考虑评估可靠性的2.25Cr-lMo钢蠕变损伤剩余寿命预测方法

Creep rupture residual life prediction method of 2.25Cr-1Mo considering reliability evaluation

蠕变损伤是火电厂管道最常见失效形式之一,对其进行剩余寿命预测是确保设备使用安全性、利用率和效益最大化的有效保障。基于实际服役超20万h 2.25Cr-lMo耐热钢蠕变持久试验数据,综合考虑工作应力与时间-温度热强参数(TTP),分析了TTP选择原则及对寿命预测精度的影响,利用Z参数法的关系曲线族表征了不同电厂管道持久性能数据的垂直分散性,建立了评估寿命预测可靠性的应力-TTP-可靠度曲线,得出不同电厂管道预测寿命与机组工作状态的关系,获得不同电厂试样在540℃/45.26 MPa环境下运行的蠕变剩余寿命分别为1.7256×10^(5) h和3.3788×10^(5) h,且预测可靠度达到99%。研究结果可为电厂设备运行可靠性提供检修建议。

Creep rupture is one of the most common failure modes of pipelines used in thermal power plants.Residual life prediction is an effective guarantee to ensure the safety,utilization and benefit maximization of equipment.Based on the creep rupture test data of 2.25Cr-lMo heat-resistant steel in actual service for over 200000 hours,the selection principle of TTP parameters and its influence on the accuracy of life prediction are analyzed by comprehensively considering the working stress and TTP parameters.The relationship curve family of Z-parameter method is used to characterize the vertical dispersion of pipeline durability data in different power plants.The stress-TTP-reliability curve for evaluating the reliability of life prediction is established,and the relationship between the predicted life of different power plant pipelines and the working state of the unit is obtained.The creep residual life of different power plant samples at 540℃/45.26 MPa is 1.7256×10^(5) h and 3.3788×10^(5) h respectively,and the predicted reliability reaches 99%,which provide maintenance suggestions for the operation reliability of power plant equipment.