Analysis of creep crack growth behavior of P92 steel welded joint by experiment and numerical simulation

High temperature creep crack growth tests were carried out on standard compact specimens machined from the welded joint of ASME P92 steel pipe. The creep crack growth behaviors of the distinct sub-regions of welded joint were investigated to clarify the ability of creep crack resistance under high temperature. In addition, good correlations between creep crack growth rate and C⁎ for different microzones of welded joint were obtained. The tested results revealed that the sub-regions of welded joint exhibited different creep crack behaviors and at the same value of C* the highest creep crack growth rate occurred in the fine grained heat affected zone (FGHAZ) which was known as Type IV cracking zone. Furthermore, finite element method analyses coupled with continuum damage mechanics were conducted to predict the creep crack growth behavior and to study the effect of multistress state on crack propagation.