About four balls scuffing test parameters

Abstract

Abstract The paper aims to contribute to the understanding of scuffing occurrence. The evolution of surface topography during four balls tests using two types of grease was investigated. For testing, a four balls experimental setup was used. The test rig allows loading the contact between balls while maintaining relative motion between surfaces. Constant velocity is maintained for 10 seconds as per the EN ISO 20623:2003 procedure. The wear scar produced during testing was investigated by means of an optical 3D profilometer and the roughness parameters were analysed. Experimental results reveal that the values of arithmetical mean height Sa and root mean square height Sq, have a significant growth and they are correlated with the occurrence of the scuffing phenomenon.