Multi-Response Optimization in AA6063/SS304 Bimetalic Friction Welding using Taguchi Grey Relational Analysis

This study aimed to create a robust joint between dissimilar materials, specifically AA6063-T6 aluminium alloy and SS304 austenitic stainless steel (ASS), and optimize the parameters. The experiments were conducted by employing the rotary friction welding (RFW) process, with an experimental setup devised on a conventional lathe machine utilizing friction-generated heat and plastic deformation. The joint's performance was evaluated as per ASTM standards through hardness and Charpy impact tests, demonstrating favourable results and the results were used for further analysis. Higher hardness was observed at higher friction pressure with higher speed of rotation. It reached a maximum of 85 HRC. Conversely, the maximum impact energy was obtained at low speed with 32 J. According to microstructure of the dissimilar joint, very narrow welding interface (WI) was found, which is less than 20 microns in width. The Taguchi-Grey relational analysis (GRA)-L9 method with Minitab software was utilized for optimize the process parameters, providing insights into effective parameter selection and multi-response optimization for improved performance. The results indicated that the welding speed was the most influential parameter. Weld pressure also influenced the weld zone’s hardness. Through the results, it is confirmed that RFW is emerged as a promising method for creating dissimilar joints, surpassing the limitations of fusion welding techniques.