辙叉用高锰钢的加工硬化机理

Work hardening mechanism of Hadfield steel used for railway crossing

对铁路辙叉用高锰钢进行不同变形量的大吨位快速压缩试验,采用金相显微镜、透射电子显微镜以及X射线衍射仪等方法对变形样品的微观组织进行分析,研究高锰钢在压缩状态下的加工硬化机理。结果表明,在压缩状态下,高锰钢以形变孪晶硬化为主,亚结构主要为孪晶和位错缠结,硬化组织中没有发现形变诱发马氏体;随着变形量的增加,晶粒畸变严重,孪晶密度增大,硬度升高,变形量达到40%时,硬化程度趋于饱和。

Work hardening mechanism of Hadfield steel used for railway crossing was studied by means of analyzing the microstructure of the steel after different compression deformation made by large tonnage rapid test using optical microscopy,transmission electron microscopy and X-ray diffraction methods. The results show that in compressed state,the main work hardening mechanism of Hadfield steel is deformation twins,the main sub-structures are twins and dislocations tangles,and no strain-induced martensite were found. Hardness,grain distortion serious and twin density increased with the increase of the deformation rate. When the deformation rate reaches 40%,the hardening effect saturated.