Effects of hard turning on the fatigue life of ball bearings

The purpose of this paper is to examine how the fatigue life of ball bearings is affected by hard turning. Two different batches of 6309 deep-groove ball bearings were manufactured. The batches had identical balls, cages, and outer rings. The inner rings were soft machined and heat treated in the same way. The inner rings were subsequently processed in two different ways; one batch was ground and honed and the other was hard turned and honed. The bearings were then assembled, and tests were conducted on test rigs designed for bearings. The purpose of the test was to determine the fatigue life of the bearings by means of the inner ring. Based on the results it can be concluded that hard turning improves the fatigue life of ball bearings