Numerical and experimental study of nugget size growth in resistance spot welding of austenitic stainless steels

A 2D axisymmetric electro-thermo-mechanical finite element (FE) model is developed to study the effect of welding time and current intensity on nugget size in resistance spot welding process of AISI type 304L austenitic stainless steel sheets using ANSYS commercial software package. In order to improve the accuracy, temperature-dependent properties of materials are taken into account during the simulation. The diameter and thickness of computed weld nuggets are compared with experimental results. The FE predicted weld nugget growth and nugget size agree well with experimental results. The effects of welding time and current intensity on nugget growth are also studied. Generally, increasing welding time and current is accompanied by an increase in the fusion zone size with a decreasing slope. However if expulsion occurs, nugget size reduces due to melt spattering. Except for an initial nugget formation stage, welding time has minor effect on nugget size in comparison with welding current.