FATIGUE-CREEP LIFE PREDICTION OF 2-1/4CR1MO STEEL UNDER COMBINED TENSION-TORSION AT 600-DEGREES-C

The results of fatigue-creep life prediction for 2 1/4 Cr-1Mo steel under multiaxial stress conditions of combined tension-compression and cyclic torsion are summarized. This work was performed as the second task A-II of the cooperative project of phase 3 by the Subcommittee on Inelastic Analysis and Life Prediction of High Temperature Materials, JSMS. The ratios of axial to torsional strain range, Delta epsilon/Delta(gamma/3(1/2)), were set to be non-unity in these phase 3 tests for both in-phase and out-of-phase (with 90 degrees phase difference) strain-controlled wave patterns, including pure torsion, while the ratios were unity in phase 2. By comparing the evaluted failure lives with the corresponding data of phase 2, some discussion on the effect of the wave patterns is presented and the validity of the life prediction methods is evaluated.