Abstract: The two procedures based on the strain range partitioning approach are proposed for evaluating the remaining life by measuring the surface crack length. Both the procedures require that the material parameters describing the creepfatigue damage rule built and modified by the authors and the strain waveform applied have been clarified before the evaluation. One of the procedures can be used only when the total number of the operation cycles n are known, whereas the other is useful even when n is unknown, though it needs the additional crack length measurement. In the latter the surface crack length must be measured not only at n but also at n+n, where n is a given interval of cycles. The results of their application to Mod.9Cr1Mo and 316LC steel smooth specimens subjected to the IJ type creepfatigue loading are shown.

Key words: creepfatigue, material damage, remaining life, Modified 9Cr1Mo steel, 316LC steel