Fatigue Flaking (Spalling)
Subsurface fatigue causing material to flake from raceways — the classic end-of-life failure.
Symptoms
Flaking or pitting on the raceway surface, often starting just below the surface and breaking through as the bearing cycles. Patches of material lift away, leaving a rough, cratered track.
Likely causes
Repeated cyclic stressing of the raceway material over millions of revolutions. Normal fatigue at the end of the bearing's calculated L10 life, but premature fatigue is accelerated by overload, poor lubrication, misalignment or contamination that raises sub-surface stress.
Prevention
Size the bearing correctly for the application load and life requirement. Maintain clean, adequate lubrication. Ensure correct mounting and alignment. Replace at the calculated service life before fatigue initiates, and investigate premature flaking for root cause.