The effects of particulate contamination in rolling bearings-a state of the art review

The role played by particulate contamination in rolling contacts has formed the subject of much research in recent years. Bearing-steel quality has improved to a level where the long established sub-surface-inclusion based fatigue failures are being replaced by surface or near-surface initiated failures caused by surface defects resulting mainly from rolled-in debris particles. The paper reviews the reasons and mechanisms involved, and shows how particle material, size, concentration and hardness can all have effects on bearing reliability. 1 TNTRODUCTION The improvement in steel quality, design and manufac-ture over the past 20 years has been accompanied by a corresponding increase in rolling bearing contact fatigue life. The full explanation for this has emerged from the realization that inclusion induced sub-surface fatigue, the Lundberg and Palmgren (1, 2) basis of our original life prediction, was often avoided with clean steels and replaced by surface or near-surface initiated fatigue mechanisms. The effect of roughness, and surface defects largel