控轧控冷T92耐热钢的显微组织结构研究

Microstructure of T92 Heat Resistant Steel Manufacturing by TCMP

利用光学显微镜、X射线衍射仪、透射电子显微镜研究了电站锅炉用耐热钢T92(9Cr-0.5Mo-1.8W-V-Nb)的显微组织结构。结果表明,试验用T92钢在供货状态下的显微组织由板条状回火马氏体、薄片状的ε马氏体、弥散分布的M23C6及MX、少量块状α相组成。板条状回火马氏体为体心立方结构的Fe-Cr固溶体相;在板条马氏体基体上弥散分布着棒状和点状两种形态的析出物,其中主要的析出物为棒状的富含Fe、Cr元素的M23C6型合金碳化物,少量点状析出物为MX型碳氮化物;在板条马氏体之间分布的薄片相为六方结构的ε马氏体,其点阵常数为a=0.25588 nm,c=0.41237 nm,内部为孪晶亚结构。

The microstructure of T92 steel （9Cr-0. 5Mo-1.8W-V-Nb） used for power plant was studied by optical microscope, XRD and TEM. The results show that the predominant phases in T92 steel are tempered martensite laths, thin-slice martensite ,dispersed carbides（ M23C6 ） and carbonitrides （MX） ,a small amount of α-phase. The tempered martensite is Fe-Cr solid solution with the cubic lattice. There are two shapes of precipitates between and inside martensite laths ,one is short stick-like Mz3C6carbide and the other is dot-like MX carbonitride with very small amount. The thin slice phase be- tween martensite is ε-martensite with the hexagonal lattice whose lattice parameters is a=0. 25588 nm and c = 0. 41237 nm and sub-structure is twin crystal.