Prediction of creep crack growth behavior in Cr–Mo–V steel specimens with different constraints for a wide range of C∗

Unified characterization of in-plane and out-of-plane creep constraint based on crack-tip equivalent creep strain

“…We have developed the 2RN creep model in Eq. (2) in the previous work [40] for the Cr-Mo-V steel used in this work by using the relation between minimum creep rate and stress, and the different Norton model parameters of (A 1 , n 1 ) in low stress regime and (A 2 , n 2 ) in high stress regime are listed in Table 1 [40]. This 2RN behavior of the Cr-Mo-V steel is similar to that of the 316H steel [46,47].…”

“…The Young's modulus E and yield stress r y of the steel at 566°C is 160 GPa and 383 MPa, respectively. For the Cr-Mo-V steels and welded joints with higher yield stress, the two-regime Norton (2RN) creep model is usually developed by using the relations between minimum creep rate (steady state creep rate) and stress in the literature [40][41][42][43][44][45]. We have developed the 2RN creep model in Eq.…”

“…The true stress-strain curve of the steel at 566°C is shown in Fig. 1 [40]. The Young's modulus E and yield stress r y of the steel at 566°C is 160 GPa and 383 MPa, respectively.…”

“…The element size in the crack growth zone is usually taken to be similar to grain size of the steels examined [49,50]. For the Cr-Mo-V steel used in this study, the average grain size is estimated to be around 100 lm [40,41], thus the element size of 100 lm is uniformly set in the crack growth zone, as shown in Fig. 3(d).…”

“…The ductility exhaustion based creep damage model has been widely used in the simulations of CCG rate [40,41,49,50]. In this damage model, the rate of damage _ Table 2 The sizes of the specimens with different in-plane and out-of-plane constraints and the initial stress intensity factor K in (load levels) in CCG simulations.…”