【作者】 李珍；

【导师】 陈跃；

【作者基本信息】 河南科技大学 ， 材料加工工程， 2005， 硕士

【摘要】 本文以列车车钩钩腔配件为应用背景, 用普通铸渗工艺在ZG25表面制备了一层耐磨复合材料,并对铸渗成形工艺因素进行了探讨,分析了浇注温度、浇注位置、铸渗剂中合金配比、粒度、粘结剂、熔剂等工艺因素对复合层质量的影响。采用光学显微镜、扫描电镜、能谱仪、X 衍射仪等微观分析手段对铸渗复合层的微观组织、碳化物的形态、化学成分的变化、复合层与基体结合的情况等进行了分析, 并对复合层的形成机理进行了探讨。结果表明:合金粉依靠高温钢液提供的热量开始熔化、溶解并与钢液互渗, 铸渗层因稀释扩散而产生明显的过渡层, 铸渗层与钢基体为良好的冶金结合, 最后形成的铸渗层组织主要是硬质相的钨的碳化物镶嵌在高铬铸铁基体上, 铸渗层存在的增强相有（ Fe,Cr）₇C₃、Fe₃W₃C、WC 等。用显微硬度仪对复合层的硬度进行了测试, 结果表明:由于存在过渡层, 从复合层到基体显微硬度呈梯度分布, 铸渗层硬度达HV1000 左右,同时, 以表面复合材料与基体材料为配副, 对不同成分的铸渗复合层的冲击磨损性能进行了研究。用扫描电镜对磨损形貌进行了观察, 分析了不同成分的复合层对冲击磨损性能的影响, 并对磨损机理进行探讨。结果表明, 表面复合材料具有良好的抗冲击磨损性能, 当WC 的含量在20%³0%,Cr-Fe 的含量在30%⁵0%时候铸渗层冲击磨损性能较好, 与ZG25 相比复合层的耐冲击磨损性能提高了1² 个数量级,具有良好的应用前景。更多还原

【Abstract】 In this paper, by combining conventional sand casting with penetration technology, a wear-resistant tungsten-hi-Cr cast iron compound layer can be gained on the cast steel in order to prolong the serving life-time of train coupler according to the work conditions of train coupler. The elements of molding process of cast penetration are also discussed. The major influenceable process parameters on the quality and property of cast-penetrating composite materials are optimized. Influence rules of pouring temperature , pouring position, alloy granularity , alloy power percentage, coat thickness and cement on the quality of cast penetration are also discussed. By using SEM, EPMA and XRD, the microstructures, appearances of carbides and changes of chemical composition have been studied. The formation mechanisms of the wear-resistant composite layer are also disccused. The results showed: high temperature molten steel has infiltrated into the alloying layer and a part of alloy powder melted and molten steel diffuse each other. An excellent metallurgical combination existed between the cast-infiltration layer and the steel base. The structure of the composite-layer is similar to that of high chromium cast iron with the carbide of tungsten. The carbide particle-strengthened structures of the cast-infiltration layer are（ Fe,Cr）₇C₃,Fe₃W₃C and WC mainly. The hardness of the composite layer is tested. The result showed: the hardness of the cast-infiltration layer is about HV1000, matrix is about HV200, there is a hardness grads from the composite-layer to the steel base. The impact wear resistance of the composite layer is tested and wear mechanism is analyzed. The result showed: the composite layer has the better impact wear-resistance when the volume percentage of WC particles is about 20³0% and that of Cr-Fe is about 30⁵0% in the composite layer. Compared with cast steel, impact wear resistance of the composite is greatly superior to the cast steel. So it has a good prospect.更多还原