Effects of welding parameters on mechanical properties and microstructure of resistance spot welded DP600 joints

This paper experimentally investigates the effects of welding parameters including electrode force, welding current and welding time on the mechanical properties and microstructure of resistance spot welded DP600 joints. The experimental results show that there exists an optimum value for each set of welding parameters that can maximise the mechanical properties and welding nugget size. The welding nugget size is a key factor controlling the mechanical properties of resistance spot welded DP600 joints; there is a relationship among welding nugget size, tensile shear load and failure energy. A larger welding nugget size leads to a greater probability of pullout failure. In addition, welding parameters also affect the microstructure, grain size, crack initiation and microhardness of resistance spot welded DP600 joints.