Effect of post-weld tempering treatment on performance of DP600 spot welded joint

In order to meet the increasing requirements of automotive industry for material strength grades and performance, application advanced highstrength steel panels, represented by dual-phase steel, in lightweight vehicle bodies is increasing. Resistance spot welding main joining process body manufacturing. How improve tensile fatigue performance resistance joints great significance structure body. this paper, cold rolled DP600 dual phase current range 9000A-12000A was carried out. The effects post-weld tempering treatment on microstructure, microhardness, shearing were compared. results show that microstructure transformation occurs weld nugget area after tempering, tempered martensite appears reduce microhardness area; diameters, tensile-shear failure energy are all higher than those without treatment; improves joints, regardless whether welded tempered, cracks generated near heat affected zone joint test.