Effects of electrode force on microstructure and mechanical behavior of the resistance spot welded DP600 joint

In this paper, the effects of electrode force on the mechanical properties, weld nugget size, failure mode, microstructure and microhardness of the resistance spot welded dual-phase steel joint were investigated experimentally. The results indicate that different electrode forces generate different weld nugget sizes and there is a critical electrode force with which the weld nugget size and mechanical properties of the welded joint can accomplish their maximum values. The mechanical properties and failure modes of the welded joint are directly associated with the weld nugget size. In addition, the electrode force also alters the microscopic structure and grain size of the welded joint, but has a weak effect on the microhardness and martensite content of the welded joint.