Indentations from Particles Causes and Countermeasures
How:
Solid contaminants can be introduced into a bearing via the seals or lubricant. After constant rotation, particles will be pressed into raceways and causes indentation.
Possible source of particles:
Dust and metal debris exist in bearing assembly or operating environment.
Indentations resulting from particles:
Indentations by soft metal debris
Indentations by hardened steel debris
Example of SEM/EDS elemental analysis:
Countermeasures
Improve the cleanliness of entire environment to reduce the possibility of particle intrusion.