拉伸保載對2.25Cr1MoV鋼高溫低周疲勞行為的影響

拉伸保載對2.25Cr1MoV鋼高溫低周疲勞行為的影響Effect of Tensile Holding on High Temperature Low Cycle Fatigue Behavior of 2.25Cr1MoV Steel

利用液壓疲勞試驗機, 采用軸向應變控制方法在455 ℃下對2.25Cr1MoV鋼進行高溫低周疲勞試驗, 通過在峰值應變拉伸時保載0,60,600 s, 研究了拉伸保載時間對該鋼低周疲勞行為的影響, 并用掃描電鏡對斷口形貌進行了觀察。結(jié)果表明: 2.25Cr1MoV鋼呈明顯的循環(huán)軟化特性, 拉伸保載會明顯降低循環(huán)應力幅, 但保載時間對循環(huán)應力幅的影響不大; 拉伸保載使該鋼的疲勞壽命降低, 但保載時間超過60 s后, 疲勞壽命基本不受保載時間的影響; 拉伸保載沒有改變試驗鋼的疲勞斷裂模式。

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.

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