Damage Condition Possible Causes Countermeasures

Discoloration of cages, rolling elements and raceway rings occurs due to their reacting with lubricant at high temperature

Poor lubrication
Oil stain due to a reaction with lubricant
High temperature
  • Improve the lubrication method

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Discoloration 1

Discoloration 1

Part: Inner ring of an angular contact ball bearing
Symptom: Bluish or purplish Discoloration on raceway surface
Cause: Heat generation due to poor lubrication

Discoloration 2

Discoloration 2

Part : Inner ring of a 4-point contact ball bearing
Symptom : Bluish or purplish Discoloration on raceway surface
Cause : Heat generation due to poor lubrication