The Effect of Water in Lubricating Oil on Bearing Fatigue Life

The effect of water in an SAE 20 oil on tapered roller bearing fatigue life was evaluated. Full-scale bearing life tests were conducted with water concentrations of 25, 100, and 400 ppm. Good correlation was obtained between fatigue life and water content and the detrimental effects of water on fatigue life at these levels were clearly demonstrated. As a result of the fatigue life findings at the specified water concentrations, the water absorption properties of various oils were evaluated under controlled relative humidity conditions. These results indicated that a lubricant's capacity for water absorption represents an important factor that could significantly affect bearing fatigue life. The evaluation of a water-inhibiting additive was also included in this study. Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10—13, 1976