A more Accurate Constraint Parameter to Characterize the Creep Constraint Effect at Crack Tip of Cr-Mo-V Steel

A suitable constraint parameter is a key to quantify the creep crack tip constraint levels. In this study, a new more accurate creep constraint parameter As of brazed joint was proposed based on the existing constraint parameters R* and Ac. The CCG rate equation of Cr-Mo-V steel related to the constraint parameter As is obtained. The results show that the constraint parameter As is basically unchanged with the increase of creep time. The crack growth data predicted by the constraint dependent CCG rate equation are in good agreement with the experimental data. The established constraint dependent CCG rate equation can predict the CCG rate at other constraint levels very well.