Numerical and experimental investigations on welding residual stress in multi-pass butt-welded austenitic stainless steel pipe

During the course of the welding, high residual stress and distortion often occur. This causes the problem in nuclear power plant components especially where the danger of stress corrosion cracking (SCC) exists. In this study, both the experiment and the finite element method (FEM) are utilized to investigate the welding residual stress distribution in medium thick-walled austenitic stainless steel pipe. Firstly, the experiments are carried out to examine the characteristics of the temperature cycle and the welding residual stress in SUS304 stainless pipe, which is performed using a multi-pass welding process. Secondly, 2-D axi-symmetric FEM models are developed to simulate the welding temperature field and the residual stress field. In the finite element models, the temperature-dependent material properties, work hardening behavior, and annealing of historical plastic strain are taken into account. Finally, the influence of the yield strength of the weld metal on the welding residual stress is clarified by means of numerical simulation.