Abstract
The creep crack growth rate in Cr-Mo-V steel has been numerically predicted for specimens with different constraints for a wide range ofC*by using stress dependent creep model and ductility, and the simulatedda/dt-C*curves were compared and analyzed with experimental data. The results show that the simulatedda/dt-C*curves agree well with experimental data. At low and transitionC*regions, the crack-tip constraint has obvious effect on CCG rates, while at highC*region it almost has no effect. With increasing constraint, the CCG rates and transition region size onda/dt-C*curves increase due to higher stress traxiality ahead of crack tip and stress-regime dependent creep ductility. If the extrapolation CCG rate data of standard high constraint CT specimen from highC*region (above the turning point 2) or from transitionC*region are used in life assessments of the components with various constraints at lowC*region (below the turning point 1), the non-conservative or excessive conservative results may be produced. Therefore, the CCG rate data for considering constraint effect should be obtained for a wide range ofC*by long-term laboratory tests or numerical predictions using the stress dependent creep model and ductility.
Published Version
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