Bearing Analysis: Speckles and Discolouration
Condition
Speckles:
Raceway surface is matted and speckled. Speckles are clusters of tiny dents
Discoloration:
The surface colour has changed
Cause
Ingress of foreign objects Poor lubrication Temper colour by overheating. Deposition of deteriorated oil on surface
Solution
Speckles
- Improvement in sealing efficiency
- Filtration of oil
- Improvement in lubrication system
Discoloration
- Oil deposition is removable by wiping with an organic solvent (oxalic acid).
- If roughness is not removable by polishing with sandpaper, it is rust or corrosion. If completely removable, it is temper colour due to overheating.
Image example one • Image example two • Image example three • Image example four
