Developing an Accelerated Endurance Test for Greases - A Status Report

摘要

The objective of this study was to develop a grease endurance test method which can be utilized in the comprehensive test methodologies being developed for predicting the performance life of military grease under laboratory environment. In an initial study, the ASTM D3527 test method, Life Performance of Automotive Wheel Bearing Grease has been evaluated because it is supposedly simulating an operating environment and has widespread applications. The results show that this method has poor precision, long-endurance test time and poor simulation of field conditions. In particular, the termination criteria used in this method tend to extend grease life. To solve the problem, tentative termination criteria were developed based on the softening of grease, which reduced the test time and distinguished between a good and a poor grease as well as the current method is able to do. To define the L10 life of MIL-G-10924 grease, baseline tests were conducted using the ASTM D3527 method. The L10 life of this grease is less than 20 h. Such a grease is not satisfactory in military vehicles with wheel bearings that are equipped with disc brakes.