceted fracture surface. The important feature of the fractographs is the appearance of inclusions associated with the dimpled surfaces at RT down to -120°C, whereas no evidence of inclusions is present at -196°C. This elucidates the fact that at -196°C, where material fai ls by brittle fracture processes, and where cleavage fracture mechanism is operational, the non-metallic inclusions of the material do not play a dominant role in the fracture processes. Similar observations have been reported for a SIS 2140 tool s t e e l 1 6 0 in the hardness range Rc 50 to 60 where the material is very britt le. It has also been reported 1 6 1 that the second phase particles have l i t t le influence on brittle crack initiation at temperatures where complete cleavage takes place. 4.7.3 88% and 97% Reduced Material (S4 and S6) The fracture toughness data for 88% and 97% hot rolled CON steel (S4 and S6) in the HT condition as obtained by Kj^ and J-integral testing are included in the Appendix V (Tables 5.5, 5.6,' 5.7, 5.8) and graphically represented in Figures 4.17(a) and (b) and 4.18(a) and (b). These figures illustrate the temperature dependence of Kg/Kj^ and -J I C toughness and their relationship with the crack parallel and trans-verse to the rolling direction. Here also, at the brittle temperature region, Kj C and Kj C - J I C toughness values are comparable. Figure 4.19 shows the fractographs of the 97% reduced CON steel; each is tested at 120 Figure 4.17 H T S 4 CRACK 1 RD - 2 0 0 (a) - 1 5 0 - / 0 0 - 5 0 TEMPERATURE. °c 5 0 A — K 0 -( c CALCULATED FROM Jlc j TCT V K l c T T C T H T S 4 CRACK II RD - 2 0 0 ( b ) - 1 5 0 - 1 0 0 - 5 0 TEMPERATURE , °c 5 0 Temperature dependence of k Q / K I C ~ " ^ I C ^ r a c t u r e toughness of HT S4 (88% reduced) CON pipeline steel (a) in LT orientation (b) in TL orientation 121 Figure 4.18 H T S 6 CRACK 1 RD - 2 0 0 (a) -150 -100 - 5 0 0 TEMPERATURE ,°c A - K | C CALCULATED • — H T S 6 CRACK II RD FROM J | E 2 T C T V K , e * T C T - 2 0 0 (b) -150 -100 - 5 0 0 TEMPERATURE ,°c. 50 Temperature dependence of K q / K I G - J I C fracture toughness of HT S6 (97% reduced) CON pipeline steel (a) in LT orientation (b) in TL orientation 122 (e) Figure 4.19 Fractographs of J-integral/K I C specimens of HT S6 (97% reduced) CON pipeline steel in TL orientation tested at (a) RT, (b) -40°C, (c) -80°C, (d) -120°C and (e) -196°C X400 123 RT, - 40°C, -80°C, -120°C and -196°C. These are comparable to those shown in Figure 4.16 for the 70% hot rolled CON steel. 4.7.4 63% and 95% Reduced CAT Material (CI and C2) The fracture toughness data for 63% and 95% hot rolled CAT steels in the HT condition as obtained by and J-integral testing are included in Appendix V (Tables 5.9, 5.10, 5.11 and 5.12). Figures 4.20(a) and (b) and Figures 4.21(a) and (b) show the fracture toughness results of CI and C2 material in terms of Kg/KjC and K J C - J j C toughness as a function of temperature. Similar trends are observed as with the fracture toughness data of S2, S3, S4 and S6 material; however the magnitude of the fracture toughness of CAT steel data are different and much higher than that of CON steel data. Figure 4.22 shows the fractographs of the 95% reduced CAT steel (C2) tested at RT, -40°C, -80°C, -120°C and -196°C. A comparison of the fractographs of the CON and CAT steel shows that: a) At RT, the fracture surfaces of the CON and CAT steel consists of 100% dimpled structure; the fracture occurs by coalescence of voids with considerable evidence of non-metallic inclusions associ-ated with the dimples. b) At -40°C, -80°C and -120°C, the fracture surface consists of fibrous as well as faceted surface; the CAT steel shows more dimpled surface at -120°C; therefore, the fracture occurs by a combination of ductile and brittle failure. c) At -196°C, the fracture surface of both consists of 100% faceted surface. Therefore, the fracture occurs by brittle failure and no inclusions are visible on either the CAT or the CON steel fracture surfaces. 124 Figure 4.20 (60 HTCI CRACK 1 RD < 0 to U J 2 X e o <t ct u. - 2 0 0 -150 -100 -50 TEMPERATURE ,°c. M V ) U J I (9 O h-O <t or u. 160 120 80 4 0 HTCI CRACK Jl RD 0 50 A - K ( C CALCULATED FROM J | E 7 T C T I ® " K 0 / K l c 2 T C T 1160 s / ®~-~® © J 1 I l - 2 0 0 - / 5 0 -100 -50 0 . . . TEMPERATURE, »c \0) 120 » 6 E b 0. 80 £ 40 50 Temperature dependence of k Q / K I C ~ J I C f r a c t u r e toughness of HT Cl (63% reduced) CAT pipeline steel (a) in LT orientation (b) in TL orientation 125 HTC2 CRACK ± RD V) CO Ul Z I o e ct 160 ic 120 80 4 0 1 1 ' L A —• \' / -/ / A / _ / / / / s> - ® - -1 1 - @ ® 160 120 6 o 0. 80 s H 4 0 - 2 0 0 -150 -100 - 5 0 0 50 TEMPERATURE , °C. A - K(c CALCULATED FROM J ( e "jTCT HTC2 CRACK ll RD ®~KQ 2 " T C T 1160 - 2 0 0 -150 -100 - 5 0 lb) TEMPERATURE , C. Figure 4.21 Temperature dependence of k Q / K I C ~ J I C ^ r a c t u r e toughness of HT C2 (95% reduced) CAT pipeline steel (a) in LT orientation (b) in TL orientation 126 Figure 4.22 Fractographs of J-integral/K T C specimens of HT C2 (^reduced) CAT pipeline steel in TLorientation tested at (a) RT, (b) -40 C, (c) -80°C, (d) -120°C and (e) -196°C X400 127 4.8 Correlation of the Fracture Toughness of the CON and CAT Steels  in the Heat-Treated Condition with Percent Reduction The fracture toughness properties of the S2, S3, S4, and S6 stages of reduction of the CON steels and the CI and C2 stages of reduction of the CAT steels in the HT condition have been correlated with percent hot reduction in Figures 4.23(a) to (f). Since the heat treatment is effec-tive in removing the structure differences, the fracture toughness vs percent reduction is a measure of the effect of inclusion morphology on the fracture toughness and is therefore most important. The Figure 4.23 reveals the following: a) At RT and -80°C, the fracture toughness values decrease from 38% reduction to 70% reduction and beyond 70% reduction, Kj^ - J j C toughness increases with increasing i percentage of reduction. This is true for both the LT and TL orientations. b) In all cases Figures 4.23(a) to (d), the fracture toughness of CAT steels l ie at a much higher level than that of the CON high sulphur steels. c) It is also important that a similar trend is exhibited by the CON and the CAT steel; but the cleaner CAT steel (S « 0.005 wt%) is displaced to a higher toughness value. d) At -196°C, the fracture toughness values are similar for all stages of the CON and CAT steels. Thus the data indicates that i f the inclusion content is compar-' able for each stage of rolling - this is consistent with the comparable sulphur content of the steel from each stage of reduction - increasing the degree 128 HT RT TL HT RT LT H l 2 0 160 o o Q. 20 40 60 80 (a) % D E F HT -80°C TL HT -8CTC LT 20 40 60 80 100 20 40 60 80 100 (c) %DEF. HT - I 9 6 ° C . TL (d) % DEF. HT - I96°C. LT 1 " •-T 1 CAT 63%STEEL _ A- CAT 95% STEEL o- CON STEEL -o * 8 & © 1 J 1 o 80 £ b 0 . 40 S 2^ 40 60 80 100 20 40 60 80 100 (e) %DEF ( f ) %DEF Figure 4.23 Correlation of Kj C - J j C fracture toughness of heat-treated materials with percentage deformation a) at RT in TL orientation b) at RT in LT orientation c) at -80°C in TL orientation d) at -80°C in LT orientation e) at -196°C in TL orientation f) at -196°C in LT orientation 129 of hot rolling generally does not improve the ductile fracture toughness of the product since the TL and LT toughness values between 38% and 88% reduction at RT and -80°C indicate a very l i t t le change. It may be noted that each S2 (38% reduced), S4 (88% reduced) and S6 (97% reduced) material contains a sulphur of 0.026%, whereas S3 (70% reduced) material contains ^ 0.032% sulphur. The lowest Kj^ toughness achieved for the S3 material is thought to be due to high sulphur content. The higher toughness with S6 (97% reduced) material is due to the presence of fractured inclusions. As the test temperature decreases, the effect of hot reduction on the fracture toughness decreases and at -196°C, the degree of hot rolling has no effect on the brittle fracture characteristics of the CON and CAT steels. The effect of inclusion morphology on fracture toughness could as well be explained in terms of inclusion parameters of the CON and CAT steel as shown in Table 4.1. a) The S2 (38% reduction) material possesses higher toughness than S3 material because of its smaller inclusion length, smaller inclusion density, less stringering effect and higher interparticle distance, consistent with the lower sulphur content of the S2 material. b) From 70% deformed material to 97% deformed material the fracture tough-ness increases with increasing percentage of reduction. One obvious reason is the decrease in the area fraction of inclusions and an increase in the inter-inclusion distance. Although, the S4 (88% reduction) material stringer out more than S3 (70% reduction) material which is reflected in the FF parameter, i t contains a smaller area fraction of inclusions than the S3 material. The superior fracture 130 toughness of the S6 material over that of the S2, S3 and S4 is due to its smaller inclusion length and smaller area fraction of inclusions. c) The higher fracture toughness properties of the Cl and;C2 CAT steels over those of the semi-killed CON steel are due to the reduced inclusion content (in conformation with S-level) and the equiaxed nature of the inclusions in this steel, as shown by the reduced AF, Co, FF, N parameters in the Table 4.1. 4.9 Anisotropy It is well-known that the mechanical properties of wrought steel plates are not the same in all directions. The dependence of properties on orientation is called anisotropy. Two types of anisotropy are common l fi? in metals: a) Crystallographic anisotropy b) Mechanical fibering. Crystallographic anisotropy arises from a preferred orientation of the grains which is produced by severe reduction, whereas mechanical fiber-ing is due to the preferred alignment of structural discontinuities such as inclusions, voids, segregations and second phases in the rolling direction. 4.9.1 Anisotropy of Yield Strength The yield strength values determined with longitudinal speci-mens (that is with the specimen axis parallel to the rolling direction) as well as transverse specimens (that i s , with the specimen axis normal to the rolling direction) are also plotted in Figures 4.24, 4.25, 4.26, 131 4.27, 4.28 and 4.29 as a function of temperature. It should be noted that the two yield strength values are identical at each testing tempera-ture. This shows that the S2 (38% reduction), S3 (70% reduction) S4 (88% reduction) and S6 (97% reduction) stages of reduction of the CON steel and the Cl (63% reduction) and C2 (95% reduction) stages of reduction of the CAT steel in the HT condition possess isotropic yield strength properties. Since the CAT steel possesses globular inclusions, the yield strength values in the two orientations are expected to be very close. However, the semi-killed materials contain elongated inclusions, but s t i l l exhibit isotropic yield strength properties. Therefore, it is apparent that the inclusion morphology does not affect the yield strength 149 of a material. T. GIadman pointed out that non-metallic inclusions have l i t t le effect on the yield strength because this property is depen-dent upon the initiation of plastic deformation. However Thronton7 reported that the yield strength increases with increasing ultrasonic inclusion category. He attributed this to a higher degree of triaxial stress present in the dirtier (higher category) specimens with a greater constraint for lateral contraction. Kozasu and Kubota observed no variation of yield strength as the test direction of the specimen varied from 0° to the rolling direction to 90° to the rolling direction. It is to be emphasized that the inclusions participate in the fracture pro-cesses and in fact, promote fracture processes that initiate after the yield point, during a tensile test. Void nucleation and growth occur during plastic reduction of a material; in other words, stable crack growth takes place during plastic reduction in tensile testing. In the elastic region of a tensile test, the role of inclusions remains insigni-ficant as the stress and strain necessary for the nucleation of voids cannot 132 8 0 0 h £ 7 0 0 6 0 0 g 3 0 0 or i « ) 4 0 0 ^ 300 >-( 2 0 80 6 0 H O - 5 Hoo © c < or 140 55 1 2 0 - 2 0 0 - 1 5 0 - 1 0 0 - 5 0 TEMPERATURE , °C. YD. STN. a - II RD X — _LRD ef O - II RD A - 1 R D % RA O RD + - ± R D Figure 4.24 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated S2 (38% reduced) COM pipeline steel. 133 800 h £ 7001 I 600| z W 500| V ) Q 400| -J UJ >" 3001 (20 6 \ 100 r- \ _ 80 (A 60 40 8 8 -"A" -/ / - 2 0 0 -150 -100 - 5 0 T E M P E R A T U R E , C. (•50 I 25 100 *-0 75 £ c 0-50 ~ u - 0-25 VlT - 0 00 50 80 H60 or 40 H20 YD. STN. % RA • — II RD X - ±RD O- II RD A - J.RD O - llRD + - -LRD Figure 4.25 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated S3 (70% reduced) CON pipeline steel. 134 800 H S. 700 ( 120 I h-O 2 Ul Ct t~ co 600 500f 4 0 0 Ul >: 3001 HO - 5 H O O - 2 0 0 -150 -100 - 5 0 TEMPERATURE , °C. 80 \60 o c II ft |40 20 YD. STN. % RA • X o A O + II RD _I_RD II RD - _L RD •II RD • _LRD Figure 4.26 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated S4 (88% reduced) CON pipeline steel 135 8 0 0 x 600 K Lu 500 or CO 4 0 0 O _J UJ >• 300 120 100 - 80 IA I — •* L 6 0 40 1 1 53 i ^ i i Q & f - " A 4 T + 1 1 1-5 10 0-5 0 0 - 5 0 0 0, - 2 0 0 -150 -100 TEMPERATURE , WC. YD . STN. • - II RO X — J.RD 6, O - II RD 50 H 8 0 H60 N o rr 140 ^ 120 % RA A —_1_RD O -II RD + —_LRD Figure 4.27 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated S6 (97% reduced) CON pipeline steel 136 1 2 0 H 8 0 6 0 H 0 - 5 H 0 0 < o n - 2 0 0 - 1 5 0 - / O O - 5 0 TEMPERATURE ,°C. YD. STN. • — II RD X — J_RD 6 f O - II RD A - _LRD % RA O - I I R D + - ± R D | « 0 ^  120 5 0 Figure 4.28 Temperature dependence of yield strength, true strain to fracture and percent reduction in area of heat-treated Cl (63% reduced) CAT pipeline steel 137 800 o a- 700\ x 600 [ r-o £ 500f fr r-120 4 0 0 y 3 0 0 HO -5 Hoo o < c II V l f - 2 0 0 -150 -100 80 60 or 20 TEMPERATURE , C. YD. STN. % R A • - II RO X — _L RD o - 11 RO A - JLRD o -11 RD + - RD Figure 4.29 Temperature dependence of yield strength true strain to fracture and percent reduction in area of heat-treated C2 (95% reduced) CAT pipeline steel 138 be attained. Therefore, the shape, size, volume fraction, spacing or density of inclusions do not have any effect on the mechanical properties in the elastic region. This could be the reason for the isotropic yield strength properties of the S2, S3, S4 and S6 stages of the semi-killed steel and the CI and C2 stages of the CAT steels. In this study, the calcium treatment does not improve the yield strength value of the semi-killed steel as the yield strength is comparable 12 for both the CON and CAT steels at any test temperature. A. D. Wilson, however, reported that the yield strength of A533B steels improved from a value of 64.4 KSi(444 MPa) in CON steel to 71.7 KSi (494 MPa) with Ca-115 138 139 treatment. On the other hand various other research studies * ' have established that Ca-treatment does not affect the yield strength properties of a steel, which is in agreement with the observations in this study. 4.9.2 Anisotropy of True Strain.to Fracture (e^) and Percent Reduction area (% RA) By comparing the total ductility parameters viz , the true strain to fracture, e^, and the percentage reduction area (% RA) in the longitudinal and transverse direction, i t may be noted that the longi-tudinal specimens possess higher and % RA than do the transverse speci-mens at temperatures -150°C and above HT S2 (Figure 4.24), HT S3 (Figure 4.25), HT S4 (Figure 4.26), HT S6 (Figure 4.27) material. The heat-treated semi-killed material shows appeciable ductility even at -196°C; for example, the % RA is 31% for the S2 material in the longitudinal direction and - 19% in the transverse direction. It is apparent that the 139 heat-treated semi-killed material possesses anisotropy in the total ductility throughout the temperature region RT down to -196°C. The Ca-treated steel exhibits isotropic ductility; the longitudinal and the transverse e f and % RA are comparable over the whole temperature range (Figure 4.28 and Figure 4.29). It is well e s t a b l i s h e d 5 ' 6 ' 8 " 1 1 ' 1 6 3 ' 1 that the total ductility is dependent upon the orientation of the tensile specimen relative to the long axis of inclusions (i .e. rolling direction). This anisotropy in ductility is a consequence of the shape of the in-clusions. Elongated, stringer type inclusions tested parallel to their length give much higher ductility than do plate-shaped oblate inclusions 5 tested perpendicular to their planar dimensions. F. B. Pickering and T. Gladman et a l . 6 have developed a theoretical model in which higher tensile ductility is realized for inclusions having their long axis parallel to the tensile axis and for inclusions with increasing length-163 width ratio. In structural steel, Kozasu and Kubota have shown that the total ductility of a tensile specimen increases as the specimen orientation changes from 90° to the rolling direction to parallel to the rolling direction. The anisotropy in total ductility is a common feature in hot rolled steel plate and is due to the presence of elongated, stringer type inclusions. It is also known that the ductile failure of a material is a con-sequence of void nucleation, growth and coalescence. These voids nucleate either by cracking of inclusions or by a process of decohesion along the inclusion-matrix interface. It i s , therefore, apparent that the non-metallic inclusions provide the active sites for void nucleation, 140 subsequent growth and final propagation of fracture. Figure 4.30 schematically illustrates the orientation of the elongated inclusions with respect to the axis of a- longitudinal tensile specimen and a transverse tensile specimen. It is quite obvious that the cross-section of the inclusions will contribute to the fracture process in the case of the longitudinal specimens; i f the strain in the metal exceeds the fracture strain, e^, on inclusions, cracks form in inclusions and act as nuclei for voids. Even i f inclusion cracking does not occur, too much strain in the adjacent metal matrix will give rise to debonding at the interface and thereby void formation will occur at the TS plane. Thus, the fracture path encounters the inclusions on the TS plane for the longitudinal specimen. Hence, the inclusion parameters of the TS plane become significant and should contribute to the total ductility for the longitudinal specimen. Similarly, in the transverse tensile specimen, the inclusion inter-facial area in the LS plane could act as a void nucleation site; hence the inclusion parameters in the LS plane should contribute to the total ductility for the transverse tensile specimen. An example of the anisotropy in total ductil ity, e^, in terms of inclusion parameters is shown for the S4 88% reduction stage of the semi-killed steel. The inclusion parameters in LS and TS plane and values at different temperatures of S4 material are shown in Table 4.3. It may be noted that the AF, Co, FF parameters in the LS plane are greater than those in the TS plane; in particular the average length of inclusion and area fraction of inclusions. Since, the inclusions provide active sites for void Figure 4.30 Schematic representation of the orientation of elongated inclusions in longitudinal and transverse tensile specimens of a hot •.rolled plate. 142 Table 4.3 Inclusion Parameters in LS and TS plane and e f Values at Various Temperatures for Longitudinal and Transverse  Specimens of HT S4 (88% reduced) CON Pipeline Steel Inciusion Parameters e f LS Plane TS Plane Temp °C 11RD AF (%) 0.929 0.408 RT 1.599 1.200 Co (y) 60.29 11.93 -40 1.486 1.190 D (n) 365 906 -80 1.417 1.260 FF 25.00 4.05 -120 1J319 1.052 N (no/mm ) 200 205 -196 0.447 0.362 Fracture Path (N x Co) H 12056 2445 nucleation, growth and coalescence, the density (N) multiplied by average inclusion length (Co) could be considered as a measure of the fracture path. It may be noted that inclusions in the LS plane provide much longer fracture path than the inclusions in the TS plane. Thus, the pro-portion of the steel matrix involved in the fracture process in the LS plane will be much less than that in the TS plane. Hence, the total ductility in a longitudinal tensile specimen would be expected to be higher than the total ductility in a transverse tensile specimen of rolled plates containing elongated stringer type inclusions, consistent with the data reported in Table 4.3. In the case of the Ca-treated steel which contains globular in-clusions in both the LS and the TS plane, isotropic ductility (e^) 143 properties are observed. An example of the isotropy in total ductil ity, e^, in terms of inclusion parameters is shown for a CAT 95% hot rolled steel. The inclusion parameters in the LS and TS plane and e^ . values at different temperatures of the material are shown in Table 4.4. Table 4.4 Inclusion Parameters in LS and TS Plane and Values at Various Temperatures for Longitudinal and Transverse Specimens of HTC2 (95% reduced) CAT Pipeline Steel Inclusion Parameters G f LS Plane TS Plane Temp °C 11 RD 1.RD AF (%) 0.211 0.204 RT 1.580 1.645 Co (y) 5.447 5.570 -40 1.572 1.581 D (y) 4489 3863 -80 1.438 1.476 FF 1.187 1.150 -120 1.416 1.410 p N(no/mm ) , 47.98 52.32 -196 0.696 0.617 Fracture Path (N x Co) y 261 281 It is quite evident from the above data that the inclusion parameters viz AF, Co, FF, N and D are comparable in both the LS and the TS plane for the CAT steels. The fracture path data is also very close in both the planes. Therefore, no marked anisotropy of e^ . would be expected. The data in Table 4.3 confirms the above prediction from the inclusion analysis. Various research s t u d i e s 1 2 , 1 1 5 ' 1 3 8 ' 1 3 9 ' 1 4 2 also established that 144 Ca-treatment eliminates the anisotropy of mechanical properties in the LT plane. 4.9.3 Anisotropy in Fracture Toughness Figures 4.13(a) and (b), 4.31(a) and (b), 4.32(a) and (b), 4.33(a) and (b), 4.34(a) and (b) and 4.35(a) and (b) illustrate the temperature dependence of J J C fracture toughness and the -fracture toughness for the LT and the TL orientation of the S2 (38% reduction), S3 (70% reduction), S4 (88% reduction) and S6 (97% reduction) stages of reduction of the semi-killed CON steel and the CI (63% re-duction) and C2 (95% reduction) stages of reduction of the CAT steels respectively. The following points may be noted: a) The semi-killed CON steels (S2, S3, S4, S6) possess a higher frac-ture toughness in the LT crack orientation than in the TL crack orien-tation at temperatures above -120°C. b) At temperatures below -120°C i.e. in the brittle temperature region, the difference between the LT and TL fracture toughness values diminish and at -196°C both values are comparable. c) In the case of the CAT steels, for the entire temperature region from RT down to -196°C, the LT and TL fracture toughness values are comparable. The elastic-plastic fracture toughness test data show that semi-killed steels containing elongated inclusions along their rolling direction possess anisotropic fracture toughness properties whereas, calcium treated steels containing globular inclusions possess isotropic fracture toughness properties. 145 400 300 HTS3 — 1 1 A — L T ( J - R D ) L O - T L ( l l R D ) A 1 £> I 200 c 100 •A s / ' ' O - 2 0 0 -I50 -I00 - 5 0 (a) TEMPERATURE. C. 60 40 20 E v. 50 I20 •4 m so 40 HTS3 I 1 1 I I A ' A ^ ^A A - " 9 " ' / ' " " o - — / ^ - o I —I A O l - L T ( X R D ) --TL( l lRO) I-I20 80 D a. 40 s - 2 0 0 (b) -I50 -I00 - 5 0 TEMPERATURE.°C 50 Figure 4.31 Temperature dependence of (a) J J C fracture toughness and ' ( b ) K - J T r fracture toughness of HT S3 (70% reduced) IC IC CON pipeline steel in LT and TL orientation 146 HTS4 6 0 0 M c £ 4 0 0 2 0 0 1 — 1 1 i A - L T ( l R O ) O -TL(l lRD) > -^ - - O - " o -~ C — •*-' 1 1 -• | 9 0 N E 6 0 \ 3 0 - 2 0 0 - 1 5 0 - 1 0 0 • 5 0 5 0 (a) TEMPERATURE, C. HTS4 1 6 0 1 (A it Figure 4.32 1 2 0 h 6 0 4 0 T A' A / -A o ' _ A - - O A — LT (J-RD) O -TL(llRD) J 1 1 6 0 1 2 0 6 8 0 40 o 0 . S - 2 0 0 (b) - 1 5 0 - 1 0 0 - 5 0 5 0 TEMPERATURE, C Temperature dependence of (a) J j C fracture toughness and (b) K - J T r fracture toughness of HT S4 (88% reduced) IC IC CON pipeline steel in LT and TL orientation 147 800 600 c £ 4 0 0 I c u ~>~ 200 HTS6 / / A _LT<±RD) o -TL ( I IRD) 120 90 N E 60 ^ 30 -200 -150 -100 - 5 0 50 160 ^ 120 o 80 I 40 HTS6 i r / A ' / / V • y Ax s s I A - - O A -LT(-LRD) O -TL(llRD) 60 120 n 6 80 40 - 2 0 0 -150 -100 -50 50 (b) TEMPERATURE. C. Figure 4.33 Temperature dependence of (a) J j C fracture toughness and (b) K r - J T r fracture toughness of HT S6 (97% reduced) CON pipeline steel in LT and TL orientation HTCI 148 HI20 6 0 0 h 4 0 0 2 0 0 h E -200 H 5 0 -100 - 5 0 ( a ) TEMPERATURE , C. HTCI 160 120 80 4 0 r - 1 s l 0 -1 - X _ /? / / A ' • ' 0 • -- L T O i ' I - T L 1 60 ' 2 0 . 6 E b 2 so a 4 0 - 2 0 0 -150 -100 - 5 0 5 0 (b) TEMPERATURE, C. Temperature dependence of (a) J I C fracture toughness and (b) K - J T r fracture toughness of HT CI (63% reduced) IC I c CAT pipeline steel in LT and TL orientation 149 HTC2 BOO 600 .o T 400 c 200 1 1 1 1 0 _ / / / / / / 8 A - LT s O - TL i 1 1 i -200 -150 -100 -50 (a) TEMPERATURE , C. (20 90 « E 60 * 30 50 HTC2 m JC "3 I 160 1 1 '.a 120 -80 / o / / -40 / A - LT O - TL 1 1 -200 -150 -100 -50 (b) TEMPERATURE. C. 160 120 80 £ 40 E b Q_ s 50 Figure 4.35 Temperature dependence of (a) J j C fracture toughness and (b) K I C - J T C fracture toughness of HT C2 (95% reduced) CAT pipeline steel in LT and TL orientation. 150 It is well established that the presence of elongated inclusions in hot rolled steel plates causes mechanical anisotropy. Anisotropy in notch impact strength has been associated with banding and sulphide inclusions. The banding of elongated inclusions, mainly sulphides, is a major contributing factor to the poor transverse impact properties of wrought products. The anisotropic impact toughness property of HSLA steels 22 has been reported by L. Luyckx et a l . Similar observations have been reported by several researchers 2 0 " 2 4 ' 2 6 - 3 1 Research s t u d i e s 1 5 ' 9 6 ' 9 7 have also shown that the hot rolled HSLA steels possess anisotropy in fracture thoughness properties; testing in the longitudinal LT direction yields much higher values than testing in the transverse TL direction. The major cause of the anisotropy is due to the presence of elongated flat ribbon type or planar arrays of silicate and MnS inclusions. In the 115 148 case of CAT steel, H. Nashiwa et a l . and T. Uemura et a l . observed that as the Ca/S ratio reaches 0.3 and over, the steel possesses isotropic impact toughness properties. This effect of * V E 0 ( T ) / V E 0 ( L ) ~ 1 A T Ca/S ^ 0.3 is closely related to the presence of inclusions as globular shapes instead of stringers; this occurs when the [Ca] in the molten 135 steel reaches approximately a value of 15 ppm. E. Forster et a l . also observed isotropic impact toughness properties in a Ca (CaC2 + CaO com-pound) treated steel. However, H. Bremen140 reported that an addition of RE Ca-Si-Fe alloy to X52 and X80 grades of steel considerably increased the notch toughness both in LT and TL orientations; but anisotropy in \ Q ( T ) 85 Transverse Impact Energy, V E Q ( L ) = Longitudinal Impact Energy. 151 121 toughness was maintained. Similar results have been reported by Saxena 142 and A. D. Wilson. However, Ca-treatment reduces the degree of aniso-139 tropy. Similar results have also been reported by Clayton and Knott. As seen in Figure 4.36 for LT specimens, the fracture path encounters inclusions in the TS plane. Similarly for TL specimens the fracture path sees inclusions in the LS plane. Hence to account for the enhanced fracture toughness of the LT specimen, the inclusion parameters of the TS plane should be considered. Similarly, to account for the fracture toughness of the TL specimens, the inclusion parameters of the LS plane should be considered. Table 4.5 shows the inclusion rating of the S2, S3, S4, S6 stages of the CON steel and the C2 stage of the CAT steel for the TS and LS planes. The poor transverse fracture toughness of S2, S3, S4, and S6 stages of the semi-killed CON steel with respect to longitudinal fracture toughness is mainly due to the greater area fraction, higher average inclusion length, greater aspect ratio and closer inclusion spacing of the inclusions in LS plane with respect to inclusions in TS plane. In the case of the CAT steels, the inclusion parameters in the LS plane and the TS plane do not differ markedly as may be seen in Table 4.5; the fracture path in the.LT and TL crack orientations, therefore, encounters a similar non-metallic inclusion distribution and thus fracture toughness properties are comparable for both test directions. Hence, CAT steel exhibits isotropic fracture toughness. 152 Figure 4.36 Schematic representation of the inclusion morphology with respect to LT and TL CT specimen Tabel 4.5 Comparison of Inclusion Parameters i n LS and TS Planes of S2, S3, S4, S6 Stages of CON Steels and Ci and C2 Stages of CAT Steel Inclusion Parameters S2 S3 S4 S6 Cl C2 LS Plane TS Plane LS Plane TS Plane LS Plane TS Plane LS Plane TS Plane LS Plane TS Plane LS Plane TS Plane Area Fraction % (AF) 1.595 0.938 1.086 0.734 0.929 0.408 0.431 0.318 0.178 0.228 0.211 0.204 Average Inclu-sion Length ( C O . P ) 27.98 10.26 64.39 13.88 60.29 11.93 3.958 3.472 4.492 5.046 5.447 5.570 I n t e r p a r t i c l e Distance •D' (u) 536 698 351 559 365 906 825 793 4.305 2755 4489 3863 Aspect Ratio FF 4.13 1.86 11.83 3.30 25.00 4.05 2.531 1.718 1.167 1.137 1.187 1.150 No. of Inclu-sions/mm^ N 131 280 119 348 199 205 759 412 70 82 48 52 Chapter 5 154 RELATIONSHIP BETWEEN FRACTURE TOUGHNESS AND INCLUSION PARAMETERS 5.1 Correlation of Fracture Toughness with Inclusion Parameters In the previous section 4.9.3, it has been pointed out that the fracture path in a LT specimen encounters inclusions on the TS plane, whereas the TL specimen is influenced by inclusions on the LS plane as shown schematically in Figure 4.36. For this reason, the LT fracture toughness values were correlated with the inclusion parameters of the TS plane and the TL specimen properties were correlated with the in-clusion parameters of the LS plane. The fracture toughness values obtained at RT, -80°C and -196°C with the corresponding inclusion para-meters are shown in Tables 6.1, 6.2(Appendi:x VI). 5.1.1 Correlation of Fracture Toughness with Area Fraction (AF) Figures 5.1(a) and (b) show the relationship between the fracture toughness and the area fraction of inclusions at RT and -80°C respectively for the heat-treated material. In the HT condition, since the microstructure and grain size of each sample from the different stages are comparable, the variation of fracture toughness with different stages of hot reduction can, therefore, be attributed to the variation of in-clusion morphology. Therefore, in the HT condition, the dependence of fracture toughness can be related to the inclusion parameters. The following points may be noted from the Figures 5.1(a) and (b): 155 160 120 -i I 80 40 RT i 1 1 r 0 (a) £ 120 r-0 4 0 8 (-2 AF -5 I -I96°C. (c) 08 12 AF -H60 120 J 1 L 80 16 TS LS A - A - CON # _ O- CAT Figure 5.1 Correlation of HT Kj C - J T C fracture toughness data with area fraction (AF) of inclusions at (a) RT, (b) -80°C and (c) -196°C. 156 a) The fracture toughness decreases with increasing area fraction of inclusions for both TL and LT specimens. b) The toughness realized for the LT specimens are much higher than that for TL specimens. c) CAT steel possesses the highest toughness. The polynomial regression analysis determined the best f i t curve to the data presented in Figure 5.1(a). The relation between fracture tough-ness and area fraction of inclusions is given by the equation KIC " JIC = 1 6 8 - 0 9 " H6.28 AF + 45.04 (AF)2 in KSi/Tn 2* This equation gives a best f i t correlation as R is 0.933 at 95% level of significance (S.L.). It may be noted (Figure 5.1(a)) that as the area fraction of in-clusions increases from 0.2 percent to ^ 1.08 percent, . the fracture toughness of the steel decreases from 152.00 KSi/Tn (167 MPa/E")"" to 90.00 KSi/Tn (98.91 MPa /C ) . This correlation is appar-ent for data obtained at RT where the fracture processes take place by void nucleation, growth and coalescence. 1 6 5 " 1 6 7 As the area fraction of inclusions increase, the area for void nucleation increases; subsequently *R = coefficient of correlation = + /Explained variation^ ~ V Total variation J 157 void growth and propagation processes enlarge the void areas and hence the fracture toughness decreases. Various research s t u d i e s 5 , 8 , 1 1 ' 1 4 , 1 6 , 1 9 , 9 3 , 94,137,144,149,168,169 h a y e e s t a b l i s n e d t h e f a c t t n a t a s t h e v o l U me fractfon of inclusions in a steel increases, its impact upper shelf energy (USE) i.e. notch toughness decreases. As in the case of USE, the volume fraction of inclusions also plays an important role in deciding the fracture tough-ness of a material. Increasing the volume fraction of inclusions de-creases the K I C toughness v a l u e . 3 , 7 , 1 7 0 - 1 7 2 Spitzig 3 suggested that the influence of increasing the sulphur content on Kj^ is to decrease the fracture strain by increasing the number of crack-nucleation sites ahead of the crack. This decrease in fracture strain results in a decrease in the size of the zone of plastic instability at the crack tip and thereby 173 in a decrease in Kj C . Hahn and Rosenfield formulated the following expression correlating Kj^ with volume fraction of inclusions: K, c = (1.6 R p o 2 ED) 1 ' 2 r 1 ' 6 where Rpg 2 is the 0.2% offset yield stress, E, the elastic modulus, D, the inclusion diameter and f, the volume fraction of inclusions. For a particular yield strength class, this equation illustrates that de-creases with increasing f, volume fraction of inclusions. The -80°C data (Figure 5.1(b)) shows a similar effect and is due to the fact that at -80°C the fracture processes partially occur by the process of microvoid coalescence. In this study, volume fraction of inclusions is different from CAT steel to semi-killed CON steel as the CAT steel contains «\. 0.005% S and the CON steels 0.025% S. Therefore 158 the CAT steel is a much cleaner steel than the CON steel and hence possesses a much higher fracture toughness property- In semi-killed CON steels, as the chemistry is very similar for each stage of deformation, the volume fraction of inclusions is expected to be constant for all stages. However, since the inclusion content is inhomogenous in the original ingot, the inclusion content in any specific section may be quite variable. In addition, even i f the inclusion content in the original ingot section remains the same, the area fraction of inclusions would vary with the percentage of hot deformation. Therefore the data for semi-killed CON steel represents the variation in inclusion content. The data shows a decrease in fracture toughness with increasing area fraction of inclusions as reported in the literature. Figure 5.1(c) depicts the correlation of fracture toughness data with area fraction of inclusions at -196°C. The figure indicates that the fracture toughness is independent of area fraction of inclusions. It is apparent that inclusions play a definite role in ductile fracture and minor role, i f any. in cleavage fracture. D.A. Curry 1 7 4 has pointed out that cleavage fracture in steels con-taining discrete carbide particles is nucleated by microcracks formed in the carbide particles. The critical tensile stress known as the cleavage fracture stress must be exceeded over some microstructurally determined characteristic distance before cleavage fracture can occur. The micro-mechanism of cleavage fracture in steels which do not contain brittle second phase particles is not established. However, Tetelman and McEvily 1 6 1 reported that the second phase particles have l i t t le influence 159 on brittle crack initiation at temperatures where complete cleavage takes place. Similar observations have been cited by Er ikson 1 6 0 while studying the effect of inclusion content on the fracture toughness of a SIS 2140 type tool steel. He reported that in the hardness range of HRC 50-60 where the material is very brit t le, there is no difference in fracture behaviour between a material with and without inclusions. 5.1.2 Correlation of Fracture Toughness With Average Inclusion  Length (Co) Figure 5.2(a) and (b) show the correlation between fracture toughness and average inclusion length at RT and -80°C temperature respec-tively for heat-treated samples. These figures indicate that as the average inclusion length increases in the fracture path, the fracture toughness decreases. For example, the toughness value of ^ 150.00 KSi/irT (164.85 MPa/itTJat 3.4 y average inclusion length decreases to a value of ^ 90 KSi/Tn (98.91 MPa/te ) at a 64 y average inclusion length (Figure 5.2(a). The data presented in Figure 5.2(a) are analysed by polynomial regression analysis. The best f i t equation is given below. KIC " JIC = 1 5 2 - 4 9 " 3 - 1 3 8 0 0 + 0.035(Co)2 in KSi/Tn 2 with R = 0.735 at 95% level of significance. The correlations at RT and -80°C suggest that in the transition tempera-ture region and upper shelf temperature region where the fracture pro-cesses involve ductile fracture the inclusion length plays a dominant role in the fracture process. The decrease of toughness with increasing inclusion length indicates that as the length of the inclusion increases, 160 160 « 120 - 8 0 ° C . c s 120 < JC » 80 u u 40 9 \ • J L 0 20 40 60 (b) C~0.fi. - I 9 6 ° C . -H60 -H20 ° 120 80 40 g T S L S £ A - A - C O N S • - O - C A T 80 (C) CO. fL Figure 5.2 Correlation of HT K J C - J j C fracture toughness data with average length (Co) of inclusions at (a) RT, (b) -80°C and (c) -196'°C 161 the joining of microvoids become easier and fracture can propagate easily along the length of the inclusions causing a lowering of the fracture toughness. The experimental data of the average inclusion length as obtained 95 in the present work is very close to the data reported by T. Ikeshima for line-pipe materials. Several a u t h o r s 1 1 - 1 7 ' 2 5 ' 1 7 5 - 1 7 7 reported a similar dependence of notch toughness on the size of inclusions. A.D. 15 Wilson reported that the J J C fracture toughness of A516-70 steel de-creases as the average length of inclusions increases. Baker and Charles 1 7 7 showed that as the total projected inclusion length per unit area in-creases, COD toughness decreases exponentially. G. Bernard et a l . 1 1 reported that the degree of anisotropy measured as the ratio of the longitudinal impact strength to the transverse impact strength increases as the projected inclusion length increases. This Co parameter is related to the elongation of silicate and sulphide inclusions on hot rolling of semi-killed steels. The CAT process limits the presence of long inclusions via de-sulphurization and inclusion shape control and thus leads to the improved toughness properties in these steels in all testing orientations. There-fore, it is apparent that as the inclusion length increases, void coalescence becomes easier; hence the fracture toughness of steel decreases. Figure 5.2(c) depicts the correlation between Kj^ and Co at -196°C. It reveals that the toughness values at this temperature do not depend upon the average length of inclusions. In the previous section 5.1.1, i t has already been shown that the inclusion content does not play any role in fracture processes occuring in the zero ductility 162 temperature region where brittle fracture takes place by the mechanism of cleavage. Figure 5.2(c) again consolidates the fact. 5.1.3 Correlation of Fracture Toughness with Inter-Inclusion Distance Figures 5.3(a), (b), and (c) depict the correlation of frac-ture toughness data with inter-inclusion distance (D) in HT condition. Figures 5.3(a) and (b) are both for RT data; Figure 5.3(b) shows the init ial portion of Figure 5.3(a) on an expanded D scale; Figure 5.3(c) shows the correlation at -80°C. The polynomial regression analysis applied to data in Figure 5.3(a) suggested that a second order polynomial with R = 0.857 at 95% level of significance best f i ts the curve and is given by the equation KIC " JIC = 8 5 - 5 6 9 + 0.0410D- 0.631 x 10~5 D2 in Ksi/Tn These figures reveal that as the inter-inclusion distance increases, the fracture toughness of the material increases. This dependence suggests a parabolic relationship between Kj C and D. In the ductile fracture pro-cesses, as the inter-inclusion distance increases, greater fraction of steel matrix must be traversed by a growing crack. Therefore, the number and lengths of voids available to aid crack propagation are reduced. As a result, the fracture toughness of a material increases to a considerable degree. The initiation of ductile fracture at the tip of a precrack has been 178 modelled by Rice and Johnson. This model predicts that fracture initiates at a ratio <S.j/X0 =0.5 for non hardening materials, where 6^  179 stands for COD and X f t is the spacing of inclusions. Clayton and Knott 163 160 I20h 5.3 - O -CON CAT HI60 -W20 b Correlation of HT K T C - J J C fracture toughness data with inter-inclusion spacing (D) at RT (a) CON and CAT steel data, (b) CON steel data 164 1000 (c) 2000 3000 4000 H / 2 0 • o 2 TS LS A-A - CON • - O - CAT -/96 W C. 1000 2000 3 0 0 0 4 0 0 0 (d) 'D' Figure 5.3 Correlation of HT Kj C - J j C fracture toughness data with inter-inclusion spacing (D) at (c) - 80°C and (d) -196°C 165 argued that a crack must blunt sufficiently for the logarithmic spiral slip-l ine f ield ahead of the blunted tip to envelope the void. They observed for low work hardening material, processes of crack growth takes place by shear decohesion along straight slip lines with 6./lQ< 0.5. For high work hardening material processes of crack growth occurs by void 165 coalescence with 6 i /X Q > 0.5. Knott compiled the COD values at initiation with non-metallic inclusion spacing as per Rice and Johnson's model and experimental values and observed a good agreement for steels with high work-hardening capacities. It was shown that parabolic relation exists with COD at initiation with inclusion spacing; that means, materials containing closely spaced inclusions exhibit low crack tip 1 fip> ductility. According to H. Anderson, the crit ical J-integral for crack initiation is J = 0.46 K . X o o where K = the shear yield stress and X = the inclusion spacing, o "I Of) Francois also established the influence of interparticle spacing on the COD 6^ toughness. He showed that the materials with widely spaced inclusions would possess enhanced COD toughness. The results of this study, did indicate similar effects. It may be noted that as the inclusion shape changes from elongated in CON steel to globular in CAT steel, the inter-inclusion spacing improves dramatically with the result that the fracture toughness of CAT steel is enhanced and shows very l i t t le dependence on D. Figure 5.3(d) shows the correlation of fracture toughness with 166 inclusion spacing at -196°C. This figure clearly demonstrates that at the brittle temperature region, the inter-inclusion distance does not have any effect on the fracture toughness of the material. 5.1.4 Correlation of Fracture Toughness with Aspect Ratio (FF) Figures 5.4(a) and (b) illustrate the correlation between fracture toughness and form factor (FF) or aspect ratio of inclusions in the HT condition. The polynomial regression analysis applied to data 2 in Figure 5.4(a) suggested that a second order polynomial with R = 0.696 at 95% S.L. best represents the data and is given by KIC " JIC = 1 4 9 - 6 0 4 ~ 9-991(FF) + 0.323(FF)2in KSi/Tn Figure 5.4(a) shows that the fracture toughness is affected by the aspect ratio of the non-metallic inclusions. An increase in the aspect ratio of the inclusion means that the length of the inclusion becomes extremely large with respect to the width of the inclusion. Therefore, as the aspect ratio increases, the inclusions get more stringered out along the rolling direction and thus the fracture toughness of the material decreases. This is equivalent to saying that as the average length of inclusions increases, the fracture toughness of the materials decrease. Figure 5.4(b) shows the dependence of fracture toughness on aspect ratio of inclusions at -80°C. Here also the trend is similar to that observed in Figure 5.4(a) for RT data. Figure 5.4(c) depicts the relation between fracture toughness and the aspect ratio of inclusions at -196°C. At this temperature, the fracture toughness does not depend on the stringering effect or the size of the inclusions. This is evident from the flat nature of the curve. 167 160 ~ 120 « 80 "5 I 40 • A R T i 1—i 1 r j i i I 1 L 160 to 120 °E o CL so (a) 4 8 12 16 20 24 F F -I96°C. v> 40 JC "3 I 20 1 1 1 1 1 T i I I L _ — L 40 20 TS LS A - A - CON • - O - CAT o a. 5 (C) 4 8 12 16 20 24 F F Figure 5.4 Correlation of HT K J C - J j C fracture toughness data with aspect ratio (FF) at (a) RT, (b) -80°C and .(c) -196°C 168 5.1.5 Correlation of Fracture Toughness with Number of Inclusions Per mm (N) Figures 5.5(a) and (b) illustrate the relationship between fracture toughness and the number of inclusions per mm at RT and -80°C respectively under HT condition. The data in Figure 5.5(a) as analysed by polynomial regression analysis are best fitted by a second order polynomial that is given by the following equation: K i c " J i c = 1 4 4 - 7 1 - ° - 1 7 4 N + 0 J 9 4 x 1 0 ~ 3 n 2 i n K S i / T n ~ 2 with R = 0.232 at 95% level of significance. The data points do not reveal any marked dependence of fracture tough-2 ness on the number of inclusions per mm . However, considering the CAT steel data i t may be noted that the fracture toughness increases with 2 decrease in number of inclusions per mm . The CAT steel possesses around 50-80 inclusions per mm , whereas CON semi-killed steel contains 2 more than 125 inclusions per mm . Therefore the CON steel, being a dirtier steel, provides more initiation sites per unit area for void nucleation. Hence the fracture toughness of CON steel is much inferior to CAT steel. The data at -196°C, Figure 5.5(c) illustrates that the fracture tough-ness of X-70 pipeline steel does not depend on inclusion density i r -respective of Ca-treatment for sulphide shape control. 5.2 Analysis of the incliisiOh Parameters Correlation matrices have been generated amongst the variables KIC " J I C A F ' D ' F f : a n d N "sing a triangular regression package and are shown in Table 5.1. 169 1 6 0 RT w 1 2 0 I 8 0 u 4 0 * ' 1 • 1 A A A A 1 1 6 0 1 2 0 °E o 0. - 1 8 0 c s 1 2 0 < 8 0 -»"* 1 V 4 0 m 4 0 u I 2 0 Figure 5.5 Correlation of HT - 0^ fracture toughness data with rt the number of inclusions per mm (N) at (a) RT, (b) -80°C and (c) -T96°C 170 Considering the correlation ^coefficient between the dependent vari-able Kj£ - J j C and other independent variables, AF, Co, D, FF and N at RT, i t may be noted that: a) Correlation between Kj C - and AF is best as revealed by the cor-relation coefficient (-0.8882) b) Worst correlation exists between Kj C - J j C and N c) Second best correlation exists between Kj^ - 0 a n d inter-inclusion distance D as revealed by the magnitude of the correlation co-efficient (0.8658). The worst correlation between Kj C - J j C and N could be due to the fact that the parameter N in the Quantimet analysis included all of the inclusions, i .e . , those less than 3 micron as well as greater than 3 micron in size. In the microstructural analysis, only inclusions of maximum sizes greater than 3 micron were considered. Therefore, this correlation suggested that not al l the inclusions per frame are participating in the ductile fracture process. According to Simpson and Wilson, 1 6 only the larger inclusions, those greater than 70 ym, influence the upper shelf energy and ductil ity, because of their decohesion or cracking that helps in the final separation. Therefore, the results of this present study support the later observation. 181 5.3 Regression Analysis Multiple regression analysis was used to define the fracture tough-ness of the X-70 steel at RT, -80°C and -196°C using the inclusion para-meters. 171 Table 5.1 Correlation Matrix Between K T r - J T r and inclusion Parameters Correlation Matrix KF AF Co D FF N KJ 1,0000 AF -0.8882 1.0000 Co -0.7468 0.6583 1.0000 D 0.8658 -0.6886 00.5033 1.0000 FF -0.5915 0.4427 -0.8784 -0.4502 1.0000 N -0.2537 -0.0003 -0.1950 -0.5248 -0.0603 1.0000 The equations of fracture toughness in terms of inclusion parameters for RT data is given by KIC' JIC = 1 3 9 -15 -'21.85 AF- 0.452 Co+ 0.00428 D +0.377 FF-0.019N with R2 = 0.962 at 95% S.L. Similarly, the equation of fracture toughness for -80°C data is given by K I C - J j C = 100.97 - 5.91 AF- 0.664 Co+ 0.0049 D +1.101 FF-0.0103N with R2 = 0.776 at 95% S.L. The equation of fracture toughness for -196°C data is given by KIC~°IC = 3 5 - 7 4 ~ ° - 4 3 AF - 0.168 Co - 0.0035 D + 0.311 FF - 0.0158 N with R2 = 0.231 at 95% S.L. 2 It may be noted that the R value diminishes as test temperature decreases from RT to -196°C. This indicates that the f i t is best in the fully ductile (RT) conditions, is poorer in the transition region and the 172 inclusion parameters have l i t t le effect on the low temperature brittle fracture condition. Forward stepwise regression analysis as well as the backward stepwise regression analysis discards the insignificant variables and considers the significant variables. Both these analyses have resulted in the following regression equation for fracture toughness (KJQ - J j C ) in terms of the most important inclusion parameters: 1. K I C - J I C = 127.58 - 27.36 AF + 0.00679 D Ksi/Tn at RT with R2 = 0.917 at 95% S.L. 2. K I C - J I C = 81.468 + 0.009 D KSi/irii at -80°C with R2 = 0.607 at 95% S.L. 3. K I C - J I C = 24.231± 2.266 Ksi/in" at -196°C with R2 = 0.0 at 95% S.L. The regression equations show that the AF and the inter-inclusion distance are the most important inclusion parameters in determining the elastic-plastic fracture toughness of the CON and CAT steels. The inclusion para-meters become less significant as the test temperature decreases and the fracture process changes from coalescence of voids to cleavage. Chapter 6 172a SUMMARY OF OBSERVED EFFECTS OF INCLUSION PARAMETERS ON DUCTILITY AND FRACTURE TOUGHNESS 6.1 Effect of Hot Rolling on the Inclusion Shape Change The major effect of increasing hot reduction on inclusion shape (consequently on inclusion parameters) is shown schematically in Figure 6.1. On the TS plane, the inclusion diameter, or length in T-direction remains essentially constant, while the thickness decreases with in-creasing percentage of reduction. On the LS plane, the length of inclusion increases with increas-ing percentage of reduction; the thickness of the inclusion in the S-direction decreases with increasing percentage of reduction such that at any percentage of reduction the thickness of inclusions in the LS plane are the same as that in the TS plane. 6.2 The Effect of Inclusion Shape on Tensile Ductility The influence of inclusions on ductile fracture of metals during 87 182 tensile testing is considered to consist of three steps: ' a) Decohesion of metal/inclusion interface or cracking of the inclusion to create a void at very low plastic strains. b) Growth of the void due to strain concentration with increasing plastic deformation. 172b Figure 6.1 Inclusion shape change with increasing hot reduction. 172c c) Final fracture of the ligaments between voids by either necking or localised shear. The f i rst two steps remain essentially unaltered in longitudinal and transverse tensile specimens; step (c) differs in two specimens de-pending upon the orientation of inclusions. There are several m o d e l s 1 6 4 ' 1 6 5 ' 1 7 9 ' 1 8 3 available that explain the final fracture of longitudinal specimens by the process of necking down of the ligaments. According to Baker and Charles, 1 7 7 in case of longitudinal tensile specimen where the long axis of the voids (inclusions) is aligned parallel to the tensile axis, the voids will grow until the remaining ligaments fai l by internal necking. The large plastic strain required for the internal necking process results in a high ductility. In contrast, when the plate steels are tested in transverse direction, the long axis of the voids (inclusions) is perpendicular to the testing direction, the voids grow only to a small amount before the remaining ligaments fai l by localised shear. The low plastic strains required for the shear instability to be initiated results in a low ductility. It is established that a lenticular void acts as a notch on a microscale. The stress concentration at the tip of the void when the principal stress axis is normal to the inclusion is much greater than that which exists at the side of the void when the principal stress axis is parallel to the rolling direction., The effective stress at the tip of a notch is enhanced by the notch geometry according to the Inglis relationship: 172d ^effective = l a applied Jah where a = half notch length p = radius of curvature at the tip of the notch Since in the case of the LS plane (transverse specimen)'a' is 64.39/2 = 32.19 ym compared to 'a' equal to 13.88/2 - 6.94 ym in the TS plane of 70% reduced material, the stress at the tip of LS plane inclusions is much higher than that in the TS plane inclusion. Thus the high local stress concentrations would promote the development of localised shear at smaller plastic strains and subsequently result in lower ductility for the transverse specimen. 184 McClintock has shown that the conditions for development of a shear band in the presence of one set of inclusion nucleated voids were governed by an inequality of the form e = true strain K = a constant F = a hole-growth factor f = volume fraction of inclusions Y = the aspect ratio of voids (h aspect ratio of inclusions). Thus, increasing the volume fraction or the aspect ratio of inclusions where a = true stress 172e increases the right hand side of the equation and makes development of a shear band easier, resulting in a lower ductility for a material with a given flow stress and work hardening rate. This model explains the smaller ductility values for transverse specimen. The fibrous fracture mechanism in the case of longitudinal specimens is shown schematically in,Figures 6.2(a), (b), (c), (d) and (e) and that of transverse specimens is shown schematically in Figures 6.3(a), (b), (c) and (d). It may be noted that the plastic deformation during the fracture process is confined to a very narrow region on each side of the fracture plane. 6.3 Effect of Inclusion Shape on Ductile Fracture Toughness The plastic zone size under plane strain condition in front of a 185 growing crack could be calculated using the relationship: In case of 70% reduced TL specimen, using the above relation, r y has been calculated and is foundto be - 6.83 mm; the average inclusion length (Co) and the inter-inclusion distance in the same TL specimen are 0.064 mm and 0.351 mm respectively. Hence, there will be approximately 16 inclusions per unit length of the crack front inside the plastic zone. In case of 70% reduced LT specimen, the plastic zone size is 9.49 mm, the average inclusion length (Co), 0.013 mm and the inter-inclusion distance (D), 0.559 mm. The number of inclusions inside the plastic zone per unit length of the crack front in this case will be 2 172f ^ TS plane (a) t I + 1 J + cr I i I I i i (b) Fracture plane failure of ligaments by internal necking cr t i I i (c) (d) (e) Figure 6.2 Schematic illustration of micro-mechanical model for inclusion initiated fracture in a longitudinal tensile specimen. 172g IRD LS plane \ (a) t t Fracture plane 1 1 t (b) failure of ligaments by localised shear (c) 1 1 (d) Figure 6.3 Schematic illustration of micro-mechanical model for inclusion initiated fracture in a transverse tensile specimen. 172h approximately 16. These inclusions do form voids by a decohesion process at the metal/inclusion interface and void sizes grow with increasing plastic strain. An increase in the inclusion parameters such as area fraction (AF), average inclusion length (Co), aspect ratio (FF) and density of inclusions. (N) per unit area of fracture plane has been observed to be associated with a decrease in the fracture toughness of the speci-men. An increase in the inter-inclusion distance in the fracture plane increases the fracture toughness of the material. This means that when the inclusions are elongated along the crack path, the longer the inclusion, the smaller will be the fracture toughness or the load to extend the fracture. Similarly, an increase in the area fraction in the crack path reduces the length of the steel matrix through which the crack must propagate, thereby reducing the fracture toughness of the material. The smaller is the inter-inclusion distance along the crack path, the smaller will be the steel matrix path and therefore, the lower will be the fracture toughness of the steel. However, the "fracture" of inclusion alone, either at the matrix interface or of the particle cannot account for the fracture toughness of the material in any of the TL and LT orientations. This point will be clear from the following example. The fracture energy of a speci-men can be expressed in terms of inclusion parameters by the relation: ^specimen ~ "^inclusion + Gsteel without inclusion where a = fractional area of inclusions G = fracture energy in crack plane per unit area of crack plane. 1721 In case of 70% reduced material at RT, Area fraction a = 0.03086 TL specimen fracture toughness = 90.10 KSi/irT Fracture toughness without inclusion = 150.00 KSi/Tn 2 Now, using the relationship G = ^JX (1-v2), the fracture energy can E be calculated and was found to be G specimen with inclusion = 246.24 lbf G steel without inclusion = 682.50 lbf Now, 246.24 = 0.01086 x G i n c l u s i o n + 0.989 x 682.50 • ' • inclusion = " y e v a l u e Assuming G 1 n c l u s 1 o n =0, 246.24 = 682.50 (1-a) a = 0.639 The value of a is found to be extremely large. This indicates that to account for the decrease in fracture toughness due to increasing area fraction of inclusion, the value of a has to be of the order of 58.83 times greater than the observed area fraction of the inclusions which seems to be quite absurd. Therefore, the increase in inclusion para-meters like AF, Co, FF and N alone cannot account for the decrease in fracture energy (G) for the specimen. Thus, the inclusion parameters indirectly affect the fibrous fracture processes, particularly those processes that take place in the inter-inclusion segment or the ligament 172j region of the steel matrix. In the previous section, it was pointed out that the stress value at the tip of the elongated inclusions in the LS plane will be much higher than that at the width of the inclusion in the TS plane. Thus, the high local stress concentrations would promote the failure of the ligament by localised shear mechanism at smaller plastic strain and thus would result in lower fracture tough-ness for the TL specimen. On the other hand, the small local stress concentration at the TS plane inclusions would slowly promote the failure of the ligament by internal necking at much higher plastic strain values and would thus result in higher fracture toughness of LT specimen in a hot rolled material. 6.4 Brittle Fracture The plastic zone is very small or negligible for the fracture data obtained at -196°C. For this reason, the separation at the inclusion/ matrix interface in the form of microvoids does not occur ahead of the advancing crack. Thus the crack advances at a toughness level which is controlled by the elastic properties of the material. 173 Chapter 7 CONCLUSIONS 7.1 Conclusions The following thesis conclusions are in agreement with already . published research: 1. The semi-killed X-70 CON pipeline steels possess elongated in-clusions which mainly consists of silicates (Fe,Mn)0.8i02 and Type I MnS. The fully-kil led calcium treated (CAT) X-70 pipeline steels contain globular inclusions of CaO.Al^O^ calcium-aluminate in the central part with (Ca,Mn)S and A^O^ in the periphery. 2. Inclusions of CON steel undergo stringering as a consequence of hot roll ing; whereas the inclusions in the CAT steel do not undergo any plastic deformation during hot roll ing; their shape and size remain unaltered. 3. The measured inclusion parameters, AF, Co, D, FF and N do not affect the yield strength properties of the X-70 steel over the test temperature range. 4. The semi-killed CON steel possesses higher tensile ductility in the longitudinal test direction than in the transverse test direction. 5. The effect of the inclusion parameters, Af, Co and D on fracture toughness agrees with those effects reported for the impact 174 toughness of the steel. 6. At 97% hot deformation, the silicate inclusions undergo fragmenta-tion. The following conclusions are unique to this study and help to clarify the role of inclusion shape, size and distribution on ductile and brittle fracture in X-70 pipeline steel. 1. Up to 88% hot reduction, the MnS phase in the CON steel inclusions does not undergo any significant plastic deformation compared to that of the silicate phase. From 88% hot reduction to 97% hot reduction, the inclusions break down into small fragments by fracture of the silicates and stringering of the MnS phase; but the effective inclusion length decreases. 2. In the CON steel, with increasing percentage of hot deformation, the inclusion length increases, the width remains unaffected and the thickness of the inclusions gradually decreases. The thickness of inclusions in the LS plane are the same as that in the TS plane. 3. The CAT steel possesses isotropic ductility i.e. true strain to fracture properties. 4. The inclusion parameters which affect the elastic plastic fracture toughness properties of the CON steel are area fraction (AF), inclusion length (Co), inter-inclusion distance (D), the aspect ratio (FF) and the density of distribution (N). The most impor-tant parameters are AF and D. 175 The semi-killed CON steel containing elongated inclusions shows anisotropy in elastic-plastic fracture toughness; whereas the CAT steels with globular inclusions possess isotropic elastic-plastic fracture toughness properties. CAT steel possesses much higher toughness properties than CON steel at any temperature of testing. The inclusion parameters AF and D markedly affect the elastic-plastic fracture toughness properties of the X-70 steel, particu-larly in the ductile and transition temperature region where ductile fracture mechanisms operate. The inclusion parameters have insignificant effect on the fracture toughness properties of the X-70 steel in the brittle temperature region. The experimental data at -196°C shows clearly that the inclusion size, shape and density do not influence the cleavage mechanism of fracture. The regression analysis of the data established that the greatest inclusion effects are present when the steel fai ls by elastic-plastic fracture processes in the fully ductile zone whereas in the ductile-brittle transition region, the influence of the inclusions is reduced and in the brittle temperature region, their effect is negligible. A second order polynomial regression analysis relating the RT K T r - J T r fracture toughness data to the independent inclusion 1 7 6 2 parameters gives rise to a relationship with the following R values. Relation It IC - J I C with A F 0 . 9 3 3 IC - Jj£ with Co 0 . 7 3 5 IC - J I C with D 0 . 8 5 7 IC - J J Q with F F 0 . 6 9 2 IC - J j C with N 0 . 2 3 2 It is apparent that the inclusion parameters which influence the elastic-plastic fracture toughness of the X - 7 0 pipeline steel, in order of significance are the area fraction (AF), the inter-inclusion distance (D), the inclusion length (Co), the aspect ratio or form factor (FF) and the inclusion density (N). 11. The elastic-plastic fracture toughness of the CON and CAT steel can be combined and examined in terms of specific inclusion para-meters. In particular, the AF and D variation of the inclusions can be used to explain the observed elastic-plastic fracture toughness of the two steels. 7 . 2 Suggestions for the Future Work 1. The use of a computer with a data acquisition system and a graphics terminal would be advantageous for reducing and plot-ting the data to determine the JJQ elastic-plastic fracture toughness by the single specimen technique that utilizes the unloading compliance method. It would be worthwhile to investigate the effect of inclusion parameters on a) the through thickness ductil ity, b) elastic-plastic fracture toughness in the LS orientation, and c) the fatigue crack propagation in different orientations. A study on the tessellated stress that arises from the dif-ferences in thermal contraction between the inclusion and the steel and its effect on the elastic-plastic fracture toughness properties of the X-70 CON and CAT steel could also be con-sidered. 1 7 8 BIBLIOGRAPHY 1. Edelson, B.J. and Baldwin, W.M.: Trans ASM, v.55, 1962, pp. 230-250. 2. Gurland, J . and Plateau, J . : Trans ASM, v.56, 1963, pp. 442-454. 3. 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E. : International Metals Reviews, 1978, No.2, pp.876-888. 101. Sponseller, D. L. and Flinn, R. A.: Trans. AIME, v.230, 1964, pp. 876-888. 102. Salter, W. J . M. and Pickering, F. B.: JISI, July 1969, pp. 992-1002. 184 103. Hilty, D. C. and Popp, V. T.: AIME Electric Furnace Steel Conf. P r o c , 1969, v.27, pp. 52-66. 104. Hacket, F. C. and Mclver, J . : ibid, v.29, 1971, pp. 117-121. 105. Dunn, E. J . J r . : ibid, v.29, 1971, pp. 122-127. 106. Ototani, T. and Kataura, Y.: Trans. ISIJ, v.12, 1972, pp. 334-342. 107. Hilty, D. C. and Farrel, J . W.: 13th Annual Conf. of Metal-lurgists, Toronto, Aug. 27, 1974, pp. 1-15. 108. Saxena, S. K., Engh. T. and Pednekar, S.: Scand. J . of Metal-lurgy, v.4, 1975, pp. 42-48. 109. de Barbadillo, J . J . : "Sulphide Inclusions in Steel", ASM Pub., 1975, pp. 70-99. 110. Hilty, D. C. and Farrel, J . W.: Iron and Steelmaker, v.2, No.5, 1975, pp. 17-22. 111. Hilty, D. C. and Farrel, J . W.: ibid, v.2, No.6, 1975, pp. 20-27. 112. Ototani, T . , Kataura, Y. and Degawa, T.: Trans. ISIJ, v.16, 1976, pp. 275-282. 113. Saxena, S. K. and Engh, T.A.: Scand. J . of Metallurgy, v.5, 1976, pp. 105-112. 114. Farrel, J . W. and Hilty, D. C : Iron and Steelmaker, August 1976, pp. 17-23. 115. Nashiwa, H., Mori, A . , Ura, S . , Ikeda, T . , Matsuno, H. and Ishikawa, R.: Special Report, Iron and Steel Institute of Japan, 6th Japan-USSR Joint Symp. Phys. Chem. Metal!. Processes, 1977, pp. 81-94. 116. Gammal, T. El and Kroker, M.: 61st National Open Hearth and Basic Oxygen Steel Cont., Chicago, AIME, 16-20 Apri l , 1978, pp. 546-554. 117. Saxena, S. K., Engh. T.A. and Tveit, H.: ibid, pp. 561-573. 118. Gammal, T. E l : Radex-Rundschau, 1981, Heft 1/2, pp. 380-390. 119. Holappa, L.: Swedish Symp. on "Non-metallic Inclusions in Steel", URF and SIMR, 27-29 April 1981, pp. 19-34. 120. Gustafsson, S. and Mellberg, P. 0.: ibid, pp. 35-68. 185 121. Saxena, S. K.: ibid, pp. 69-90. 122. Mihelich, J . L. , Bel l , J . R. and Korchynsky, M.: JISI, June 1971, pp. 469-475. 123. Pollard, B.: Metals Technology, July 1974, pp. 343-347. 124. Meyer, L. , Heisterkamp, F. and Lauterborn, D.: "Processing and Properties of Low Carbon Steel", TMS-AIME, 1973, pp. 297-330. 125. Wilson, W. G.: Welding Research Supplement, January 1971, pp.425-465. 126. Wilson, W. G. and Wells, R. G.: Metal Progress, December 1973, pp. 75-77. 127. Wilson, W. G.: AIME Electric Furnace Steel Conf. P r o c , 1973, v.31, pp. 154-161. 128. LuyckxL.S Jackman, J . R.: AIME Electric Furnace Steel Conf. P roc , 1973, v.31, pp.175-181. 129. McLean, A. and Kay, D. A. R.: "Microalloying 75", P r o c , Washington, D . C , ASM Pub., 1975, pp. 215-230. 130. MacDonald, J . K.: ibid, pp. 359-366. 131. Ishiguro, M., Ito, M. and Osuga, T. : Trans. ISIJ, v.16, 1976, pp. 359-367. 132. Dahl, W., Gamma!, T. El and Schulze, W.: Arch. Eisenhuttenwes, 53, No. 1, 1982, pp. 5-12. 133. Paul, S. K., Chakrabarty, A. K. and Basu, S.: Met. Trans., V.13B, June 1982, pp.185-192. 136 Pircher, H. and Klapdar W.: "Microalloying 75", P r o c , Washington, D. C , ASM Pub., lo75, pp. 232-240. 137 Taeffner, K. D., Georges, G. , Haneke, M.A. and Rocknagel: ibid, pp. 425-434. 134. Jager, H. and Holzgruber, W.: Proc. Intl. Symp. Chem. Metallurgy of Iron and Steel, Sheffield, July 1971,pp. 198-201. 135. ster, E . , Klapdar, tzler E . , Wendorff 186 138. Uemura, T . , Nashiwa, H., Ikeda, T . , Mori, A. and Tokuda, M.: AIME Proc. Open Hearth Comm., v.59, 1976, pp. 457-478. 139. Clayton, J . Q. and Knott, J . F.: The J . of Australian Institute of Metals, v.22, No.2, June 1977, pp. 132-138. 140. Bremen, H.: Stahl U. Eisen, 97, No.10, 1977, pp.477-486. 141. Emi, T . , Haida, 0., Sakuraya, T. and Sanbongi, K.: Tetsu-to-Hagane, 64(10), 1978, pp. 1538-1547. 142. Wilson, A. D.: "Elastic Plastic Fracture", ASTM, STP668, American Society for Testing and Materials, 1979, pp. 469-492. 143. Wilson, A. D.: Lukens Steel Co., RDR-79-16, November 1979, pp. 1-15. 144. David, M., Jeanneau, M., Poupon, M. and Senaneuch, D.: Scaninject II - 2nd Intl. Conf. on Injection Metallurgy, Lulea, Sweden, June 12-13, 1980, pp. 25:1-25:17. 145. Haastert, H., Maas, H. and Richter, H.: ibid, pp.26:1-26:13. 146. Wilson, A. D.: Metal Progress, April 1982, pp. 41-46. 147. Saxena, S. K.: Ironmaking and Steelmaking, v.9, No.2, 1982, pp. 50-57. 148. Quantimet 720, operation manual. 149. Gladman, T.: Inclusion, F. B. Pickering, The Institution of Metallurgists, Monograph No. 3, London, 1979, pp. 157-171. 150. Mechanical Testing: Metals Handbook, ASM, 1948, p.85. 151. Standard Methods of Tension Testing of Metallic Materials: ANSI/ASTM E8-77a, p. 154. 152. Maiti, R.: M.A.Sc. Thesis, University of British Columbia, December 1978. 153. Landes, J . D. and Begley, J . A. : ASTM STP 632, "Developments in Fracture Mechanics Test Methods Standardisation", American Society for Testing and Materials, 1977, pp. 57-81. 154. Landes, J . D. and Begley, J . A. : Post-Yield Fracture Mechanics, Ed. D. G. H. Latzko, Applied Sc. , London, 1979, pp. 211-253. 155. Clarke, G. A. and Landes, J . D.: "Toughness Characterisation and Specifications for HSLA and Structural Steels", TMS-AIME Symp., Atlanta, Georgia, March 6-10, 1977, pp. 79-111. 187 156. Joyce, J . A. and Gudas, J . P.: Elastic-Plastic Fracture, ASTM STP 668, American Society for Testing and Materials, 1979, pp. 451-468. 157. Robinson, J . N. and Tetelman, A.S. : Fracture Toughness and Slow Stable Cracking, ASTM STP 559, American Society for Testing and Materials, 1974, p.139. 158. Wessel, E. T. : LEFM for Thick Walled Welded Steel Pressure Vessels; Mateials Property Considerations. 'Practical Fracture Mechanics for Structural Steel' - 1969, Ukaea, Risley. 159. Barson, J . M. and Rolfe, S. T.: Engg. Fracture Mechanics, v . l , 1971, pp. 341. 160. Erikson, K.: Scand. J . of Metallurgy, v.4, 1975, pp. 131-139. 161. Tetelman, A. S. and McEvily, J . J r . : Fracture of Structural Materials, Wiley & Sons, 1967, p. 316. 162. Dieter, G. E. : Mechanical Metallurgy, McGraw H i l l , 1976, p.374. 163. Kozasu, I. and Kubota, H.: Trans. ISIJ, v.11, 1971, pp. 321-330. 164. Kozasu, I., Shimizu, T. and Kubota, H.: Trans. ISIJ, v.13, 1973, pp. 20-28. 165. Knott, J . F.: Metal Sc. , 14, 1980, pp. 327-336. 166. Hertzberg, R. W.: Deformation and Fracture Mechanics of Engineer-ing Materials, John Wiley & Sons, 1976, p.243. 167. Knott, J . F.: Fundamentals of Fracture Mechanics, Butterworths, London, 1979, p. 204. 168. Lagneborg, R.: Swedish Symp. on 'Non-metallic Inclusions in Steel ' , URF and SIMR, 27-29 Apri l , 1981, pp. 285-352. 169. Hodge, J . M., Frazier, R. H. and Boulger, F. W.: Trans. AIME, v.215, 1959, pp. 745-753. 170. Birkle, A. J . , Wei, R. P. &PellissierjG.E.:Trans. ASM, 59, 1966, pp. 981-990. 171. Evans, P. R., Wilkins, M. A. and Owen, N. B.: JISI, March 1972, pp. 200-202. 172. Lagneborg, R.: Intl. Conf. on Injection Metallurgy, Lulea, Sweden, 1977, pp. 1:1-1:15. 188 173. Hahn, G. T. and Rosenfield, A. R.: Intl. Congress on Fracture, Munich 8-13 Apri l , 1973, paper PL 111-211. 174. Curry, D. A.: Metal Sc. , v.14, No. 8 and 9, August - September, 1980, pp. 319-326. 175. Lowes, J . M.: Inst, of Metallurgists Spring Meeting, Younger Met'Is Comm., Newcastle-upon-Tyne, March 1973, pp. 41-53. 176. Hood, J . E. and Jamieson, R. M.: JISI, May 1973, pp. 369-373. 177. Baker, T. J . and Charles, J . A.: The Effect of Second Phase Particles on the Mechanical Properties of Steel, ISI Pub., London, 1971, pp. 79-87. 178. Rice, J . R. and Johnson, M. F.: Inelastic Behaviour of Solids, Ed. M. F. Kanninen et a l . , McGraw H i l l , New York, 1970, p. 641. 179. Clayton, J . Q. and Knott, J . F . : Metal Sc. , February 1976, pp. 63-71. 180. Francois, D.: Mec. Mat. Electr. , February 1978, (338), pp. 71-78. 181. UBC TRP, Triangular Regression Package Computing Centre, UBC, October 1978, p.109. 182. Speich, G. R. and Spitzig, W. A.: Met. Trans. V.13A December, 1982, pp. 2239-2258. 183. Widgery, D. J . and Knott, J . F.: Metals Sc. , January, 1978, pp. 8-11. 184. McClintock, F.A.: Ductility, ASM, Metals Park, OH, 1968, pp.255-278. 185. Rolfe, S. T. and Barsom, J . M.: Fracture and Fatigue Control in Structures, Prentice Hall Inc., Englewood Cl i f fs , New Jersey, 1977, p.61. 189 APPENDIX I - The FORTRAN Program, Modified Inclusion Rating (MIR) for  Inclusion Analysis From Quantimet Data •C THIS PROGRAM PERFORMES INCLUSION RATING USING DATA FROM QUANTIMET 720. C IT CALCULATES AVERAGE AREA FRACTION,AVERAGE PARTICLE SI2E,INTERPARTICLE C DISTANCE,FORM FACTOR,NO OF PARTICLES PER MILLIMETER SQUARE C J-NO OF FIELDS OF VIEW C A-AREA OF INCLUSIONS,PPS C AL=AREA OF LIVE FRAME,PPS C PH-HORIZONTAL INTERCEPTS,PPS C PV-VERTICAL INTERCEPTS,PPS C NFF-NO OF PARTICLES IN AL C AF-AREA FRACTION IN PERCENT C CO-AVERAGE PARTICLE LENGTH,MICRON C C=AVERAGE PARTICLE WIDTH,MICRON C D=INTERPARTICLE DISTANCE,MICRON C FF-FORM FACTOR C N-NO OF PARTICLES PER MILLIMETER SQUARE DIMENSION CODE(50,6),A(50),PH(50),PV(50),NFF(50),AF(50),CO(50) DIMENSION C(50),E(50),D(50),FF(50),N(50),AVE(6),STAN(6) REAL MN(6,50) READ(5,1)J 1 FORMAT(13) DO 10 1-1,J READ(5,39)(CODE(I,K),K=1,6),A(I),PH(1),PV<I),NFF(I) 39 FORMAT(5X,6A1,5X,F8.0,5X,F5.0,5X,F5.0,5X,13) C AL IS COMPOSED OF 750 HORIZONTAL PPS & 600 VERTICAL PPS AL=750.*600. AF(I)=(A(I)*100.)/AL CO(I)-(A(I)*0.26)/PV(I) C(I)=(A(I)*0.26)/PH(I) D(I)-(AL-A(I))/PH(I) FF(I)-PH(I)/PV(I) N(I)=32.873*NFF(I) 10 CONTINUE DO 21 M-1 ,6 AVE(M)»0.0 21 STAN(M)-0.0 DO 25 M-1,6 GOTO (11,12,13,14,IS,16),M 11 DO 30 NO-1,J 30 MN(M,NO)-AF(NO) GO TO 18 12 DO 31 NO=1,J 31 MN(M,NO)«CO(NO) GO TO 18 13 DO 32 NO-1,J 32 MN(M,NO)»C(NO) GO TO 18 14 DO 33 NO-1.J 33 MN(M,NO)-D(NO) GO TO IB 15 DO 34 NO-1,J 34 MN(M,NO)»FF(NO) GO TO 18 16 DO 35 NO«1,J 35 MN(M,NO)»N(NO) GO TO 18 18 SUM-0.0 DO 37 MO»1,J SUM«SUM+MN(M,MO) 37 CONTINUE AVE(M)-SUM/J SUMS-0.0 DO 38 MP-1,J SUMS=SUMS+((ABS(MN(M,MP)-AVE(M)))**2.0) 38 CONTINUE SUMS-SUMS/J STAN(M)«SUMS**0.5 25 CONTINUE WRITE(6 41) 41 FORMAT(M',2X,'CODE',6X,'AF\7X,'CO',BX,'C\9X,'D',7X,'FF',6X,'N') WRITE(6,42) 42 FORMAT(2OX,'MICRON',4X,'MICRON',4X,'MICRON ) DO 43 1-1,J WRITE(6,44)(CODE(I,K),K-1,6),AF(I),CO(I),C(I),D(I),FF(I),N(I) 43 CONTINUE 44 FORMAT(2X,6A1,2X,F6.3,4X,F6.3,4X,F6.3,4X,F6.0,2X,F6.3,2X,I4) WRITE(6,45)(AVE(I),STAN(I),I-1,6) 45 FORMAT(10X,F8.3,10X,F8.3) STOP END APPENDIX II Table 2.21 Quantimet Data for S2 LT Plane SI.No. A PH v Nff S2LT01 3431 0 106.0 62.0 2 S2LT02 6019 0 206.0 116.0 3 S2LT03 3218 0 121.0 85.0 2 S2LT04 4774 0 217.0 106.0 3 S2LT05 1989 0 101 .0 78.0 3 52LT06 2399 0 102.0 91 .0 4 S2LT07 13432 0 231 .0 140.0 3 S2LT08 4105 0 264.0 235.0 12 S2LT09 4174 0 123.0 86 .0 4 S2LT10 11530 0 214.0 112.0 3 S2LT11 3975 0 125.0 49.0 1 S2LT12 18114 0 297 .0 174 .0 1 S2LT13 5052 0 183 .0 152 .0 1 S2LT14 24600 0 346.0 149.0 2 S2LT15 19001 0 369.0 215.0 2 S2LT16 10715 0 195.0 123.0 1 S2LT17 4811 0 194.0 82.0 2 S2LT18 3570 0 319.0 248.0 20 S2LT19 7413 0 604.0 500.0 64 S2LT20 2870 0 192.0 75.0 2 S2LT21 16840 0 560.0 491 .0 20 S2LT22 7285 0 219.0 127.0 4 S2LT23 6199 0 117.0 73.0 1 S2LT24 9857 0 393.0 233.0 5 S2LT25 5963 0 220.0 124.0 3 S2LT26 3829 0 144.0 93.0 3 S2LT27 3844 0 135.0 69.0 3 S2LT28 4046 0 111.0 60.0 2 S2LT29 2540 0 108.0 81 .0 3 S2LT30 6091 0 139.0 104.0 1 S2LT31 6871 0 175.0 110.0 1 S2LT32 2755 0 185.0 100.0 4 S2LT33 7400 0 192.0 98.0 1 S2LT34 3848 0 165.0 96.0 • 3 52LT35 3014 0 129.0 79.0 2 S2LT36 3783 0 173.0 133.0 4 S2LT37 6347 0 111.0 79.0 1 S2LT38 5854 0 266.0 176.0 5 S2LT39 23515 0 389.0 217.0 3 S2LT40 7642 o 302.0 173.0 5 S2LT41 2425 0 126.0 72.0 4 S2LT42 6911 0 181 .0 164.0 3 S2LT43 5806 0 175.0 114.0 2 S2LT44 3218 0 121 .0 85.0 2 S2LT45 1883 0 96.0 52.0 2 S2LT46 4756 0 200.0 138.0 5 S2LT47 4796 .0 156.0 103.0 3 S2LT48 10680 0 178.0 96.0 1 S2LT49 . 8110 .0 191.0 112.0 3 S2LT50 6451 .0 250.0 141 .O 4 APPENDIX II Table 2.22 Quantimet Data for S2 TS Plane Sl:No. A P V . N f f S2TS01 4199 .0 1 14.0 70.0 2 S2TS02 3119 .0 163.0 120.0 6 S2TS03 3054 .0 145.0 98.0 4 S2TS04 3256 .0 116.0 91 .0 5 S2TS05 1354 O 115.0 71 .O 5 S2TS0G 2569 0 117.0 98.0 3 S2TS07 3518 0 174.0 124.0 5 S2TS08 1709 0 153.0 104.0 9 S2TS09 2619 .0 186.0 130.0 6 S2TS10 3004 .0 228 .0 165.0 9 S2TS11 2366 .0 113.0 66.0 2 S2TS12 2326 .0 163.0 107.0 6 S2TS13 2230 .0 234.0 142 .0 12 S2TS14 2551 .0 175.0 102.0 6 S2TS15 6581 .0 377.0 260.0 12 S2TS16 6058 .0 206.0 107.0 4 S2TS17 3175 .0 150.0 107.0 4 S2TS18 2442 0 158.0 113.0 6 S2TS19 4260 .0 330.0 170.0 13 S2TS20 3919 0 194.0 95.0 4 S2TS21 1817 .0 130.0 86.0 7 S2TS22 2352 0 179.0 126.0 8 S2TS23 3788 0 183.0 102.0 4 S2TS24 4219 0 266.0 208.0 1 1 S2TS25 3457 o 270.0 150.0 13 S2TS26 5928 0 272 .0 150.0 9 S2TS27 3017 0 215.0 186.0 8 S2TS28 2882 0 228.0 170.0 12 S2TS29 6838 0 263.0 241 .0 4 S2TS30 4039 0 221 .0 1 19.0 5 S2TS31 10526 0 247.0 133.0 5 S2TS32 6329 0 216.0 137.0 4 S2TS33 19555 0 370.0 238.0 4 S2TS34 3752 0 352.0 209.0 16 S2TS35 4102 0 289.0 200.0 14 S2TS36 1102 0 127.0 85.0 6 S2TS37 1580 0 153.0 140.0 9 S2TS38 14803 0 468.0 219.0 16 S2TS39 401 0 28.0 25.0 2 S2TS40 5197 0 241 .0 145.0 10 S2TS41 2814 0 123.0 90.0 4 S2TS42 2166 0 246.0 175.0 18 S2TS43 2150 0 188.0 133.0 9 S2TS44 1212 0 147.0 140.0 19 S2TS45 6860 0 139.0 88.0 2 S2TS46 4912 0 261 .0 179.0 7 S2TS47 2117 0 130.0 85.0 3 S2TS48 11360 0 280.0 186.0 4 S2TS49 3560 0 438.0 430.0 67 S2TS50 3807 0 141 .0 99.0 5 APPENDIX II Table 2.23 Quantimet Data for $2 LS Plane SI.No. A PH p v S2LS01 10939 0 319 0 157.0 7 S2LS02 2173. 0 106 0 50.0 4 S2LS03 7710 O 308 0 258 .0 7 S2LS04 6493 0 195 0 89.0 3 S2LS05 13004 0 328 0 142.0 2 S2LS06 4408 0 227 0 67 .0 2 52LS07 4891 0 199 0 89.0 2 S2LS08 2564 0 192 0 143.0 6 S2LS09 2595 0 150 0 67.0 3 S2LS10 51274 0 605 0 291 .0 1 S2LS1 1 10774 0 372 0 175.0 3 S2LS12 3482 0 220 0 163 .0 5 52LS13 3135 0 183 0 108.0 3 S2LS14 17965 0 377. 0 151.0 2 S2LS15 8350 0 219 0 89.0 2 S2LS16 4561 0 332 0 154.0 7 S2LS17 5124 0 301 0 160.0 9 S2LS18 2475 0 259 0 156.0 9 S2LS19 5670 0 358 0 156.0 11 S2L520 4749 0 349 0 138.0 6 S2LS21 6209 0 195 0 54.0 1 S2LS22 12095 0 496 0 201 .0 5 S2LS23 3763 0 326 0 161 .0 8 S2LS24 4413 0 286 0 121 .0 7 S2LS25 10582 0 284 0 100.0 3 S2LS26 2424 0 193 0 110.0 5 S2LS27 6906 0 346 0 186.0 10 S2LS28 5035 0 310 .0 152.0 6 S2LS29 6549 0 309 .0 227.0 6 S2LS30 14333 .0 397 .0 201 .0 5 S2LS31 7462 .o 293 .0 100.0 2 S2LS32 13699 .o 662 .0 309.0 7 S2LS33 7603 .0 263 .0 113.0 1 S2LS34 4467 .0 158 .0 50.0 1 S2LS35 14326 .0 303 .0 146.0 2 S2LS36 1814 .0 107 .0 65.0 2 S2LS37 4745 .0 177 .0 59.0 1 S2LS38 4759 .0 177 .0 45.0 1 S2LS39 2106 .0 145 .0 58.0 4 S2LS40 1970 .o 79 .0 45.0 1 S2LS41 2390 .0 216 .0 135.0 10 S2LS42 97B2 .0 333 .0 224.0 5 S2LS43 4772 .0 155 .0 81 .0 1 S2LS44 8018 .0 181 .0 73.0 1 S2LS45 2222 .0 128 .0 76.0 2 S2LS46 4631 .0 193 .0 73.0 2 S2LS47 3217 .o 190 .0 83.0 3 S2LS48 10238 .0 399 .0 196.0 3 S2LS49 2968 .0 114 .0 47.0 1 S2LS50 3048 .0 134 .0 42.0 1 Table 2.31 APPENDIX II Quantimet Data for S3 LT Plane SI.No. S3LT01 S3LT02 S3LT03 S3LT04 S3LT05 S3LT06 S3LT07 S3LT08 S3LT09 S3LT10 S3LT11 S3LT12 S3LT13 S3LT14 S3LT15 S3LT1G S3LT17 S3LT18 S3LT19 S2LT20 S3LT21 S3LT22 S3LT23 S3LT24 S3LT25 S3LT26 S3LT27 S3LT28 S3LT29 S3LT30 S3LT31 53LT32 S3LT33 S3LT34 S3LT35 S3LT36 S3LT37 S3LT38 S3LT39 S3LT40 S3LT41 S3LT42 S3LT43 S3LT44 S3LT45 S3LT46 S3LT47 S3LT48 S3LT49 S3LT50 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 3022.0 4584.0 3591 20228. 2831 2757. 4301 2468. 2348. 3732 .0 984.0 4159. 3604. 5014. 25652 8058.0 4424 .0 9998.0 3679.0 3489.0 42037.0 2593.0 886.0 5208.0 6218.0 1742.0 2007.0 2531 .0 4088.0 8368.0 5820.0 5879.0 11278.0 14304.0 8591.0 11001.0 3477.0 4479.0 3449.0 5388.0 5605.0 11287.0 8446.0 7217.0 1775.0 5679.0 2945.O 8353.0 4742.0 15892.0 158 .0 320.0 265 .0 571 .0 141 .0 222 .0 215.0 141 .0 142.0 201 .0 58 .0 166 .0 202.0 214.0 854.0 234.0 269.0 584 .0 168.0 152.0 663.0 206.0 63.0 250.0 344 .0 107.0 165.0 178.0 263.0 553.0 230.0 258.0 355.0 422.0 320.0 266.0 212.0 149.0 249.0 312.0 118.0 644.0 548.0 249.0 188.0 271 .0 248.0 235.0 275.0 389.0 84 .0 186.0 164.0 170.0 81.0 81 .0 130.0 77.0 60.0 119.0 32 .0 100.0 142.0 166.0 438.0 114.0 187.0 333.0 139.0 117.0 368.0 96.0 44.0 196.0 259.0 93.0 110.0 146.0 186.0 438.0 129.0 112.0 261 .0 229.0 226.0 188.0 133.0 71 .O 135.0 157.0 72.0 546.0 444.0 116.0 76.0 103.0 115.0 127.0 157.0 196.0 5 11 12 4 2 8 8 5 5 7 4 6 10 10 46 3 10 12 11 7 16 5 2 8 16 7 7 13 21 31 3 7 15 10 1 10 12 1 12 5 2 30 32 5 5 2 4 3 3 4 APPENDIX II Table 2.32 Quantimet Data for S3 TS Plane SI.No. A PH v N f f S3TS01 921 .0 95. 0 74 .0 6 S3TS02 5972 .0 514 . 0 222.0 16 S3TS03 7826 .0 409 . 0 203 .0 19 S3TS04 9424.0 407. 0 257 .0 18 S3TS05 2888.0 199. 0 118.0 8 S3TS06 5454 .0 290. 0 179.0 18 S3TS07 2113.0 1 10. 0 99 .0 4 S3TS08 2359.0 252. 0 147 .0 14 S3TS09 2552.0 190. 0 150.0 14 S3TS10 3586.0 222. 0 173.0 1 1 S3TS1 1 2308.0 211. 0 97 .0 6 S3TS12 1496 .0 1 18 0 84 .0 7 S3TS13 1792 .0 123 0 120.0 8 S3TS14 2510.0 174 0 131.0 8 S3TS15 2844 .0 181 0 108.0 7 S3TS16 11212.0 422 0 118.0 9 S3TS17 4097.0 460 0 199.0 23 S3TS18 2358 .0 208 0 110.0 10 S3TS19 3737.0 313 0 148.0 13 S3TS20 2413 .0 159 0 124.0 16 S3TS21 4065.0 323 0 214.0 19 S3TS22 3870.0 273 0 106.0 8 S3TS23 2214.0 234 0 137 .O 16 S3TS24 1906.0 202 0 94 .0 10 S3TS25 2221.0 224 0 114.0 12 S3TS26 2533.0 246 0 135.0 15 S3TS27 1544 .0 220 0 126.0 19 S3TS28 2843.0 264 0 135.0 9 S3TS29 3967.0 219 0 95.0 5 S3TS30 1916.0 136 0 98.0 11 S3TS31 3602.0 169 .0 73.0 4 S3TS32 2051.0 165 .0 97.0 6 S3TS33 1954.0 200 .0 120.0 9 S3TS34 3348.0 255 .0 124 .0 9 S3TS35 2213.0 251 .0 163.0 1 1 S3TS3G 1450.0 129 .0 77.0 7 S3TS37 2240.0 193 .0 106.0 9 S3TS38 2942.0 281 .0 124.0 12 S3TS39 5660.0 266 .0 109.0 10 S3TS40 2325.0 221 .0 136.0 9 S3TS41 7330.0 386 .0 186.0 14 S3TS42 1875.0 152 .0 113.0 12 S3TS43 3802.0 181 .0 140.0 4 S3TS44 2579.0 209 .0 97.0 12 S3TS45 1663.0 188 .0 92.0 5 S3TS4G 2185.0 191 .0 83.0 5 53TS47 2820.0 222 .0 156.0 9 S3TS4B 3151 .O 265 .0 141 .O 6 S3TS49 4444.0 426 .0 , 209.0 14 S3TS50 3197.0 185 .0 130.0 5 APPENDIX II Table 2.33 Quantimet Data for S3 LS Plane SI.No. A PH pv N f f S3LS01 3416 0 266 .0 64 .0 1 S3LS02 3119 0 200.0 108.0 6 S3LS03 2806 0 259.0 79 .0 3 S3LS04 6119 0 406 .0 200.0 14 S3LS05 3105 0 249.0 50.0 4 S3LS06 2332 0 226.0 56.0 4 S3LS07 4825 0 270.0 56.0 2 S3LS08 2580 0 188.0 34.0 3 S3LS09 5728 0 315.0 85.0 3 S3LS10 4847 0 428 .0 123.0 4 S3LS11 2315 0 230.0 68.0 2 S3LS12 4302 0 276 .0 95.0 2 S3LS13 5080 0 515.0 130.0 8 53LS14 6718 0 689.0 218.0 10 S3LS15 2654 0 289.0 68 .0 2 S3LS16 2490 0 314.0 86.0 3 S3LS17 5005 0 210.0 114.0 3 S3LS18 2575 0 199.0 57.0 2 S3LS19 3220 0 244.0 57.0 4 S3LS20 6773 0 409.0 171 .0 7 S3LS21 3570 0 255.0 50.0 1 S3LS22 3426 0 250.0 60.0 1 S3LS23 5439 0 440.0 154.0 3 S3LS24 2482 0 287 .O 83.0 2 S3LS25 9331 0 541 .0 136.0 2 S3LS2S 4054 0 417.0 103.0 3 S3LS27 1703 0 219.0 47.0 1 S3LS28 5917 0 407.0 105.0 2 S3LS29 5253 0 443.0 105.0 3 S3LS30 3154 0 371 .0 82.0 2 S3LS31 3505 0 311.0 79.0 1 S3LS32 13088 0 741.0 206.0 6 S3LS33 7400 o 619.0 171 .0 5 S3LS34 2422 0 291 .0 66.0 3 S3LS35 9766 0 756.0 184.0 2 S3LS36 4016 .0 470.0 134 .0 4 S3LS37 2647 .0 369 .0 85.0 3 S3LS38 4148 .0 375.0 75.0 2 S3LS39 21812 .0 986.0 250.0 5 S3LS40 5563 .0 880.0 257.0 4 S3LS41 1677 .0 195.0 66.0 2 S3LS42 1742 .0 180.0 93.0 8 S3LS43 461 1 .0 403.0 131 .0 5 S3LS44 4528 .0 399.0 134 .0 5 S3LS45 7796 .0 604.0 158.0 3 S3LS4S 3475 .0 377.0 87 .0 2 S3LS47 3568 .0 317.0 101 .0 4 S3LS48 4754 .0 490.0 120.0 4 S3LS49 7634 .0 766.0 181 .0 4 S3LS50 5758 .0 491 .0 134.0 4 APPENDIX II Table 2.41 Quantimet Data for S4 LT Plane SI.No. A P H pv N f f S4LT01 5078.0 129.0 120.0 2 S4LT02 5853.0 228.0 225.0 3 S4LT03 1729 .0 108 .0 85.0 4 S4LT04 3258.0 301 .0 153.0 17 S4LT05 6815.0 370.0 251 .0 4 S4LT06 14441 .0 763 .0 543.0 10 S4LT07 1717.0 80.0 59.0 2 S4LT08 1155.0 77.0 73.0 2 S4LT09 9538.0 431 .0 249.0 5 S4LT10 3294.0 132.0 113.0 5 S4LT1 1 6027.0 288 .0 257.0 7 S4LT12 5924.0 204.0 162.0 5 S4LT13 3984 .0 233.0 173.0 6 S4LT14 5960.0 386.0 282.0 5 S4LT15 3094.0 162.0 123.0 5 S4LT16 5056.0 114.0 92.0 4 S4LT17 3915.0 167.0 103.0 1 S4LT18 8958.0 199.0 145.0 2 S4LT19 8087.0 282.0 173.0 17 S4LT20 9473.0 146.0 100.0 1 S4LT21 2610.0 126.0 108.0 3 S4LT22 8751.0 497.0 308.0 15 S4LT23 3607.0 380.0 282.0 25 S4LT24 8847.0 522.0 317.0 30 S4LT25 6037.0 195.0 144.0 1 S4LT26 6273.0 203.0 157.0 2 S4LT27 9531.0 502.0 370.0 3 S4LT28 3684.0 144.0 100.0 6 S4LT29 7995.0 249.0 176.0 5 S4LT30 9697.0 313.0 284 .0 3 S4LT31 5036.0 111.0 66.0 1 S4LT32 899.0 93.0 71.0 7 S4LT33 1935.0 124.0 122.0 6 S4LT34 12910.0 638.0 354.0 12 S4LT35 8684.0 711.0 587.0 40 S4LT36 5387.0 178.0 139.0 3 S4LT37 2998.0 194.0 134.0 10 S4LT38 10736.0 317.0 188.0 6 S4LT39 7659.0 369.0 223.0 8 S4LT40 9759.0 609.0 446.0 42 S4LT41 8601.O 182.0 84.0 2 S4LT42 2232.0 108.0 85.0 3 S4LT43 3128.0 107.0 59.0 1 S4LT44 4141 .0 198.0 195.0 4 S4LT45 5727.0 521 .0 350.0 5 S4LT46 1231.0 116.0 91.0 4 S4LT47 1927.0 74.0 71.0 2 S4LT48 2190.0 82.0 56.0 1 S4LT49 9354.0 369.0 290.0 10 S4LT50 11643.0 692.0 489.0 31 APPENDIX II Table 2.42 Quantimet Data for S4 TS Plane SI.No. A PH pv N f f S4TS01 2463.0 178 .0 101 .0 5 S4TS02 3093.0 84 .0 82 .0 3 S4TS03 3452 .0 280.0 117.0 7 S4TS04 1192.0 148.0 52.0 5 S4TS05 1174 .0 152 .0 81.0 9 S4TS06 1241 .0 61.0 40.0 1 S4TS07 1173.0 57.0 35.0 1 S4TS08 3884.0 251 .0 133.0 7 S4TS09 847.0 90.0 54 .0 6 S4TS10 1042.0 160.0 45 .0 7 S4TS1 1 2361.0 255.0 120.0 13 S4TS12 1699.0 163.0 116.0 12 S4TS13 1258.O 172.0 61.0 9 S4TS14 562 .0 69.0 57.0 6 S4TS15 902 .0 86.0 46.0 5 S4TS16 1360.0 151 .0 39 .0 4 S4TS17 1501.0 147.0 61 .0 7 S4TS18 2204.0 152.0 106.0 7 S4TS19 719.0 196.0 66.0 15 S4TS20 2154.0 129.0 77.0 5 S4TS21 1762.0 165.0 69.0 6 S4TS22 2437.0 166 .0 80.0 2 S4TS23 949.0 90.0 32 .0 2 S4TS24 1585.0 76.0 46.0 6 S4TS25 1628 .0 104.0 49.0 5 S4TS26 2978.0 98.0 54.0 2 S4TS27 2086.0 118.0 67 .0 4 S4TS28 1182.0 162.0 54.0 7 S4TS29 1357.0 217.0 75.0 7 S4TS30 1568.0 211.0 91 .0 11 S4TS31 3163.0 256.0 160.0 10 S4TS32 2530.0 171.0 90.0 6 S4TS33 1974.0 189.0 76.0 9 S4TS34 2186 .0 276.0 103.0 8 S4TS35 3337.0 111.0 100.0 4 S4TS3S 736.0 54.0 40.0 2 S4TS37 1330.0 80.0 51 .0 4 S4TS38 1710.0 259.0 74.0 8 S4TS39 1087.0 82.0 50.0 3 S4TS40 1322.0 110.0 57.0 2 S4TS41 2258.0 349.0 98.0 13 S4TS42 1715.0 127.0 77.0 6 S4TS43 1531 .0 201 .0 79.0 10 S4TS44 1597.O 164.0 68 .0 6 S4TS45 1925.0 162.0 80.0 6 S4TS46 2331.O 105.0 91.0 5 S4TS47 2492.O 138.0 88.0 2 S4TS48 2346.0 175.0 110.0 7 S4TS49 1627.0 145.0 68.0 6 S4TS50 2737.0 333.0 125.0 10 APPENDIX II Table 2.43 Quantimet Data for S4 LS Plane SI. No *ff S4LS01 S4LS02 S4LS03 S4LS04 S4LS05 S4LS06 S4LS07 S4L508 S4LS09 S4LS10 S4LS11 S4LS12 S4LS13 S4LS14 S4LS15 S4LS16 54LS17 S4LS18 S4LS19 S4LS20 S4LS21 S4LS22 S4LS23 S4LS24 S4LS25 S4LS26 S4LS27 S4LS28 S4LS29 S4LS30 S4LS31 S4LS32 S4LS33 S4LS34 S4LS35 S4LS36 S4LS37 S4LS38 S4LS39 54LS40 S4LS41 S4LS42 S4LS43 S4LS44 S4LS45 S4LS46 S4LS47 S4LS48 S4LS49 S4LS50 1359 .0 1533.0 1734.0 2437 .0 1957.0 4G06.0 2124.0 4295 .0 1700.0 2621 .0 4663.0 8190.0 4734.0 3316.0 5560.0 3651 .0 4576.0 4297.O 7090.0 3024.0 3501.0 3001.0 5145.0 4266.0 8923.O 3860.0 2594 .0 5727.0 291 1 .O 5661 .0 3416.0 7640.0 5010.0 2738 .O 3156.0 2392.0 4681 .0 2025.0 2911 .0 4428.0 6584.0 6593.0 5546.0 4512.0 3309.0 2944.0 5497.0 7269.0 3858.0 5436.0 221 .0 209 .O 204 .0 152.0 218.0 503.0 305.0 453 .0 278 .0 222.0 210.0 369.0 420.0 210.0 348 .0 284.0 31 1 .0 249.0 489.0 290.0 370.0 501 .0 529.0 438. 489. 605. 200. 478. 375.0 510.0 299 0 251 .0 652.0 321 .0 430.0 274.0 516.0 325.0 336.0 507.0 270.0 266.0 446.0 301 .0 216.0 296 .O 360.0 613.0 279.0 658.0 .0 .O .0 .0 .0 .0 .0 .0 .0 .0 .0 89. 84  69. 97  66  163. 105.0 160.0 82 .0 66 .0 101 .0 214.0 91.0 60.0 134.0 94.0 118.0 86.0 147.0 201 .0 91 .0 130.0 159.0 141 .0 172 .O 136.0 56.0 93.0 105.0 208.0 184.0 118.0 244.0 99.0 106.0 78.0 143.0 62.0 145.0 134.0 129.0 99.0 125.0 119.0 87.0 97 .0 136.0 174.0 88.0 201 -O 8 4 7 5 8 20 12 7 14 1 1 3 15 3 1 5 6 8 2 2 11 2 3 3 5 5 6 3 1 4 4 17 3 10 6 1 3 4 2 5 2 4 3 8 6 3 5 13 7 2 13 APPENDIX II Table 2.61 Quantimet Data for S6 LT PIane SI.No. A N f f S6LT01 1452 0 89.0 60.0 5 S6LT02 1281 o 112.0 107.0 9 S6LT03 2933 0 163.0 132 .0 2 S6LT04 5547 0 391 .0 265.0 9 S6LT05 3094 0 239.0 212.0 20 S6LT06 2594 0 350.0 343 .0 25 S6LT07 4917 0 344.0 194 .0 13 S6LT08 5420 0 418.0 417.0 20 S6LT09 2216 0 199.0 190.0 11 S6LT10 6097 0 566.0 427.0 31 S6LT11 555 0 131.0 120.0 27 S6LT12 2598 0 256.0 147.0 17 S6LT13 3247 0 358.0 236.0 19 S6LT14 2772 0 271 .0 245.0 28 S6LT15 2305 0 290.0 208.0 39 S6LT16 3640 0 276.0 194.0 12 S6LT17 4746 0 512.0 409.0 30 S6LT18 6772 0 562.0 417.0 24 S6LT19 5982 0 485.0 421 .0 24 S6LT20 682 0 106.0 56.0 3 S6LT21 540 0 112.0 100.0 15 S6LT22 1429 0 234.0 194.0 28 S6LT23 1713 0 216.0 165.0 12 S6LT24 1524 0 172.0 1 16.0 12 S6LT25 1817 0 179.0 172.0 2 S6LT26 3713 0 287.0 151.0 3 S6LT27 1408 0 117.0 88.0 7 S6LT28 985 0 149.0 136.0 6 S6LT29 548 0 33.0 27.0 7 S6LT30 1999 0 190.0 1 16 .0 20 S6LT31 2322 0 205.0 90.0 20 S6LT32 1870 0 203.0 126.0 23 S6LT33 1930 0 165.0 163.0 12 S6LT34 2517 0 285.0 152.0 19 S6LT35 3264 0 365.0 267.0 12 S6LT36 2919 0 306.0 239.0 24 56LT37 1058 0 112.0 41.0 2 S6LT38 360 0 33.0 17.0 1 S6LT39 2876 0 243.0 190.0 17 S6LT40 434 0 48.0 25.0 6 S6LT41 4398 0 444.0 245.0 20 S6LT42 518 o 43.0 20.0 1 S6LT43 2353 0 197.0 188.0 17 S6LT44 817 0 123.0 110.0 15 S6LT45 3014 0 312.0 190.0 27 S6LT46 2973 0 330.0 317.0 22 S6LT47 4712 0 284.0 240.0 12 S6LT48 1746 0 194 .0 148.0 7 S6LT49 2937 0 286.0 226.0 23 S6LT50 970 0 153.0 123.0 18 APPENDIX II Table 2.62 Quantimet Data for S6 TS PIane SI.No. ' A. p v N f f S6TS01 297. 0 49. 0 31 . 0 3 S6TS02 852 . 0 89 . 0 59 . 0 9 S6TS03 461 . 0 122 . 0 88. O 14 S6TS04 638. 0 85. 0 42. 0 5 S6TS05 574. 0 98. 0 60. 0 5 S6TS06 274. 0 44. 0 • 34 . 0 10 56TS07 1823 . 0 127 . 0 80. 0 7 S6TS08 305. 0 54. 0 34. 0 2 S6TS09 283. 0 64. 0 28. 0 2 S6TS10 536. 0 1 10. 0 54. 0 12 S6TS11 517. 0 89. 0 66. 0 7 S6TS12 1 153. 0 128. 0 91 . 0 8 S6TS13 922. 0 151 . 0 56. 0 13 S6TS14 501 . 0 73. 0 53. 0 9 56TS15 666 0 86. 0 48. 0 5 S6TS16 863 0 100. o 85 0 12 S6TS17 1410 0 206 o 53 0 11 S6TS18 598 0 110 0 50 0 6 SGTS19 624 0 114 0 54 0 8 S6TS20 667 0 1 17 0 75 0 6 SGTS21 1084 0 158 0 11 1 0 7 S6TS22 790 0 91 0 69 0 14 S6TS23 565 0 98 0 87 0 5 S6TS24 874 0 128 0 74 0 15 S6TS25 997 0 130 0 105 0 8 S6TS26 269 0 34 0 33 0 5 S6TS27 1323 0 150 0 105 0 12 S6TS28 378 0 67 0 48 0 7 S6TS29 533 .0 88 0 70 .0 7 S6TS30 703 .0 87 0 47 .0 3 S6TS31 B10 .0 86 .0 66 .0 4 S6TS32 370 .0 70 .0 61 .o 7 S6TS33 245 .0 40 .0 28 .0 6 S6TS34 1601 .0 203 .0 153 .0 12 S6TS35 1074 .0 185 .0 128 .0 23 SSTS3S 1453 .0 320 .0 134 .0 30 S6TS37 1115 .0 135 .0 62 .0 4 S6TS38 1284 .0 153 .0 94 .0 9 S6TS39 787 .0 109 .0 48 .0 5 S6TS40 615 .0 99 .0 66 .0 13 SGTS41 883 .0 85 .0 67 .0 7 S6TS42 1615 .0 237 .0 146 .0 22 S6TS43 908 .0 141 .0 110 .0 14 S6TS44 497 .0 96 .0 21 .o 14 S6TS45 1139 .0 179 .0 73 .0 9 SGTS46 397 .0 61 .0 55 .0 6 S6TS47 537 .o 79 .0 52 .0 7 S6TS48 494 .0 72 .0 43 .0 5 SGTS49 330 .0 62 .0 42 .0 9 S6TS50 506 .0 83 .0 41 .0 3 APPENDIX II Table 2.63 Quantimet Data for S6 LS Plane SI.No. A PH pv N f f . S6LS01 3192. 0 492.0 155.0 23 S6LS02 1534 . 0 236 .0 86.0 14 S6LS03 616 . 0 208.0 64 .0 24 S6LS04 1298. 0 302.0 83.0 51 S6LS05 1797. 0 407.0 178.0 29 S6LS06 2721 . 0 710.0 208 .0 100 S6LS07 2964. 0 544.0 242 .0 46 S6LS08 5617 . 0 976 .0 443.0 92 S6LS09 1155. 0 143.0 46.0 2 S6LS10 2195. 0 215.0 89.0 8 S6LS1 1 1123. 0 420.0 167.0 45 S6LS12 468. 0 67.0 41 .0 1 S6LS13 1091 0 469.0 176.0 47 S6LS14 52. 0 25.0 6.0 11 S6LS15 671 0 206.0 76.0 26 S6LS16 9845 0 999.0 453.0 49 S6LS17 397 0 84.0 41.0 6 S6LS18 573 0 133 .0 45.0 18 S6LS19 577 0 125.0 57.0 6 S6LS20 1485 0 353.0 130.0 57 S6LS21 1368 0 300.0 121.0 30 S6LS22 1 142 0 215.0 96.0 23 SGLS23 343 0 72.0 31 .0 2 S6LS24 754 0 97.0 29.0 2 S6LS25 936 o 200.0 82.0 24 S6LS26 757 0 102.0 41.0 3 S6LS27 1313 0 132.0 64.0 4 SGLS28 3112 0 478.0 180.0 31 S6LS29 1402 0 104.0 51 .0 2 S6LS30 391 .0 72.0 29.0 2 S6LS31 570 .0 169.0 80.0 16 S6LS32 946 .0 307 .0 53.0 76 SGLS33 6714 .0 922.0 431 .0 70 S6LS34 1273 .0 262.0 135.0 25 S6LS35 279 .0 102.0 70.0 15 S6LS36 1264 .0 244.0 144.0 17 S6LS37 84 .0 34.0 14.0 5 S6LS38 3588 .0 421 .0 215.0 25 S6LS39 1278 .0 251 .0 185.0 14 SGLS40 431 .0 98.0 31 .0 17 SGLS41 529 .0 145.0 56.0 12 S6LS42 382 .0 69.0 36.0 6 S6LS43 1362 .0 218.0 100.0 7 S6LS44 374 .0 128.0 46.0 20 S6LS45 679 .0 104.0 29.0 1 S6LS4G 484 .0 105.0 40.0 12 S6LS47 742 .0 204.0 93.0 31 S6LS48 4897 .0 803.0 392.0 76 S6LS49 783 .0 123.0 76.0 5 S6LS50 103 .0 30.0 14.0 3 APPENDIX II Table 2.71 Quantimet Data for CI LT Plane SI.No. " f f C1LT01 C1LT02 C1LT03 C1LT04 C1LT05 C1LT06 C1LT07 C1LT08 C1LT09 C1LT10 C1LT 11 C1LT12 C1LT13 C1LT14 C1LT15 C1LT16 C1LT17 C1LT18 C1LT19 C1LT20 C1LT21 C1LT22 C1LT23 C1LT24 C1LT25 C1LT26 C1LT27 C1LT28 C1LT29 C1LT30 C1LT31 C1LT32 C1LT33 C1LT34 C1LT35 C1LT36 C1LT37 C1LT38 C1LT39 C1LT40 C1LT41 C1LT42 C1LT43 C1LT44 C1LT45 C1LT46 C1LT47 C1LT48 C1LT49 C1LT50 179.0 533 .0 1658.0 132.0 161 .0 126.0 693.0 1386 .0 938 .0 198.0 1308.0 1411.0 408.0 949.0 647.0 255.0 549.0 1854.0 1034.0 940.0 159.0 949.0 390.0 1107 .0 349.0 554.0 1107.0 357.0 471 .0 815.0 1643.0 397 .0 494.0 830.0 710.0 760.0 275.0 665.0 975.0 358.0 368.0 3439.0 758 .0 1209.O 757.0 425.0 780.0 1629.0 599.0 2414.0 18.0 52.0 71.0 14.0 16.0 18.0 35.0 80.0 51 .0 22.0 55.0 60.0 42.0 63.0 33.0 25.0 69.0 128.0 42.0 58.0 18.0 53.0 27.0 71.0 33.0 32.0 76.0 41 .0 27 .0 37.0 67.0 24.0 28.0 58.0 33.0 52.0 21 .0 47.0 77.0 36.0 56.0 126.0 51 .0 85.0 53.0 34.0 43.0 84.0 38.0 79.0 .0 .0 .0 .0 .0 .0 16 .0 49.0 67 12 12 16 30 74 39.0 17 .0 44 .0 55.0 40.0 62.0 30.0 24.0 50.0 122.0 38.0 49.0 15.0 45.0 23 62 31 26 65 34.0 26.0 30.0 62.0 22.0 26.0 56.0 29.0 51 .0 20.0 46.0 68.0 35.0 54.0 118.0 40 61 39 31 42 74 34.0 75.0 1 3 3 1 1 3 1 4 3 1 2 2 3 3 1 2 4 7 1 4 1 2 1 4 3 1 4 3 1 1 2 1 1 3 1 3 1 3 4 3 5 4 2 4 2 2 2 3 2 4 APPENDIX II Table 2.72 Quantimet Data for Cl TS Plane SI.No. i j f f C1TS01 C1TS02 C1TS03 C1TS04 C1TS05 C1T506 C1TS07 C1TS08 C1TS09 C1TS10 C1TS11 C1TS12 C1TS13 C1TS14 C1TS15 C1TS16 C1TS17 C1TS18 C1TS19 C1TS20 C1TS21 C1TS22 C1TS23 C1TS24 C1TS25 C1TS26 C1TS27 C1TS28 C1TS29 C1TS30 C1TS31 C1TS32 C1TS33 C1TS34 C1TS35 C1TS36 C1TS37 C1TS38 C1TS39 C1TS40 C1TS41 C1TS42 C1TS43 C1TS44 C1TS45 C1TS46 C1TS47 C1TS48 C1TS49 C1TS50 .0 .0 .0 .0 .0 .0 .0 1098.0 458.0 182.0 628.0 1046.0 452.0 1067.0 5552 1175. 350. 389. 381 780. 274. 707.0 228.0 1456.0 285.0 304.0 724.0 1153.0 619.0 448.0 350.0 204.0 1126.0 770.0 390.0 661.0 347.0 170.0 770.0 229. 1052. 1875. 1883. 2840. 312. 333. 342.0 825.0 1314.0 1124.0 483.0 182.0 848.0 1266.0 S66.0 350.0 620.0 .0 .0 .0 .0 .0 .0 .0 62.0 39.0 28.0 75.0 53.0 35.0' 74.0 127 .0 91.0 22.0 33.0 44.0 56.0 34.0 72.0 18.0 71.0 45.0 29.0 63.0 63.0 30.0 48.0 38.0 17.0 40.0 41 .0 29.0 55.0 25.0 23.0 49.0 22.0 95.0 101.0 57.0 68.0 40.0 23.0 39.0 37.0 71 .0 89.0 53.0 17.0 61.0 114.0 41.0 2S.0 31.0. 59.0 36.0 27 .0 73.0 52.0 34.0 71 .0 123.0 76.0 21 .0 30.0 35.0 50.0 33.0 60.0 17.0 67.0 40.0 27.0 61.0 61 .0 29.0 44 .0 29.0 16.0 38.0 34 27 33 17 21 46 17 73 84 51 65 34 0 O O .0 .0 .0 .0 .0 .0 .0 .0 .0 18.0 33.0 32.0 65.0 79.0 49.0 16.0 49.0 97.0 39.0 20.0 27.0 3 3 3 5 2 2 4 2 4 1 2 3 3 3 5 2 4 4 2 4 4 1 4 3 1 1 2 2 2 1 2 1 1 5 3 1 1 3 1 3 2 3 5 4 2 3 7 3 1 1 APPENDIX II Table 2.73 Quantimet Data for CI LS Plane SI.No. V f C1LS01 C1LS02 C1LS03 C1LS04 C1LS05 C1LS06 C1LS07 C1LS08 C1LS09 C1LS10 C1LS11 C1LS12 C1LS13 C1LS14 C1LS15 C1LS16 C1LS17 C1LS18 C1LS19 C1LS20 C1LS21 C1LS22 C1LS23 C1LS24 C1LS25 C1LS26 C1LS27 C1LS28 C1LS29 C1LS30 C1LS31 C1US32 C1LS33 C1LS34 C1LS35 C1LS36 C1LS37 C1LS38 C1LS39 C1LS40 C1LS41 C1LS42 C1LS43 C1LS44 C1LS45 C1LS46 C1LS47 C1LS48 C1LS49 C1LS50 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 636.0 908.0 190.0 334 .0 323.0 263.0 853 98. 791 215. 10422. 517 275.0 63.0 777. 870. 2016. 860. 213. 88.0 181.0 509.0 864.0 224.0 94.0 140.0 826.0 351 .0 418.0 333.0 600.0 146. 43. 317. 186. 286. 1103. 15.0 365.0 200.0 357.0 364.0 206.0 125.0 136.0 1189.0 614.0 85.0 679.0 388.0 .0 .0 .0 .O .0 .0 46.0 49.0 25.0 41 .0 34.0 36.0" 42.0 13.0 71.0 23.0 168.0 51 .0 28.0 12.0 51 .0 39 55 34 19 12 17.0 31 .O 78.0 24.0 19.0 14.0 57.0 41.0 25.0 25.0 37.0 16.0 11 .0 23.0 27 .0 30.0 67.0 10.0 33.0 20.0 34.0 25.0 22.0 17.0 13.0 60.0 38.0 16.0 32.0 32.0 .0 .0 .0 .0 .0 .0 39.0 36.0 21 .0 35.0 33.0 29.0 37.0 11.0 65.0 16.0 162.0 45.0 24.0 9.0 50.0 35.0 54. 31 13  9. 15. 30. 71.0 23.0 16.0 13.0 45.0 34.0 24.0 19.0 31 .0 15.0 6.0 20.0 25.0 27.0 59.0 9.0 31.0 18.0 27.0 2 3 0 20.0 15.0 12.0 56.0 36.0 12.0 29.0 28.0 4 2 3 5 3 3 3 1 5 2 2 5 2 1 3 1 2 1 1 2 1 2 6 2 3 1 3 5 1 1 2 1 4 1 3 2 4 1 2 1 2 1 2 2 1 3 2 2 1 2 APPENDIX II Table 2.81 Quantimet Data for C2 LT Plane SI. No. A PH P v % C2LT01 1308.0 68.0 52.0 2 C2LT02 469.0 27.0 25.0 1 C2LT03 366.0 34.0 30.0 2 C2LT04 417.0 46.O 45.O 3 C2LT05 862.0. 38.0 35.0 1 C2LT06 157.0 18.O 13.O 2 C2LT07 137.0 15.0 14.0 1 C2LT08 137.0 13.0 10.0 1 C2LT09 193.0 24.0 21.0 2 C2LT10 142.0 15.0 13.0 1 C2LT11 180.0 22.0 20.0 2 C2LT12 303.0 40.0 27.0 3 C2LT13 916.0 34.0 33.0 1 C2LT14 3180.0 77.0 62.0 1 C2LT15 274.O 27.0 26.0 2 C2LT16 263.0 20.0 18.0 1 C2LT17 301.0 26.0 24.0 2 C2LT18 868.0 52.0 37.0 1 C2LT19 853.0 49.0 47.0 2 C2LT20 3405.0 80.0 71.0 1 C2LT21 139.0 14.0 13.0 1 C2LT22 1148.0 45.0 41.0 1 C2LT23 372.0 26.0 22.0 1 C2LT24 1318.0 52.0 50.0 1 C2LT25 45.0 10.0 9 .0 1 C2LT26 288.0 36.0 33.0 3 C2LT27 364.0 31.0 28.0 2 C2LT28 140.0 17.0 15.0 1 C2LT29 81.0 24.0 21.0 3 C2LT30 80.0 15.0 14.0 2 C2LT31 187.O 18.0 16.O 1 C2LT32 365.0 30.0 26.0 2 C2LT33 81.0 10.0 9.0 1 C2LT34 58.0 9 .0 8.0 1 C2LT35 246.0 23.0 21.0 2 C2LT36 1217.0 51.0 38.0 1 C2UT37 407.0 29.0 28.0 2 C2LT38 115.0 18.0 15.0 2 C2LT39 434.0 32.0 31.0 2 C2LT40 36.0 7.0 6.0 1 C2LT41 1257.0 60.0 51.0 2 C2LT42 1615.0 54.0 49.0 2 C2LT43 605.0 39.0 36.0 2 C2LT44 319.0 36.0 26.0 2 C2LT45 167.0 17.0 12.0 2 C2LT46 669.0 57.0 53.0 4 C2LT47 881.0 62.0 52.0 3 C2LT48 176.0 18.0 17.0 2 C2LT49 1990.0 84.0 60.0 4 C2LT50 283.O 2 1 0 17.0 1 APPENDIX II Table 2.82 Quantimet Data for C2 TS PIane SI.No. H V *ff C2TS01 C2TS02 C2TS03 C2TS03 C2TS05 C2TS06 C2TS07 C2TS08 C2TS09 C2TS10 C2TS11 C2TS12 C2TS13 C2TS14 C2TS15 C2TS1G C2TS17 C2TS18 C2TS19 C2TS20 C2TS21 C2TS22 C2TS23 C2TS24 C2TS25 C2TS26 C2TS27 C2TS28 C2TS29 C2TS30 C2TS31 C2TS32 C2TS33 C2TS34 C2TS35 C2TS36 C2TS37 C2TS38 C2TS39 C2TS40 C2TS41 C2TS42 C2TS43 C2TS44 C2TS45 C2TS46 C2TS47 C2TS48 C2TS49 C2TS50 144.0 260.0 173.0 149.0 415.0 . 564.0 1247.0 340.0 928.0 698.0 161 .0 1646.0 1070.0 2364.0 243.0 850.0 133.0 876.0 820.0 596.0 410.0 367.0 937.0 1822.0 312.0 183.0 1564. 536. 540. 1470. 183. 325. 610. 1360.0 939.0 341.0 398.0 5116.0 209.0 316.0 149.0 2304.0 368.0 45.0 454.0 202.0 153.0 118.0 309.0 1067.0 .0 .0 .0 .0 .0 .0 .0 19.0 32.0 17 .0 16.0 26.0 34 .0 ' 59.0 52.0 52.0 33.0 17.0 52.0 41.0 60.0 21.0 35.0 13.0 37.0 48.0 36.0 38.0 38.0 43.0 60.0 20.0 20.0 55.0 46.0 28.0 50.0 17.0 21 .O 43.0 109.0 48 .O 27.0 34.0 87.0 38.0 50.0 25.0 81.0 23.0 7.0 25.0 26.0 16.0 13.0 26.0 58.0 17.0 26.0 15.0 14 .0 23.0 27.0 53.0 43.0 49.0 31 .0 15.0 51 .0 38.0 56.0 15.0 34.0 12.0 34.0 42.0 31 .0 34.0 31 .0 39.0 59.0 19.0 14.0 45.0 45.0 26.0 48.0 16.0 20.0 38.0 58.0 4 4 .0 26.0 31 .0 84.0 32.0 42.0 19.0 72.0 22.0 5.0 24.0 23.0 14.0 12.0 18.0 57.0 2 3 1 1 1 1 2 3 2 1 1 2 1 1 1 1 1 1 2 1 2 2 2 2 1 2 1 3 1 2 2 1 2 5 2 3 2 1 4 4 2 1 1 1 1 2 1 1 1 2 APPENDIX II Table 2;83 Quantimet Data for C2 LS Plane SI.No. A PH v Nff C2LS01 430.0 46.0 39.0 3 C2LS02 1824.0 99.0 80.0 3 C2LS03 372.0 26.0 22.0 1 C2LS04 3072.0 82.0 65.0 1 C2LS05 €9.0 10.0 8 .0 * C2LS06 206.0 18.0 ' 16.0 1 C2LS07 375.0 24.0 21.0 1 C2LS08 239.0 21.0 18.0 1 C2LS09 108 .0 14 .0 11 .0 , * C2LS10 385.0 26.0 21.0 1 C2LS11 485.0 40.0 30.0 2 C2LS12 733.0 49.0 39.0 2 C2LS13 186.0 25.0 19.0 2 C2LS14 269.0 37.0 22.0 3 C2LS15 389.0 35.0 27.0 2 C2LS16 589.0 29.0 27.0 1 C2LS17 883.0 61 .0 51.0 4 C2LS18 1086.0 40.0 37.0 1 C2LS19 202.0 17.0 16.0 1 C2LS20 524.0 26.0 25.0 1 C2LS21 302.0 20.0 19.0 1 C2LS22 184.0 16.0 14.0 1 C2LS23 382.0 23.0 22.0 1 C2LS24 1830.0 60.0 51 .O 1 C2LS25 123.0 14 .0 13.0 1 C2LS26 311 .0 23.0 22.0 1 C2LS27 281.0 21.0 19.0 1 C2LS28 48.0 9 .0 8.0 1 C2LS29 491.0 35.0 22.0 2 C2LS30 997.0 38.0 37.0 1 C2LS31 411.0 42.0 32.0 4 C2LS32 1786.0 57.0 54.0 2 C2LS33 415.0 38.0 32.0 2 C2LS34 941.0 37.0 36.0 1 C2LS35 242 .0 20.0 18.0 1 C2LS36 577.0 31.0 24.0 1 C2LS37 579.0 29.0 28.0 1 C2LS38 922.0 50.0 43.0 3 C2LS39 141.0 16.0 13.0 1 C2LS40 331 .0 29.0 28.0 2 C2LS41 11116.0 146.0 137.0 1 C2LS42 91.0 17.0 10.0 2 C2LS43 1562.0 67.0 63.0 2 1 C2LS44 116.0 12.0 11.0 C2LS45 156.0 28.0 22.0 3 C2LS46 270.0 27.0 24.0 2 C2LS47 110.0 11.0 10.0 1 1 C2LS48 65.0 9.0 8.0 C2LS49 281.0 31.0 22.0 2 C2LS50 495.0 35.0 30.0 2 APPENDIX III T a b l e 3 ' 2 1 delusion Parameters of S2 LT Plane as Analysed From Quantimet Data 208 CODE AF S2LT01 S2LT02 S2LT03 S2LT04 S2LT05 S2LT06 S2LT07 S2LT08 S2LT09 S2LT10 S2LT11 S2LT12 S2LT13 S2LT14 S2LT15 S2LT16 S2LT17 S2LT18 S2LT19 S2LT20 S2LT21 S2LT22 S2LT23 S2LT24 S2LT25 S2LT26 S2LT27 S2LT28 S2LT29 S2LT30 S2LT31 S2LT32 S2LT33 S2LT34 S2LT35 S2LT36 S2LT37 S2LT38 S2LT39 S2LT40 S2LT41 S2LT42 S2LT43 S2LT44 S2LT45 S2LT46 S2LT47 S2LT48 S2LT49 S2LT50 1 . 0. 0. 2. 0.762 1 .338 0.715 061 442 533 985 0.912 0.928 2.562 0.883 4.025 1 .123 5.467 4.222 2.381 1 .069 0.793 1 .647 0.638 3.742 1.619 1 .378 2.190 1.325 0.851 854 699 564 1 .354 1 .527 0.612 1 .644 0.855 0.670 0.841 1.410 1 .301 5.226 698 539 536 290 0.715 0.418 1.057 1.066 2.373 1 .802 1 .434 1 .546 14.367 8.576 672.349 1.648 155.820 0. 0. 0. CO MI CRON 14.388 13 .491 9.843 11.710 6.630 6.854 24.945 4.542 1 2 . 6 1 9 26.766 21.092 27.067 8.642 42.926 22.978 22.650 15.254 3.743 3.855 9.949 8.917 14.914 22.079 10.999 12.503 10.705 14.485 17.533 8.153 15.227 16.241 7.163 19.633 10.422 9.919 7.395 20.889 8.648 28.175 1 1 .485 8.757 10.956 13.242 9.843 9.415 8.961 12.106 28.925 18.827 11.895 C MICRON 8.416 7.597 915 720 120 115 D MICRON FF N 15.118 4.043 8.823 14.008 8.268 15.857 7. 178 18.486 13.388 14.287 6.448 2.910 3.191 3.886 7.819 8.649 13.776 6.521 7.047 6.913 7.403 9.477 6.115 11.393 10.208 3.872 10.021 6.064 6.075 5.685 14.867 5.722 15.717 6.579 .004 .927 8.626 6.915 5.100 6.183 7.993 15.600 11.040 6.709 1.163 7.644 3.788 266.959 0.338 304.829 5. 9. 1095. 560. 960. 533. 1153. 1141. 491. 439. 942. 533. 928. 378. 632. 320. 304. 586. 597. 364. 191 . 605. 201. 526. 986. 291. 525. 806. 859. 1045. 1077. 830. 658. 629. 599. 703. 901. 671. 1039. 434. 285. 381. 924. 636. 660. 960. 1214. 579. 742. 642. 602. 461 . 1.710 1 .776 1 .424 2.047 1 .295 1.121 1.650 1 . 123 1 .430 1.911 2.551 1 .707 1 .204 2.322 1.716 1 .585 2.366 1 .286 1 .208 2.560 1.141 1 .724 1 .603 1 .687 1 .774 1.548 1.957 1.850 1.333 1 .337 1 .591 1.850 1.959 1.719 1.633 1.301 1.405 1.511 1.793 1.746 1.750 1.104 1.535 1.424 1.846 1 .449 1.515 1.854 1 .705 1.773 65 98 65 98 98 131 98 394 131 98 32 32 32 65 65 32 65 657 2103 65 657 131 32 164 98 98 98 65 98 32 32 131 32 98 65 131 32 164 98 164 131 98 65 65 65 164 98 32 98 131 APPENDIX III Table 3.22 Inclusion Parameters of S2 TS Plane as Analysed From Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON S2TS01 0.933 15.596 9.577 1017. 1.629 bb S2TS02 0.693 6.758 4.975 713. 1.358 197 S2TS03 0.679 8.102 . 5.476 801 . 1 .480 131 S2TS04 0.724 9.303 7.298 1001 . 1.275 164 S2TS05 0.301 4.958 3.061 1014. 1 .620 164 S2TS06 0.571 6.816 5.709 994. 1 .194 98 S2TS07 0.782 7.376 5.257 667. 1 .403 164 S2TS08 0.380 4.272 2.904 762. 1 .471 295 S2TS09 0.582 5.238 3.661 625. 1 .431 197 S2TS10 0.668 4.734 3.426 510. 1 .382 295 S2TS11 0.526 9.321 5.444 1030. 1 .712 65 S2TS12 0.517 5.652 3.710 714. 1 .523 197 S2TS13 0.496 4.083 2.478 498. 1 .646 394 S2TS14 0.567 6.503 3.790 665. 1.716 1 97 S2TS15 1 .462 6.581 4.539 306. 1 .450 394 S2TS16 1 .346 14.720 7.646 560. 1 .925 131 S2TS17 0.706 7.715 5.503 774. 1 .402 131 S2TS18 0.543 5.619 4.018 736. 1 .398 197 S2TS19 0.947 6.515 3.356 351. 1 .941 427 S2TS20 0.871 10.726 5.252 598. 2.042 131 S2TS21 0.404 5.493 3.634 896. 1 .512 230 S2TS22 0.523 4.853 3.416 650. 1 .421 262 S2TS23 0.842 9.656 5.382 634. 1 .794 131 S2TS24 0.938 5.274 4. 124 436. 1 .279 361 S2TS25 0.768 5.992 3.329 430. 1.800 427 S2TS26 1.317 10.275 5.666 424. 1.813 295 S2TS27 0.670 4.217 3.648 541 . 1 .156 262 S2TS28 0.640 4.408 3.286 510. 1 .341 394 S2TS29 1 .520 7.377 6.760 438. 1 .091 131 S2TS30 0.898 8.825 4.752 525. 1.857 164 S2TS31 2.339 20.577 11.080 463. 1 .857 164 S2TS32 1 .406 12.011 7.618 534. 1 .577 131 S2TS33 4.346 21.363 13.741 302. 1 .555 131 S2TS34 0.834 4.668 2.771 330. 1.684 525 S2TS35 0.912 . 5.333 3.690 401 . 1 .445 460 S2TS36 0.245 3.371 2.256 919. 1 .494 197 S2TS37 0.351 2.934 2.685 762. 1 .093 295 S2TS38 3.290 17.574 8.224 242. 2.137 525 S2TS39 0.089 4.170 3.724 4175. 1 .120 65 S2TS40 1.155 9.319 5.607 480. 1.662 328 S2TS41 0.625 8.129 5.948 945. 1.367 131 S2TS42 0.481 3.218 2.289 473. 1.406 591 S2TS43 0.478 4.203 2.973 619. 1.414 295 S2TS44 0.269 2.251 2.144 794. 1.050 624 S2TS45 1 .524 20.268 12.832 829. 1.580 65 S2TS46 1.092 7.135 4.893 443. 1.458 230 S2TS47 0.470 6.476 4.234 896. 1.529 98 S2TS48 2.524 15.880 10.549 407. 1.505 131 S2TS49 0.791 2.153 2.113 265. 1.019 2202 S2TS50 0.846 9.998 7.020 823. 1 .424 164 0.938 0.758 7.960 4.703 5.149 2.659 698.471 542.482 1.509 0.253 280.860 308.371 APPENDIX III 210 T a b 1 e 3 ' 2 3 delusion Parameters of S?LS Plane as Analysed From Quantimet Data CODE S2LS01 S2LS02 S2LS03 S2LS04 S2LS05 S2LS06 S2LS07 S2LS08 S2LS09 S2LS10 S2LS11 S2LS12 S2LS13 S2LS14 S2LS15 S2LS16 S2LS17 S2LS18 S2LS19 S2LS20 S2LS21 S2LS22 S2LS23 S2LS24 S2LS25 S2LS26 S2LS27 S2LS28 S2LS29 S2LS30 S2LS31 S2LS32 S2LS33 S2LS34 S2LS35 S2LS36 S2LS37 S2LS38 S2LS39 S2LS40 S2LS41 S2LS42 S2LS43 S2LS44 S2LS45 S2LS46 S2LS47 S2LS48 S2LS49 S2LS50 AF 2.431 0.483 1.713 1 .443 2.890 0.980 1 .087 0.570 0.577 11.394 2.394 0.774 0.697 3.992 1 .856 1.014 1.139 0.550 1 .260 1 .055 1.380 2.688 0.836 0.981 2.352 0.539 1 .535 1.119 .455 .185 658 044 690 993 184 403 054 058 468 0.438 0.531 2.174 1 .060 1 .782 0.494 1 .029 0.715 2.275 0.660 0.677 1.595 15.001 6.579 536.687 2.226 131.540 1 , 3, 1. 3. 1 . 0. 3. 0. 1 . 1 . 0. CO . MICRON. 18.116 11.300 7.770 18.968 23.810 17.106 14.288 4.662 10.070 45.812 16.007 5.554 7.547 30.933 24.393 7 8 4 9 8 29 15 27 5 9 8 700 .326 125 450 947 895 645 6.077 9.482 513 729 654 612 7.501 18.540 19.401 11.527 17.494 23.228 25.512 7.256 20.910 27.496 9.441 1 1 .382 4.603 1 1 .354 15.318 28.557 7.602 16.494 10.077 13.581 16.419 18.869 C MICRON 8.916 5.330 6.508 8.657 10.308 5.049 6.390 3.472 4.498 22.035 7.530 4.115 4.454 12.390 9.913 3.572 4.426 2.485 4.118 3.538 8.279 6.340 3.001 4.012 9.688 3.265 5.189 4.223 5.510 9.387 6.622 5.380 7.516 7.351 12.293 4.408 6.970 6.991 3.776-6.484 2.877 7.638 8.005 518 513 239 402 6.671 6.769 5.914 1 .643 8.550 3.291 259.615 0.579 92.986 . D. . . MICRON FF N 1 1 . 4. 6. 4. 358. 1098. 373. 591. 346. 510. 582. 606. 776. 171. 307. 528. 635. 298. 524. 349. 384. 449. 323. 332. 592. 230. 356. 405. 402. 603. 333. 373. 373. 285. 393. 171. 437. 733. 374. 1089. 654. 654. 803. 1475. 539. 344. 747. 635. 910. 600. 611. 287. 1020. 867. 2.032 2.120 1 .194 2.191 2.310 3.388 2.236 1 .343 2.239 2.079 2.126 1 1 2, 2. 2. 1 1 2. .350 .694 .497 .461 156 .881 .660 .295 2.529 3.611 2.468 2.025 2.364 2.840 1 .755 1 .860 2.039 1.361 1.975 2.930 2.142 2.327 3.160 075 646 000 933 500 1.756 1.600 1.487 1.914 2.479 1.684 2.644 289 036 426 190 230 131 230 98 65 65 65 197 98 32 98 164 98 65 65 230 295 295 361 197 32 164 262 230 98 164 328 197 197 164 65 230 32 32 65 65 32 32 131 32 328 164 32 32 65 65 98 98 32 32 . APPENDIX III Table 3.31 Inclusion Parameters of S3 LT Plane as Analysed From Quantimet Data CODE AF C O M I C R O N C MICRON 4 D MICRON FF N S3LT01 S3LT02 S3LT03 S3LT04 S3LT05 S3LT06 S3LT07 S3LT08 S3LT09 S3LT10 S3LT1 1 S3LT12 S3LT13 S3LT14 S3LT15 S3LT16 S3LT17 S3LT18 S3LT19 S2LT20 S3LT21 S3LT22 S3LT23 S3LT24 S3LT25 S3LT26 S3LT27 S3LT28 S3LT29 S3LT30 S3LT31 S3LT32 S3LT33 S3LT34 S3LT35 S3LT36 S3LT37 S3LT38 S3LT39 S3LT40 S3LT41 S3LT42 S3LT43 S3LT44 S3LT45 S3LT46 S3LT47 S3LT48 S3LT49 S3LT50 0.672 1.019 0.798 4.495 0.629 0.613 0.956 0.548 0.522 0.829 0.219 924 801 ,114 .700 1 .791 0.983 222 818 .775 342 ,576 ,197 ,157 .382 387 446 ,562 ,908 1.860 1.293 1.306 2.506 3.179 1.909 2.445 0.773 0.995 0.766 1 .197 1 .246 2.508 . 1 .877 1.604 0.394 1 .262 0.654 1 .856 1 .054 3.532 1 .512 10.350 5.829 557.466 1 .754 313.740 2. 0, 0. 9. 0. 0, 1, 1. 0. 0. 0. 0. 9.354 6.408 5.693 30.937 9.087 8.850 8.602 8.334 10.175 8.154 7.995 10.813 6.599 7.853 15.227 18.378 6.151 7.806 6.882 7.753 29.700 7.023 5.235 6. 6. 4. 4, .909 .242 .870 .744 4.507 5.714 4.967 11.730 13.648 11.235 16.240 9.883 15.214 6.797 16.402 6.643 8.923 20.240 5. 4. .375 .946 16.176 6.072 14.335 6.658 17.101 7.853 21.081 973 3.724 3.523 9.211 5.220 3.229 5.201 4.551 4.299 4.827 4.411 6.514 4.639 6.092 7.810 8.953 4.276 4.451 5.694 5.968 16.485 3.273 3.657 5.416 4.700 4.233 3.163 3.697 4.041 3.934 6.579 5.925 8.260 8.813 6.980 10.753 4.264 7.816 3.601 4.490 12.350 4.557 4.007 7.536 2.455 5.448 3.087 9.242 4.483 10.622 1 .540 5.931 2.697 351.764 0.447 288.977 736. 362. 438. 196. 825. 524. 539. 825. 820. 577. 2013. 698. 575. 541 . 129. 491. 431 . 196. 691. 764. 160. 565. 1853. 463. 335. 1089. 706. 654. 441 . 208. 502. 448. 321 . 268. 359. 429. 548. 777. 466. 371 . 979. 177. 209. 462. 620. 426. 469. 489. 421 . 290. 1.881 1.720 1 .616 3.359 1.741 2.741 1 .654 1 .831 2.367 1.689 1 .813 1 .660 1 .423 1.289 1.950 2.053 1.439 1 .754 1.209 1.299 1.802 2.146 1 .432 1 .276 1 .328 1.151 1 .500 1.219 1.414 1.263 1 .783 2.304 1 .360 'l .843 1.416 1.415 1 .594 2.099 1.844 1 .987 1.639 1.179 1.234 2.147 2.474 2.631 2.157 1.850 1.752 1.985 164 361 394 131 65 262 262 164 164 230 131 197 328 328 1512 98 328 394 361 230 525 164 65 262 525 230 230 427 690 1019 98 230 493 328 32 328 394 32 394 164 65 986 1051 164 164 65 131 98 98 131 APPENDIX III 212 Table 3.32 Inclusion Parameters of S3 TS Plane as Analysed From  Quantimet Data CODE AF CO MICRON . . C. MICRON D . . . . MICRON FF N S3TS01 0.205 3.236 2.521 1229. 1 .284 197 S3TS02 1 .327 6.994 3.021 225. 2.315 525 S3TS03 1 .739 10.023 4.975 281 . 2.015 624 S3TS04 2.094 9.534 6.020 281 . 1 .584 591 S3TS05 0.642 6.363 3.773 584. 1 .686 262 S3TS06 1.212 7.922 4.890 399. 1 .620 591 S3TS07 0.470 5.549 4.994 1059. 1.111 131 S3TS08 0.524 4.172 2.434 462. 1.714 460 S3TS09 0.567 4.423 3.492 612. 1 .267 460 S3TS10 0.797 5.389 4.200 523. 1 .283 361 S3TS11 0.513 6.186 2.844 552. 2.175 197 S3TS12 0.332 4.630 3.296 988. 1 .405 230 S3TS13 0.398 3.883 3.788 947. 1 .025 262 S3TS14 0.558 4.982 3.751 669. 1 .328 262 S3TS15 0.632 6.847 4.085 642. 1 .676 230 S3TS16 2.492 24.704 6.908 270. 3.576 295 S3TS17 0.910 5.353 2.316 252. 2.312 756 S3TS18 0.524 5.573 2.947 560. 1.691 328 S3TS19 0.830 6.565 3.104 . 371 . 2.115 427 S3TS20 0.536 5.060 3.946 732. 1.282 525 S3TS21 0.903 4.939 3.272 359. 1.509 624 S3TS22 0.860 9.492 3.686 425. 2.575 262 S3TS23 0.492 4.202 2.460 498. 1.708 525 S3TS24 0.424 5.272 2.453 577. 2.149 328 S3TS25 0.494 5.065 2.578 520. 1.965 394 S3TS26 0.563 4.878 2.677 473. 1.622 493 S3TS27 0.343 3.186 1 .825 530. 1 .746 624 S3TS28 0.632 5.475 2.800 440. 1 .956 295 S3TS29 0.882 10.857 4.710 530. 2.305 164 S3TS30 0.426 5.083 3.663 857. 1 .388 361 S3TS31 0.800 12.829 5.542 687. 2.315 131 S3TS32 0.456 5.498 3.232 706. 1 .701 197 S3TS33 0.434 4.234 2.540 582. 1 .667 295 S3TS34 0.744 7.020 3.414 455. 2.056 295 S3TS35 0.492 3.530 2.292 464. 1 .540 361 S3TS36 0.322 4.896 2.922 904. 1 .675 230 S3TS37 0.498 5.494 3.018 603. 1 .821 295 S3TS38 0.654 6.169 2.722 414. 2.266 394 S3TS39 1 .258 13.501 5.532 434. 2.440 328 S3TS40 0.517 4.445 2.735 527. 1 .625 295 S3TS41 1.629 10.246 4.937 298. 2.075 460 S3TS42 0.417 .4.314 3.207 767. 1 .345 394 S3TS43 0.845 7.061 5.461 641 . 1.293 131 S3TS f44 0.573 . 6.913 3.208 557. 2.155 394 S3TS45 0.370 4.700 2.300 620. 2.043 164 S3TS46 0.486 6.845 2.974 610. 2.301 164 S3TS47 0.627 4.700 3.303 524. 1.423 295 S3TS48 0.700 5.810 3.092 438. 1.879 197 S3TS49 0.988 5.528 2.712 272. 2.038 460 S3TS50 0.710 6.394 4.493 626. 1 .423 164 0.737 0.448 6.519 3.436 3.541 1.103 559.495 210.766 1.817 0.455 348.560 151.694 APPENDIX III 213 Table 3.33 Includiori Parameters of S3 LS PIahe as Analysed From Quantimet Data CODE AF CO MICRON S3LS01 S3LS02 S3LS03 S3LS04 S3LS05 S3LS06 S3LS07 S3LS08 S3LS09 S3LS10 S3LS11 S3LS12 S3LS13 S3LS14 S3LS15 S3LS16 S3LS17 S3LS18 S3LS19 S3LS20 S3LS21 S3LS22 S3LS23 S3LS24 S3LS25 S3LS26 S3LS27 S3LS28 S3LS29 S3LS30 S3LS31 S3LS32 S3LS33 S3LS34 S3LS35 S3LS36 S3LS37 S3LS38 S3LS39 S3LS40 S3LS41 S3LS42 S3LS43 S3LS44 S3LS45 S3LS46 S3LS47 S3LS48 S3LS49 S3LS50 0.759 0.693 0.624 1.360 0.690 0.518 1 .072 0.573 1.273 1 .077 0.514 0.956 1 .129 1 .493 0.590 0.553 1.112 0.572 0.716 1.505 0.793 0.761 1 .209 0.552 2.074 0.901 0.378 1.315 1 .167 .701 .779 .906 .644 .538 2.170 0.892 .588 .922 .847 .236 .373 .387 .025 .006 1.732 0.772 0.793 1.056 1.696 1 .280 1 .086 11.621 3.165 351.133 3.724 119.700 0. 0, 2. 1 0. 0. 0. 4. 1 0. 0. 1 1 13.877 7.509 9.235 7.955 16.146 10.827 22.402 19.729 17.521 10.246 8.851 11.774 10.160 8.012 10.148 7.528 11.415 11 .746 14.688 10.298 18.564 14.846 9.183 7.775 17.839 10.233 9.421 14.652 13.007 10.000 1 1 .535 16.519 11.251 9.541 13.800 7.792 8.097 14.380 22.684 5.628 6.606 4.870 9.152 8.786 12.829 10.385 9.185 10.300 10.966 11.172 ' ' c MICRON 3. 4. 2. 3, 3, 2, 4. 2, 2. 4. 2. 2. 2, 2. 6. 3. 3. 4. 3, 3. 3, .055 .817 .919 .242 .683 .646 3.568 4.728 .944 .617 .053 .565 .535 .388 .062 .197 .364 .431 .306 .640 563 .214 2.249 4.484 2.528 2.022 3.780 3.083 2.210 2.930 4.592 ,108 .164 .359 .222 1.865 2.876 .752 .644 .236 .516 .975 2.951 3.356 2.397 2.926 2.523 2.591 3.049 0.733 3.987 0.943 140.060 0.821 79.431 3. 2. 3. 2. 5. 1 2, 2. 2  ~^ E5 MICRON V5TT 581 . 449. 284. 467. 515. 429. 619. 367. 270. 506. 420. 225. 167. 402. 371 . 551 . 585. 476. 282. 455. 464. 263. 405. 212. 278. 532. 284. 261 . 313. 373. 153. 186. 400. 151 . 247. 315. 309. 113. 131. 598. 647. 287. 290. 190. 308. 366. 236. 150. 235. FF T T 4.156 1.852 3.278 2.030 980 036 821 529 706 3.480 3.382 2.905 3.962 3.161 4.250 3.651 1 .842 3.491 4.281 2.392 5.100 4.167 2.857 3.458 3.978 4.049 4.660 3.876 4.219 4.524 3.937 3.597 3.620 4.409 4.109 3.507 4.341 5.000 3.944 3.424 2.955 1.935 3.076 2.978 3.823 4.333 3.139 4.083 4.232 3.664 32 197 98 460 131 131 65 98 98 131 65 • 65 262 328 65 96 98 65 131 230 32 32 98 65 65 98 32 65 98 65 32 197 164 98 65 131 98 65 164 131 65 262 164 164 98 65 131 131 131 131 APPENDIX III 3.41 Inclusidn Parameters of 54 LT PIane as Analysed From  Quantimet Data CODE AF co MICRON S4LT01 S4LT02 S4LT03 S4LT04 S4LT05 S4LT06 S4LT07 S4LT08 S4LT09 S4LT10 S4LT11 S4LT12 S4LT13 S4LT14 S4LT15 S4LT16 S4LT17 S4LT18 S4LT19 S4LT20 S4LT21 S4LT22 S4LT23 S4LT24 S4LT25 S4LT26 S4LT27 S4LT28 S4LT29 S4LT30 S4LT31 S4LT32 S4LT33 S4LT34 S4LT35 S4LT36 S4LT37 S4LT38 S4LT39 S4LT40 S4LT41 S4LT42 S4LT43 S4LT44 S4LT45 S4LT46 S4LT47 S4LT48 S4LT49 S4LT50 1 .128 1 .301 0.384 0.724 1.514 3.209 0.382 0.257 2.120 0.732 1 .339 1.316 0.885 1 .324 0.688 1 .124 0.870 1 .991 1 .797 2.105 0.580 11.002 6.763 5.289 5.536 7.059 6.915 7.566 4.114 9.959 C MICRON 10.235 6.674 4.162 945 802 1.966 1 .342 1 .394 2.118 0.819 1 .777 2.155 119 200 430 869 1.930 1 .197 0.666 2.386 1.702 2.169 1.911 0.496 0.695 0.920 1.273 0.274 0.428 0.487 2.079 2.587 1.318 8.864 6.287 637.344 1.393 261.100 7, 6. 9. 5. 5. 6. .579 ,097 .508 .988 .495 ,540 14.289 9.883 16.063 12.154 24.630 6.283 7.387 3.326 7.256 10.900 10.388 6.697 9.578 11.811 8.878 19.839 3.292 4.124 9.482 3.846 10.076 5.817 14.848 8.930 5.689 26.622 6.827 13.784 5.521 4.254 3.517 7.057 10.168 8.386 6.191 2. 4, 4. 5. 3, 5. 6. 5, 7, 4. .814 .789 .921 .580 .900 .754 .488 .441 .550 .446 4.015 4.966 1 1 .531 6.095 1 1 .704 7.456 16.870 5.386 4.578 2.468 4.407 8.049 8.034 4.936 6.652 8.348 8.055 1 1 .796 2.513 4.057 5.261 3.176 7.869 4.018 8.806 5.397 4.166 12.287 5.373 7.601 5.438 2.858 2.759 6.771 6.944 6.591 4.375 0.736 4.853 2.866 389.373 0.248 314.572 D F F N MICRON 897. i .075 65 506. 1.013 98 1079. 1.271 131 386. 1.967 558 311 . 1 .474 131 148. 1 .405 328 1457. 1 .356 65 1516. 1 .055 65 266. 1 .731 164 880. 1.168 164 401 . 1.121 230 566. 1 .259 164 498. : .347 197 299. 1.369 164 717. 1.317 164 1015. 1.239 131 695. 1.621 32 576. 1.372 65 407. 1.630 558 785. 1.460 32 923. 1.167 98 231. 1.614 493 305. 1.348 821 220. 1 .647 986 592. 1 .354 32 568. 1.293 65 228. 1 .357 98 806. 1.440 197 462. 1.415 164 366. 1.102 98 1042. 1.682 32 1256. 1.310 230 939. 1.016 197 178. 1.802 394 161. 1.211 1314 649. 1.281 98 599. 1 .448 328 360. 1.686 197 312. 1.655 262 188. 1.365 1380 631. 2.167 65 1078. 1.271 98 1086. 1.814 32 585. 1.015 131 222. 1.489 164 1006. 1.275 131 1574. 1 .042 65 1420. 1 .464 32 310. 1.272 328 165. 1.415 1019 APPENDIX III 215 T ^ W . Tnrltision Parametprs of S4 TS Plane as Analysed From Quantimet Data CODE AF S4TS01 S4TS02 S4TS03 S4TS04 S4TS05 S4TS06 S4TS07 S4TS08 S4TS09 S4TS10 S4TS11 S4TS12 S4TS13 S4TS14 S4TS15 S4TS16 S4TS17 S4TS18 S4TS19 S4TS20 S4TS21 S4TS22 S4TS23 S4TS24 S4TS25 S4TS26 S4TS27 S4TS28 S4TS29 S4TS30 S4TS31 S4TS32 S4TS33 S4TS34 S4TS35 S4TS36 S4TS37 S4TS38 S4TS39 S4TS40 S4TS41 S4TS42 S4TS43 S4TS44 S4TS45 S4TS46 S4TS47 S4TS48 S4TS49 S4TS50 547 687 767 265 261 276 ,261 ,863 0.188 0.232 0.525 0.378 0.280 0.125 0.200 0.302 0.334 0.490 0.160 0.479 0.392 0.542 0.211 0.352 0.362 0.662 0.464 0.263 0.302 0.348 0.703 0.562 0.439 0.486 0.742 0.164 0.296 0.380 0.242 0.294 0.502 0.381 0.340 0.355 0.428 0.518 0.554 0.521 0.362 0.608 0.408 6.429 3.392 906.729 2.117 . 205.320 CO .MICRON C MICRON D MICRON FF N 6.340 9.807 7.671 5.960 3.768 8.066 8.714 7.593 4.078 6.020 5.115 3.808 5.362 2.564 5.098 9.067 6.398 5.406 2.832 7.273 6.639 7.920 7.711 8.959 8.638 14.339 8.095 5.691 4.704 4.480 5.140 7.309 6.753 5.518 8.676 4.784 6.780 6.008 5.652 6.030 5.991 5.791 5.039 6.106 6.256 6.660 7.363 5.545 6.221 5.693 3.598 9.574 3.205 2.094 2.008 5.290 5.351 4.023 2.447 693 407 710 902 118 2.727 2.342 2.655 3.770 0.954 4.341 2.776 3.817 2.742 5.422 4.070 7.901 4.596 1 .897 1 .626 1 .932 3.212 3.847 2.716 2.059 7.816 3.544 4.322 1 .717 447 3, 3. 1 3. 1 2. 3, 5, 4, .125 .682 .511 .980 .532 .090 .772 .695 3.485 2.917 2.137 0.170 1.941 1.694 435.625 0.678 105.420 654. 1383. 415. 788. 768. 1913. 2047. 462. 1298. 730. 456. 715. 678. 1694. 1358. 772. 793. 766. 596. 903. 706. 701 . 1297. 1534. 1121. 1186. 987. 720. 538. 553. 454. 680. 616. 422. 1046. 2163. 1458. 450. 1423. 1061 . 334. 918. 580. 711. 719. 1109. 843. 665. 804. 349. ,762 ,024 .393 .846 1 .877 1 .525 1 .629 1 .887 1.667 3.556 2.125 1 .405 2.820 1 .211 1 .870 3.872 2.410 1 .434 2.970 1 .675 2.391 2.075 2.813 1.652 2.122 1.815 1 .761 3.000 2.893 2.319 1.600 1.900 2.487 2.680 1.110 1.350 1 .569 3.500 1.640 1.930 3.561 1.649 2.544 2.412 2.025 1.154 1.568 1.591 2.132 2.664 164 98 230 164 295 32 32 230 197 230 427 394 295 197 164 131 230 230 493 164 197 65 65 197 164 65 131 230 230 361 328 197 295 262 131 65 131 262 98 65 427 197 328 197 197 164 65 230 197 328 APPENDIX III Table 3.43 Includion Parameters of S4 LS PIane as Analysed From  Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON S4LS01 S4LS02 S4LS03 S4LS04 S4LS05 S4LS06 S4LS07 S4LS08 S4LS09 S4LS10 S4LS11 S4LS12 S4LS13 S4LS14 S4LS15 S4LS16 S4LS17 S4LS18 S4LS19 S4LS20 S4LS21 S4LS22 S4LS23 S4LS24 S4LS25 S4LS26 S4LS27 S4LS28 S4LS29 S4LS30 S4LS31 S4LS32 S4LS33 S4LS34 S4LS35 S4LS36 S4LS37 S4LS38 S4LS39 S4LS40 S4LS41 S4LS42 S4LS43 S4LS44 S4LS45 S4LS46 S4LS47 S4LS48 S4LS49 S4LS50 0, 0.341 0.385 0.542 0.435 1 .024 0.472 0.954 0.378 0.582 1 .036 1 .820 1 .052 0.737 1 .236 0.81 1 1.017 0.955 1 .576 0.672 0.778 0.667 1 .143 0.948 1 .983 0.858 0.576 1 .273 0.647 1 .258 0.759 1 .698 1.113 0.608 0.701 0.532 1 .040 0.450 0.647 0.984 1 .463 1 .465 1 .232 1 .003 0.735 0.654 1 .222 1.615 0.857 1.208 0.929 9.216 3.167 365.246 3.076 199.980 4.745 6.534 6.532 7, 7, 5. 6, 5. .709 .347 .259 .979 .390 10.325 12.004 9.950 13.526 14.369 10.788 10.099 10.083 12.991 12.540 3.912 10.003 6.002 8.413 7.866 13.488 7.379 12.044 16.011 7.208 7.076 4.827 16.834 5.339 7.191 7.741 7.973 8.511 8.492 5.220 8.592 13.270 17.315 11.536 9.858 9.889 7.891 10.509 10.862 11.399 7.032 1 .907 2.210 4.169. 2.334 2.381 1.811 2.465 1.590 3.070 5.773 5.771 2.931 4.106 4.154 3.342 .826 .487 770 711 460 1 .557 2.529 2.532 4.744 1 .659 3.372 3.115 2.018 2.886 2.970 7.914 1.998 2.218 1.908 2.270 2.359 1 .620 2.253 2.271 6.340 6.444 3.233 3.897 .983 .586 .970 .083 .595 ,148 .398 3.269 1.390 131.728 0.818 143.995 3, 2, 3. 3, 3, 2. 0, 558. 571 . 766. 534. 230. 382. 256, 419. 524. 551 . 311. 276. 553. 332. 409. 372. 465. 235. 401 . 314. 232. 219. 265. 235. 192. 582. 242. 310. 227. 388. 458. 177. 362. 270. 425. 224. 358. 346. 228. 427. 433. 259. 385. 538. 393. 321. 188. 416. 176. 2.488 2.957 1 .567 3.303 3.086 2.905 2.831 3.390 3.364 2.079 1 .724 4.615 3.500 2.597 3.021 2.636 2.895 3.327 1.443 4.066 3.854 3.327 3.106 2.843 4.449 3.571 5.140 3.571 2.452 1 .625 127 672 242 057 513 608 5.242 2.317 3.784 2.093 2.687 3.568 2.529 2.483 3.052 2.647 3.523 3.170 3.274 .131 230 164 262 657 394 230 460 361 98 493 98 32 164 197 262 65 65 361 65 98 98 164 164 197 98 32 131 131 558 98 328 197 32 98 131 65 164 65 131 98 262 197 98 164 427 230 65 427 APPENDIX III Table 3.61 Indusion Parameters of S6 LT PIahe as Analysed From  Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON S6LT02 S 6 L T 0 3 S6LT04 S 6 L T 0 5 S 6 L T 0 6 S 6 L T 0 7 S6LT08 S 6 L T 0 9 S6LT10 S6LT11 S 6 L T 1 2 S 6 L T 1 3 S 6 L T 1 4 S 6 L T 1 5 S 6 L T 1 6 S 6 L T 1 7 S 6 L T 1 8 S 6 L T 1 9 S 6 L T 2 0 S6LT21 S 6 L T 2 2 S 6 L T 2 3 S 6 L T 2 4 S 6 L T 2 5 S 6 L T 2 6 S 6 L T 2 7 S6LT28 S 6 L T 2 9 S 6 L T 3 0 S6LT31 S 6 L T 3 2 S 6 L T 3 3 S 6 L T 3 4 S 6 L T 3 5 S 6 L T 3 6 S 6 L T 3 7 S 6 L T 3 8 S 6 L T 3 9 S 6 L T 4 0 S6LT41 S 6 L T 4 2 S 6 L T 4 3 S 6 L T 4 4 S 6 L T 4 5 S 6 L T 4 6 S 6 L T 4 7 S6LT48 S 6 L T 4 9 S 6 L T 5 0 356 815 541 859 721 366 1 .506 0 . 6 1 6 694 154 722 902 770 640 1.011 1 . 318 1 .881 1 .662 0 . 1 8 9 150 397 476 423 505 031 0.391 0 .274 152 555 645 519 536 699 907 811 0 . 2 9 4 0 . 1 0 0 0 . 7 9 9 0.121 1.222 0 .144 0 . 6 5 4 0 . 2 2 7 0 . 8 3 7 0 . 8 2 6 1 . 3 0 9 0 . 4 8 5 0 . 8 1 6 0 . 2 6 9 0 . 7 1 4 4 . 4 6 2 3 . 1 3 9 6 9 9 . 0 1 7 1 .418 4 7 9 . 7 4 0 0. 0. 0. 0. 0. 1 . 0. 0. 0. 0. 0. 0 . 0. 0 . 3 . 592 6 . 6 6 6 6 .280 4 . 3 7 8 2 . 2 6 9 7 .604 3 . 8 9 9 .499 .284 .387 .302 ,128 3 .394 3 . 3 2 5 5 . 6 2 9 3.481 .872 .263 .654 .620 2 . 2 1 0 3 . 1 1 5 .941 ,169 .377 .800 ,173 6 . 0 8 9 5 .170 7 . 7 4 0 4 . 4 5 2 3 .552 4 . 9 6 8 3 . 6 6 7 3 .664 7.741 6 . 3 5 3 4 .541 5 .208 5 . 3 8 5 7 . 7 7 0 3 . 7 5 5 2 . 2 2 8 4 . 7 5 9 2 . 8 1 4 5 . 8 9 0 3 . 5 3 9 3 . 8 9 9 2 . 3 6 6 .431 .398 .256 .884 .223 ,288 .890 ,341 .232 .271 ,045 .721 ,069 .384 3 . 9 5 7 2 .781 3 . 6 1 5 3 . 7 0 0 1 . 9 3 0 1 . 4 4 6 1 . 832 2 . 3 7 9 2 . 6 5 8 3 . 0 4 5 3.881 3. 5 . 4. 3. 2 . 4 . 3 . 3 . 3 . 1 3 . 2 . 3 . 2 . 3 . 1, 4 . 3 . 3 . 2 . 3 . ,610 .983 .982 156 ,398 .764 .509 2 . 6 4 9 2 . 6 8 3 2 . 8 6 2 2 . 8 3 4 3 . 2 7 3 3.551 2 . 7 1 2 ,972 .614 .583 .993 2 . 8 9 8 2 . 7 0 3 4 . 9 7 7 2 . 7 0 0 3.081 1 .902 0 .451 1.662 0 . 8 8 6 6 8 3 . 1 2 8 0 . 3 7 2 2 8 1 . 2 5 2 961 . 6 5 7 . 2 7 2 . 4 4 8 . 3 0 6 . 3 1 0 . 2 5 4 . 5 3 9 . 188. 8 2 3 . 4 1 9 . 2 9 9 . 3 9 5 . 3 7 0 . 3 8 7 . 2 0 8 . 189 . 2 1 9 . 1017 . 9 6 3 . 4 6 0 . 4 9 8 . 6 2 5 . 6 0 0 . 3 7 2 . 9 1 9 . 7 2 3 . 3 2 6 8 . 5 6 5 . 5 2 3 . 5 2 9 . 6 5 1 . 3 7 6 . 2 9 3 . 3 5 0 . 9 6 1 . 3 2 6 9 . 441 . 2 2 4 7 . 2 4 0 . 2 5 0 8 . 5 4 5 . 8 7 6 . 3 4 3 . 3 2 5 . 3 7 5 . 5 5 4 . 3 7 5 . 7 0 4 . 1 .047 1 . 2 3 5 1 .475 1 .127 1 .020 1 . 773 1 .002 1 .047 1 . 3 2 6 1 .092 1.741 1.517 1 . 1 0 6 1.394 1.423 1.252 1.348 1 .152 1.893 1 .120 1.206 1 .309 1.483 1.041 1 .901 1.330 1.096 1.222 1 .638 2 . 2 7 8 1.611 1.012 1 . 875 1 .367 1.280 2 . 7 3 2 1 .941 1 . 279 1.920 1.812 2 . 1 5 0 1.048 1.118 1.642 1.041 1.183 1.311 1 .265 1.244 277 61 277 617 771 401 617 339 956 833 524 586 864 1203 370 925 740 740 92 462 864 370 370 61 92 216 1B5 216 617 617 709 370 586 370 740 61 30 524 185 617 30 524 462 833 679 370 216 709 555 APPENDIX III Table 3.62 Inclusiori Parameters of S6 TS PIaiie as Analysed From Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON S6TS01 0.124 2.874 1.818 1468. 1.581 138 S6TS02 0.355 4.332 2.872 806. 1 .508 416 S6TS03 0.192 1 .572 1 .1 34 589. 1.386 648 S6TS04 0.266 4.557 2.252 845. 2.024 231 S6TS05 0.239 2.870 1 .757 733. 1.633 231 S6TS06 0.114 2.418 1.868 1634. 1 .294 462 S6TS07 0.760 6.836 4.306 563. 1 .587 324 S6TS06 0.127 2.691 1 .694 1332. 1.588 92 S6TS09 0.118 3.032 1 .327 1 124. 2.286 92 S6TS10 0.223 2.978 1 .462 653. 2.037 555 S6TS11 0.215 2.350 1 .743 807. 1 .348 324 S6TS12 0.480 3.801 2.702 560. 1 .407 370 S6TS13 0.384 4.939 1 .832 475. 2.696 601 S6TS14 0.209 2.636 2.059 984. 1 .377 416 S6TS15 0.277 4.162 2.323 835. 1 .792 231 S6TS16 0.360 3.046 2.589 717. 1 .176 555 S6TS17 0.587 7.981 2.053 347. 3.887 509 S6TS18 0.249 3.588 1.631 653. 2.200 277 S6TS19 0.260 3.467 1 .642 630. 2.111 370 S6TS20 0.278 2.668 1.710 614. 1.560 277 S6TS21 0.452 2.930 2.058 454. 1 .423 324 S6TS22 0.329 3.435 2.604 769. 1.319 646 S6TS23 0.235 1 .948 1 .730 733. 1 .126 231 S6TS24 0.364 3.543 2.048 560. 1 .730 694 S6TS25 0.415 2.849 2.301 552. 1 .238 370 S6TS26 0.112 2.445 2.374 2115. 1 .030 231 S6TS27 0.551 3.780 2.646 477. 1 .429 555 S6TS28 0.157 2.362 1 .693 1073. 1 .396 324 S6TS29 0.222 2.284 1.817 616. 1 .257 324 S6TS30 0.293 4.487 2.424 825. 1.851 138 S6TS31 0.337 3.682 2.826 834. 1 .303 185 S6TS32 0.1 54 1 .820 1.586 1027. 1.148 324 S6TS33 0. 102 2.625 1 .837 1798. 1 .429 277 S6TS34 0.667 3. 139 2.366 352. 1.327 555 -S6TS35 0.447 2.517 1 .742 387. 1 .445 1064 S6TS36 0.605 3.253 1 .362 224. 2.388 1388 S6TS37 0.465 5.395 2.478 531 . 2. 177 185 S6TS38 0.535 4.098 2.518 468. 1 .628 416 S6TS39 0.328 4.919 2. 166 658. 2.271 231 S6TS40 0.256 2.795 1 .864 725. 1 .500 601 S6TS41 0.368 3.954 3.116 844. 1 .269 324 S6TS42 0.673 3.318 2.044 302. 1.623 1018 S6TS43 0.378 2.476 1 .932 509. 1.282 648 S6TS44 0.207 7.100 1.553 748. 4.571 648 S6TS45 0.475 4.681 1.909 400. 2.452 416 S6TS46 0. 165 2.165 1.952 1 178. 1 .109 277 S6TS47 0.224 3.098 2.039 909. 1.519 324 S6TS48 0.206 3.447 2.058 998. 1 .674 231 S6TS49 0.137 2.357 1.597 1160. 1 .476 416 S6TS50 0.211 3.702 1.829 866. 2.024 138 0.318 0.162 3.472 1.291 2.065 0.531 793.651 376.575 1 .718 0.645 412.480 249.599 APPENDIX III 219 Table 3.63 Inclusion Parameters of S6 LS PIane as Analysed From Quantimet Data CODE AF CO MICRON C MICRON D MICRON FF N S6LS01 0.887 6.178 1 .946 218. 3. 174 709 S6LS02 0.426 5.351 1 .950 456. 2. 744 432 S6LS03 0.171 2.887 0.888 518. 3. 250 740 S6LS04 0.361 4.692 1 .289 356. 3. 639 1574 S6LS05 0.499 3.029 1.325 264. 2. 287 895 S6LS06 0.756 3.925 1.150 151 . 3. 413 3086 S6LS07 0.823 3.674 1.635 197. 2. 248 1419 S6LS0B 1 .560 3.804 1 .727 109. 2. 203 2839 S6LS09 0.321 7.533 2.423 753. 3. 109 61 S6LS10 0.610 7.399 3.063 499. 2. 416 246 S6LS11 0.312 2.017 0.802 256. 2. 515 1388 S6LS12 0.130 3.424 2.096 1610. 1. 634 30 S6LS13 0.303 1 .860 0.698 230. 2. 665 1450 S6LS14 0.014 2.600 0.624 4319. 4. 167 339 S6LS15 0.186 2.649 0.977 523. 2. 711 802 S6LS16 2.735 6.520 2.956 105. 2. 205 1512 S6LS17 0.110 2.905 1.418 1284. 2. 049 185 S6LS18 0.159 3.820 1.292 811. 2. 956 555 S6LS19 0.160 3.037 1 .385 863. 2. 193 185 S6LS20 0.412 3.427 1 .262 305. 2. 715 1759 S6LS21 0.380 3.392 1 .368 359. 2. 479 925 S6LS22 0.317 3.569 1 .593 501 . 2. 240 709 S6LS23 0.095 3.319 1 .429 1499. 2 323 61 S6LS24 0.209 7.800 2.332 1111. 3 345 61 S6LS25 0.260 3.424 1 .404 539. 2 439 740 S6LS26 0.210 5.539 2.226 1057. 2 488 92 S6LS27 0.365 6.155 2.984 815. 2 063 123 S6LS28 0.864 5.187 1 .953 224. 2 656 956 S6LS29 0.389 8.247 4.044 1034. 2 .039 61 S6LS30 0.109 4.045 1 .629 1498. 2 .483 61 S6LS31 0.158 2.137 1.012 638. 2 .112 493 S6LS32 0.263 5.355 0.924 351 . 5 .792 2345 S6LS33 1.865 4.673 2.185 115. 2 .139 2160 S6LS34 0.354 2.829 1 .458 411 . 1 .941 771 S6LS35 0.077 1.196 0.821 1058. 1 .457 462 S6LS36 0.351 2.633 1 .554 441. 1 .694 524 S6LS37 0.023 1 .800 0.741 3176. 2 .429 154 S6LS38 0.997 5.007 2.557 254. 1 .958 771 S6LS39 0.355 2.072 1 .527 429. 1 .357 432 S6LS40 0.120 4.171 1.319 1101. 3 .161 524 S6LS41 0.147 2.834 1 .094 744. 2 .589 370 S6LS42 0.106 3.183 1 .661 1564. 1 .917 185 S6LS43 0.378 4.086 1 .874 494. 2 .180 216 S6LS44 0.104 2.439 0.877 843. 2 .783 617 S6LS45 0.189 7.024 1.959 1037. 3 .586 30 S6LS46 0.134 3.630 1.383 1027. 2 .625 370 S6LS47 0.206 2.394 1.091 528. 2 .194 956 S6LS48 1.360 3.748 1.830 133. 2 .048 2345 S6LS49 0.217 3.091 1.910 876. 1 .618 154 S6LS50 0.029 2.207 1.030 3599. 2 .143 92 0.431 0.506 3.958 1.697 1.614 0.685 825.583 840.127 2.531 0.740 759.320 755.009 APPENDIX III 220 Table 3.71 Inclusion Parameters of Cl LT PIahe as Analysed From  Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON C1LT01 0.050 3.356 2.983 5997. 1 .125 30 C1LT02 0.148 3.263 3.075 2074. 1 .061 92 C1LT03 0.461 7.424 7.006 1514. 1 .060 92 C1LT04 0.037 3.300 2.829 771 1 . 1 . 167 30 C1LT05 0.045 4.025 3.019 6747. 1 .333 30 C1LT06 0.035 2.362 2.100 5998. 1 .125 92 C1LT07 0.192 6.930 5.940 3080. 1 . 167 30 C1LT08 0.385 5.619 5. 197 1345. 1 .081 123 C1LT09 0.261 7.215 5.518 2112. 1.308 92 C1LT10 0.055 3.494 2.700 4906. 1 .294 30 C1LT11 0.363 8.918 7. 135 1957. 1 .250 61 C1LT12 0.392 7.696 7.055 1793. 1 .091 61 C1LT13 0.113 3.060 2.914 2569. 1 .050 92 C1LT14 0.264 4.592 4.519 1710. 1.016 92 C1LT15 0.180 6.470 5.882 3267. 1.100 30 C1LT16 0.071 3.187 3.060 4317. 1 .042 61 C1LT17 0. 152 3.294 2.387 1563. 1.380 123 C1LT18 0.515 4.559 4.345 839. 1.049 216 C1LT19 0.287 8.163 7.386 2564. 1.105 30 C1LT20 0.261 5.755 4.862 1857. 1 .184 123 C1LT21 0.044 3.180 2.650 5997. 1 .200 30 C1LT22 0.264 6.327 5.372 2032. 1 .178 61 C1LT23 0.108 5.087 4.333 3996. 1 .174 30 C1LT24 0.307 5.356 4.677 1516. 1 .145 123 C1LT25 0.097 3.377 3.173 3270. 1 .065 92 C1LT26 0. 154 6.392 5.194 3370. 1 .231 30 C1LT27 0.307 5.109 4.370 1417. 1 .169 123 C1LT28 0.099 3.150 2.612 2632. 1 .206 92 C1LT29 0.131 5.435 5.233 3995. 1 .038 30 C1LT30 0.226 8.150 6.608 2912. 1 .233 30 C1LT31 0.456 7.950 7.357 1605. 1 .081 61 C1LT32 0.110 5.414 4.962 4495. 1 .091 30 C1LT33 0.137 5.700 5.293 3852. 1.077 30 C1LT34 0.231 4.446 4.293 1B58. 1.036 92 C1LT35 0.197 7.345 6.455 3266. 1.136 30 C1LT36 0.211 4.471 4.385 2073. 1 .020 92 C1LT37 0.076 4.125 3.929 5139. 1 .050 30 C1LT38 0. 185 4.337 4.245 2294. 1.022 92 C1LT39 0.271 4.301 3.799 1399. 1.132 123 C1LT40 0.099 3.069 2.983 2997. 1.029 92 C1LT41 0.102 2.044 1 .971 1927. 1.037 154 C1LT42 0.955 8.743 8.188 849. 1.068 123 C1LT43 0.211 5.685 4.459 2113. 1.275 61 C1LT44 0.336 5.946 4.267 1266. 1.393 123 C1LT45 0.210 5.823 4.285 2033. 1 .359 61 C1LT46 0.118 4.113 3.750 3173. 1.097 61 C1LT47 0.217 5.571 5.442 2506. 1 .024 61 C1LT48 0.452 6.604 5.818 1280. 1 .135 92 C1LT49 0.166 5.285 4.729 2837. 1.118 61 C1LT50 0.671 9.656 9.167 1358. 1.053 123 0.228 0.172 5.298 1.840 4.678 1.648 2867.479 1588.704 1.137 0.101 75.260 41.224 APPENDIX III Table 3.72 Inclusion Parameters of CI TS Plane as Analysed From  Quantimet Data CODE AF CO MICRON C MICRON D MICRON FF N C1TS01 C1TS02 C1TS03 C1TS04 C1TS05 C1TS06 C1TS07 C1TS08 C1TS09 C1 TS 1 0 C1 TS 11 CITS 12 C1TS13 C1 TS 1 4 C1TS15 C1TS16 C1 TS 1 7 CITS 18 C1TS19 C1TS20 C1TS21 C1TS22 C1TS23 C1TS24 C1TS25 C1TS26 C1TS27 C1TS28 C1TS29 C1TS30 C1TS31 C1TS32 C1TS33 C1TS34 C1TS35 C1TS36 C1TS37 C1TS38 C1TS39 C1TS40 C1TS41 C1TS42 C1TS43 C1TS44 C1TS45 C1TS46 C1TS47 C1TS48 C1TS49 C1TS50 0.305 0.127 0.051 0.174 0.291 0.126 0.296 1 .542 0.326 0.097 0.108 0.106 0.217 0.076 0.196 0.063 0.404 0.079 0.084 0.201 0.320 0.172 0.124 0.097 0.057 0.313 0.214 0.108 0.184 0.096 0.047 0.214 0.064 0.292 0.521 0.523 0.789 0.087 0.092 0.095 0.229 0.365 0.312 0.134 0.051 0.236 0.352 0.157 0.097 0.172 0.228 5.046 4.491 2755.362 1.137 82.080 5.583 3.817 2.022 2.581 6.035 3.988 4.508 13.541 4.638 5.000 3.890 3.266 680 4. 2.491 3.535 4.024 6.519 2.137 3.378 3.561 5.670 6.403 3.055 3.621 3.825 8.889 6.794 .333 .009 ,124 .429 5.022 4.041 4.323 6.696 11.076 13.108 2.753 .550 ,109 .734 .065 .268 .220 .412 ,192 .915 .354 .250 4. 6. 6. 2. 5. 3. 7, 6. 4. 3, 3. 5. 3. 4, 5. 6.889 5.313 3.523 1 .950 2.512 5.921 3.874 4.326 13.115 3.874 4. 3. 4.773 3.536 2.598 4. 179 2.418 2.946 3.800 6.152 1.900 3.145 3.448 5.490 6.190 2.800 2.763 3.600 8.445 5.634 .034 .605 4.164 2.217 4.714 3.123 3.322 5.569 9.911 12.529 2.340 4.343 2.631 6.689 5.552 3.789 2.734 3.212 4.170 3.332 4.141 4.200 6.000 0.237 2.424 2.319 1398.389 0.123 42.704 1737. 2766. 3855. 1437. 2032. 3082. 1455. 837. 1183. 4904. 3269. 2452. 1924. 3174. 1497. 5996. 1515. 2398. 3721 . 1711. 1709. 3594. 2247. 2839. 6349. 2692. 2629. 3720. 1960. 4316. 4693. 2199. 4906. 1134. 1064. 1885. 1576. 2698. 4691 . 2767. 2912. 1516. 1210. 2035. 6350. 1766. 944. 2630. 4316. 3478. 1 .051 1 .083 1 .037 1 .027 1.019 1 .029 1 .042 1.033 1.197 1 .048 1 .100 1 .257 1 .120 1.030 1 .200 1 .059 1.060 1 .125 1 .074 1.033 1.033 1 .034 1.091 1.310 1 .063 1 .053 1 .206 1 .074 1.667 1 .471 1 .095 1.065 1 .294 1 .301 1 .202 1.118 1 .046 1 .176 1 .278 1.182 1.156 1.092 1.127 1.178 1.063 1.245 1.175 1 .051 1.250 1.148 92 92 92 154 61 61 123 61 123 30 61 92 92 92 154 61 123 123 61 123 123 30 123 92 30 30 61 61 61 30 61 30 30 154 92 30 30 92 30 92 61 92 154 123 61 92 216 92 30 30 APPENDIX III 222 Table 3.73 Inclusion Parameters of C M S Plane as Analysed From Quantimet Data CODE AF CO C MICROS MICRON C1LS01 0.177 4.B92 4.14B C1LS02 0.252 7.567 5.559 C1LS03 0.053 2.714 2.280 C1LS04 0.093 2.863 2.444 C1LS05 0.090 2.936 2.850 C1LS06 0.073 2.721 2. 192 C1LS07 0.237 6.916 6.093 C1LS08 0.027 2.673 2.262 C1LS09 0.220 3.651 3.342 C1LS10 0.060 4.031 2.804 C1LS11 2.895 19.300 18.611 C1LS12 0.144 3.447 3.041 C1LS13 0.076 3.437 2.946 C1LS14 0.017 2.100 1 .575 C1LS15 0.216 4.662 4.571 C1LS16 0.242 7.457 6.692 C1LS17 0.560 11.200 10.996 C1LS18 0.239 8.323 7.588 C1LS19 0.059 4.915 3.363 C1LS20 0.024 2.933 2.200 C1LS21 0.050 3.620 3.194 C1LS22 0.141 5.090 4.926 C1LS23 0.240 3.651 3.323 C1LS24 0.062 2.922 2.800 C1LS25 0.026 1 .762 1 .484 C1LS26 0.039 3.231 3.000 C1LS27 0.229 5.507 4.347 C1LS28 0.097 3.097 2.568 C1LS29 0.116 5.225 5.016 C1LS30 0.092 5.258 3.996 C1LS31 0.167 5.806 4.865 C1LS32 0.041 2.920 2.737 C1LS33 0.012 2.150 1 .173 C1LS34 0.088 4.755 4.135 C1LS35 0.052 2.232 2.067 C1LS36 0.079 3. 178 2.860 C1LS37 0.306 5.608 4.939 C1LS38 0.004 0.500 0.450 C1LS39 0.101 3.532 3.318 C1LS40 0.056 3.333 3.000 C1LS41 0.099 3.967 3.150 C1LS42 0.101 4.748 4.368 C1LS43 0.057 3.090 2.809 C1LS44 0.035 2.500 2.206 C1LS45 0.038 3.400 3.138 C1LS46 0.330 6.370 5.945 C1LS47 0.171 5.117 4.847 C1LS48 0.024 2.125 1 .594 C1LS49 0.189 7.024 6.366 C1LS50 0.108 4.157 3.637 0.178 0.402 4.492 2.851 3.956 2.766 4305.457 2382.652 1.167 0.143 70.300 40.300 FF MICRON 2344. 1 .17a i £i 2199. 1.361 61 4318. 1 .190 92 2632. 1.171 154 3174. 1 .030 92 2998. 1 .241 92 2565. 1 .135 92 8305. 1 .182 30 1518. 1 .092 154 4693. 1 .438 61 624. 1 .037 61 2115. 1 . 133 154 3P.54. 1 .167 61 8998. 1 .333 30 2113. 1.020 92 2763. 1.114 30 1953. 1.019 61 3169. 1.097 30 5681 . 1 .462 30 8998. 1.333 61 6350. 1.133 30 3479. 1.033 61 1381. 1.099 185 4497. 1.043 61 5683. 1 .188 92 771 1 . 1 .077 30 1890. 1 .267 92 2632. 1 .206 154 4315. 1 .042 30 4316. 1.316 30 2914. 1 .194 61 6747. 1 .067 30 9817. 1.833 123 4692. 1.150 30 3998. 1.080 92 3597. 1.111 61 1607. 1.136 123 10800. 1.111 30 3269. 1.065 61 5397. 1.111 30 3173. 1.259 61 4316. 1.087 30 4906. 1.100 61 6351 . 1.133 61 8305. 1.083 30 1794. 1.071 92 2837. 1.056 61 6748. 1.333 61 3369. 1.103 30 3371 . 1.143 61 APPENDIX III Table 3.81 Inclusion Parameters of C2 LT Plane as Analysed from  Quantimet Data CODE AF CO C D F F N MICRON MICRON MICRON 7 . 5 4 6 5.771 1582. 1 .308 61 5 . 6 2 8 5.21 1 3 9 9 5 . 1 .080 30 3 . 6 6 0 3 . 2 2 9 3 1 7 3 . 1 .133 61 2 . 7 8 0 2 . 7 2 0 2 3 4 5 . 1.022 92 7 . 3 8 9 6 . 8 0 5 2 8 3 5 . 1 . 086 30 3 . 6 2 3 2 . 6 1 7 5 9 9 7 . 1 .385 61 2 . 9 3 6 2 . 7 4 0 7 1 9 7 . 1 .071 30 4 . 1 1 0 3 .162 8 3 0 5 . 1 .300 30 2 . 7 5 7 2 . 4 1 2 4 4 9 8 . 1 .143 61 3 . 2 7 7 2 . 8 4 0 7 1 9 7 . 1 . 154 30 2 . 7 0 0 2 . 4 5 5 4 9 0 7 . 1.1 00 61 3 .367 2 . 2 7 2 2 6 9 8 . 1 .481 92 8 . 3 2 7 8 . 0 8 2 3168 . 1 .030 30 1 5 . 3 8 7 12 .390 1390 . 1 . 242 30 3 . 1 6 2 3 . 0 4 4 3 9 9 7 . 1 .038 61 4 . 3 8 3 3 . 9 4 5 5 3 9 6 . 1.111 30 3 . 7 6 2 3 . 4 7 3 4 1 5 0 . 1 . 083 61 7 . 0 3 8 5 . 0 0 8 2 0 7 2 . 1 . 4 0 5 30 5 . 4 4 5 5 . 2 2 2 2 1 9 9 . 1 . 043 61 14 .387 1 2 . 7 6 9 1337 . 1 .127 30 3 .208 2 . 9 7 9 7711 . 1 .077 30 8 . 4 0 0 7 . 6 5 3 2 3 9 2 . 1 . 098 30 5 . 0 7 3 4 . 2 9 2 4 1 5 0 . 1 .182 30 7 . 9 0 8 7 . 6 0 4 2 0 6 9 . 1 .040 30 1 .500 1 . 350 10799 . 1.111 30 2 . 6 1 8 2 . 4 0 0 2 9 9 8 . 1.091 92 3 . 9 0 0 3 . 5 2 3 3 4 8 0 . 1 .107 61 2 . 8 0 0 2 .471 6 3 5 0 . 1 .133 30 1.157 1.012 4 4 9 9 . 1 . 143 92 1 .714 1 . 600 7 1 9 8 . 1.071 61 3 . 5 0 6 3 . 1 1 7 5 9 9 7 . 1 . 1 2 5 30 4 . 2 1 2 3 . 6 5 0 3596 . 1 .154 61 2 . 7 0 0 2 . 4 3 0 10798 . 1.111 30 2 . 1 7 5 1 .933 11998. 1 . 1 2 5 30 3 .514 3 . 2 0 9 4 6 9 2 . 1 .095 61 9 . 6 0 8 7 . 1 5 9 2 1 1 0 . 1 .342 30 4 .361 4 . 2 1 0 3 7 2 0 . 1 . 036 61 2 . 3 0 0 1.917 5 9 9 8 . 1 . 200 61 4 . 2 0 0 4 . 0 6 9 3371 . 1 . 032 61 1 .800 1 . 543 15427 . 1 . 167 30 7 . 3 9 4 6 . 2 8 5 1794. 1 . 176 61 9 . 8 8 8 8 . 9 7 2 1991 . 1 . 102 61 5 . 0 4 2 4 . 6 5 4 2 7 6 5 . 1 .083 61 3.681 2 . 6 5 8 2 9 9 7 . 1 .385 61 4 . 1 7 5 2 . 9 4 7 6 3 5 0 . 1.417 61 3 . 7 8 7 3.521 1891 . 1 .075 123 5 . 0 8 3 4 . 2 6 3 1738 . 1 . 192 92 3 . 106 2 . 9 3 3 5 9 9 7 . 1 . 0 5 9 61 9 . 9 5 0 7 . 1 0 7 1279 . 1 .400 123 4 . 9 9 4 4 . 0 4 3 0 . 1 9 7 3 . 0 0 3 2 .531 2 9 6 1 . 1 9 5 0 . 1 1 7 2 4 . 6 5 2 5 1 3 9 . 1 .235 30 C2LT01 C 2 L T 0 2 C 2 L T 0 3 C2LT04 C 2 L T 0 5 C 2 L T 0 6 C 2 L T 0 7 C 2 L T 0 8 C 2 L T 0 9 C 2 L T 1 0 C2LT1 1 C2LT1 2 C 2 L T 1 3 C 2 L T 1 4 C 2 L T 1 5 C 2 L T 1 6 C 2 L T 1 7 C 2 L T 1 8 C 2 L T 1 9 C 2 L T 2 0 C2LT21 C 2 L T 2 2 C 2 L T 2 3 C 2 L T 2 4 C 2 L T 2 5 C 2 L T 2 6 C 2 L T 2 7 C 2 L T 2 8 C 2 L T 2 9 C 2 L T 3 0 C2LT31 C 2 L T 3 2 C 2 L T 3 3 C 2 L T 3 4 C 2 L T 3 5 C 2 L T 3 6 C 2 L T 3 7 C 2 L T 3 8 C 2 L T 3 9 C 2 L T 4 0 C2LT41 C 2 L T 4 2 C 2 L T 4 3 C 2 L T 4 4 C 2 L T 4 5 C 2 L T 4 6 C 2 L T 4 7 C 2 L T 4 8 C 2 L T 4 9 C 2 L T 5 0 0 . 3 6 3 0 . 1 3 0 0 .102 0 . 1 1 6 .239 .044 .038 .038 .054 . 039 .050 .084 0 .254 0 . 8 8 3 0 . 0 7 6 0 . 0 7 3 084 241 237 946 039 319 103 366 0 . 0 1 2 0 . 0 8 0 0.101 0 . 0 3 9 022 022 052 101 0 . 0 2 2 0 . 0 1 6 0 . 0 6 8 0 .338 0 . 1 1 3 0 . 0 3 2 • 0 .121 0 . 0 1 0 0 . 3 4 9 0 . 4 4 9 0 . 1 6 8 0 . 0 8 9 0 . 0 4 6 0 . 1 6 6 0 . 2 4 5 0 . 0 4 9 0 . 5 5 3 0 . 0 7 9 0 . 1 6 6 4 . 9 0 8 4 . 2 3 3 4 5 9 4 . 6 5 2 1 .158 5 2 . 9 4 0 0 . 0 . 0 . 0 . 0 . 0. 0. 0. 0 . 0 . 0. 0. APPENDIX III Table 3.82 Inclusion Parameters of C2TS Plane as Analysed From Quantimet ...Data . CODE AF CO C D FF N MICRON MICRON MICRON C2TS01 0.040 2.541 2.274 5682. 1.118 61 C2TS02 0.072 3.000 2.437 3373. 1 .231 92 C2TS03 0.048 3.460 3.053 6350. 1.133 30 C2TS03 0.041 3. 193 2.794 6747. 1 .143 30 C2TS05 0.115 5.413 4.788 4149. 1 . 130 30 C2TS06 0. 157 6.267 4.976 3171 . 1 .259 30 C2TS07 0.346 7.058 6.341 1824. 1.113 61 C2TS08 0.094 2.372 1 .962 2075. 1 .209 92 C2TS09 0.258 5.682 5.354 2072. 1 .061 61 C2TS10 0.194 6.755 6.345 3266. 1.065 30 C2TS11 0.045 3.220 2.841 6350. 1 .133 30 C2TS12 0.457 9.682 9.496 2067-. 1 .020 61 C2TS13 0.297 8.447 7.829 2626. 1 .079 30 C2TS14 0.657 12.664 11.820 1788. 1 .071 30 C2TS15 0.067 4.860 3.471 5139. 1 .400 30 C2TS16 0.236 7.500 7.286 3078. 1 .029 30 C2TS17 0.037 3.325 3.069 8305. 1 .083 30 C2TS18 0.243 7.729 7.103 2912. 1.088 30 C2TS19 0.228 5.857 5. 125 2245. 1.143 61 C2TS20 0.166 5.768 4.967 2995. 1.161 30 C2TS21 0.114 3.618 3.237 2839. 1.118 61 C2TS22 0.102 3.552 2.897 2839. 1.226 61 C2TS23 0.260 7.208 6.537 2505. 1.103 61 C2TS24 0.506 9.264 9.110 1791 . 1.017 61 C2TS25 0.087 4.926 4.680 5395. 1 .053 30 C2TS26 0.051 3.921 2.745 5397. 1.429 61 C2TS27 0.434 10.427 8.531 1955. 1.222 30 C2TS28 0.149 3.573 3.496 2344. 1 .022 92 C2TS29 0.150 6.231 5.786 3851 . 1 .077 30 C2TS30 0.408 9.187 8.820 2151 . 1.042 61 C2TS31 0.051 3.431 3.229 6350. 1 .063 61 C2TS32 0.090 4.875 4.643 5138. 1 .050 30 C2TS33 0.169 4.816 4.256 2507. 1 .132 61 C2TS34 0.378 7.034 3.743 987. 1.879 154 C2TS35 0.261 6.402 5.869 2244. 1.091 61 C2TS36 0.095 3.935 3.789 3996. 1.038 92 C2TS37 0.111 3.852 3.512 3173. 1.097 61 C2TS3B 1 .421 18.271 17.641 1224. 1 .036 30 C2TS39 0.058 1.959 1 .650 2840. 1.188 123 C2TS40 0.088 2.257 1.896 2158. 1.190 123 C2TS41 0.041 2.353 1 .788 4318. 1.316 61 C2TS42 0.640 9.600 8.533 1325. 1.125 30 C2TS43 0.102 5.018 4.800 4691 . 1.045 30 C2TS44 0.012 2.700 1.929 15427. 1.400 30 C2TS45 0.126 5.675 5.448 4315. 1.042 30 C2TS46 0.056 2.635 2.331 4152. 1.130 61 C2TS47 0.042 3.279 2.869 6747. 1 .143 30 C2TS48 0.033 2.950 2.723 8305. 1.083 30 C2TS49 0.086 5.150 3.565 4150. 1 .444 30 C2TS50 0.296 5.616 5.519 1857. 1.018 61 0.204 0.233 5.570 3.031 4.978 2.949 3863.727 2442.475 1.150 0.149 52.320 28.439 APPENDIX III Table 3.83 Inclusion Parameters of C2LS Plane as Analysed  From Quantimet Data CODE AF CO C D FF N MICRON MICRON MICRON C2LS01 0.119 3.308 2.804 2345. 1.179 92 C2LS02 0.507 6.640 5.527 1085. 1 .237 92 C2LS03 0. 103 5.073 4.292 4150. 1 .182 30 C2LS04 0.853 14.178 11.239 1306. 1 .262 30 C2LS05 0.019 2.587 2.070 10798. 1 .250 30 C2LS06 0.057 3.862 3.433 5997. 1 .125 30 C2LS07 0. 104 5.357 4.687 4495. 1 .143 30 C2LS08 0.066 3.983 3.414 5139. 1 .167 30 C2LS09 0.030 2.945 2.314 7712. 1 .273 30 C2LS10 0.107 5.500 4.442 4149. 1 .238 30 C2LS11 0.135 4.850 3.637 2696. 1 .333 61 C2LS12 0.204 5.638 4.488 2200. 1 .256 61 C2LS13 0.052 2.937 2.232 4318. 1.316 61 C2LS14 0.075 3.668 2.181 2917. 1.682 92 C2LS15 0.108 4.322 3.334 3062. 1.296 61 C2LS16 0.164 6.544 6.093 3718. 1 .074 30 C2LS17 0.245 5.194 4.343 1766. 1 .196 123 C2LS18 0.302 8.805 8.145 2692. 1 .081 30 C2LS19 0.056 3.787 3.565 6349. 1.063 30 C2LS20 0.146 6.288 6.046 4148. 1.040 30 C2LS21 0.084 4.768 4.530 5395. 1.053 30 C2LS22 0.051 3.943 3.450 6747. 1.143 30 C2LS23 0.106 5.209 4.983 4691 . 1.045 30 C2LS24 0.508 10.765 9.150 1791 . 1 .176 30 C2LS25 0.034 2.838 2.636 7712. 1.077 30 C2LS26 0.086 4.241 4.057 4692. 1 .045 30 C2LS27 0.078 4.437 4.014 5139. 1 .105 30 C2LS28 0.013 1 .800 1 .600 11998. 1 .125 30 C2LS29 0.136 6.695 4.209 3082. 1 .591 61 C2LS30 0.277 8.084 7.871 2834. 1 .027 30 C2LS31 0.114 3.853 2.936 2568. 1.313 123 C2LS32 0.496 9.922 9.400 1885. 1 .056 61 C2LS33 0.115 3.891 3.276 2839. 1 .188 61 C2LS34 0.261 7.842 7.630 2911. 1 .028 30 C2LS35 0.067 4.033 3.630 5396. 1.111 30 C2LS36 0.160 7.212 5.584 3478. 1 .292 30 C2LS37 0.161 6.204 5.990 3718. 1 .036 30 C2LS38 0.256 6.433 5.532 2154. 1 .163 92 C2LS39 0.039 3.254 2.644 6747. 1 .231 30 C2LS40 0.092 3.546 3.424 3721 . 1.036 61 C2LS41 3.088 24.342 22.841 717. 1.066 30 C2LS42 0.025 2.730 1 .606 6351 . 1.700 61 C2LS43 0.434 7.438. 6.994 1605. 1.063 61 C2LS44 0.032 3.164 2.900 8997. 1.091 30 C2LS45 0.043 2.127 1.671 3855. 1.273 92 C2LS46 0.075 3.375 3.000 3997. 1 .125 61 C2LS47 0.031 3.300 3.000 9815. 1 .100 30 C2LS48 0.018 2.437 2.167 11998. 1.125 30 C2LS49 0.078 3.832 2.719 3481 . 1 .409 61 C2LS50 0.137 4.950 4.243 3081 . 1 .167 61 0.211 0.441 5.447 3.585 4.719 3.349 4489.172 2669.696 1.187 0.152 47.980 25.631 APPENDIX IV Microstructural Analysis of Ingot Stage Inclusions — DTa flag-Size SL No. x  1 11.72 880 13.31 2 7.82 880 8.88 3 4.02 880 4.56 4 3.82 880 4.34 5 13.74 508 27.04 6 13.38 508 26.33 7 14.22 508 27.99 8 21.26 508 41.85 g 3.40 508 6.69 1 0 4.62 508 9.09 11 2.56 508 5.03 12 8.56 508 16.88 13 3.68 508 7.24 1 4 4.10 508 8.07 15 6.50 508 12.79 16 4.02 508 7.91 17 18 19 2.72 508 5.35 6.64 508 13.07 3.80 508 7.48 20 2.24 508 4.40 21 2.04 508 4.01 22 13.08 508 25.74 24 25 26 27 4.48 508 8.81 6.02 508 11.85 4.00 508 7.87 4.06 508 7.99 4.94 508 9.72 28 6.78 508 13.34 29 1.96 508 3.85 30 4.32 880 4.90 31 2.92 880 3.31 32 3.34 880 3.79 33 2.28 880 2.59 34 4.28 880 4.86 35 3.48 880 3.95 36 2.78 880 3.15 37 3.48 460 7.56 38 1.50 460 3.26 39 2.40 460 5.21 40 8.34 800 10.42 Mean . ".11 v Std. Dev. 8.53 u * Dia = a = b a = Major axis of an el l ipse b = Minor axis of an el l ipse APPENDIX IV Table 4.2 Microstructural Analysis of S2 (38% reduced) Stage LS Plane Inclusions 227 SI.No. a (mm) b(mm) Mag a(y) bin) FF=a/b 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 30.04 39.70 47.20 36.52 25.28 9.26 15.10 9.36 4.50 6.10 6.78 7.14 14.64 10.34 9.38 37.12 16.30 25.42 19.38 7.96 15.20 9.10 6.78 10.40 6.44 23.24 9.02 7.22 6.68 15.46 8.70 8.64 6.80 33.74 6.24 6.72 54.62 38.04 33.34 18.26 7.84 15.02 12.02 6.68 6.44 8.88 32.30 5.88 6.14 28.82 8.36 6.24 9.80 5.04 4.12 1.92 2.74 2.42 1.02 I. 48 2.22 2.92 4.82 3.72 2.60 6.50 2.80 4.48 3.54 2.00 2.38 2.02 1.68 1.84 2.06 6.00 2.52 2.00 2.44 7.00 2.46 3.84 3.50 8.68 2.20 1.78 II. 18 6.98 6.10 4.46 2.10 3.28 2.66 2.18 3.00 2.52 7.44 2.24 2.26 5.24 x560 x834 x930 x834 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x508 x930 x930 x930 x930 x930 x930 X930 x930 x930 x930 x930 Mean Std.Dev. 53.64 47.60 50.75 43.78 49.76 18.22 29.72 18.42 8.85 12.00 13.34 14.05 28.81 20.35 18.46 73.07 32.08 50.03 38.14 15.66 29.92 17.91 13.34 20.47 12.67 45.74 17.75 14.21 13.14 30.42 17.12 17.00 13.38 66.41 12.28 13.32 107.51 74.88 65.62 19.63 8.43 16.15 12.92 7.18 6.92 9.54 34.73 6.32 6.60 30.98 27.98 21.77 14.92 7.48 10.53 6.04 8.11 3.77 5.39 4.76 2.00 2.91 4.48 5.74 9.48 7.32 5.11 12.79 5.51 8.81 6.96 3.93 4.68 3.97 3.30 3.62 4.05 11.81 4.96 3.93 4.80 13.77 4.84 7.55 6.88 17.08 4.33 3.50 22.00 13.74 12.00 4.79 2.25 3.52 2.86 2.34 3.22 2.70 8.00 2.40 2.43 5.63 6.55 4.34 3.59 6.36 4.81 7.24 6.13 4.83 5.51 3.86 4.41 4.12 2.97 2.44 3.03 2.77 3.60 5.71 5.82 5.67 5.47 3.98 6.38 4.50 4.03 5.65 3.12 3.87 3.57 3.61 73 20 53 25 94 83 77 4.88 5.44 5.46 4.09 3.73 4.57 4.51 3.06 2.14 3.52 4.34 2.62 2.71 5.50 4.13 1.28 APPENDIX IV 228 Table 4.3 Microstructural Analysis of S2 (38% reduced) Stage TS Plane Inclusions SI.No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 a(nrn) b(mm) Mag 16.92 8.18 x930 4.52 2.94 x930 3.50 2.28 x930 4.62 3.40 x930 2.72 2.34 x930 14.28 5.68 x930 6.92 4.24 x930 5.30 2.94 x930 4.36 2.74 x930 7.94 5.96 x930 4.70 2.82 x834 7.38 3.68 x834 8.02 3.46 x834 4.46 3.12 x834 5.50 3.50 x834 4.10 2.94 x834 10.42 5.62 x834 6.38 3.50 x834 5.64 3.68 x834 6.74 4.38 x834 4.02 2.58 x834 5.12 3.54 x504 4.34 2.22 X504 5.14 1.92 x504 5.12 2.86 x504 7.92 3.90 x504 4.18 2.48 x504 3.12 2.44 x504 20.92 7.20 x504 6.94 3.16 x504 2.88 1.32 x504 3.94 2.26 x504 5.24 3.04 x504 3.58 2.00 x504 5.08 2.88 x504 2.70 1.54 x504 5.22 1.56 x504 6.54 2.52 x504 7.52 2.68 x504 4.70 1.58 x504 4.80 1.28 x504 5.38 3.64 x504 5.96 4.26 x504 13.60 8.58 x504 7.48 4.64 x504 5.64 3.60 X504 4.90 3.62 x504 3.46 2.76 x504 7.56 4.10 x504 10.50 7.00 x504 a(u) b(u) FF=a/b Mean Std.Dev. 18.19 8.79 2.06 4.86 3.16 1.53 3.76 2.45 1.53 4.96 3.65 1.35 2.92 2.51 1.16 15.35 6.10 2.51 7.44 4.55 1.63 5.69 3.16 1.80 4.68 2.94 1.59 8.53 6.40 1.33 5.63 3.38 1.66 8.84 4.41 2.00 9.61 4.14 2.31 5.34 3.74 1.42 6.59 4.19 1.57 4.91 3.52 1.39 12.49 6.73 1.85 7.64 4.29 1.78 6.76 4.41 1.53 8.08 5.25 1.53 4.82 3.09 1.55 10.15 7.02 1.44 8.61 4.40 1.95 10.19 3.80 2.67 10.15 5.47 1.85 15.71 7.73 2.03 8.29 4.92 1.68 6.19 4.84 1.27 41.50 14.28 2.90 13.76 6.26 2.19 5.71 2.61 2.18 7.81 4.48 1.74 10.39 6.03 1.72 7.10 3.96 1.79 10.07 5.71 1.76 5.35 3.05 1.75 10.35 3.09 3.34 12.97 5.00 2.59 14.92 5.31 2.80 9.32 3.13 2.97 9.52 2.53 3.75 10.67 7.22 1.47 11.82 8.45 1.39 26.98 17.02 1.58 14.84 9.20 1.61 11.19 7.14 1.56 9.72 7.18 1.35 6.86 5.47 1.25 15.00 8.13 1.84 20.83 13.88 1.50 10.26 5.56 1.86 6.44 3.02 0.55 APPENDIX IV Table 4.4 Microstructural Analysis of S3 (70% reduced) Stage LS Plane Inclusions 229 SI.No. a(mm) b(mm) Mag a(v) b(y) FF=a/b 1 97.72 5.58 x900 2 66.22 2.92 x902 3 84.38 5.00 x900 4 17.98 4.18 x900 5 6.18 2.28 x900 6 33.56 2.78 x900 7 24.00 2.38 x900 8 7.48 1.08 x900 9 20.48 3.96 x900 10 24.58 6.58 x900 11 36.68 2.72 x506 12 104/14 4.24 x506 13 47.68 4.24 x506 14 64.76 3.82 x506 15 19.50 1.78 x506 16 45.48 3.30 x506 17 14.62 1.92 x506 18 43.74 3.18 x506 19 32.42 1.94 x506 20 8.16 1.00 x506 21 18.34 1.16 X506 22 12.90 1.32 x506 23 97.74 7.64 x506 24 26.48 2.58 x442 25 8.50 1.12 x442 26 37.78 2.78 x442 27 50.64 2.40 x442 28 11.78 1.52 x442 29 8.08 4.30 x442 30 6.78 3.62 X442 31 12.82 2.56 x442 32 13.40 3.40 x442 33 5.62 2.12 x442 34 11.84 3.12 x442 35 10.08 2.56 x442 36 53.18 3.48 x442 37 25.38 2.00 x442 38 80.06 4.06 x442 39 60.20 3.42 x442 40 12.30 1.20 x442 41 7.34 3.20 x442 42 7.66 3.14 x442 43 29.32 1.54 x442 44 19.14 1.06 x442 45 8.68 0.76 x442 46 7.42 0.60 x442 47 37.08 1.78 X442 48 53.72 4.00 x442 49 103.24 3.12 x442 50 49.88 2.24 x442 Mean Std.Dev. 108.57 73.41 93.71 19.97 6.86 37.28 26.66 8.31 22.75 27.31 72.49 205.81 94.22 127.98 38.53 89.88 28.89 86.44 64.07 16.12 36.24 25.49 193.16 59.90 19.23 85.47 114.57 26.65 18.28 15.33 29.00 30.31 12.71 26.78 22.80 120.31 57.42 181.13 136.19 27.82 16.60 17.33 66.33 43.30 19.63 16.78 83.89 121.53 233.57 112.85 64.39 55.73 6.20 3.23 5.55 4.64 .2.53 3.08 2.64 1.20 4.40 7.31 5.37 8.37 8.37 7.54 3.51 6.52 3.79 6.28 3.83 1.97 2.29 2.60 15.09 . 5.83 2.53 6.28 5.42 3.43 9.72 8.19 5.79 7.69 4.79 7.05 5.79 7.87 4.52 9.18 7.73 2.71 7.23 7.10 3.48 2.39 1.71 1.35 4.02 9.04 7.05 5.06 5.38 2.68 17.51 22.67 16.87 4.30 2.71 12.07 10.08 6.92 5.17 3.73 13.48 24.56 11.24 16.95 10.95 13.78 7.61 13.75 16.71 8.16 15.81 9.77 12.79 10.26 7.58 13.58 21.10 7.75 1.879 1.872 5.00 3.94 2.65 3.79 3.93 15.28 12.69 19.71 17.60 10.25 2.29 2.43 19.03 18.05 11.42 12.36 20.83 13.43 33.08 22.26 11.83 6.99 APPENDIX IV Table 4.5 Microstructural Analysis of S3 (70% reduced) Stage TS Plane Inclusions 230 >l.No. a(m) b(m) Mag a(v) 1 29.92 11.50 x902 33.17 2 18.40 4.12 x902 20.39 3 11.12 3.80 x902 12.32 4 6.98 3.04 x902 7.73 5 12.42 2.72 x504 24.64 6 9.12 2.10 x504 18.09 7 3.16 2.28 x504 6.26 8 8.38 2.10 x504 16.62 9 5.30 1.30 x504 10.51 10 3.32 1.40 x504 6.58 11 5.72 1.42 x504 11.34 12 12.48 2.42 x504 24.76 13 4.12 1.18 x504 8.17 14 10.70 2.02 x504 21.23 15 11.32 3.52 x504 22.46 16 12.08 3.42 x504 23.96 17 21.30 5.62 x504 42.26 18 11.18 2.94 x504 22.18 19 4.68 1.50 x504 9.28 20 3.48 0.98 X504 6.90 21 4.00 1.52 x504 7.93 22 10.22 2.30 x504 20.27 23 8.74 1.74 x504 17.34 24 5.64 1.64 X504 11.19 25 8.12 1.92 x504 16.11 26 2.12 1.20 x504 4.20 27 6.50 3.88 x504 12.89 28 6.12 3.64 x504 12.14 29 18.78 4.58 x504 37.26 30 11.42 1.62 x504 22.65 31 3.36 2.24 x504 6.66 32 1.76 1.16 x504 3.49 33 1.84 0.72 x504 3.65 34 6.68 2.28 x504 13.25 35 12.24 2.70 x504 24.28 36 3.34 0.96 x504 6.62 37 2.52 1.08 X504 5.00 38 4.20 1.24 x504 8.33 39 5.90 1.46 x504 11.70 40 2.46 1.08 x504 4.88 41 6.20 1.60 x504 12.30 42 3.84 0.90 x504 7.61 43 2.18 0.78 x504 4.32 44 11.00 2.74 x504 21.82 45 5.10 2.08 x504 10.11 46 6.6? 2.68 x504 13.13 47 2.88 1.22 x504 5.59 48 • 3.38 2.06 x504 6.70 49 3.50 1.84 x504 6.94 50 3.58 1.12 X504 7.10 Mean - 13.88 Std.Dev. 8.94 b(y) FF=a/b 12.74 4.56 4.21 3.37 5.39 4.16 4.52 4.16 2.57 2.77 2.81 4.80 2.34 4.00 6.98 6.78 11.15 5.83 2.97 1.94 3.03 4.56 3.45 3.25 3.80 2.38 7.69 7.22 9.08 3.21 4.44 2.30 1.42 4.52 5.35 1.90 2.14 2.46 2.89 2.14 3.17 1.78 1.54 5.43 4.12 5.31 2.42 4.08 3.65 2.22 4.18 2.32 2.60 4.46 2.92 2.29 4.56 4.34 1.38 3.99 4.07 2.37 4.02 5.15 3.49 5.29 3.21 3.53 3.79 3.80 3.12 3.55 2.63 4.44 5.02 3.43 4.22 1.76 1.67 1.68 4.10 7.04 1.50 1.51 2.55 2.92 4.53 3.47 2.33 3.38 4.04 2.27 3.87 4.26 2.79 4.01 2.45 2.47 2.31 1.64 1.90 3.19 3.30 1.17 APPENDIX IV Table 4.6 Microstructural Analysis of S4 (88% reduced) Stage LS Plane Inclusions 231 SI.No. a(nm) b(mm) Mag a(u) b(w) FF=a/b 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 114.62 1.84 x900 127.35 67.58 3.18 x900 75.08 20.14 0.68 x900 22.37 37.18 1.00 x900 41.31 42.98 0.60 x900 47.75 7.00 0.92 x900 7.77 58.28 0.94 x900 64.75 12.20 4.60 x900 13.55 68.82 2.12 x442 155.70 13.12 2.48 x442 29.68 9.48 2.50 x442 21.44 72.18 1.10 x442 163.30 7.44 0.62 x442 16.83 12.70 4.18 x442 28.73 27.48 2.44 x442 62.17 32.40 4.96 x442 73.30 10.20 0.30 x442 23.07 75.84 1.80 x442 170.76 9.88 2.92 x442 22.35 20.90 3.54 x442 47.28 73.14 1.14 x442 165.47 28.14 0.88 x442 63.66 21.58 1.16 x442 48.82 10.24 1.14 x442 23.16 15.56 2.08 X442 35.20 42.16 1.32 x442 95.38 48.36 1.18 x442 109.41 12.40 0.94 x442 28.05 15.92 1.58 x442 36.01 11.74 3.94 x442 26.56 28.11 5.64 x442 63.59 18.70 1.38 x442 42.30 16.20 4.80 x442 36.65 12.42 4.40 x442 28.09 25.44 0.60 X442 57.55 17.48 0.58 x442 39.54 27.88 0.62 x442 63.07 39.50 1.10 x442 89.36 19.80 0.48 x442 44.79 45.14 0.92 x442 102.12 26.00 3.86 x442 58.82 Mean 60.29 Std.Dev. - 43.84 2.04 3.53 0.75 1.11 0.66 1.02 1.04 5.11 4.79 5.61 5.65 2.48 1.40 9.45 5.52 11.22 0.67 4.07 . 6.60 8.00 2.57 1.99 2.62 2.57 4.70 2.98 2.66 2.12 3.57 .8.91 12.76 3.12 10.85 9.95 1.35 1.31 1.40 2.48 1.08 2.08 8.73 4.15 3.33 62.29 21.25 29.61 37.18 71.63 7.60 62.00 2.65 32.46 5.29 '3.79 65.61 12.00 3.03 11.26 • 6.53 34.00 42.13 3.38 5.90 64.15 31.97 18.60 8.98 7.48 31.93 40.98 13.19 10.07 2.97 4.98 13.55 3.37 2.82 42.40 30.13 44.96 35.90 41.25 49.06 6.73 25.00 21.03 APPENDIX IV Table 4.7 Microstructural Analysis of S4 (88% reduced) Stage TS Plane Inclusions 232 SI.No. a(mm) b(mrn) Mag a(u) b(ii) FF=a/b 1 5.62 1.20 x504 2 5.84 1.12 x504 3 4.32 1.08 x504 4 8.04 1.94 x504 5 11.58 1.42 x504 6 9.74 0.68 x504 7 4.32 2.70 x504 8 6.28 3.06 x504 9 5.62 2.76 x504 10 2.74 1.78 x504 11 8.80 6.28 x504 12 6.92 1.72 x504 13 6.76 3.76 x504 14 11.10 1.40 x504 15 6.00 1.70 x504 16 5.04 3.04 x504 17 4.98 1.80 x504 18 4.38 1.88 x504 19 2.58 0.66 x504 20 6.14 1.18 x504 21 9.68 3.52 x504 22 4.60 2.66 x504 23 3.68 0.82 x504 24 4.00 1.16 x504 25 2.98 0.56 x504 26 5.58 3.24 x504 27 6.00 1.44 x504 28 6.24 0.66 x504 29 2.94 1.00 x504 30 4.64 1.02 x504 31 3.64 0.56 x504 32 3.42 1.14 x504 33 4.26 1.34 x504 34 2.94 1.48 x504 35 16.68 11.14 x900 36 12.00 7.16 x900 37 8.04 3.20 x900 38 14.22 2.48 x900 39 5.14 1.04 x900 40 9.98 1.58 x900 41 19.00 6.28 x900 42 13.94 2.40 x900 43 23.08 4.82 x900 44 13.00 1.88 x900 45 10.40 2.28 x900 46 8.14 4.76 x900 47 13.60 5.50 x900 48 8.20 2.10 x900 49 8.82 1.34 x900 50 11.32 3.94 x900 Mean StdiDev: 11.15 11.58 8.57 15.95 22.97 19.32 8.57 12.46 11.15 5.43 17.46 13.73 13.41 22.02 11.90 10.00 9.88 8.69 5.11 12.18 19.20 9.12 7.30 7.93 5.91 11.07 11.90 12.38 5.83 9.20 7.22 6.78 8.45 5.83 18.53 13.33 8.93 15.80 5.71 11.08 21.11 15.48 25.64 14.44 11.55 9.04 15.11 9.11 9.80 12.57 11.93 4.88 2.38 4.68 2.22 5.21 2.14 4.00 3.84 4.14 2.81 8.15 1.34 14.32 5.35 1.60 6.07 2.05 5.47 2.03 3.53 1.53 12.46 1.40 3.41 4.02 7.46 1.79 2.77 7.92 3.37 3.52 6.03 1.65 3.57 2.76 3.73 2.32 1.30 3.90 2.34 5.20 6.98 2.75 5.27 1.72 1.62 4.48 2.30 3.44 1.11 5.32 6.42 1.72 2.85 4.16 1.30 9.45 1.98 2.94 2.02 4.54 1.11 6.50 2.26 3.00 2.65 3.17 2.93 1.98 12.37 1.49 7.95 1.67 3.55 2.51 2.75 5.73 1.15 4.94 1.75 6.31 6.97 3.02 2.66 5.80 5.35 4.78 2.08 6.91 2.53 4.56 5.28 1.71 6.11 2.47 2.33 3.90 1.48 6.58 4.37 2.87 3.82 4.05 2.56 2.44 APPENDIX V Table 5.1 K(/Kic' Kic " J I C R e s u 1 t s o f S 2 ( 3 8 5 8 reduction) Stage With Crack Transverse to Ro l l ing Direct ion Specimen Code Temp A/W K Q Bl F J Q B2 K IC * J IC °C KSi fin MPa/nT inch mm i n - l b i n * KJ ~7 m inch mm K S i / i n MPa/nT HTS2LT01 HTS2LT03 23 . 23 0.520 0.516 27.13 26.70 29.81 29.34 1.163 1.127 29.54 28.62 2.254 2.256 360.00 390.00 63.07 68.32 0.171 0.185 4.34 4.69 108.94 113.38 119.72 124.60 HTS2LT02 -40 0.518 25.57 28.10 0.863 21.92 2.255 330.00 57.81 0.141 3.58 104.30 114.62 HTS2LT04 HTS2LT05 -80 -80 0.509 0.522 28.75 30.99 31.59 34.05 0.802 0.932 20.37 23.67 2.261 2.254 229.67 248.34 40.23 43.50 0.087 0.094 2.20 2.38 87.01 90.48 95.62 99.43 HTS2LT06 HTS2LT07 -120 -120 0.534 0.538 39.26 39.60 43.14 43.52 1.045 1.063 26.54 27.00 2.247 2.245 173.56 147.88 30.40 25.90 0.058 0.050 1.47 1.27 75.64 69.82 83.12 76.73 HTS2LT08 -196 0.528 26.56 29.18 0.141 3.58 2.250 23.12 4.05 0.005 0.12 27.61 30.34 Footnote: Bl = 2.5 | -S-F = f(a /W) = 2(J+a2) w h e r e a =*/ 2(2a / b ) 2 + 2(2a /b) + 2 - (2a /b+1) o 1 + a <: o o o B2 = 25 — ^ ~ "flow APPENDIX V Table 5.2 K n / K l r , K l r - J . r Results of S2 (38% reduction) Stage With Crack Para l le l to the Rol l ing Di rect ion Specimen Temp A/W B 1 F J Q [ i 2 K IC " J I C Code °C KSi/Tn" MPa«fiT inch mm i n - l b i n 2 KJ ~7 m inch mm KSi/Tn MPa/fiT HTS2TL01 23 0.518 26.68 29.32 1.094 27.78 2.255 270.00 47.30 0.126 3.20 94.34 103.67 HTS2TL03 23 0.548 25.88 28.44 1.030 26.16 2.254 290.00 50.80 0.136 3.45 97.77 107.44 HTS2TL02 -40 0.548 30.29 33.28 1.213 30.81 2.240 265.00 46.42 0.114 2.89 93.46 102.71 HTS2TL04 -80 0.528 31.60 34.72 1.055 26.79 2.251 227.29 39.82 0.089 2.26 86.56 95.12 HTS2TL05 -80 0.538 33.50 36.81 1.185 30.09 2.245 208.88 36.59 0.081 2.05 82.98 91.19 HTS2TL06 -120 0.546 38.27 42.05 1.043 26.49 2.241 79.81 13.98 0.027 0.68 51.29 56.36 HTS2TL07 -120 0.588 40.34 44.33 1.159 29.43 2.219 140.51 24.66 0.048 1.21 68.06 74.79 HTS2TL08 -196 0.538 26.95 29.61 0.140 3.556 2.245 22.78 3.99 0.005 0.127 27.40 30.11 ro co APPENDIX V Table 5.3 K n / K . r , K l r - J , r Results of S3 (70* reduction) Stage With Crack Transverse to the Rol l ing Di rect ion Specimen Temp A/W B l F ) B2 K IC " J I C Code °r KSi/Tn HPa^T inch mm i n - l b KJ inch mm KSi/Tn MPa /ST L . 2 1 in m HTS3LT01 23 0.520 26.06 28.63 0.895 22.73 2.254 300.00 52.56 0.131 3.32 99.44 109.28 HTS3LT09 23 0.554 26.45 29.06 0.921 23.39 2.236 380.00 66.57 0.166 4.21 112.92 124.09 HTS3LT02 -40 0.529 28.46 31.27 0.935 23.74 2.260 216.77 37.97 0.087 2.20 84.54 92.90 HTS3LT10 -40 0.536 29.65 32.58 1.014 25.75 2.247 261.36 45.79 0.105 2.66 92.82 102.00 HTS3LT03 -80 0.552 33.03 36.29 1.056 26.82 2.238 148.43 26.00 0.055 1.39 69.95 76.87 HTS3LT04 -80 0.528 30.86 33.91 0.922 23.41 2.251 184.51 32.32 0.068 1.72 77.99 85.71 HTS3LT05 -120 0.512 38.53 42.34 0.967 24.56 2.259 125.07 21.91 0.040 1.01 64.21 70.56 HTS3LT07 -120 0.563 39.13 43.00 0.998 25.34 2.232 126.65 22.18 0.041 1.04 64.62 71.01 HTS3LT06 -196 0.518 25.63 28.16 0.129 3.27 2.256 15.68 2.74 0.003 0.07 22.74 24.99 HTS3LT08 -196 0.577 26.56 29.18 0.139 3.53 2.225 22.78 3.99 0.005 0.12 27.40 30.11 ro Co tn APPENDIX V /K K - J Results of S3 (70% reduction) Stage With Crack Para l l e l to the Rol l ing Di rect ion I IC t 1^  — — • ————•—~ ~ • ' * Specimen Temp A/W Bl F Jq B 2 K IC " J IC Code °C K s i / i n MPa/m inch mm i n - l b ~7T in KJ ~2 m inch mm KSi/Tn MPa/FT HTS3TL01 23 0.542 23.43 25.74 0.751 19.07 2.242 220.00 38.54 0.096 2.43 85.16 93.53 HTS35L02 23 0.548 25.12 27.60 0.864 21.94 2.240 255.00 44.67 0.112 2.84 91.68 100.75 HTS3TL08 23 0.537 27.28 29.98 1.019 25.88 2.245 265.00 46.42 0.116 2.95 93.46 102.71 HTS3TL03 -40 0.536 24.11 26.49 0.626 15.90 2.246 192.81 33.78 0.075 1.90 79.73 87.62 HTS3TL06 -80 0.538 28.54 31.36 0.763 19.38 2.245 134.49 23.56 0.049 1.24 66.58 73.17 HTS3TL07 -80 0.531 29.12 32.00 0.794 20.16 2.249 125.95 22.06 0.046 1.16 64.44 70.81 HTS3TL04 -120 0.582 30.77 33.81 0.605 15.36 2.222 33.30 5.83 0.011 0.27 33.13 36.40 HTS3TL10 -120 0.557 31.58 34.70 0.637 16.17 2.235 34.17 5.98 0.011 0.27 33.56 36.88 HTS3TL05 -196 0.539 22.44 24.66 0.090 2.28 2.245 16.18 2.83 0.003 0.07 23.10 25.38 HTS3TL11 -196 0.538 23.21 25.50 0.097 2.46 2.245 16.88 2.95 0.003 0.07 23.59 25.92 HTS3TL12 -196 0.528 27.57 30.29 0.136 3.45 2.250 23.34 4.08 0.005 0.12 27.74 30.48 APPENDIX V Table 5.5 K./K , K - J . . Results of S4 (88% reduction) Stage With Crack Transverse to the Rol l ing D i rec t ion . ^ IC IC IC " • • ~~ Specimen Temp A/W Kg B l F J q e 2 K IC " J IC Code ° r K s i / i n MPavfiT inch mm i n - l b KJ inch mm KSi/Tn MPa^T C i n 2 m HTS4LT04 23 0.547 26.44 29.05 1.015 25.78 2.241 450.00 78.84 0.205 5.20 121.79 133.86 HTS4LT06 23 0.549 27.45 30.16 1.095 27.81 2.239 445.00 77.96 0.202 5.13 121.12 133.11 HTS4LT18 -40 0.518 22.71 24.95 0.590 14.98 2.256 310.00 54.31 0.107 2.71 101.09 111.09 HTS4LT01 -80 0.543 33.80 37.14 1.115 28.32 2.243 276.91 48.51 0.104 2.64 95.55 105.00 HTS4LT19 -80 0.516 20.52 22.55 0.411 10.43 2.257 247.95 43.44 0.093 2.36 90.41 99.36 HTS4LT03 -120 0.559 39.39 43.28 1.053 26.74 2.235 87.47 15.32 0.029 0.73 53.70 59.01 HTS4LT20 -120 0.528 27.23 29.92 0.503 12.77 2.251 102.96 18.03 0.034 0.86 58.26 64.02 HTS4LT05 -196 0.549 26.32 28.92 0.137 3.47 2.240 22.02 3.85 0.005 0.12 26.94 29.60 HTS4LT07 -196 0.540 25.16 27.65 0.125 3.17 2.245 19.94 3.49 0.004 0.10 25.64 28.17 ro CO APPENDIX V , K - J Results of S4 (88% reduction) Stage With Crack Para l le l to the Rol l ing Di rect ion Specimen Temp A/W Bl F B2 K IC " J I C Code °C KSi/Tn MPa/irT inch mm i n - l b i n 2 KJ 7 inch mm KSi/Tn" MPa^ fiT HTS4TL05 23 0.524 27.13 29.81 1.118 28.39 2.252 290.00 50.80 0.131 3.32 97.77 107.44 HTS4TL17 23 0.524 25.35 27.85 0.988 25.09 2.252 310.00 54.31 0.140 3.55 101.09 111.09 HTS4TL18 -40 0.533 19.49 21.41 0.476 12.09 2.248 227.90 39.92 0.095 2.41 86.68 95.26 HTS4TL02 -80 0.539 34.16 37.54 1.176 29.87 2.245 215.70 37.79 0.082 2.08 84.33 92.67 HTS4TL19 -80 0.518 21.08 23.16 0.448 11.37 2.256 207.79 36": 40 0.079 2.00 82.77 90.96 HTS4TL01 -120 0.565 39.75 43.68 1.058 26.87 2.231 81.11 14.21 0.027 0.68 51.71 56.82 HTS4TL20 -120 0.524 34.85 38.30 0.813 20.65 2.253 67.86 11.88 0.023 0.58 47.30 51.98 HTS4TL03 -196 0.604 30.00 32.97 0.171 4.34 2.211 28.48 4.98 0.006 0.15 30.64 33.67 HTS4TL04 -196 0.557 26.09 28.67 0.129 3.27 2.235 21.87 3.83 0.005 0.12 26.85 29.50 APPENDIX V K I C K IC " J IC R e s u 1 t s o f S 6 * 9 7 * r e d u c t i o n ) s t a 9 e W i t h C r a c k Transverse to the Rol l ing Di rect ion Specimen Temp A/W K Q Bl F B2 K IC " J I C Code °C Ksi/Tn MPa/ST inch mm 1n-lb i n 2 KJ 1 m inch mm K S i / i n MPa^iT HTS6LT04 23 0.526 22.38 24.59 0.727 18.46 2.251 580.00 101.61 0.272 6.90 138.27 151.95 HTS6LT05 23 0.523 22.07 24.25 0.708 17.98 2.253 560.00 98.11 0.262 6.65 135.87 149.32 HTS6LT06 -40 0.515 24.70 27.14 0.777 19.73 2.257 445.00 77.96 0.189 4.80 121.12 133.11 HTS6LT08 -40 0.540 23.40 25.71 0.697 17.70 2.244 510.00 89.35 0.217 5.51 129.66 142.49 HTS6LT10 -80 0.531 27.91 30.67 0.772 19.60 2.248 434.11 76.05 0.167 4.24 119.62 131.46 HTS6LT11 ' -80 0.526 28.46 31.27 0.802 20.39 2.251 366.25 64.16 0.140 3.55 109.88 120.75 HTS6LT12 -120 0.511 40.55 44.56 1.152 29.26 2.259 209.67 36.73 0.071 1.80 82.47 90.63 HTS6LT13 -120 0.507 42.21 46.38 1.248 31.69 2.261 132.47 23.20 0.045 1.14 66.08 72.62 HTS6LT14 -196 0.505 26.37 28.98 0.137 3.47 2.262 19.91 3.48 0.004 0.10 25.62 28.15 HTS6LT15 -196 0.509 21.98 24.15 0.095 2.41 2.260 17.57 3.07 0.004 0.10 24.06 26.44 APPENDIX V K , K r - J , r Results of S6 (97% reduction) Stage With Crack Para l le l to the Ro l l ing Di rect ion Specimen Temp A/W K 0 B l F J C B > K IC " J I C Code °C KSi/iTT MPa^T Inch mm i n - l b . 2 in KJ ~1 m inch mm KSi/Tn MPa/fiT HTS6TL01 23 0.527 25.20 27.69 0.923 23.44 2.251 460.00 80.59 0.203 5.15 120.43 132.35 HTS6TL02 23 0.521 24.31 26.71 0.895 21.81 2.254 400.00 70.08 0.184 4.67 114.83 126.19 HTS6TL03 -40 0.527 26.30 28.90 0.858 21.79 2.251 383.00 67.10 0.158 4.01 110.89 121.86 HTS6TL04 -40 0.538 24.42 26.83 0.739 18.77 2.245 360.00 63.07 0.152 3.86 108.94 119.72 HTS6TL05 -80 0.520 26.37 28.98 0.697 17.70 2.255 281.84 49.37 0.109 2.76 96.39 105.93 HTS6TL06 -80 0.518 28.04 30.81 0.788 20.01 2.255 260.00 45.55 0.100 2.54 92.58 101.74 HTS6TL07 -120 0.534 36.32 39.91 0.917 23.29 2.247 109.96 19.26 0.037 0.93 60.21 66.17 HTS6TL08 -120 0.518 34.41 37.81 0.823 20.90 2.263 100.39 17.58 0.034 0.86 57.53 63.22 HTS6TL09 -196 0.528 23.48 25.80 0.112 2.84 2.260 14.96 2.62 0.003 0.07 22.21 24.40 HTS6TL10 -196 0.518 22.03 24.21 0.098 2.48 2.255 15.62 2.73 0.003 0.07 22.69 24.93 APPENDIX V K /K , K - J l r Results of CI (63* reduction) Stage With Crack Transverse to the Rol l ing Direct ion Specimen Temp A/W Bl F J 0 B I K IC " " J I C Code °C Ksi /Tn MPa/nT inch mm i n - l b i n 2 KJ 7 inch mm KSi/Tn MPa«fiT HTC1LT01 23 0.555 24.50 26.92 0.999 25.37 2.236 627.00 109.85 0.285 7.23 143.77 158.00 HTC1LT02 23 0.546 23.80 26.15 0.943 23.95 2.241 648.00 113.52 0.294 7.46 146.15 160.61 HTC1LT03 -40 0.527 25.50 28.02 0.877 22.27 2.251 553.00 96.88 0.224 5.68 135.02 148.38 HTC1LT04 -80 0.532 29.07 31.94 0.899 22.83 2.248 375.48 65.78 0.138 3.50 111.26 122.27 HTC1LT05 -80 0.536 29.74 32.68 0.941 23.90 2.246 347.05 60.80 0.128 3.25 106.96 117.54 HTC1LT06 -120 0.542 32.38 35.58 0.633 16.07 2.243 153.28 26.85 0.048 1.21 71 .:08 78.11 HTC1LT07 -196 0.537 26.37 28.98 0.147 3.73 2.246 21.87 3.83 0.005 0.127 26.85 29.50 HTC1LT08 -196 0.550 28.46 31.27 0.171 4.34 2.239 26.08 4.56 0.006 0.152 29.32 32.22 ro 4 ^ APPENDIX V K - J Results of CI (63% reduction) Stage With Crack Para l l e l IC IC . -• • .—• ~ Specimen Temp A/W B 1 F 'I B; > K IC " J I C Code °C KSi/Tn MPa^T inch mm i n - l b i n 2 KJ 7 inch mm KSi/Tn MPa^T HTC1TL01 23 0.539 24.08 26.46 1.072 27.22 2.245 645.00 113.00 0.301 7.64 145.82 160.25 HTC1TL02 -40 0.521 25.11 27.59 1.166 29.61 2.254 544.00 93.50 0.240 6.09 133.42 146.62 HTC1TL03 -80 0.543 27.96 30.72 0.831 21.10 2.243 409.43 71.73 0.150 3.81 116.17 127.67 HTC1TL04 -80 0.532 28.51 31.33 0.864 21.94 2.249 265.89 46.58 0.098 2.48 93.62 102.88 HTC1TL05 -120 0.545 35.16 38.64 0.913 23.19 2.242 114.56 20.07 0.038 0.96 61.46 67.54 ro ro APPENDIX V Table 5.11 K r / K i c * K IC " J I C R e s u , t s o f C 2 < 9 5 ? reduction) Stage With Crack Transverse to the Rol l ing Di rect ion Specimen Code Temp A/W Bl F J( B2 K IC " J I C °c K s i / i n H P a ^ T inch mm i n - l b i n 2 KJ 7 inch mm KSI/Tn MPAi f iT HTC2LT01 HTC2LT02 23 23 0.539 0.536 24.40 24.23 26.81 26.62 1.086 1.071 27.58 27.20 2.341 2.246 705.00 690.00 123.51 120.88 0.329 0.322 8.35 8.17 152.45 150.22 167.54 165.09 HTC2LT03 -40 0.523 24.32 26.72 0.977 24.81 2.253 555.00 97.23 0.242 6.14 135.26 148.65 HTC2LT04 HTC2LT05 -80 -80 0.530 0.517 27.90 26.99 30.66 29.66 0.849 0.795 21.56 20.19 2.249 2.256 512.93 425.82 89.86 74.60 0.190 0.157 4.82 3.98 130.07 118.48 142.94 130.20 HTC2LT06 -120 0.528 35.25 38.73 1.096 27.83 2.250 198.68 34.80 0.071 1.80 80.93 88.94 HTC2LT07 -196 0.533 27.31 30.01 0.157 3.98 2.248 24.04 4.21 0.005 0.12 28.15 30.93 ro co APPENDIX V /K , K - J Results of C2 (95% reduction) Stage With Crack Para l le l to the Ro l l ing I IC 1 IC IC — •• ——————————— — — — • Specimen Code Temp A/W Bl F B2 K IC " J I C °C KSi/Tn MPa/nT inch mm i n - l b i n 2 KJ 7 inch mm KSi/Tn MPa/m HTC2TL03 23 0.527 23.72 26.06 0.860 21.84 2.250 685.00 120.01 0.305 7.74 150.27 165.14 HTC2TL04 23 0.537 24.01 26.38 0.882 22.40 2.245 710.00 124.39 0.316 8.02 152.99 168.13 HTC2TL02 -40 0.547 27.15 29.83 1.035 26.28 2.240 517.00 90.57 0.216 5.48 130.55 143.47 HTC2TL05 -40 0.521 25.24 27.73 0.894 22.70 2.254 535.00 93.73 0.224 5.68 132.80 145.94 HTC2TL01 -80 0.525 27.71 30.45 1.035 26.28 2.252 444.64 77.90 0.17? 4.44 121.07 133.05 HTC2TL06 -80 0.540 28.19 30.98 1.072 27.22 2.244 505.26 88.52 0.199 5.05 129.06 141.83 HTC2TH07 -120 0.547 34.54 37.95 0.823 20.90 2.241 170.55 29.88 0.055 1.39 74.98 82.40 HTC2TL08 -120 0.521 32.39 35.59 0.724 18.38 2.254 159.35 27.74 0.052 1.32 72.47 79.64 HTC2TL09 -196 0.554 27.27 29.96 0.122 3.09 2.237 22.15 3.88 0.004 0.10 27.02 29.69 HTC2TL10 -196 0.540 27.23 29.92 0.122 3.09 2.244 23.22 4.06 0.005 0.12 27.67 30.40 -p». APPENDIX VI Table 6.1 Inclusion Parameters of TS Plane With K i r - J I r With LT Orientat ion % Reduction Inclusion Parameters of TS Plane K IC ~ J I C W i t h ^ Or ientat ion Area Fraction Average Inclusion Length Inter-Inclusion Distance Aspect Ratio Number of 2 Inclusions/mm RT -80°C -196°C AF(%) Cb(y) 'D'(u) ' F F ' ' N' KSi/Tn MPa*fiT KSi/Tn MPa/nT KSi/Tn" MPa/GT S2 38% 0.938 10.26 698 1.860 280.860 111.16 122.16 88.74 97.52 27.61 30.34 S3 70% 0.737 13.88 559 3.300 348.560 106.18 116.69 73.97 81.29 25.07 27.55 S4 88% 0.408 11.93 906 4.050 205.320 121.45 133.47 92.98 102.18 26.29 28.89 S6 97% 0.318 3.472 793 1.718 412.480 137.07 150.63 114.75 126.11 24.84 27.29 CI 63% 0.228 5.046 2755 1.137 82.080 145.00 159.35 109.11 119.91 28.08 30.85 C2 95% 0.204 5.570 3863 1.150 52.320 151.33 166.31 124.27 136.57 28.15 30.93 ro APPENDIX VI e 6.2 Inclusion Parameters of LS Plane With K l f - J I C Toughness Inclusion Parameters of LS Plane K I C - J 1 C With TL Oriental ion % Reduction Area Average Inclusion Inter-Inclusion ni ctanrp Aspect Ratio Number of 2 Inclusions/mm RT -80°< -19( i°C Fraction AF(%) Lenqth Co(w) U i i taiioc 'O' (y) ' F F ' 'N ' KSi/Tn MPa/iTT KSi/Tn HPa/in" KSi/Tn MPartn S2 38% 1.595 27.98 536 4.130 131.54 96.05 105.55 84.77 93.16 27.40 30.11 S3 70% 1.086 64.39 351 11.830 119.70 90.10 99.01 65.51 71.99 24.81 27.26 S4 88% 0.929 60.29 365 25.000 199.98 99.44 109.28 83.55 91.82 28.74 31.58 S6 97% 0.431 3.958 825 2.531 759.32 117.63 129.27 94.48 103.83 22.45 24.67 Cl 63% 0.178 4.492 4305 1.167 70.30 145.83 160.26 104.89 115.27 - -C2 95% 0.211 5.447 4489 1.187 47.98 151.63 166.64 125.06 137.44 27.34 30.04 1 • — = ' LIST OF PUBLICATIONS 1. Y.G. Andreev and R. Maiti, "Experimental techniques for Studying Microplasticity of Metals." Sixteenth Congress of Indian Society of Theoretical and Applied Mechanics, Allahabad, India, 1972. 2. R. Maiti and M.K. Mukherjee, "Effect of Thermal Cycling on the Hardening Behaviour of Wrought AZ-61 Mg- alloy," I.R.S. Symp., Trivandrum, India, Sept. 1973. 3. S.K. Dutta, M.K. Mukherjee and R. Maiti, "Experimental and Theoretical Studies on the Problem of Shielding in Welding of Mg- alloy," I.I.W. Symp., Durgapur, India, November 1974. 4. S.K. Dutta, R. Maiti and M.K. Mukherjee, "Development of a Procedure for Surfacing Welded Mg- alloy Pressure Vessels," I.I.W. Symp., Tiruchirapally, India, Dec. 1975. 5. R. Maiti, B.R. Ghosh et. a l , "C r i t i c a l Heat Treatment Parameters for AZ-92 Mg- alloy Castings for Satellite Application," I.I.Fi Symp., I.I.T. Madras, Jan. 1976. 6. P.P. Sihha, R. Maiti,K.V. Nagrajan, M.K. Mukherjee, "Kinetics of Elevated Temperature Reactions i n Maraging Steel," I.I.M. Symp., Suratkal, India, March, 1976. 7. R.Maiti, J.S. Kadeau and E.B. Hawbolt, "The Characterisation of Fracture Toughness of Two X-70 Pipeline Steels," J. Mat. for Energy Systems, V.2, June'l980, p. 34-50. 

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