EFFECTS OF LUBRICANT VISCOSITY AND SLIDING VELOCITY ON WEAR OF STEEL UNDER LUBRICATED ROLLING-SLIDING CONTACT.

Wear experiments are carried out using two-disk type rolling-sliding friction apparatus with several lubricating oils containing no additive. Wear of steel is accelerated by the oxidation of steel. The wear rate increases and then decreases from a certain value of the sliding velocity with the increasing velocity. It is considered that the increased rate in the low sliding velocity region is associated with energy of asperity collision, and that the decreased rate in the higher sliding velocity region is related with the hydrodynamic action of the lubricating oil. In the latter region, the higher the viscosity of lubricant is, the less the wear of steel, even with the same calculated EHL film thickness. This is explained from the squeezing action of lubricating oil between asperities.