davefitz
Mechanical
- Jan 27, 2003
- 2,927
Can anyone advise if the fatigue curves , EN12952-3 app B fig B-9 , automatically include the creep-fatigue interaction for the locally stressed zones?
The curves of Fig B-9 are a function of the creep strength at the governing temperature, so one would like to think the answer is "yes". Other long term creep effects for the parent material are accounted for in EN 12952-4. My concern is that some persons are recommending a further reduction in allowable total fatigue life consumption based on creep-fatigue interaction as treated in API 530 and ASME III code case N47-32. It is my guess that further adjustments to fatigue life are not required if the curves of B-9 are used; the reason such adjustments are required in ASME cases is because the ASME fatigue curves are not adjusted for creep stregth at elevated temperature.
Can anyone confirm this guess, or cite the reference for the curves of fig B-9?
The curves of Fig B-9 are a function of the creep strength at the governing temperature, so one would like to think the answer is "yes". Other long term creep effects for the parent material are accounted for in EN 12952-4. My concern is that some persons are recommending a further reduction in allowable total fatigue life consumption based on creep-fatigue interaction as treated in API 530 and ASME III code case N47-32. It is my guess that further adjustments to fatigue life are not required if the curves of B-9 are used; the reason such adjustments are required in ASME cases is because the ASME fatigue curves are not adjusted for creep stregth at elevated temperature.
Can anyone confirm this guess, or cite the reference for the curves of fig B-9?
