【作者】 贾利晓；

【导师】 兰晔峰； 陈跃；

【作者基本信息】 兰州理工大学 ， 材料加工工程， 2004， 硕士

【摘要】 本文以火车连接装置的核心部件——车钩系统为研究背景，采用传统的铸渗工艺在现用车钩材料ZG230-450的表面制备出具有高耐磨性的钨铬复合层和高铬铸铁复合层，并对铸渗成型工艺进行了探讨。同时，以表面复合材料与基体材料为配副，采用MLD-10型冲击磨损试验机，模拟火车车钩的工况条件，对铸渗复合层的冲击磨损性能进行了研究。采用JSM5600LV型扫描电子显微镜对试样的磨损面和正切面磨损形貌进行了观察，分析了表面复合材料的磨损机理，并讨论了冲击磨损条件下，试验条件对复合层耐磨性及其磨损机理的影响。 对铸渗成型工艺研究的试验结果表明：浇注温度是影响渗层形成的首要因素，渗剂成分和粒度、熔剂以及粘结剂都要有适当的加入量，才能形成形状完整、轮廓清晰的铸渗层。渗层的形成主要是依靠渗剂颗粒之间毛细管的毛细吸附作用，加上基体金属液和渗剂元素之间的互扩散作用。 对表面复合层冲击磨损性能研究的试验结果表明：渗剂中加入WC颗粒后，复合层的耐磨性显著提高；在前后两个试验周期内，表面复合材料的耐磨性随渗剂中WC含量的增加呈现出不同的变化规律；随渗剂中高碳铬铁含量的增加，表面复合材料的磨损率先减少后增加；随机冲击条件下，表面复合材料的磨损率随冲击功增大而减小，但固定冲击次数条件下，表面复合材料的磨损率随冲击功增大而增大；表面复合材料的磨损率随冲击次数的增加而增加，但变化较平稳，没有大的突变。 表面复合材料的磨损机理主要是反复塑性变形和疲劳剥落。冲击能量大小对表面复合材料的磨损机理影响不大，随着冲击能的增大，表面复合材料的磨损由碳化物的碎裂、脱落转变为大块剥落，在磨损表面形成较大的剥落坑。更多还原

【Abstract】 The background of this thesis is the key parts of joint equipment - hamulus. The composite layer with tungsten and chromium and the composite layer with high chromium cast iron have been formed on the surface of cast steel by conventional cast penetration. The molding process of cast penetration is also discussed in this paper, moreover, the impact wear properties of composites has investigated in this paper by MLD-10 impact wear experiment machine, with the couple of composites and matrix material, simulating the status of hamulus. The wear mechanism of composites is analyzed after observed the wear features of section and wear surface by JSM5600LV SEM. The influence on wear-resistance properties of test condition at the condition of impact wear is also discussed.The experiment result of molding process has shown that the mould temperature is the chief factor to the form of composite layer. If you want to acquire fine composite layer, you should add suitable flux and cement and the infiltrate must have suitable ingredient and granularity. The form of composite layer depends on capillary among the infiltrate grain and pervasion between liquid metal and infiltrate element.The experiment result of the impact wear properties ofcomposites has shown that the wear-resistance properties of composites have been improved notably if WC particles are added. In the two period of test, the wear-resistance properties of composites present different variety disciplinarian with the increase of the content of WC particles. The wear rate of composites decreases firstly and increases subsequently with the increase of the content of high carbon chromium iron. The wear rate of composites decreases with the increase of impact energy at the condition of stochastic impact, but increases at the condition of invariable impact numbers. The wear rate of composites increases with the increase of impact numbers. But the variety is smooth relatively and has no marked mutation.The wear mechanism of composites is mainly repeating toughness deform and fatigue flaking off. The magnitude of impact energy influences the wear mechanism of composites slightly. With the increase of impact energy, the wear of composites changes to flaking off in the form of blocks from the disintegrating of carbide, and forms deep hole on the wear surfaces.更多还原