Cavitation erosion and rolling contact fatigue

A cavitation apparatus has been used to evaluate the fatigue-resistance of lubricants, and a good correlation is found between cavitation and laboratory fatigue tests. Both fatigue pitting and cavitation pitting appear to be due primarily to hydrogen penetration, which is aggravated by reactive gas atmospheres, chemically-active lubricants or additives and especially by water.Cavitation tests differ from laboratory fatigue tests in that anti-friction additives such as oleic acid are found to be harmful and not helpful. In this respect, cavitation may be a better predictor of fatigue performance in actual service, where sub-surface fatigue predominates.