Investigation on shearing strength of resistance spot-welded joints of dissimilar steel plates with varying welding current and time

The present research investigated the effects of welding current and welding time on the shearing strength of resistance spot-welded joints of low carbon steel and stainless steel plates. The macro characteristics, microstructure and micro-hardness of welded joints were also examined. It was found that the welded joints produced with a welding current of 10 kA and welding time of 80 ms showed the highest shearing strength. The diameter of welded joints and nuggets increased with increasing welding current and welding time. For evaluation of the microstructure, different regions including the nugget, coarse heat-affected zone, fine heat-affected zone and base materials were observed within the welded joints. Also, the nugget and coarse heat-affected zone showed higher hardness than the fine heat-affected zone and base materials due to the presence of martensite. The findings obtained in this research are applicable in the development of resistance spot welding processes for joining dissimilar steel plates.