Adhesive mechanisms in the wear of some tool steels

Abstract

The adhesive wear properties of a number of tool steels have been investigated, with special emphasis on the formation and action of prows. The test pieces were worn by dry sliding in a pin-on-ring machine. A special specimen preparation technique made it possible to study the internal structure of wear fragments and prows as a function of depth under the external surface. It was found that prows form in successive steps. The initial step has been reported earlier for pure metals and low carbon steel. A detailed explanation of material deterioration in adhesive wear has been worked out. The dominating mechanism was found to be an abrasive dead zone action, rather than the shearing off or destruction of prows. Investigations by X-ray and electron microscope techniques revealed extensive transformations between the austenite and martensite phases, an extremely fine grain size and a redistribution of carbide and oxide particles during the formation of prows. Correspondingly high microhardness values, up to 1600 HV 0.15N, were measured in the transformed material. Distortion of the retained austenite lattice contributes to the high hardness.