Influence of Lubricants Degradation Level over Tribological Properties

The paper presents the tribological aspects of the solid-fluid interaction, in order to develop an easy to use fast diagnoses method for the liquid lubricants, with minimal investments and a high precision level. The test program, using a TIMKEN equipment, analyzed the influence of the lubricant state of degradation, considering the tribological behavior of the friction couple during the working time. Two different lubricants (15W-40 and H46-EPS/1) were tested, in both fresh and used state. Tests were performed using three values of the normal load and two sliding velocities. During the tests, the wear trace (width and depth) was measured. Finally, pictures of the damage area were obtained with NEOPHOT 21 metallographic microscope. Spectrometric analysis was performed to identify the geometry, shape and concentration of the wear particles for fresh and used lubricants. The main result of this research is an altenative method of evaluating and quantifying the wear degree and lubricants durability.