EXTRAPOLATION OF CREEP CURVE AND CREEP LIFE PREDICTION FROM SECONDARY CREEP BY EVALUATION OF STRAIN RATE CHANGE

摘要

New method of creep life prediction by Strain-Acceleration-Parameter, SAP, is presented.rnSato has found that shapes of creep curves can be characterized by the SAP that reflects magnitude of strain-rate change in secondary creep [1-4]. The SAP values are defined at minimum creep rates, and show the shapes of a creep curve, that depends on stress and temperature. Reconstruction of creep curves by a combination of SAP and a minimum-creep rate is successfully performed, and the extrapolated curves agree well with experiment. The predicted life times also reasonably agree with that obtained by experiment. The possibility of precise life prediction by SAP is pronounced.