Comparative study of welding residual stresses in carbon and stainless steel butt welds

With the increased use of stainless steels in construction, it has become of critical importance to estimate the magnitude and distribution of welding residual stresses in a welded structure made of stainless steels. Simulation tools based on the finite element (FE) method are very useful to predict welding-induced residual stresses. Welding residual stresses in carbon steel welds have been thoroughly investigated through numerous FE models. In the case of stainless steel welds, a large number of FE simulations focusing on welding residual stresses have been performed; however, most of them have been confined to circumferential welding with the emphasis on pressurized pipe components, whereas few analyses have been carried out on a conventional structural member such as a butt-welded plate. Stainless steel has material stress-strain characteristics and thermal properties that differ from those of carbon steel; both properties influence the formation of welding residual stresses. This suggests that established FE models for predicting welding residual stresses in carbon steel welds may not be appropriate for stainless steel welds. Three-dimensional FE simulation of welding residual stresses in stainless steel butt welds has therefore been carried out. The thermomechanical FE model and the simulation methodology used are detailed and the results are discussed. In addition, welding residual stresses in carbon steel butt welds are examined for comparison.