Numerical simulations of creep damage and crack growth in P92 steel welded joints

Premature failures caused by creep damage occurred frequently in high-temperature steam pipes welded joints. Therefore, it is of great significance to predict the evolution of creep damage and crack growth behaviors in order to ensure structural integrity of high-temperature equipment. This paper investigated the effects of structural factors to creep failure behaviors of thick-wall welded joints using finite element methods based on a ductility exhaustion model. It is shown that the width of heat affected zone would affect the creep crack initiation and growth behavior. The width of fine grain heat affected zone (FGHAZ) had little effect on the crack initial time, but it would change the initial location of the crack. In comparison, the width of coarse grain heat affected zone (CGHAZ) had slightly larger effect on the crack initial time. Four welded joints with different groove types exhibited different crack initiation and growth behaviors. Double V type groove was considered to be an optimal choice in four groove types.