Optimization of process parameters for autogenous TIG welding of austenitic stainless-steel SS-304

This work presents the effect of process parameters viz., current, speed, gas flow rate, and arc gap on characteristics of austenitic stainless steel SS304 bead-on plate welds and determines the optimal combination of parameters. Experiments were conducted as per Taguchi L9 orthogonal array and the effect of process parameters on weld bead profile, penetration depth, bead width, microstructure, and hardness were analysed. An optimum value was obtained for each process parameter to maximize penetration depth and hardness and minimize the bead width and HAZ. It was found that heat input per unit weld length is crucial in controlling the weld characteristics. Stronger inward flow patterns were responsible for beads with a narrower width and deeper penetration because of higher heat input however, excessive heat input was detrimental and produced wider beads and HAZ. Current and speed were most dominant in deciding weld characteristics than gas flow rate and arc gap. Predicted results are in close agreement with the confirmation experiments.