The Remaining Life Evaluation Based on a New Creep-Fatigue Damage Rule for 316LC
Katsuyuki TOKIMASA and Mitsuo MIYAHARA
Abstract:The remaining life evaluation is conducted on PP tested and CP tested 316LC steel by using the two procedures previously proposed for Mod.9Cr-1Mo steel by the authors. The creep-fatigue damage rules determined by the authors for 316LC steels are used, where the crack initiation period cannot be neglected in CP type straining as well as in PP type straining. @As the results, it is found that both the proposed procedure 1 and 2 can estimate the remaining life, the material damage and the applied inelastic strain range with better accuracy in case of 316LC steel than in case of Mod.9Cr-1Mo steel. Among the two the procedure 1 is superior to in prediction accuracy to the procedure 2, where the former needs the measured surface crack length at a given total number of cycles while the latter the measured surface crack growth rate. Especially satisfactory results are obtained when the procedure 1 is adopted and the measured surface crack length is 300 or longer. That is, the ratio of the predicted value to the actual one is ranged below 1.1 for the remaining life and from 0.9 to 1.3 for both the material damage and the applied inelastic strain range. Key Words:Creep-fatigue, Damage rule, Material damage, Small crack, Crack growth , Remaining life evaluation, Life prediction, 316LC steel