Numerical study of nugget formation in resistance spot welding

Abstract

Resistance spot welding is a widely used joining process for fabricating sheet metal assemblies in automobile industry. In comparison with other welding processes, RSW is fast and easy for automation. This process involves electrical, thermal and mechanical interactions. These make the whole welding procedure highly non-linear and difficult to model. This paper presents the modeling and simulation of spot welding, using finite element code, ANSYS. A two-dimentional axisymmetric model was used to simulate the thermo-electro-mechanical coupling of process. In order to improve accuracy, material properties were defined temperature- dependent and phase transformation was taken into account in simulation. Also thermal contact conductivity (TCC) and electrical contact conductivity (ECC) were considered temperature-dependant. Through simulation, thermal history of process and temperature distributions were predicted. Development of weld nugget during process and effect of process parameters on nugget formation were investigated.