Finite-element-based parametric study on welding-induced distortion of TIG-welded stainless steel 304 sheets

Abstract

Finite element (FE) simulation of welding processes enables the prediction of component distortions which significantly reduces the need for physical trials. This facilitates reduction in lead time and costs associated with process planning. In this paper, FE modelling of tungsten inert gas welding is performed using SYSWELD for a butt joint between 2 mm thick stainless steel 304 (SS304) sheets. A three-dimensional double ellipsoid (Goldak) heat source is used to model the heat flow during welding. The heat source definition as validated against an experimentally obtained grain structure (macrograph) and thermal history. The isotropic hardening material behaviour model is used in the mechanical analysis and the annealing is considered at 1300 °C. FE-predicted distortion for an unclamped situation is compared with an experimental trial. The FE-predicted fusion zone, thermal histories, and residual distortion are found to be in reasonably good agreement with experimental results. The validated FE methodology is further used to perform a parametric study on the effect of natural and forced cooling, clamp release times, and welding sequence on distortion.