Study of the weld pool shape variations with the welding parameters for optimization under tig welding process

Abstract

This study investigated the multi-response optimization of tungsten inert gas welding (TIG) process for an optimal parametric combination to yield favourable weld pool shape of welded joints using the Taguchi and Grey relational analysis method. Four experimental runs based on L4(23) orthogonal array of Taguchi method were performed to derive the desire objective function to be optimised within experimental domain correspond to the number of parameters and their levels which is welding current (amp), gas flow rate (l/min), and tungsten stickout (mm). The objectives function have been selected in relation to parameters of TIG welding weld pool shape or weld bead geometry i.e. weld bead height and weld bead width of material austenitic 302 stainless steel with 3 mm thickness. The Taguchi approached followed by Grey relational analysis used to solve the multi-response optimization problem. Result based on this method shows that the optimised process combination parameter for TIG welding process are welding current at level 2 (185 amp), gas flow rate at level 1 (10 l/min), and tungsten stickout at level 1 (3 mm). The significance of the factors on overall quality characteristics of the weldment has also been evaluated quantitatively by the analysis of variance (ANOVA). Based on the ANOVA it shows that welding current is the most significant factor with 0.948341, followed by tungsten stickout (0.039414) and gas flow rate (0.012245). Optimal result have been verified through additional experiments. The conformation test indicates the grey relational grade is improved to the significant value of 0.338903.