高性能渗碳轴承钢组织结构与疲劳及磨损性能研究

发布时间：2018-08-11 20:23

【摘要】：渗碳轴承钢因其高承重和耐大冲击性能的特点,能很好的满足我国航空航天,冶金和高铁等需求。为此,试验钢试图通过获得高洁净度,细晶化和均匀化等良好的组织特点来满足其成为构件时的使用要求。因此本论文首先对影响晶粒的锻造工艺进行了热变形行为的模拟研究,同时分析后续热处理和渗碳等对晶粒的影响。其次对试验钢心部组织特点和强韧性能进行分析研究,也为获得良好的渗层组织打下基础。然后分析研究渗碳后渗层的组织特点和性能。最后进行旋转弯曲疲劳及摩擦磨损性能试验,分析心部和渗层的组织性能对疲劳和磨损性能的影响。试验中主要采用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)等测试手段。试验钢在应变量0.6、变形速率0.01 s-1、变形温度1 000℃时发生了完全动态再结晶。将变形温度控制在1 000~1 050℃之间可以得到均匀细小的晶粒组织。试验钢的心部可达到抗拉强度1 413 MPa和冲击韧性162 J/cm2的良好强韧性,其原因是细小晶粒和板条马氏体下的细晶强化和细小弥散的M3C和VC下的第二相强化。细小均匀的组织利于渗碳后得到良好的组织性能。渗层经回火后组织主要为针状马氏体,少量残余奥氏体和细小弥散的M3C与VC,晶粒仍保持在10~15μm,表层硬度可达到700 HV以上。在近表层时固溶强化起主要作用,随着距离渗层表层越来越远,第二相强化逐渐起主要作用。旋弯疲劳的断裂机制由表层的沿晶断裂转变为过渡区的沿晶断裂和韧性断裂,中心区域为韧性断裂。提高渗层表层硬度有利于提高旋转弯曲疲劳性能。干摩擦滑动磨损的磨损机制以粘着磨损和氧化磨损为主,在脂润滑条件下主要为疲劳磨损。脂润滑与干摩擦相比,大大减小了摩擦系数和磨斑的尺寸。干摩擦微动磨损时,磨损机制均为粘着磨损和剥落。与载荷增大相比,频率增大对磨斑直径和剥落的产生影响较小。
[Abstract]:Carburized bearing steel can meet the requirements of aerospace, metallurgy and high iron due to its high bearing capacity and high impact resistance. Therefore, the test steel tries to meet the requirements of its use when it becomes a member by obtaining good microstructure characteristics such as high cleanliness, fine crystallization and homogenization. In this paper, the effect of heat treatment and Carburizing on the grain is analyzed. Secondly, the characteristics of the core microstructure and the strength and toughness of the test steel were analyzed and studied, which also laid the foundation for obtaining good infiltrating layer structure. Then the microstructure and properties of carburized layer were studied. Finally, the effects of the microstructure and properties of the core and infiltrating layer on the fatigue and wear properties were analyzed by means of rotating bending fatigue and friction and wear tests. (OM), scanning electron microscope (SEM), (SEM), transmission electron microscope (TEM), (TEM) X ray diffraction (XRD) and so on were used in the test. When the strain variable is 0.6, the deformation rate is 0.01 s ~ (-1) and the deformation temperature is 1 000 鈩，

本文编号：2178143