Effect of Molybdenum Addition on Solidification Structure, Mechanical Properties and Wear Resistivity of High Chromium Cast Irons

Abstract

Mo₂C was formed as a eutectic in the final stage of solidification of high Cr cast iron containing Mo. This finely dispersed carbide that is harder than Cr₇C₃ is expected to give good wear resistivity of hot rolls. The effect of addition of Mo up to 10 mass% in 3mass%C-20mass%Cr iron was investigated. With increasing Mo content, tensile strength and fracture toughness decreased monotonically, and hot wear resistivity increased. These effects could be explained by the amount of Mo₂C. Fine particles of Mo₂C provided crack initiation and growth sites to cause fracture. However they prevented the propagation of wear cracks. Eutectic carbides should be controlled within about 35 vol% considering a balance between mechanical properties and wear resistivity.