Effects of Carbon and Molybdenum on Mechanical and Hot Wear Properties of Multi-component White Cast Irons for Steel Rolling Mill Roll

Abstract

  Multi-component white cast irons containing carbide-forming elements such as Cr, Mo, Wand V have been widely popularized as roll materials for hot rolling mills because of their excellent performance. In this research, influence of C and Mo contents on mechanical properties, hot wear properties and their correlation were investigated using Fe-5%Cr-5%W-5%V-5%Co-Mo-C (mass%) cast alloys. Cast irons with M₂C eutectic carbides and martensitic matrix were obtained in a wide range of Mo contents above 2.5 mass%. Micro-hardness in such martensitic matrices showed over 600HV, and macro-hardness showed similar tendency to matrix hardness. Tensile strength, compressive 0.2% proof strength, and fracture toughness were found to be high in cast irons with high hardness, but they were decreased in cast irons with excessive carbide content. It was found that wear resistance was greater in cast irons with high Mo content which show high hardness and high fracture toughness.