On Characteristics of DP600 Resistance Spot Welds

In this study, effects of resistance spot welding parameters on weld performance, metallurgical features and formation of imperfections in DP600 spot welds were investigated. Optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the weld. No heat-affected zone (HAZ) softening was found for DP600. Weld nugget microhardness profile results indicated that DP600 welds had no hold time sensitivity. Shrinkage, solidification cracks and liquid metal embrittlement were also found in some of the welds. Factors affecting formation of the weld imperfections were discussed. Similarly to those found in HSLA steels, imperfections in resistance spot welds of DP600 can be minimized or even eliminated using a proper welding schedule.