In this paper, dissimilar resistance spot welding of AISI 1075 eutectoid steel to AISI 201 stainless steel is investigated experimentally. For this purpose, the experiments are designed using response surface methodology and based on four-factor, five-level central composite design. The effects of process parameters such as welding current, welding time, cooling time and electrode force are investigated on the tensile-shear strength of resistance spot welds. The results show that tensile-shear strength of spot welds increases with the increase in the welding current and welding time. Also, it is concluded that with increasing the electrode force and the cooling time, tensile-shear strength of the welded joints will decrease. During tensile-shear tests, three failure modes are observed, namely interfacial, partial pullout and pullout modes. The analysis of variance for the tensile-shear strength indicates that the main effects of welding current, electrode force, welding time, cooling time, second-order effect of the welding current and cooling time, two level interactions of welding current with welding time, welding current with cooling time and electrode force with cooling time are significant model terms. The results of analysis of variance (ANOVA) show that the presented model for tensile-shear strength of dissimilar resistance spot welds of AISI 1075 eutectoid steel to AISI 201 stainless steel can predict 95.00% of the experimental data and leave only 5.00% of the total variations as unexplained.
