Friction and wear properties of Stellite 31 at temperatures from 293 to 1073K

Abstract

Measurements are presented of the friction and wear during sliding of Stellite 31 on like specimens in air at temperaturesfrom 293 to 1073K. During sliding at low temperatures, metal-metal contact is always maintained under the present conditions. The observed, initially low coefficients of friction and wear rate are largely associated with the close-packed hexagonal structure of the alloy matrix, and the higher frictional values at a later stage of sliding possibly result from a change in structure of the bearing surfaces to face-centred cubic. Work hardening of these surfaces is largely responsible for maintaining the low wear rates in the later stages of sliding. Above an ambient temperature of about 523 K, a stable, adherent, thermally softened oxide layer - a ‘glaze’ - is formed on the bearing areas after a certain time that decreases with increasing temperature. Once the glaze is established, very little further wear occurs and the coefficient of friction remains low.