Effect of Tensile Holding on High Temperature Low Cycle Fatigue Behavior of 2.25Cr1MoV Steel

High temperature low cycle fatigue test was carried out on 2.25Cr1MoV steel by using a hydraulic fatigue testing system under strain-controlled mode at 455 ℃. Different tensile hold time (0, 60, 600 s) was imposed at peak strain to study the effect of tensile holding load time on low cycle fatigue behavior of the steel. The fracture morphology of the steel was observed by scanning electron microscopy. The results reveal that the steel showed cyclic softening characteristics. The applied tensile holding load caused the stress amplitude obviously reduced, but the holding load time had little effect on cyclic stress amplitude. The fatigue life of the steel decreased because of tensile holding, but the life changed little when holding time exceeded 60 s.The fracture mode was not changed by the tensile holding load.