应变强化022Cr17Ni12Mo2奥氏体不锈钢室温低周疲劳性能研究

Study on Room Temperature Low-cycle Fatigue of Strain-strengthening Austenitic Stainless Steels 022Cr17Ni12Mo2

采用MTS809伺服液压试验机、金相显微镜、扫描电子显微镜、X射线衍射仪,研究了应变强化022Cr17Ni12Mo2奥氏体不锈钢的室温低周疲劳性能。研究结果表明:与固溶处理(ST)试样相比,应变强化(PSS)试样显示了较低的全应变疲劳寿命。除预应变4%试样在应变幅0.25%以及预应变8%试样在应变幅0.25%,0.5%表现了连续的软化,ST与PSS试样在整个循环中显示了初始循环硬化的应力响应。ST和PSS试样的裂纹萌生、扩展模式均为穿晶扩展。采用Manson―Coffin方程对各试样的低周疲劳寿命进行了预测。

The low cycle fatigue of strain-strengthening 022Cr17Ni12Mo2 austenitic stainless steel was investigated by MTS fatigue testing machine,optical microscopy,SEM,X-ray diffraction.The results show that the strain-strengthening samples exhibited much lower total strain fatigue life in comparison with the solution-treatment（ST） samples.ST and PSS samples showed initial hardening in the first three cycles and then softening,reached a saturation or stable response,except at a amplitude of 0.25% in a 4% prior strain-strengthening samples and at a amplitude of 0.25%,0.5% in the prior strain-strengthening 8% samples exhibited gradual softening from the beginning until the peak stress decreased rapidly due to the formation of macrocracks.Crack initiation and propagation modes were transgranular in both ST and PSS samples.The low cycle fatigue life of materials could be predicted by Manson―Coffin equation.