Abstract
The in-phase and 90deg out-of-phase straining axial-torsional low-cycle fatigue tests were conducted on Mod.9Cr-1Mo steel at 823K under the PP-type strain waveform, and it was examined whether or not the equivalent plastic strain range proposed by the author and his colleagues to estimate the effect of nonproportional loading in case of SUS304 and 316LC steels can be applied to Mod.9Cr-lMo steel. As the results, it was found that the observed nonproportional loading effects were little in case of Mod.9Cr-1Mo steel and not only the proposed equivalent plastic strain range but also the von Mises plastic strain range and the Brown & Miller's equivalent shear strain amplitude. can well estimate the 90deg out-of-phase straining axial-torsional PP test lives of the material.
