Performance Deterioration Analysis of the Used Gear Oil

In the present paper, we have investigated the tribological properties and microstructure of the used gear oil theoretically and experimentally. The deterioration process of the in-service gear lubricant oils was also discussed. The viscosity and microstructure of oils running different mileages were analyzed by viscometer and Fourier Transform Infrared Spectroscopy (FTIR), respectively. In addition, the friction and wear behaviors of the friction pair of the GCr15 steel ball and disc were investigated using a ball on disc tribometer under different mileages’ gear oils lubrication conditions. These techniques give reproducible and reliable data with which to evaluate the severity of deterioration process of oils. The objective of this work is to understand the deterioration process of gear oil and analyze the influence of deterioration on the performance and microstructure of lubricant oils used in gear box. Possible explanations of deterioration process as well as its influence on friction and wear behaviors are also discussed. The results reveals the tribological properties of used oils depended on strongly the microstructure and its deterioration process of oil.