Using the orthogonal array with grey relational analysis to optimize the laser hybrid welding of a 6061-T6 Al alloy sheet

Abstract

A methodology for determining the optimum process conditions associated with Nd: YAG laser — gas metal arc hybrid welding of 6061-T6 Al alloy sheet is presented. The weldability is dependent on various process parameters which include the welding wire type, shielding gas, laser power, laser focus, travelling speed, welding wire feed rate, root opening tolerance, and voltage. Experiments are performed with designated welding conditions obtained using an L 18 orthogonal array. For the evaluation of weldability, comparing the result of the ultimate tensile strength on the weld zone is essential. In order to determine the optimum welding conditions, a grey relational analysis is carried out through the result of the ultimate tensile strength for each welding experiment. Based on the results of the grey relational analysis, a set of optimum welding parameters is obtained. Using the analysis of variance approach the significant welding parameters are found. The results show that the optimum welding conditions determined using grey relational analysis are much better than the original preliminary set of experimental conditions.