Practical bearing guide
Bearing Failure Analysis
Identify 5 common bearing failure modes: fatigue, wear, corrosion, lubrication failure, misalignment.
Understanding why a bearing failed helps prevent repeat failures and choose the right replacement.
1. Fatigue spalling (30% of failures)
Appearance: Pitting or flaking on raceway surfaces. Cause: End of normal fatigue life, or overload beyond design limits. Fix: Confirm the load rating (Cr) meets the application requirement. Upgrade to a higher-capacity series if needed (e.g., 6205 to 6305).
2. Lubrication failure (25%)
Appearance: Discolored (blue/brown) rings and balls, smeared metal. Cause: Insufficient grease, wrong grease type, or grease breakdown from heat. Fix: Review relubrication interval. For high-temperature applications (>100degC), use synthetic grease.
3. Contamination (20%)
Appearance: Abrasive wear, scoring, dull surfaces. Cause: Dirt, metal particles, or moisture entering the bearing. Fix: Switch from open to sealed (2RS) or shielded (ZZ). Improve housing seals.
4. Misalignment (10%)
Appearance: Wear path not centered on raceway, edge loading. Cause: Shaft deflection, housing misalignment, or bent shaft. Fix: Use self-aligning ball bearings (1200 series) or spherical roller bearings (22200 series) where misalignment is unavoidable.
5. Corrosion (8%)
Appearance: Red/brown rust, etching on surfaces. Cause: Moisture ingress, condensation during storage. Fix: Store bearings in dry conditions. Use stainless steel bearings for wet environments.
Send the old bearing marking, dimensions, quantity, and application for a manual check.