A Comparation of Standardized Methods for Lubrication Failure Determination

Abstract

Lubricants are used to prevent wear between moving parts and to resist to high pressure between them. There are standardized testing methods that determinate the wear of the contact pair pieces and the pressure that leads to lubrication failure. The standards present the conditions and procedure of the test and the equipment. This failure manifests at the beginning through a seizure and at the end through a welding between metallic separated parts. All these methods are used the four ball machine because of its constructive simplicity and easy utilization, in spite of its obsolete and given little correlation to the lubricant behaviour in real applications from the point of view of some researchers. In this paper the authors compare three such standards related to the use of four-ball machine, two American (ASTM D 2783, ASTM D 4172) and the Romanian one (SR EN ISO 20623:2004), this being adopted by the endorsement method of the standard EN ISO 20623:2003.