Evaluation of TIG Welding Parameters for Stainless Steel–Copper Alloy Dissimilar Joints Using Response Surface Methodology

To adjust the automatic welding parameters and ensure high mechanical properties of welded joints, we utilized a practical and numerical approach in this study. This approach combined response surface designs with laboratory experiments. Specifically, the Central Composite Design (CCD) within the Response Surface Methodology (RSM) was applied to optimize three crucial operating variables: current intensity, welding speed, and gas flow rate in an automatic welding process to achieve high mechanical resistance of dissimilar welds. The results indicated that the effect of current intensity was highly significant, welding speed had a limited effect, and gas flow rate showed a weak effect. Quadratic models for mechanical resistance as a function of these variables were developed based on the values obtained from the analysis of variance (ANOVA). The optimal conditions identified for automatic welding yielded a mechanical resistance of 503.2 MPa. ANOVA analysis indicates substantial positive impacts from both current and gas flow on Rm, contributing approximately 13.36% and 15.64% respectively, whereas the influence of welding speed is about 1.08%.