Finite Element Modeling of Resistance Spot Welding Process

Weld quality in Resistance Spot Welding is directly influenced by competing process transients. These transients are caused by electrical, thermal, mechanical and metallurgical interactions. Controlling the process variables such as current, clamping force and welding time requires good understanding of how these interactions evolve during the welding process. In order to better understand the process and to control the final product quality in an efficient manner, a comprehensive process model that can account for these multi physics phenomena is required. This paper describes a general methodology that is used in the commercial Finite Element code, DEFORM™ to model the resistance spot welding process incorporating all the basic mechanics of deformation, thermal, electrical and microstructure models. Modeling process is illustrated using an example from the published literature. A detailed discussion of the process mechanics based on the observed transients during various stages of the spot welding process are presented. Model predictions on the thermal, mechanical and evolving microstructural phases during the welding process are also discussed.