Austenite decomposition during hot strip rolling of microalloyed low carbon steel
department or school: Applied Science, Faculty of
department or school: Materials Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Tam, Wing Shan
issued: 2022-01-06T22:40:32Z
issued: 2021
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Hot strip rolling is one of the most critical steel manufacturing processes, and hot rolled products are utilized in a wide range of industrial sectors such as construction, automotive, and pipelines. In the final stage of hot rolling, the steels are cooled by water on the runout table; during cooling, the austenite decomposition takes place that determines the final microstructure and thus the final properties of the hot rolled products. To achieve the desired hot band microstructures and required mechanical properties during hot strip rolling, precise control of the cooling path through the runout table is critical. In this study, the austenite decomposition kinetics during continuous cooling of two microalloyed low-carbon steels have been investigated. Austenite grain growth, deformation and austenite decomposition tests were performed using a Gleeble 3500 thermomechanical simulator. The influence of processing parameters including austenite grain size (10μm to 60μm), cooling rate (3℃/s to 100℃/s), and retained strain (0.2, 0.4) on transformation kinetics and the transformation products under no-recrystallized rolling conditions were examined. With contact dilation measurements on a series of continuous cooling tests, transformation temperature was found to increase with decreasing prior austenite grain size, slower cooling rates and higher retained strain. Microstructure characterization was carried out using optical microscopy and EBSD. At higher transformation temperatures, ferrite-pearlite microstructures were observed. As transformation temperatures decrease, refinement of ferrite grains was seen. For sufficiently low transformation temperatures, bainitic structures were obtained. Hardness measurements obtained showed an inverse relationship with transformation temperature. A microstructure model describing these metallurgical phenomena considering the effect of prior austenite grain size, cooling rate and retained strain has been proposed that is applicable…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/80579
note: AUSTENITE DECOMPOSITION DURING HOT STRIP ROLLING OF MICROALLOYED LOW CARBON STEEL by Wing Shan Tam B.Sc., University of Alberta, 2018 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (MATERIALS ENGINEERING) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) December 2021 © Wing Shan Tam, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis entitled: Austenite decomposition during hot strip rolling of microalloyed low carbon steel submitted by Wing Shan Tam in partial fulfillment of the requirements for the degree of Master of Applied Science In Materials Engineering Examining Committee: Prof. Matthias Militzer, Materials Engineering, UBC Supervisor Prof. Chad W. Sinclair, Materials Engineering, UBC Supervisory Committee Member Prof. Rizhi Wang, Materials Engineering, UBC Supervisory Committee Member iii Abstract Hot strip rolling is one of the most critical steel manufacturing processes, and hot rolled products are utilized in a wide range of industrial sectors such as construction, automotive, and pipelines. In the final stage of hot rolling, the steels are cooled by water on the runout table; during cooling, the austenite decomposition takes place that determines the final microstructure and thus the final properties of the hot rolled products. To achieve the desired hot band microstructures and required mechanical properties during hot strip rolling, precise control of the cooling path through the runout table is critical. In this study, the austenite decomposition kinetics during continuous cooling of two microalloyed low-carbon steels have been investigated. Austenite grain growth, deformation and austenite decomposition tests were performed using a Gleeble 3500 thermomechanical simulator. The influence of processing parameters including austenite grain size …
has type: Thesis/Dissertation
date issued: 2022-05
is shown at: 10.14288/1.0406193
language: eng
degree discipline: Materials Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Militzer, Matthias
type: Text
identifier URI: http://hdl.handle.net/2429/80579