A complete cylindrical rolling bearing system includes a rolling bearing, a lubricant, and in most cases a lubricating system. The lubrication of ball and roller bearings is accomplished with oils, greases, or dry solid films [graphite, molybdenum disulfide (MoS2), polytetrafluoroethylene (PTFE), oil impregnated polymer oil, etc]. Rolling bearings carry the load of rotating equipment, but can not function for very long without a lubricant. If the lubricant fails the bearing will fail shortly thereafter. Lubricants are often the root cause of failure when a bearing system's temperature rises.

The steel used in cylindrical rolling bearing wholesale, both through hardened and case carburized steels, is processed to a minimum hardness of Rockwell C 60. According to the American Bearing Manufactures Association (ABMA) the maximum operating temperature of through hardened steels, AISI 52100 is 16O0C (32O0F), 440-C is 18O0C (3560F), and M50 is 32O0C (60O0F). In general for all steels, as the temperature exceeds 20O0C (3920F) the hardness begins to decrease. Thus, the rolling bearing life decreases as temperatures rise beyond 20O0C (3920F). Figures 1 and 2 shows AISI 52100 properties at various temperatures.

Without a good supply of oil a cylindrical rolling bearing manufacture will fail before its potential life (LlO life) due to friction and wear between the rolling element and the raceways. Oil between the rolling element (ball, spherical roller, cylindrical roller, etc.) and the raceway reduces friction and wear, and thus reduced heat generation.