30Cr1Mo1V转子钢应变控制下的蠕变—疲劳交互作用研究

STUDY ON CREEP-FATIGUE INTERACTION BEHAVIOR OF30Cr1Mo1V UNDER STRAIN-CONTROLLED STATE

在540 ℃和565 ℃下进行了30Cr1Mo1V带有保持时间的总应变控制轴向高温低周疲劳试验,保持时间 10～60 s,应变幅为0.6%～1.2%,采用拉应对称梯形波.对该材料蠕变-疲劳交互作用下的应力松弛现象及应变-寿命规律进行了研究.选取了几个常用的蠕变-疲劳寿命预测模型对试验数据进行分析,对各种预测模型的准确性进行了寿命预测因子和标准偏差分析.试验结果表明,随着控制应变幅的增加,第一、三阶段比例均呈增加趋势,第二阶段的比例呈现减小趋势;以应力下降比率作为参考变量,在整个寿命周期内,拉应力松弛与压应力松弛基本一致,应力下降比率基本相同.采用线性累计损伤法和应变范围划分法的准确度较高,而频率修正法和应变能划分法的准确度较差;给出了各种方法的寿命预测公式.

High temperature low-cycle fatigue test with hold time ranging from 10 s to 60 s are performed on 30Cr1Mo1V under a fully reversed axial total strain control mode at 540℃ and 565℃. The strain amplitudes are 0.6% -1.2%, the waveforms are symmetrical trapezium. The relaxation phenomena and the strain-life laws are investigated. Several commonly used fatigue-creep life prediction methods are chosen to analyze the experimental data. The scatter band factor and standard deviation are used to test validity of these life prediction methods. The results show that the ratios of the first and the third stage are increasing whereas the ratio of the second stage is decreasing with the increasing strain. The relaxation ratios are almost the same during tensile hold time and compress hold time with stress for reference. The linear damage summation method and the strain range partitioning method have higher precision, whereas the strain energy partitioning method and the modified frequency Manson-Coffin method are weaker in life-prediction. In addition, life prediction formula of this material are presented of these life-prediction modes.