Effects of welding schedules on resistance spot welding of DP600 steel

Abstract

In this study, experiments were made to investigate effects of electrode force, welding current and welding time on weld quality of resistance spot welded DP600 steel. Microstructure, microhardness and mechanical behavior of welded joints were analyzed. Martensite formation was observed in the fusion zone. Heat affected zone softening caused by martensite tempering could be detected. Increasing welding parameters would promote pullout failure occurrence and heat affected zone softening. However, the associated welding defects would have negative effects on weld quality. Welding current influence on weld quality was the most significant among the three selected welding parameters. In addition, penetration rate could probably be used to judge the weld quality.