Interference fit Too much interference fit on the conical seat or sleeve is another cause of inner ring cracking. Tensile stress (hoop stress), as a result of surplus, produces the inner ring, produces cracks when the bearing is put into operation. (Martensitic hardening rings are more sensitive to this than bainite). The same result can occur when the bearing is heated and then installed on the shaft to create the wrong (oversized) tolerance.

Forced fracture occurs when the stress concentration caused by local overload or overstress exceeds the tensile strength of the material

Start when bending exceeds fatigue strength. The cracks begin and then propagate. Eventually the entire ring or retainer breaks.

This usually occurs when the outer ring is not supported in a bearing chamber, so the outer ring has a certain degree of tolerance, or the outer ring has a point of stress concentration.

The sliding of two surfaces creates heat of friction. If the sliding speed is high, thermal development causes cracks, which are generally at right angles to the sliding direction.

A typical example is a rotating inner ring fitted with a loosely fitted shaft and subjected to axial loads. Due to creep, the side of the bearing will produce sliding motion against the base shoulder (or final gasket) on the shaft. Friction can generate (a lot of) heat, causing the ring to smudge and eventually crack.

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