Sliding fretting wear of mild steel fins on stainless steel flats in CO2 atmospheres

Abstract The sliding fretting wear of mild steel fin specimens rubbing on stainless steel flats was investigated in carbon-dioxide-based atmospheres. The effect of increasing temperature was to produce a gradual fall in specific wear rate between about 60 and about 200 °C and an abrupt transition to a much lower value between about 200 and 230 °C. The exact temperature of the transition was influenced by other parameters. At a temperature of 220 °C the effect of increasing frequency (from 50 to 250 Hz) and/or increasing stroke (from 40 to 250 μm) was to increase the specific wear rate. This effect was strongest at the higher frequency-amplitude combinations. The effect of increasing sliding distances between about 1 and about 12 km on the specific wear rate was slight at the higher strokes but produced a reduction at the lower strokes. This reduction could be explained by a transition early in a test from a very high to a much lower wear rate. A further lowering influence on the specific wear rate was the presence of carbon monoxide, moisture, methane and hydrogen in the carbon dioxide. Low wear rate specimens had a smooth “glaze”-type oxide surface, whereas the high wear rates were associated with rough metallic surfaces.