一、概述近年来,越着老机组运行时间的延长,承受蠕变载荷的部件(例如主蒸汽管道、汽轮机大轴等)的运行可靠性和使用寿命,一直是电力生产部门十分关心的问题。在高温下使用的承载材料的性能,一般是用光滑的或预制有机械缺口的拉伸试杆,通过蠕变、持久强度试验来研究。这时,典型的测量值是在一定的载荷和温度下试样断裂的时间、蠕变速度或者是断裂伸长等。建立在上述材料性能基础上的可靠性评价和寿命预测,只是对一些简单的、承受均匀载荷 I. Overview In recent years, the longer the running time of the old unit is extended, the reliability and service life of components subjected to creep load (such as the main steam pipe, the turbine shaft, etc.) have been issues of great concern to the power production department. The properties of the support material used at high temperatures are generally studied by creep, endurance tests using a smooth or preformed tensile test bar with a mechanical notch. At this time, the typical measurement is under a certain load and temperature specimen fracture time, creep speed or elongation at break. Reliability evaluation and life prediction based on the properties of the above materials are only for some simple, uniform load