Numerical analysis of elimination stainless steel welding residual stress by over load tension

The lumen parts of sterilizer pressure vessels are generally welded by austenitic stainless steel and there will be serious stress corrosion that caused by the common action by the welding residual stress and corrosion medium. Over load method can be used to reduce the residual stress. The finite element method (FEM) and experiment are adopted to quantitively analyze the effect of over load tension on residual stress. At first, SYSWELD software is used to calculate the welding residual stress contour, and then Nastran software is used to simulate the over load tensionprocess to investigate the variation of the residual stress. The simulation results show that with the increase of tensile strain, the maximum values of welding residual stress were reduced dramatically, and the welding residual stress contours become more uniform. However, once the value of tensile strain exceeds a certain critical value, the effect of reducing welding residual stress turn to being gradually weakened. The simulation results were agreed well with X ray measurement results, which shows that this method is feasible. Such research methods and results will provide reference for the elimination of welding residual stress and welding quality control.