Electrical resistance spot welding (ERSW) is an ideal assembly process for sheet metals in automotive applications because of their excellent reproducibility and weld integrity.

Dual- phase steel is one of the next-generation advanced high strength steel for bodybuilding of automobile applications. The effect of current was studied from the range of 4 kA to 6 kA, it has evident with mechanical properties and microstructural features.

Macrostructure reveals the optimum welding current (5.5 kA) for good nugget formation and complete penetration and a less heat-affected zone. The nugget microstructure is composed of lath and needle-like martensite structures. The shear fracture test revealed pull-out failure at the nugget periphery. Also, softened ten tempered martensite was assisted for weld failure in the dual-phase sheet.

Finally, these results concluded that while increasing welding current the penetration and heat- affected region were increased afterward weld deformation occurred.

This article is shared by V. Sabaraivasan, P. Sivaraj, C. Rajarajan and V. Balasubramanian of Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University.