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 35vol% considering a balance between mechanical properties and wear resistivity. © 1992, The Iron and Steel Institute of Japan. All rights reserved.