When a rolling bearing is damaged during machine operation, the entire machine or equipment can seize or malfunction. Since bearings that fail prematurely or unexpectedly cause trouble, it is important to be able to identify and predict failure beforehand, so that preventive measures can be adopted.

Damage Condition 

Dull or cloudy spots appear on surface along with light Wear. From such dull spots, tiny Cracks are generated downward to a depth of 5-10 μm. Small particles fall off and minor Flaking occurs widely.

Possible Causes

Unsuitable lubricant Entry of debris into lubrication Rough surface due to poor lubrication Surface roughness of mating rolling parts

Countermeasures

Select a proper lubricant Improve the sealing mechanism Improve the surface finish of the rolling mating parts

Peeling 1

Part: Inner ring of a spherical roller bearing
Symptom: Rounded areas of Peeling
Cause: Poor lubrication

Peeling 2

Part: Enlargement of damage “Peeling 1”

Peeling 3

Part: Convex rollers of damage “Peeling 1”
Symptom: Rounded areas of Peeling on the center of the rolling surfaces
Cause: Poor lubrication

Peeling 4

Part: Outer ring of a spherical roller bearing
Symptom: Peeling occurs near the shoulder of the raceway over the entire circumference
Cause: Poor lubrication

Source: NSK