Application of grey relational analysis to determine welding parameters for Nd:YAG laser GMA hybrid welding of aluminium alloy

Grey relational analysis is carried out to develop a new approach for optimization of Nd:YAG laser and gas metal arc hybrid welding parameters. The qualities of a welded material depend on various welding parameters. The parameters chosen for the current study include wire type, shielding gas, laser power, laser focus, travelling speed and wire feedrate. The welding experiments are performed on 6K21-T4 Al alloy sheet which are mostly used in automotive industries. The ultimate tensile stress, the bead width, and the penetration are chosen as the criterion for optimising the welding parameters. The method based on an orthogonal array following Taguchi's recommendation is adopted in the present study. Based on the results of grey relational analysis, a set of optimal welding parameters are obtained. The results show that the optimal welding parameters determined by the grey relational analysis are much improved compared to those from the preliminary set of experimental parameters.