SUMMARY
Tungsten Inert Gas welding is a fusion welding process having very wide industrial applicability. In the present study, an attempt has been made to optimize the input process variables (electrode diameter, shielding gas, gas flow rate, welding current and groove angle) that affect the output responses i.e. hardness and tensile strength at weld centre of the weld metal SS202. Process variables play an important role for a good quality weld. Taguchi based design of experiments was used for experimental planning and the results were studied using analysis of variance. The results shows that for tensile strength of the welded specimens, welding current and electrode diameter are the two most significant factors with P-values of 0.002 and 0.030 for mean analysis, respectively leading to changes in tensile strength. Whereas higher tensile strength was observed when electrode diameter used was 1.5 mm, shielding gas used was helium, gas flow rate 15 L/min, welding current 240A and groove angle 60o was used. Welding current was found to be most significant factor with P-value 0.009 leading to change in hardness at weld region. The hardness at weld region tends to decrease significantly with the increase in welding current from 160-240A. The different shielding gases and groove angle does not show any significant affect on tensile strength and hardness at weld centre. These response variables were evaluated at 95% confidence interval and the confirmation test were performed on suggested optimal process variable. The obtained results were compared with estimated mean value, which were lying within ±5%.