On the Characteristics of Creep Damage and Rupture of Dissimilar Heat-Resistant Steel Welded Joint

The mechanical properties, creep rupture strength, creep damage and failure characteristics of dissimilar metal welded joint (DMWJ) between martensitic (SA213T91) and bainitic heat-resistant steel (12Cr2MoWVTiB) have been investigated by means of pulsed argon arc welding, high temperature accelerated simulation, mechanical, creep rupture test, scanning electronic microscope (SEM). The results show that there is a marked drop of mechanical properties of undermatching joint, and low ductility cracking along weld/12Cr2MoWVTiB interface is induced due to creep damage. Creep rupture strength of overmatching joint is the least. The mechanical properties of medium matching joint are superior to those of overmatching and undermatching joint, and creep damage and failure tendency along the interface of weld/12Cr2MoWVTiB are lower than those of overmatching and undermatching joint after accelerated simulation 500 h, 1000 h, 1500 h, and the creep rupture strength of medium matching joint is the same as that of undermatching joint. Therefore, it is reasonable that the medium matching material is used for dissimilar welded joint between martensitic and bainitic steel.