Abstract
The combined creep-fatigue loading tests on 1Cr-Mo-V steel were carried out under the creep loading conditions in the transgranular fracture region on the creep fracture mode map obtained from the static creep rupture tests. The data obtained were evaluated using the linear life fraction damage rule. The specimens under combined creep-fatigue loading were ruptured by an accumulation of either creep damage (φc) or fatigue damage (φf), and the values of φc and φf at fracture were about 0.5 and 0.8, respectively. This relation for 1Cr-Mo-V steel showed the same trend as that for SUS 304 or 316 stainless steel obtained from the combined creep-fatigue loading test with the same loading condition, but the values of φc and φf for 1Cr-Mo-V steel were different from those for the stainless steels. It was considered that this difference was mainly due to lowering of creep rupture life arising from softening of 1Cr-Mo-V steel during loading.
The φc vs. φf relation obtained for the present steel almost agreed with that obtained from the interspersion test in MPC.
