Fracture Behavior of Dissimilar Resistance Spot Welded Overlap Joint

Abstract

The resistance spot welding process is also used for the welding of dissimilar materials. A dissimilar join is formed by two sheets: a 1.0 mm thick sheet of lowalloy carbon steel and a 1.5 mm thick sheet of aluminium alloy 6061 T6. In this study, the effects of welding current and nugget diameter are investigated. Welding times and welding force are kept constant. Tensile shear tests were applied in order to determine the strength parameters of the dissimilar joint. The experimental results show that an increase in the welding current increases the tensile shear stress and the weld nugget diameter. This study used a fracture mechanics-based approach, to investigate the influence of resistance spot welding parameters on the critical stress intensity factor. The results show that the critical stress intensity factor is maximal for a welding current equal to 16 kA. Also, the maximum tensile shear strength is achieved at an 8 mm nugget diameter, which is influenced by an increase in the welding current.