Numerical Simulation on the Interfacical Creep Failure of Dissimilar Welded Joint between T91 and G102 Heat-Resistant Steels

The maximum principal stress, von Mises equivalent stress, equivalent creep strain in dissimilar welded joints between martensitic heat-resistant steel (T91) and bainitic heat-resistant steel (G102) are simulated by FEM under the conditions of 833K and inner pressure of 28MPa. The results show that the maximum principal stress and von Mises equivalent stress are quit high in the vicinity of weld/G102 interface in overmatching joint, creep cavities are easy to form and expand in the weld/G102 interface. The maximum principal stresses and von Mises equivalent stresses in medium matching and under matching joints are 1/2 lower than those in overmatching joint. Accordingly, it is difficult to form and expand in the weld/G102 interface for cavities in medium matching and undermatching joints. The maximum principal stress and von Mises equivalent stress in medium matching joints are the lowest among the three joints. Consequently, the creep damage and premature failure tendency of medium matching joint are the least.