深冷处理对低碳高合金马氏体轴承钢力学性能及组织的影响  

Effect of Deep Cryogenic Treatment on Mechanical Property and Microstructure of a Low Carbon High Alloy Martensitic Bearing Steel during Tempering

作　　者：李东辉 李志敏 肖茂果 李绍宏[1] 赵昆渝[1] 杨卯生[3] Donghui LI;Zhimin LI;Maoguo XIAO;Shaohong LI;Kunyu ZHAO;Maosheng YANG(School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Yunnan College of Business Management,Kunming 650106,China;Institute for Special Steels,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]云南经济管理学院,昆明650106 [3]钢铁研究总院特钢所,北京100081

出　　处：《材料研究学报》2019年第8期561-571,共11页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51761022)~~

摘　　要：利用洛氏硬度计、X射线衍射仪、扫描电子显微镜及透射电子显微镜等研究了低碳高合金马氏体轴承钢深冷处理后的硬度变化及组织演化。结果表明:深冷处理促使部分残留奥氏体转变为马氏体,导致深冷处理后实验钢的硬度较淬火态硬度有所升高。经深冷处理后实验钢在0~100 h回火过程中的硬度均比未深冷处理实验钢的硬度高。深冷处理促使钢中碳原子偏聚并在回火过程中以碳化物的形式析出,与未经深冷处理的实验钢相比,经深冷处理的实验钢回火后马氏体基体中的含碳量更低,表明实验钢经深冷处理后在回火过程中析出更多的碳化物。透射电镜分析表明,实验钢在回火过程中析出的大量弥散分布的纳米级M2C和M6C型碳化物是实验钢长时间回火后保持高硬度的主要原因。The hardness and microstructure evolution of a low carbon and high alloy martensite bearing steel after deep cryogenic treatment were studied by means of Rockwell hardness tester, X-ray diffractometer, and scanning electron microscope and transmission electron microscope. The results show that the deep cryogenic treatment promotes the transformation of retained austenite to martensite, which leads to an increase in the hardness after quenching. In addition, the hardness of the steel subjected to deep cryogenic treatment was higher than that of the non-cryogenically treated one during tempering. The deep cryogenic treatment causes the carbon atoms in the steel to segregate and precipitate as carbides during the tempering process. Compared with the steel without deep cryogenic treatment, the carbon content in the martensite matrix of the steel subjected to deep cryogenic treatment was lower after tempering, which indicated that more carbides were precipitated in the deep cryogenic treated steel during the tempering process. According to the results of transmission electron microscope images, a large number of nano-sized M2C and M6C carbides precipitated from the martensite matrix during tempering, which may be the main reason for the maintenance of high hardness of the steel after longtime tempering.

关 键 词：金属材料 高合金钢 深冷处理 碳化物 残留奥氏体 

分 类 号：TG430.40[金属学及工艺—焊接]