Some manufacturing processes increase bearing life. Their main disadvantage is additional cost.
Forging produces a fiber orientation in the race material that makes the races less sensitive to variations in steel quality. Bearings with forged races can have dynamic capacities up to twice as high as bearings with races cut from tubing.
Compressive residual stress reduces maximum shearing stress and increases fatigue life. For bearings with light to medium loads, residual compressive stress can increase life. But for bearings with heavy loads, the effect is significant.
Controlled-hardness bearings have rolling elements and races matched for hardness. Generally, the rolling elements are 1 to 2 Rc harder than the races. Since fatigue life is related to hardness, the matching process can result in order-of-magnitude improvements in fatigue life.
