SKF Bearing Failure Analysis: 10 Common Failure Modes and Prevention
Published 15 April 2025 · Drishti Powertech LLP
When a bearing fails, the damage pattern on the rings, rolling elements, and cage tells a story. By reading that story correctly, you can identify the root cause and prevent the next failure. SKF estimates that approximately 34% of bearing failures are caused by fatigue, 36% by lubrication problems, 16% by contamination, and 14% by mounting damage. This guide covers the most common failure modes and what to look for.
1. Surface Fatigue (Flaking/Spalling)
Appearance: subsurface cracks developing into pits or flakes on the raceway. This is normal end-of-life fatigue if it occurs after the calculated L10 bearing life. Premature fatigue indicates overloading (loads higher than rated), or contamination damage that initiates subsurface cracks. Prevention: verify your load calculations are correct; ensure the bearing was sized with an adequate safety factor (service factor ≥ 1.5 for heavy-shock applications).
2. Fretting Corrosion (False Brinelling)
Appearance: reddish-brown powder (iron oxide) at the contact points between rolling elements and raceway, forming axial grooves at regular intervals. Cause: micro-oscillation when a non-rotating bearing is subjected to vibration — common in stored equipment, rail vehicles in transit, and machines vibrating from nearby equipment. Prevention: use grease with anti-fretting additives (SKF LGEM 2 or LGHB 2), apply a slight preload, or rotate shafts periodically during storage.
3. Contamination Damage
Appearance: denting (brinelling) of the raceways from hard particles, roughened surfaces, or abrasive wear tracks. Cause: inadequate sealing or improper handling during mounting. Prevention: replace or upgrade sealing (double-lip seals, labyrinth seals), use sealed bearings in contaminated environments, and always clean the shaft and housing bore before mounting.
4. Electrical Erosion (Fluting)
Appearance: washboard-like corrugated pattern on the raceways, caused by stray electric current passing through the bearing. Increasingly common with VFD-driven motors. Prevention: use insulated bearings (SKF INSOCOAT) on the non-drive end of VFD motors, install shaft grounding rings, and verify motor insulation integrity.
5. Misalignment Damage
Appearance: asymmetric contact patterns on the raceways — one side loaded more than the other — combined with cage wear and possible rolling element fracture in severe cases. Cause: shaft or housing misalignment, bent shaft, or incorrect mounting. Prevention: use self-aligning bearings (spherical roller bearings) in applications where misalignment is expected; verify shaft and housing alignment during installation with a dial gauge.
6. Inadequate Lubrication
Appearance: smearing, scoring, or adhesive wear (metal transfer between rolling elements and raceways), discolouration from heat, and cage damage. Cause: wrong grease type, insufficient quantity, incorrect interval, or lubricant contamination. Prevention: follow the relubrication interval formula, use the correct grease specification, and consider automatic lubrication for inaccessible bearing points.
Conclusion
Every failed bearing provides data. Preserve the failed bearing in a clean, dry container and examine it before discarding. If you cannot identify the failure mode, your SKF channel partner can assist with failure analysis and recommend corrective actions. Drishti Powertech provides bearing failure analysis support for customers across East India — contact us with photographs or bring the failed bearing to our Kolkata office.
Frequently Asked Questions
How long should a properly maintained bearing last?
The L10 bearing life (the life exceeded by 90% of identical bearings in the same application) is calculated during design using the ISO 281 standard. In well-maintained industrial applications, properly selected and lubricated bearings routinely achieve or exceed their calculated L10 life — often running for 3–10 years in continuous operation.
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