FRETTING WEAR OF AN AUSTENITIC STAINLESS-STEEL IN AIR AND IN CARBON-DIOXIDE AT ELEVATED-TEMPERATURES

The development of an experimental test facility designed to investigate the fretting wear of metals in high temperature gaseous atmospheres is described briefly. Small amplitude torsional fretting was produced between normally loaded annular contact surfaces at temperatures up to 650 °C. The information presented concerns the effects produced on fretting a type 321 stainless steel in air and CO2 environments. Use of electron optical and surface profiling techniques has allowed a qualitative asessment of the degree and characteristic features of the damage to specimens fretted at room temperature and 650 °C under selected oscillatory wear conditions. During simultaneous oxidation and fretting at 650 °C the initially formed protective oxide is disrupted exposing a chromium-depleted surface which subsequently oxidizes to a less protective Fe-Cr spinel. This combination of effects could have unfortunate consequences on the long term wear behaviour. © 1979.