15. Parametric Optimization of TIG Welding Process on Mechanical Properties of 316L Stainless Steel Using RSM

The mechanical properties of welded joint mainly depend on the correct selection of welding process parameters. The present work has been planned to investigate the effects of process parameters such as welding current, welding speed and shielding gas flow rate on the weld joint quality for tungsten inert gas (TIG) welding of 316L austenitic stainless steel material. Experimental runs have been planned on TIG welding machine as per Box–Behnken design of response surface methodology (RSM). Based on the experimental data, the mathematical models have been developed by RSM to identify the effect of input process parameters on tensile properties. Optimization has been done to find out the most favourable welding parametric condition to achieve maximum ultimate tensile strength as well as percentage elongation of welded specimens simultaneously. Confirmatory tests have also been made at optimum parametric conditions to check/validate the accuracy of predicted welding condition. Good agreement has been identified between the predicted and measured values. The result indicates that the gas flow rate has the greatest influence on ultimate tensile strength and it is followed by welding current and travel speed. For percentage elongation, welding current is found to be the most influencing factor.