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 un der multiaxial stress conditions of combined tension-compression and c yclic torsion are summarized. This work was performed as the second ta sk A-II of the cooperative project of phase 3 by the Subcommittee on I nelastic Analysis and Life Prediction of High Temperature Materials, J SMS. The ratios of axial to torsional strain range, Delta epsilon/Delt a(gamma/3(1/2)), were set to be non-unity in these phase 3 tests for b oth in-phase and out-of-phase (with 90 degrees phase difference) strai n-controlled wave patterns, including pure torsion, while the ratios w ere unity in phase 2. By comparing the evaluted failure lives with the corresponding data of phase 2, some discussion on the effect of the w ave patterns is presented and the validity of the life prediction meth ods is evaluated.