关键词: Fe-Ti-V-C合金, 耐磨性, 显微组织, 激光熔覆

Abstract: A series of Fe-Ti-V-C hardfacing alloys with five different Ti contents were deposited on the surface of 20G steel by laser cladding. Microstructure, hardness and wear resistance were investigated using optical microscope(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD), microhardness tester and abrasive wear testing machine. The results shows that the matrix is composed of ferrite and martensite, the matrix microstructure changes from acicular martensite to lath martensite, the morphology of primary (Ti, V)C changes from dendritic and flower-like shapes to globular shape and the volume fraction of primary (Ti, V)C complex carbides increase as the Ti content increase, the maximum volume fraction of primary (Ti, V)C complex carbides are attained when the Ti content is 14.7%. The microhardness of the cladding layer cross section appears reasonable gradient distribution, the microhardness of the surface layer reaches 700-950 HV_0.2. The results of wet sand rubber wear tests indicate that addition of proper Ti element into hardfacing alloys effectively enhances the wear resistance of alloys. When 14.7% Ti content is added, the cladding layer has an excellent wear resistance, which is attributed to the more globular (Ti, V)C complex carbides distributed uniformly and dispersely in the ferrite and lath martensite matrix.

Key words: Fe-Ti-V-C alloys, microstructure, wear resistance, laser cladding