ABRASION RESISTANCE OF THE COLUMNAR ZONE IN HIGH CR WHITE CAST IRONS

High chromium white cast irons are extremely abrasion resistant materials due primarily to their high carbide content. In the columnar zone of cast structures, eutectic carbides grow parallel to the direction of heat flow, forming a highly anisotropic morphology. In this US Bureau of Mines investigation, specimens taken from the columnar zone of these castings were tested utilizing a pin abrasion technique in order to understand the abrasive wear behavior of the eutectic carbides in two directions: parallel (longitudinal) and perpendicular (transverse) to the long axis of carbides. Also the effect of the matrix, as modified through a series of heat treatments, on wear rate was investigated. The longitudinal specimens showed 27-67% less volume loss than the transverse specimens depending upon heat treatment.