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Characterization and testing of ferrous granules as an abrasive for water jet cutting

University of British Columbia

In this research, the cutting performance of ferrous granules (FG), a by-product from a lead/zinc smelting operation, was evaluated as an abrasive for water jet cutting. The FG were characterized using scanning electron microscopy, X-EDS analysis, XRD analysis, optical microscopy and mechanical sieving. Then, the FG were crushed through different methods to obtain abrasive particles suitable for the abrasive water jet (AWJ) cutter, and the efficiency of each crushing method was evaluated based on: 1) throughput, and 2) variability of final particle size. Additionally, refining techniques were tested on the crushed FG in order to improve the mass flow rate of the FG-based abrasive entering the waterjet cutter. Finally, cutting tests were performed following a 2³ full factorial experiment selecting pressure, standoff distance and traverse speed as the AWJ process parameters of interest. The effect of these parameters on the cutting performance was evaluated by measuring the ratio of completeness, top and bottom kerf width, taper of cut and angle of striations. The effect of the process parameters on the quality indicators of the cutting process were estimated through statistical analysis and the most influential parameters were identified for each quality indicator. The results showed that the FG-based abrasive was able to successfully cut through an AISI 1020 steel plate up to 1 inch in thickness, with a ratio of completeness comparable to the ratio achieved using regular garnet abrasive with water jet tooling in advanced wear conditions. However, the cuts performed with FG-based abrasive presented surface finish and geometric quality that were below average compared to the cuts performed with garnet abrasive, with extensive surface defects on the cut surfaces. Furthermore, these cuts presented a distinctive cutting mechanism in the bottom section of the cut, which may be different from typical cutting mechanisms described in the literature. It is suggested that these effects are related to the cutting jet energy profile and coherency, which in turn have an impact on the studied quality indicators.

Text

2018-07-16

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/66504

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/