13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- W added 9Cr Steel CNS Creep Welded Joint T=650oC K in=10MPam1/2 Welded Joint T=625oC K in=12MPam1/2 Welded Joint T=625oC K in=10MPam1/2 Welded Joint T=600oC K in=10MPam1/2 Base Metal T=650oC K in=12MPam1/2 Base Metal T=650oC K in=10MPam1/2 Base Metal T=625oC K in=12MPam1/2 Base Metal T=625oC K in=10MPam1/2 Creep crack growth rate da/dt, mm/hr C*, kJ/m2hr Base Metal & Welded Joint Base Metal T=600oC K in=12MPam1/2 Welded Joint T=650oC K in=12MPam1/2 10-4 10-2 100 102 104 10-6 10-5 10-4 10-3 10-2 10-1 100 101 W added 9Cr Steel CNS Creep Welded Joint T=650oC K in=10MPam1/2 Welded Joint T=625oC K in=12MPam1/2 Welded Joint T=625oC K in=10MPam1/2 Welded Joint T=600oC K in=10MPam1/2 Base Metal T=650oC K in=12MPam1/2 Base Metal T=650oC K in=10MPam1/2 Base Metal T=625oC K in=12MPam1/2 Base Metal T=625oC K in=10MPam1/2 Creep crack growth rate da/dt, mm/hr Load line displacement rate dδ/dt, mm/hr Base Metal & Welded Joint Base Metal T=600oC K in=12MPam1/2 Welded Joint T=650oC K in=12MPam1/2 10-6 10-4 10-2 100 10-6 10-5 10-4 10-3 10-2 10-1 100 101 Figure 5. Characterization of creep crack growth rate estimated by C* parameter Figure 6. Characterization of creep crack growth rate estimated by dδ/dt parameter W added 9Cr Steel CNS Creep Base Metal T=625oC Kin=12MPam1/2 Creep crack growth rate da/dt, mm/hr C*, kJ/m2hr Base Metal & Welded Joint 10-4 10-2 100 102 104 10-6 10-5 10-4 10-3 10-2 10-1 100 101 Tail Part (Hold Region) Creep crack growth rate da/dt, mm/hr P92 Steel CNS Creep Base Metal T=650oC Base Metal T=625oC Base Metal T=600oC Q*=9.8logKin-(740/RT) Welded Joint T=650oC Welded Joint T=625oC Welded Joint T=600oC -36 -35 -34 -33 -32 -31 -30 -29 10-5 10-4 10-3 10-2 10-1 100 Data for specimen with the notch located in the fine-grained HAZ Figure 7. Example of creep crack growth data of base metal on C* parameter Figure 8. Characterization of creep crack growth rate estimated by Q* parameter W added 9Cr Steel CNS Creep Welded Joint T=625oC Kin=12MPam1/2 Base Metal T=625oC Kin=12MPam1/2 Crack length Δa, mm Time, t 0 100 200 300 400 0.2 0.4 0.6 0.8 1 1.2 tf|WJ tf|B M BM WJ dt da dt da = Base Metal Welded Joint Inverse creep crack incubation time 1/ti, 1/hr P92 Steel CNS Creep Base Metal T=650oC Base Metal T=625oC Base Metal T=600oC Q*=9.8logKin-(740/RT) Welded Joint T=650oC Welded Joint T=625oC Welded Joint T=600oC -36 -35 -34 -33 -32 -31 -30 -29 10-4 10-3 10-2 10-1 100 101 Data for specimen with the notch located in the fine-grained HAZ Figure 9. Comparison of creep crack growth behavior for base metal with that for weldment Figure 10. Creep crack initiation life estimated by Q* parameter
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