步冷试验对核电低压转子30Cr2Ni4MoV钢组织及力学性能的影响

Influence of Step-cooling Test on Microstructure and Mechanical Properties of 30Cr2Ni4MoV Steel for LP Rotor of Nuclear Power Plant

为了解决30Cr2Ni4MoV低压转子钢的长期时效脆化问题,采用化学成分和显微组织分析以及室温拉伸、硬度、冲击、韧脆转变温度测试等方法,研究了步冷试验对核电汽轮机30Cr2Ni4MoV低压转子钢组织及力学性能的影响。结果表明:步冷试验过程中,低压转子钢的晶粒长大,碳化物聚集粗化,导致其拉伸强度和硬度降低,室温冲击吸收能量降低,韧脆转变温度升高,但步冷试验后力学性能的下降并不明显,据此判断所研究的30Cr2Ni4MoV低压转子钢对时效脆化不敏感。

In order to solve the problem of long-term aging embrittlement of 30Cr2Ni4MoV steel of low pressure(LP)rotor,effect of step-cooling test on microstructure and mechanical properties of 30Cr2Ni4MoV steel for LP rotor of nuclear power plant was investigated by using chemical composition analysis and microstructure observation,tensile test,impact and hardness test at room temperature,as well as fracture appearance transition temperature(FATT)tests.Results show that tensile strength,hardness and the room-temperature impact values decrease,and the FATT rises up with the increase of grain size and coarsening of the carbide particles during step-cooling test.However,the decline of mechanical properties after step-cooling test is not obvious.It is concluded that the LP rotor with 30Cr2Ni4MoV steel used in this study is insensitive to aging embrittlement.