核电阀杆材料17-4PH不锈钢服役不同时间的组织性能分析

摘要

In this paper, the micro-structure and properties of the stem material 17-4PH stainless steel operating at 300 ℃ for a long time in nuclear power plant were studied. The materials were taken from the vital vapor plant of a nuclear power plant in China, VVP-1 to VVP-3 are main steam isolation valves of 11, 14 and 19 years, respectively. The micro-structure and properties of 17 materials were studied by impact performance test, metallographic and fracture morphology analysis. The results showed that the VVP stem materials of different service time appeared different degrees of embrittlement. The impact absorption at 0℃decreases by 118J, 132J and 156J, respectively. The growth of martensite and large size ferrite were observed. By fitting the data in the experiment and literature, the thermal aging life curve was obtained.%本文针对核电站用阀杆材料17-4PH 不锈钢,研究其长时间在300 ℃左右的环境下服役的组织和性能.材料取自国内某压水堆核电站的VVP(Vital Vapor Plant)主蒸汽系统,VVP1-3分别为服役11年、14年和19年的主蒸汽隔离阀.通过冲击性能测试、金相和断口形貌等分析方法研究了17-4PH材料的组织性能变化.结果表明,不同服役年限的VVP阀杆材料出现不同程度的脆化现象,0 ℃冲击吸收能分别下降118 J、132 J和156 J.发生热老化脆化后的不锈钢试样中观察到了马氏体长大和大尺寸铁素体存在的现象.对实验获得及文献调研到的数据进行拟合,得到了热老化冲击性能变化曲线.