WC颗粒增强铁基复合材料辊环的研究

INVESTIGATION OF WCp/Fe COMPOSITE ROLLER RING

通过力学性能测试、机械加工试验、光镜分析、ＳＥＭ分析、能谱分析及Ｘ衍射分析，研究了外径１６５ｍｍｍ、内径８０ｍｍ、高６５ｍｍ和复合材料表层１８～２５ｍｍ的ＷＣｐ／Ｆｅ－Ｃ复合材料辊环的力学性能、微观组织、冶金反应及机械加工性能。结果表明：离心铸造制备的复合材料辊环的冲击韧度ａＫ达到５～６Ｊ／ｃｍ２，复合材料表层和基体硬度分别达到６３～６５ＨＲＣ和５０－５５ＨＲＣ，复合材料层中ＷＣｐ所占体积分数约６０％，组织为Ｍ＋Ａ＋ＷＣｐ＋ＭＣ，ＷＣ颗粒表面被高温铁水局部熔解，甚至解体，原位自生成微小颗粒状ＷＣ结晶体，远离ＷＣ颗粒处析出有含Ｗ、Ｆｅ、Ｃｒ、Ｍｏ元素的细小复式碳化物。由于ＷＣ颗粒部分熔解、扩散，使复合材料层和基体被不同程度合金化。采用离心铸造制备的ＷＣｐ／Ｆｅ－Ｃ复合材料辊环的机械加工性能是可以接受的。

The mechanical properties, microstructures, metallurgical reaction and machinability of WCp/Fe-C composites roller ring with outer diameter 165mm, inner diameter 80mm, highness 65 mm and composite surface layer 18-25mm are investigated by mechanical testing ,machining testing, SEM with EDS analysis and X ray diffraction in the present work. The results show that the impact toughness of composite roller ring formed by centrifugal casting approaches to 5-6 J/cm2 , the hardnesses of composite surface layer and matrix are kept at 63-65HRC and 50-55HRC, respectively. The volume fraction of WCp in the composite surface layer reaches about 60%. The microstructure consists of M+A+WCp+MC. The surface of WC particulate is dissolved ,even WCp being separated, fine WC particulate crystallites being in situ formed, as composite roller rings are manufactured. Fine composite carbides containing W、Cr、Fe、Mo elements are distributed far apart from WCp . The matrix between WCp within the surface layer of WCp/Fe-C composites and Fe-C alloy core of cylinders are alloyed due to dissolving the surface of WCp and diffusing W and C element. The machinability of the type of roller ring made of WCp/Fe-C composites by centrifugal casting is receptable.