Dissimilar resistance spot welding of mild steel and stainless steel metal sheets for optimum weld nugget size

Abstract

Different grades of steels are regularly used for various structural applications and it is always a difficult task to produce dissimilar welded joints. An attempt is made to weld thin sheets of mild steel (MS) and stainless steel (SS) materials by spot welding process by varying the different process parameters such as welding current, sheet thickness and different combinations of mild steel and stainless steel like MS with SS, MS with MS and SS with SS. The electrode is used as a copper and chromium alloy of 6 mm diameter. The experiment is designed as per the Taguchi L9 orthogonal approach by varying the three factors at three levels. The optimization of chosen factors and obtained weld nugget diameters as response values are performed to testify the statistical significance of the model terms by using R-square, analysis of variance (ANOVA), t and F tests, and desirability function. The outcomes will be useful in choosing the exact combinations of process parameters to achieve the desired quality spot-welded joints for automotive applications.