T91/12Cr1MoV异质接头焊接残余应力模拟与分析

Numerical Simulation and Analysis of Welding Residual Stress in T91/12Cr1MoV Dissimilar Welded Joint

T91/12Cr1MoV异质接头广泛应用于热电厂主蒸汽管线。由于母材及焊材金属性能的差异,导致该异质接头中会产生较大的焊接残余应力,常常会引起早期失效。利用有限元软件ABAQUS,采用热力顺次耦合的计算程序,对主蒸汽管中T91/12Cr1MoV异质接头的焊管外表面和熔合线方向的焊接残余应力分布进行了模拟,并分析了焊后热处理对焊接残余应力的影响。结果表明,热处理前,焊接残余应力峰值位于管道外表面焊缝两侧的焊接热影响区,其中,以T91侧热影响区的应力峰值最高。焊后热处理可以有效降低焊接热影响区的残余应力峰值,且对12Cr1MoV侧热影响区残余应力的改善效果明显优于T91侧热影响区。

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.