对电厂用关键材料P91钢在546℃下进行应力控制的蠕变疲劳交互作用研究,分别对滞回线,全应变范围,平均应变和非弹性应变进行分析和讨论.基于应力控制蠕变-疲劳交互实验特点,考虑了上下保载时间对寿命的影响,采用改进型的频率修正法对P91钢进行寿命预测.研究结果表明:应力控制下的蠕变-疲劳交互作用,使P91钢呈现兼有循环蠕变与静蠕变的失效形式,随着循环数的增加,滞回线向右移动；非弹性应变影响了蠕变-疲劳交互寿命,其增长速率随着材料寿命的减小而增大.寿命预测结果与试验结果吻合较好,95％的数据点落于2倍误差带范围之内.研究结果为P91钢蠕变疲劳寿命预测提供了理论和实验基础.%Stress controlled creep-fatigue interaction test for P91 steel was investigated at 546℃. Hysteretic loops, total strain range, mean strain and inelastic strain range for the P91 steel were discussed and analyzed. Based on the characteristics of creep-fatigue interaction test controlled by stress, considering the effect of top and bottom tensile hold time on life, the frequency amendment method was used to predict the life of P91 steel. The research results show that the failure model of P91 steel is cyclic creep and static creep under the stress controlled interaction lest. With cyclic times increasing, hysteretic loops are moving rightward. Inelastic strain has great contributions for the life of P91 steel, whose rising rate is increasing with the P91 life reducing. Results of life prediction and test are inosculated better, and the 95% of the data point were in the two times error band scope. The research results can provide the theoretical and experimental base for life prediction of P91 steel.
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