论文部分内容阅读
一前言 ZG20SiMn是我国水轮机转轮的常用材料。根据水轮机的运行情况调查,在转轮的叶片上常会出现不同程度的裂纹,最严重时裂纹可贯穿整个叶片,致使发生断裂破坏。从转轮的工作条件分析,它具有如下两个主要特点 1 水轮发电机组运行工况变化频繁,负荷波动大,因而使转轮承受着交变的随机载荷。 2 转轮是在水中工作,时刻都受水介质的腐蚀作用。所以,叶片上的裂纹是属于疲劳性质的裂纹,转轮的失效也就属于淡水介质中的腐蚀疲劳破坏现象。目前,国内外都很重视腐蚀疲劳的研究,但得到的试验数据还不多,对于ZG20SiMn材料的疲劳性能更缺
A preface ZG20SiMn is a commonly used material of turbine wheel in our country. According to the turbine operation survey, often appear in the runner blade cracks of varying degrees, the most severe crack can be run through the entire blade, resulting in fracture damage. From the analysis of working conditions of the runner, it has the following two main features: 1 The running conditions of the hydro-generator set change frequently and the load fluctuates greatly, thus the runner is subjected to alternating random loads. 2 Runner is working in the water, all the time by the corrosive effects of aqueous media. Therefore, the crack on the blade belongs to the fatigue crack, and the failure of the runner also belongs to the phenomenon of corrosion fatigue destruction in the freshwater medium. At present, the domestic and international attaches great importance to the study of corrosion fatigue, but the experimental data obtained are not many, the fatigue performance of the ZG20SiMn material is more