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.