SEDL / STP / STP987-EB / STP26229S

Failsafe Rating of Ball Bearing Components

Voskamp, AP
Head, Fatigue Investigations and manager of Materials Science and Applicationdirector of Technical Development, SKF Engineering and Research Centre B.V.SKF & Dormer Tools, NieuwegeinSheffield,

Hollox, GE
Head, Fatigue Investigations and manager of Materials Science and Applicationdirector of Technical Development, SKF Engineering and Research Centre B.V.SKF & Dormer Tools, NieuwegeinSheffield,

Pages: 11    Published: Jan 1988

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Abstract

Methods used traditionally throughout the bearing industry to calculate the life of rolling bearings predict a finite life under all conditions of application, even at very low contact stresses. More recently, endurance tests on heavily loaded 6309 deep-groove ball bearings have demonstrated that virtually infinite fatigue life is a practical reality for some applications, provided that bearings are accurately manufactured from high-quality steel. Accordingly, a new method to calculate rolling contact fatigue life has been developed in which an effective fatigue limit has been introduced. Metallographic and X-ray analysis of the highly stressed subsurface volumes of tested bearings have shown that a critical stress exists for a given material and test condition, below which microplastic deformation, transformation of retained austenite, and the development of residual stresses and texture do not take place, consistent with the concept of a fatigue limit.