Prediction of Welding Residual Stress in 2. 25Cr-1Mo Steel Pipe

Introduction2.25Cr-1Mo-steel is widely used in thepetroleum industry and in steam power generatingof both nuclear and conventional power plants be-cause of its excellent high-temperature strength,corrosion resistibility,and resistance to high-tem-perature hydrogen attack.Because several alloy el-ements are added into2.25Cr-1Mo-steel,marten-site is prone to form after welding.It has been rec-ognized that phase transformation can radically af-fect the development of residual stresses1-2].Inor…

Prediction of Welding Residual Stress in 2. 25Cr-1Mo Steel Pipe

A numerical analysis method was proposed to predict the welding residual stress in 2.25Cr-1Mo steel pipe considering solid-state phase transformations. A thermal elastic plastic finite element (FE) model considering effects of martensite transformation was developed based on commercial ABAQUS software. Continuous cooling transformation (CCT) diagrams were employed to simulate the fraction of martensite in fusion zone, coarse-grained heat affected zone and fine-grained heat affected zone. The Koistinen-Marburger relationship was used to trace the formation of martensite. The effects of both volume change and yield strength change due to phase transformation on welding residual stress were considered using the proposed FE model. The result shows that the phase transformation has significant effects on the welding residual stress in multi-pass butt weld of pipe. The predicted simulation results by the proposed numerical method are generally in good agreement with experimental results.