Investigation of the effect of different welding parameters on tensile properties and failure modes of non-alloyed steel produced by powder metallurgy

Resistance spot welding was implemented to unalloyed steel produced by powder metallurgy method at different welding parameters in this study. Other welding parameters are constant, but electrode force values are 0.21-0.28-0.35 kN and welding current values are 9-10-11 kA. The effects of different welding parameters on microhardness, nugget diameter, tensile shear force, and failure mode were investigated. Consequently, the tensile shear force increased as welding current and electrode force up to a certain value increased. When critical electrode force value was exceeded, tensile shear force decreased, although nugget diameter increased. Compared to the base material, a decrease in tensile shear force has occurred in resistance spot welded joints. Except for values higher than the critical electrode force value, a linear relationship was determined between the nugget diameter, tensile shear force, and microhardness. Two different failure modes were observed, namely sheet transverse failure and partial interfacial failure.