中碳Cr、Mo渗氮轴承钢的耐磨与疲劳性能研究

发布时间：2019-06-28 11:45

【摘要】：本文采用经真空感应冶炼的32Cr3MoVE渗氮轴承钢作为试验材料,研究了不同热处理制度下钢的组织性能变化规律和钢中合金元素的作用机制。对32Cr3MoVE钢氮化层的组织特征及硬度分布进行了研究。在SRV-4磨损试验机上分别进行了点、线、面接触的磨损试验。并研究了试验钢的旋弯疲劳性能和滚动接触疲劳性能。调质处理后的组织为回火索氏体及弥散分布的碳化物,抗拉强度为1500MPa,屈服强度为1300MPa,冲击吸收功为70J。通过与30Cr3WVE轴承钢的的化学成分、组织特征及力学性能对比,分析钢中W、Mo等合金元素的作用及钢的强韧机理。32Cr3MoVE轴承钢氮化层的表层硬度达1000HV,有效氮化层深为400μm。氮化层由化合物层和扩散层组成,化合物层上弥散分布大量VN质点,扩散层存在脉状组织。不同接触方式下32Cr3MoVE轴承钢氮化层的磨损特性与加载载荷和往复运动频率有关。磨损机理主要为磨料磨损和塑性剥落,材料内部的非金属夹杂对钢的耐磨性有不利影响。32Cr3MoVE和30Cr3WVE轴承钢的室温旋转弯曲疲劳极限强度分别为804MPa、732MPa。32Cr3MoVE轴承钢渗氮后的旋弯疲劳极限强度为947MPa,增量达到143MPa。30Cr3WVE渗氮轴承钢渗氮后的旋转弯曲疲劳极限强度为850MPa,增量为118MPa。试样的表面缺陷和内部非金属夹杂物是造成疲劳破坏的主要原因,非金属夹杂物主要为为Al、Mg、Ca的氧化物。钢中非金属夹杂物的尺寸和位置与疲劳极限强度密切相关。研究了32Cr3MoVE钢的滚动接触疲劳破坏行为,接触应力为4.5GPa时32Cr3MoVE轴承钢的滚动接触疲劳寿命达到3×107,具有较好的接触疲劳性能。接触疲劳破坏形貌为剥落坑,剥落坑深度为84.6μm,面积为0.48mm2。
[Abstract]:In this paper, 32Cr3MoVE nitriding bearing steel melted by vacuum induction was used as the test material to study the change of microstructure and properties of the steel under different heat treatment systems and the action mechanism of alloy elements in the steel. The microstructure and hardness distribution of nitriding layer of 32Cr3MoVE steel were studied. The wear tests of point, line and surface contact were carried out on SRV-4 wear tester. The bending fatigue properties and rolling contact fatigue properties of the test steel were also studied. After quenching and tempering, the microstructure is tempered sorbite and dispersed carbides, the tensile strength is 1500 MPA, the yield strength is 1300 MPA, and the impact absorption work is 70J. By comparing with the chemical composition, microstructure and mechanical properties of 30Cr3WVE bearing steel, the effect of Mo and other alloy elements in the steel and the strength and toughness mechanism of the steel are analyzed. The surface hardness of the nitrided layer of 32Cr3Move bearing steel is 1000HVand the effective nitriding depth is 400 渭 m. The nitride layer is composed of compound layer and diffusion layer. A large number of VN particles are dispersed and distributed on the compound layer, and there is vein structure in the diffusion layer. The wear characteristics of nitride layer of 32Cr3MoVE bearing steel under different contact modes are related to loading load and reciprocating motion frequency. The wear mechanism is mainly abrasive wear and plastic peeling, and the non-metallic inclusions in the material have adverse effects on the wear resistance of the steel. The rotational bending fatigue ultimate strength of 32Cr3Move and 30Cr3WVE bearing steel at room temperature is 804MPA, 732MPa.32Cr3Move bearing steel is 947MPA after nitriding, and the ultimate strength of rotating bending fatigue of 143MPa.30Cr3WVE nitriding bearing steel is 850MPA and the increment is 118MPA. The surface defects and internal non-metallic inclusions are the main causes of fatigue failure, and the non-metallic inclusions are mainly Al,Mg,Ca oxides. The size and position of non-metallic inclusions in steel are closely related to fatigue ultimate strength. The rolling contact fatigue failure behavior of 32Cr3MoVE steel is studied. when the contact stress is 4.5 GPA, the rolling contact fatigue life of 32Cr3MoVE bearing steel reaches 3 脳 107, which has good contact fatigue properties. The morphology of contact fatigue failure is peeling pit, the depth of peeling pit is 84.6 渭 m, and the area is 0.48mm.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG161;TG142.12

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