Authors: Tevfik KÜÇÜKÖMEROĞLU, Temel SAVAŞKAN
Abstract: In this study, wear and fatigue behaviour of a number of radial ball bearings which are widely used in the industry were investigated under different operating conditions of loading, speed and lubrication. The temparature of the bearings were monitored as a function of radial loading, rotational speed and oil supply rate. Microstructure of the components of the bearings were investigated using optical light and electron metallography, X-ray microanalysis technique and microhardness measurements. Microstructural changes were observed in the surface material of the bearings operated under extreme running conditions including heavy loading and oil starvation. In addition, some stress-induced structural changes including band formation in dark etching regions, and butterfly formation around non metalic inclusions were observed in both rolling elements and inner rings of the bearings at the depths of maximum shear stresses. It was concluded that the observed structural changes may seriously shorten the life of the bearings by accelerating wear and the rolling contact fatigue.
Keywords: Rollings bearings, wear, rolling contact fatigue.