The damage pattern tells you what to change. This is how to read it — the six ISO 15243 modes, their signatures, and the fix each one points to.
| Standard | ISO 15243 — the failure-mode classification |
|---|---|
| Mode 1 | Fatigue — spalling, flaking on the raceway |
| Mode 2 | Wear — abrasive, adhesive, or smearing |
| Mode 3 | Corrosion — rust, fretting, false brinelling |
| Mode 4 | Electrical erosion — fluting, pitting, craters |
| Mode 5 | Plastic deformation — brinelling, dents, indentations |
| Mode 6 | Fracture — cracks in rings, balls or cage |
| Mode | What you see | Usual cause | What to change |
|---|---|---|---|
| Fatigue | Spalling or flaking on part of the raceway, often with a crescent shape | Load above the rating, or contamination shortening life | Size or rating; filtration; alignment |
| Abrasive wear | Even material removal, dull raceway, increased clearance | Dirt, inadequate sealing, poor lubricant | Sealing, filtration, lubricant |
| Adhesive wear / smearing | Rough, torn surface, material transfer between surfaces | Insufficient lubricant film, high slip, start-stop duty | Lubricant viscosity, load, speed ramp |
| Corrosion / fretting | Rust on raceways, or brown/black staining at the fit | Moisture ingress; micro-movement at the fit | Sealing, stainless or coated parts, tighter fit |
| Electrical erosion | Fluting (washboard pattern) or craters on the raceway | Shaft currents from a VFD | Hybrid ceramic bearing, shaft grounding ring |
| Plastic deformation | Brinelling (evenly spaced dents) or a single dent from debris | Static overload, shock, mounting force through the balls, dropped bearing | Mounting method, static rating, handling |
| Fracture | Cracks in the ring, ball or cage | Impact, excessive interference, thermal stress, hydrogen embrittlement | Fit, heat treatment, plating process |
Washboard marks at regular spacing on the raceway are electrical erosion from shaft currents. No bearing material or grease fixes it: the fix is a hybrid ceramic bearing, a ceramic-coated outer ring, or a shaft grounding ring. Changing the grease to a “electrically conductive” type is not a solution.
Water entered and could not leave. The seal was not the right type for washdown, the grease was not water-resistant, or the housing had no drain. The fix is a sealed, stainless or coated bearing and a housing design that does not trap water.
Brinelling: static overload or vibration while stationary. Common on bearings that sat in a warehouse near running machinery, or on a machine that vibrates during transport. The fix is storage discipline and, where transport vibration is unavoidable, a bearing with a reduced-diameter ball set or a transport lock.
Usually the mode, sometimes the cause. A photograph shows spalling; it does not show the load, the lubricant history or the mounting method. Send the part if the diagnosis matters.
Indentations caused by vibration while the bearing is stationary — the rolling elements fret against the raceway through a lubricant film that cannot replenish. It looks like brinelling but the cause is vibration, not load.
No. Noise can come from the cage, from a dry grease, from contamination, or from the housing resonance. Noise is a symptom; the failure mode is a diagnosis.
Change the cause, not the symptom. If the mode is electrical erosion and you replace the bearing with the same type, it will fail again in the same time. The mode tells you what to change.
Send the BOM, the inspection plan or the failure photos. We will run through the same checklist and send back the gaps.