试验钢在１０５０℃加热及冷却后，主要碳化物相是Ｍ２３Ｃ６、Ｍ７Ｃ３和少量的ＳｉＣ，Ｍ２３Ｃ６和Ｍ７Ｃ３中含有一定的硫。在８７０℃加热时，大块Ｍ２３Ｃ６一般不会聚集长大，粒状Ｍ２３Ｃ６的数量随着保温时间的增加而增多，冷却时在块状Ｍ２３Ｃ６之间还析出相当数量的精细颗粒和薄片Ｍ７Ｃ３，冷却速度愈慢，精细颗粒愈大和薄片愈多。这些遍布在断口面上的精细颗粒、薄片以及大尺寸块状碳化物使试验钢遭到严重弱化。利用热处理手段来改善碳化物的析出特征，大幅度降低其脆化效果还较为困难。推荐这种钢在冷拉前后的软化工艺可采取８７０℃×６ｈ，水冷 After the steel was heated and cooled at 1050 ℃, the main carbides were M23C6, M7C3 and a small amount of SiC, while M23C6 and M7C3 contained some sulfur. When heating at 870 ℃, the bulk M23C6 generally does not aggregate and grow. The amount of granular M23C6 increases with the holding time, and when cooling, a considerable amount of fine particles and flakes M7C3 are precipitated between the massive M23C6. The cooling rate The slower, the larger the fine particles and the more the flakes. The fine particles, flakes and large-sized massive carbides spread all over the fracture surface seriously weakened the test steel. The use of heat treatment means to improve the precipitation characteristics of carbide, significantly reduce the embrittlement effect is more difficult. Recommend this kind of steel before and after the cold-drawing process can take 870 ℃ × 6h, water-cooled