Numerical simulation and analysis of welding residual stress in T91/12Cr1MoV dissimilar welded joint

T91/12Cr1MoV dissimilar welded joint is widely used in main steam pipelines of power plant, and because of the different material properties of weld-metal (WM) and base-metal (BM), high welding residual stress occurred in this joint. This high residual stress would induce failure in early life of joint. By using ABAQUS software and succession coupling thermal stress computation program, welding residual stress distribution on the outer surface and along the fusion line through the wall thickness direction of T91/12Cr1MoV dissimilar welded joint was analyzed. The influence of post weld heat treatment (PWHT) on welding residual stress was studied either. Numerical simulation results show both T91 and 12Cr1MoV BM heat affect zones (HAZ) have peak residual stresses and the stress amplitude in HAZ of T91 side is larger than that of 12Cr1MoV side. The PWHT could relieve residual stress in both HAZs, while the effect in 12Cr1MoV side is more remarkable than in T91 side.