Abstract: Ferritic-martensitic steel is a kind of steel with excellent anti-radiation properties， which is one of superior candidate materials for structural components of the new generation of nuclear reactors with high radiation doses. The harsh service environment requires that ferritic-martensitic steel has good comprehensive mechanical properties， suitable grain size and few internal defects. In this paper， the effects of normalizing and tempering heat treatment on mechanical properties and microstructure evolution of new composition ferritic-martensitic steel were studied. At the same time， the ThermoCalc software is used to calculate the volume proportion of different phase states and compare it with the experimental results， it finds that the calculated results of the two-phase ratio change are highly consistent with the experimental results.After normalizing treatment， the tensile strength and yield strength of the material are mainly affected by the ratio of two phases. The results show high-martensitic steel treated with 1 080 ℃ normalizing + 670 ℃ tempering heat has a tensile strength of 903 MPa and yield strength of 732 MPa， showing the best comprehensive performance of the materials.

Key words: Ferritic-martensitic Steel； Yield Strength, Normalizing； Tempering； M₂₃C₆； Thermodynamic Calculation

摘要： 铁素体-马氏体钢抗辐照性能优越，是用于辐照剂量较高的新型核电反应堆型结构件的候选材料。苛刻的服役环境要求铁素体-马氏体钢具有良好的综合力学性能、合适的晶粒度以及较少的内部缺陷。研究了正火+回火的热处理工艺对新成分铁素体-马氏体钢力学性能和微观晶粒组织演化的影响。采用Thermo-Calc热力学软件计算了不同相态的体积比例并与试验结果进行对比，发现两相比例变化的计算结果与试验结果高度一致。正火处理后，材料的抗拉强度和屈服强度受两相比例的影响权重最大。结果表明，采用1 080 ℃正火+670 ℃回火热处理的高铬铁素体-马氏体钢的抗拉强度为903 MPa，屈服强度为732 MPa，材料的综合性能最佳。

关键词: 铁素体-马氏体钢, 屈服强度, 正火, 回火, M₂₃C₆, 热力学计算