Abstract: The mechanical properties, microstructures, metallurgical reaction and machinability of WCp/Fe-C composites roller ring with outer diameter 165 mm, inner diameter 80 mm, highness 65 mm and composite surface layer 18~25 mm are investigated by mechanical testing, machining testing, SEM with EDS-analysis and X-ray diffraction in the present work. There 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 63~65 HRC and 50~55 HRC, 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.

Key words: Machinability, Mechanical properties, Metallurgical reaction, Roller ring, WCp/Fe-C composites