Influence of grease composition on rolling contact wear: Experimental study

This paper presents an experimental study on the influence of grease composition on rolling contact wear (RCW). Experimental tests for three greases and correspondent base oils were carried out on a twin-disc machine under pure rolling conditions. The following parameters were varied: base-oil viscosity, percentage of soap concentration and the presence of additives. The second aim of these tests is to analyse the use of artificial dents as a technique to evaluate RCW: prior to the tests, artificial dents were printed on one of the contacting surfaces. These dents were used to calculate the wear volume that is removed from the surfaces, based on the assumption that when the material is removed, the diameter of these dents diminishes. For each stop, images obtained using video-microscopy were analysed and the diameter of the dents, at a given number of cycles, was calculated. It was found that tests with different lubricants resulted in different damaged areas around the dents. Based on this, a comparison of this area growth throughout the fatigue cycles was used as a way to compare the influence of grease composition on RCW.