Abstract

A method for predicting the effects of lubricant chemistry on bearing fatigue life was evaluated. The method was based on a correlation that was developed from wear test data, obtained with a ring-on-black tester, and full-scale bearing life test data. The correlation revealed that the degree of wear was inversely proportional to bearing fatigue life. The relationship between wear and bearing life was developed by using both light- and heavy-viscosity base oils, single- and multicomponent-additive formulations, and various commercial lubricant formulations. It was concluded that the ring-on-block tester may represent a method for predicting the chemical effects of mineral oil formulations on bearing fatigue life. A lubricant chemical adjustment factor for predicting such effects was derived. The wear tester appeared to identify an important property of lubricants that should enhance the process of selecting lubricants for various applications. The data revealed that a small number of lubricants exerted a detrimental influence on fatigue life, but the majority of formulations tested were either indifferent to fatigue life or had a beneficial effect. This fact correlates well with the large-scale use of additives throughout industry where bearing performance is significantly enhanced. The findings indicate that the chemical influence of lubricants can be a significant factor for both wear and fatigue processes. A mechanism for explaining the correlation for wear and bearing life is discussed. Presented as an American Society of Lubrication Englneers paper at the ASLE/ASME Lubrlcatlon Conference In New Orleans, Loulslana, October 5–7, 1981