Wide temperature range corrosion mechanism of M50 bearing steel in deteriorated oil-water mixture

Abstract

Bearing corrosion is one of the important causes of engine failures in shipborne aircraft, and solving the problem of bearing corrosion failure is urgent. This article uses chromatography, image analysis, and finite element simulation to study the high-temperature deterioration behavior of Mobil Jet Oil Ⅱ aviation lubricating oil, as well as the corrosion mechanism of M50 bearing steel in oil–water mixture under a wide temperature range. The results indicate that deteriorated lubricating oil without salt water doping does not have corrosiveness. Mobil Jet Oil Ⅱ aviation lubricating oil at 200 °C has obvious deterioration within 48 h, where consumption and decomposition of additives cause acidity changing from pH 8.1 to pH 2 and surface tension decreasing by 11.3 %. The crack corrosion caused by acid and the galvanic corrosion of secondary cementite accelerate the pitting corrosion process. The corrosion enhancement effect of temperature on oil–water mixture shows a parabolic trend. Corrosion can be effectively reduced by lowering the temperature of lubricating oil and quickly removing moisture.