一种高强耐热轴承钢的微观组织及力学性能  

Microstructure and mechanical properties of a high strength heat resistant bearing steel

作　　者：信振飞 迟宏宵[2] 于杰[1] 周健[2] 谷金波 XIN Zhen-fei;CHI Hong-xiao;YU Jie;ZHOU Jian;GU Jin-bo(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Special Steels Research Institute,Central Iron&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,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《材料热处理学报》2024年第7期127-136,共10页Transactions of Materials and Heat Treatment

基　　金：国家科技重大专项经费资助(J2019-VI-0019-0134)。

摘　　要：利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、拉伸试验和洛氏硬度计等研究了一种新型成分优化的超高强度轴承钢经不同工艺热处理后的微观组织及力学性能。结果表明,在1040~1080℃范围内,随着固溶温度的升高,试验钢的抗拉强度逐渐升高,屈服强度逐渐降低。试验钢经1060℃固溶1 h后油淬及两次(-73℃冷处理2 h+540℃回火2 h)处理后,抗拉强度达到1997 MPa,屈服强度达到1600 MPa,断后伸长率达到12%,断面收缩率为55%,具有优异的强韧性能;随固溶温度的升高,试验钢的原始奥氏体晶粒尺寸逐渐增大,从19μm增加到50.9μm,未溶碳化物含量明显减少,残留奥氏体含量逐渐增多,其中,残留奥氏体含量增多是导致屈服强度逐渐降低的主要原因;试验钢中大量存在M_(6)C和Laves两种不同种类的析出相,其中M_(6)C碳化物在固溶阶段起到细化晶粒作用,Laves相在回火过程弥散析出,是试验钢获得超高强度的主要强化机制。Microstructure and mechanical properties of a new type of ultra-high strength bearing steel with optimized composition after heat treatment by different processes were studied by means of optical microscope(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),tensile test and Rockwell hardness tester.The results show that the tensile strength of the experimental steel increases and the yield strength decreases with the increase of solution temperature in the range of 1040-1080 ℃.After solution treatment at 1060 ℃ for 1 h by oil quenching and treatment by(cryogenic treatment at-73 ℃ for 2 h+tempering at 540 ℃ for 2 h) for twice,the tensile strength of the experimental steel reaches 1997 MPa,the yield strength reaches 1600 MPa,the elongation after fracture reaches 12%,and the reduction of area is 55%,which shows excellent strength and toughness.With the increase of solution temperature,the primary austenite grain size of the experimental steel increases gradually,from 19 μm increased to 50.9 μm,the content of undissolved carbide decreases obviously,and the content of retained austenite increases gradually.The increase of retained austenite is the main reason for the gradual decrease of yield strength.There are two different kinds of precipitates,M_(6C) and Laves,in the experimental steel.Among them,the M_(6C) carbide plays a role in refining grains in the solid solution stage,and the Laves phase uniformly precipitates during the tempering,which is the main strengthening mechanism for the experimental steel to obtain ultra-high strength.

关 键 词：轴承钢 超高强度 板条马氏体 析出相 位错密度 M_(6)C碳化物 

分 类 号：TG142.4[一般工业技术—材料科学与工程]