铸钢0Cr13Ni5Mo表面WC-8Co电火花沉积层的特性研究

Study on features of WC-8Co strengthened electro-spark deposition coating on surface of ZG0Cr13Ni5Mo

采用新型电火花设备,在水轮机转轮材料铸钢0Cr13Ni5Mo表面制备了WC-8Co沉积层,研究了其微观组织、硬度及耐磨性能。结果表明,沉积层主要由Co3W3C、Fe3W3C、Fe3Mo3C、Ni3Mo、(Fe0.51Mo0.46Ni0.03)6C等相组成;沉积层与基体呈冶金结合,细晶碳化物相弥散分布在沉积层中,提高了沉积层的硬度,平均硬度为1875.9HV,比基体硬度提高了约5倍;沉积层磨损性能是基体的3.75倍,沉积层磨损机理主要是磨粒磨损、粘着磨损和氧化磨损的综合作用,细小弥散分布的细晶粒硬质相是提高沉积层硬度和耐磨性的主要因素。

WC-8Co electrode was deposited on the surface of a turbine runner of OCrl3Ni5Mo cast steel by electro-spark deposition （ESD） and a strengthened coating was formed. This study focused on the microstructure, micro-hardness and wear resistance of this coating. The results show that the coating consists of phases such as Co3W3C, Fe3W3C, Fe3Mo3C, Ni3Mo and （Fe0.51 Mo0.46 Ni0.03 ）6C, and it is bonded metallurgically with the OCr13Ni5Mo cast steel substrate. Fine-structure grain earbide phases dispersed in the strengthened layer causes an increase in micro hardness and its value is 1875.9HV or roughly five times higher than that of the steel substrate. The coating improves the wear resistance that is on an average 3.75 times of that of the steel substrate. The coating abrasion is an integrated result of abrasive wear, adhesion wear and oxidization wear, and the dispersed hard phases of fine structure are the main factors for high hardness and great wear resistance of the strengthened coating.