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403Nb是一种马氏体耐热不锈钢,主要用于制作火电机组汽轮机叶片,该钢是在AISI 403不锈钢的基础上,通过添加一定质量分数的Nb和V发展起来的。通过与传统热处理工艺对比,研究了形变热处理工艺（即高温固溶后在奥氏体亚稳态区变形后空冷）对马氏体耐热钢403Nb的组织和性能的影响。结果表明：形变热处理可以使403Nb钢组织明显细化,马氏体板条宽度由传统热处理的0.3μm减小到0.1μm,而且生成大量弥散的纳米级MX碳化物。形变热处理对403Nb钢组织改变的直接结果是可以大幅度提高403Nb钢的屈服强度,在常温拉伸时由传统热处理的800MPa提高到1 180MPa,在高温（700℃）拉伸时由246.5MPa提高到341.4MPa,其屈服强度分别提高了47.5%和38.5%。“,”403Nb is a kind of martensitic heat-resistant stainless steel which was developed from the traditional AISI 403 stainless steel by adding certain amount of Nb and V and widely used to manufacture the steam turbine blade of the heat-engine unit.Compared with the conventional normalizing and tempering treatment,thermo-mechanical treatment including normalization at elevated temperature,followed by warm-rolling in metastable austenitic phase region and subsequent air cooling has been investigated on 403Nb steel in present study.Microstructural observations show that thermo-mechanical treatment leads to a finer martensitic microstructure pinned with numerous nano-sized MX carbide particles.Microstructural changes result in the fact that the yield stress of the thermo-mechanically treated 403Nb steel is significantly improved compared with that of the normalized and tempered.The yield stresses are increased from 800 MPa to 1 180 MPa at 20 ℃ and from 246.5 MPa to 341.4 MPa at 700 ℃,and the increasing ratios are about 47.5% and 38.5% respectively.