为实现300MW汽轮机低压缸螺栓材料国产化,需要研究这种材料在运行工况下的应力腐蚀失效行为。本试验采用慢应变速率加载方式,在三种可能出现的环境条件下研究了三种材料力学性能的变化并计算了应力腐蚀断裂敏感指数。材料的化学组成和试验条件分别列入表1和表2。材料试验结果列入表3。表3结果表明:(1)在高温含氧水中合金C_(422)对应力腐蚀断裂(SCC)比较敏感,合金R_(26)和GH_(145)未出现SCC; In order to realize the domestication of low-pressure cylinder bolts in 300MW steam turbines, it is necessary to study the stress corrosion failure behavior of such materials under operating conditions. In this study, the slow strain rate loading method was used to study the mechanical properties of three materials under three possible environmental conditions and to calculate the stress corrosion cracking susceptibility index. The chemical composition and test conditions of the materials are listed in Table 1 and Table 2, respectively. The material test results are listed in Table 3. The results show that: (1) C_ (422) is sensitive to SCC in high temperature oxygenated water; SCC does not appear in R_ (26) and GH_ (145)