Field names for bearing damage

Bearing damage names explained: flaking, smearing, scuffing and more

Quick answer

The same bearing damage goes by several names. Flaking is fatigue, smearing and scuffing are sliding damage from a thin oil film, temper colour is heat, fretting and creep come from loose fits, and impressions are dents from particles or shock.

Match the name you were given to the likely cause below, then open the full profile to confirm it on your own bearing.

By Tanmay Sharma, founder of Rotec AI · Last reviewed 8 November 2026

Shop-floor reports, inspection sheets and supplier reports often use names that do not match the formal standard (ISO 15243). This page translates the common names into likely causes and the usual fix. Each section links to the full profile, which shows how to confirm the cause and what else it can be mistaken for.

Flaking (spalling)

Also described as: Flaking, spalling, peeling.

Small pieces of the raceway or rolling element break away and leave a rough, pitted patch. It is the classic end-of-life sign, but it also appears early when something is wrong.

What you see	Likely causes	What to do
Early in the bearing's life	Internal clearance too small Wrong lubricant or too little of it Load higher than calculated	Choose the right internal clearance Check lubrication method and lubricant type Re-check the real loads
On one side of the track in a radial bearing	Axial load that was not planned for	Re-check the loads Fit the free-side outer ring with clearance so it can float
At two spots opposite each other on the ring	Poor centring at assembly Bent shaft Out-of-round or out-of-square shaft, housing or bearing seat	Centre the parts carefully Correct the squareness of the shoulders Use a larger internal clearance
At the edge of the track or roller end	Heavy impact load Scratches made during assembly (separable types)	Re-check the loads Improve assembly practice
Spaced at the roller pitch	Rust formed while the machine stood idle	Protect against rust during long stops

Worth knowing: A bearing that flakes at its calculated life is simply worn out. One that flakes early is telling you about clearance, lubrication, load or alignment.

Full profiles: Subsurface-initiated fatigue, Surface-initiated fatigue.

Temper colour (heat discolouration)

Also described as: Heat tint, blue or straw colouring.

The steel surface turns straw, brown or blue because it got hot while running. Colour alone does not tell you how hot the bearing ran for how long, but it shows something was wrong with heat or lubrication.

What you see	Likely causes	What to do
Colour on the tracks, rolling surfaces, ring faces or cage guide land	Internal clearance too small Wrong lubricant or too little of it Lubricant aged or changed in quality	Choose a suitable internal clearance Check the lubrication method and the lubricant

Worth knowing: Look for colour in the cage land and on the ring faces too. If only the tracks are tinted, think clearance or load before lubricant.

Full profiles: Overheating and lubricant breakdown, Lubricant failure.

Scuffing

Also described as: Scoring, galling, rubbing.

Local patches of metal weld together and tear apart where contact pressure is high and the oil film is thin. It leaves a rough, torn patch, often with heat marks.

What you see	Likely causes	What to do
On the end faces of rollers or ring ribs	Wrong lubricant or too little of it Poor assembly Heavy axial load	Check lubrication method and lubricant Re-check the loads
On the track and rolling surfaces	Not enough lubrication in the first hours of running Rough handling	Put lubricant on the tracks and rolling elements at assembly Improve assembly practice

Worth knowing: Scuffing on roller ends points to axial load or a thin oil film at the guide faces. Scuffing on the track right after start-up points to a dry start.

Full profiles: Adhesive wear (smearing and skidding).

Smearing

Also described as: Skidding, smeared metal.

Tiny seizures spread over the rolling surface when the rolling element slides instead of rolling. Metal melts locally and the surface looks rough and smeared.

What you see	Likely causes	What to do
Tiny seizures on the track and rolling surfaces	Wrong lubricant or too little of it Sliding: the rolling elements do not roll normally and the oil film is broken	Check lubrication method and lubricant Set the correct oil pressure or preload so the elements keep rolling

Worth knowing: Smearing is common on lightly loaded roller bearings that run fast. Too little load lets the rollers slip.

Full profiles: Adhesive wear (smearing and skidding).

Wear

Also described as: Abrasion, rubbing wear.

Material is removed slowly from surfaces that slide: roller ends, cage pockets and the cage guide land. Wear is not fatigue. Dirt and corrosion can wear the rolling track as well.

What you see	Likely causes	What to do
On sliding surfaces such as roller ends and cage pockets	Wrong lubricant or too little of it Foreign matter getting in	Check lubrication method and lubricant Improve the seal Clean thoroughly around the bearing
On the track and rolling surfaces	Wrong lubricant or too little of it Foreign matter getting in	Check lubrication method and lubricant Improve the seal

Worth knowing: Wear that is even and fine points to dirt. Wear that is local points to lubrication or running position.

Full profiles: Abrasive wear.

Satin-finish surface

Also described as: Frosted or dull-grey tracks.

Many tiny particles get in and leave a mass of small dents. The track turns dull, grey and slightly rough instead of bright.

What you see	Likely causes	What to do
Dull, finely dented tracks and rolling surfaces	A small amount of mixed foreign matter gets in	Clean thoroughly around the bearing Improve the seal and stop the matter getting in

Worth knowing: A satin finish tells you the contamination is fine and constant, not one big particle. Look at the seal, the grease and the filter.

Full profiles: Indentations from particles, Abrasive wear.

Impressions (indentations)

Also described as: Dents, brinelling, particle dents.

Hollows pressed into the track. They come from a high load while the bearing stands still or turns slowly, or from hard particles rolled into the surface.

What you see	Likely causes	What to do
On the track and rolling surfaces	A particle gets caught in the contact	Clean thoroughly around the bearing Improve the seal
Spaced at the rolling-element pitch	Impact during installation Heavy load while stationary	Improve assembly practice Improve the handling of the machine

Worth knowing: If dents sit at the exact rolling-element spacing, the load came through the bearing at rest, usually at fitting or transport.

Full profiles: Indentations from particles, Overload deformation.

Chipping

Also described as: Rib or edge break-out.

Pieces break from the rib of a ring or from the corner of a roller.

What you see	Likely causes	What to do
At the rib or the corner of a roller	Rib struck during installation Heavy impact or axial load	Improve assembly practice Re-check the loads

Worth knowing: Chips at the rib usually come from a hammer blow or from forcing the bearing on at an angle.

Full profiles: Handling damage.

Cracks

Also described as: Fine cracks, split rings.

Fine cracks or full breaks in rings or rolling elements.

What you see	Likely causes	What to do
Cracked outer or inner ring	Fit too tight Heavy impact load Flaking or seizure that came first	Choose the right fit Re-check the loads
Cracked rollers	Heavy impact load Flaking or seizure that came first	Re-check the loads

Worth knowing: A ring that splits across the width usually points to a too-tight fit or heat. Look at how the crack runs.

Full profiles: Forced fracture, Thermal cracking, Fatigue fracture.

Rust and corrosion

Also described as: Water damage, pitting.

Rust is a surface film made by chemical attack. Corrosion is the loss of metal from acid, alkali or water.

What you see	Likely causes	What to do
Rust over part or all of the bearing	Poor storage Condensation	Improve storage Improve the seal Protect the bearing against rust during long stops
Rust spots at the rolling-element pitch	Water or corrosive material getting in	Improve the seal

Worth knowing: Rust spots at the rolling-element pitch mean water reached the bearing while it stood still. Look at washdown and condensation.

Full profiles: Moisture corrosion.

Seizing

Also described as: Seizure, welded parts.

The bearing overheats badly. The metal changes colour, deforms or welds together. It is the end of a failure chain.

What you see	Likely causes	What to do
Discoloured, deformed or welded parts	Internal clearance too small Wrong lubricant or too little of it Excessive load Damage in another part of the bearing	Choose the right internal clearance Check lubrication method and lubricant Check bearing type and size Detect early damage and act on it

Worth knowing: Seizure shows the end of the chain. Look back through the rest of the bearing for the first damage.

Full profiles: Seizure.

Fretting

Also described as: Fretting corrosion, rust-coloured powder.

Tiny movement between two surfaces that should be fixed wears them and makes rust-coloured powder. It shows on the bore, the outside diameter and the faces.

What you see	Likely causes	What to do
Rust-coloured powder on the fit surface	Fit too loose	Use a tighter fit Apply lubricant on the fit surface

Worth knowing: Fretting needs vibration and a loose fit. Check both, and check the shaft and housing for wear.

Full profiles: Fretting corrosion.

Electrolytic corrosion

Also described as: Electrical pitting, fluting.

Current passes through the bearing and sparks across the thin oil film. It leaves small pits that melt, and later regular ridges across the track like a washboard.

What you see	Likely causes	What to do
Pitted or washboard marks on the track and rolling surface	Sparking caused by current passing through the bearing	Give the current another path around the bearing Use an insulated bearing

Worth knowing: Look for grey washboard marks across the whole track, and for dark discolouration on the rolling elements.

Full profiles: Excessive current erosion, Current leakage erosion.

Cage damage

Also described as: Broken or deformed cage.

The cage is softer than the rings. Shock, vibration or contact with other parts can scratch, bend, crack or wear it, which upsets how the rollers move.

What you see	Likely causes	What to do
Scratches, deformation, chipping, cracks or heavy wear	Heavy vibration, shock or moment Wrong lubricant or too little of it	Check the loading Check lubrication method and lubricant
Rivet loose or cut	Poor installation, with the bearing tilted Struck during fitting	Reduce the mounting error Check the cage type Improve mounting

Worth knowing: A broken cage is often the result, not the cause. Look at what loaded it.

Full profiles: Cage damage.

Creep

Also described as: Ring slipping on the shaft or housing.

A ring turns slowly against the shaft or housing during running. It wears, discolours or scuffs the fit surfaces.

What you see	Likely causes	What to do
Wear, discolouration or scuffing on the fit side	Fit too loose Sleeve not tightened enough	Use a tighter fit Tighten sleeves correctly

Worth knowing: Look for shine, polish or scoring on the bore or outside diameter. Creep wears the seat as well, so check the shaft.

Full profiles: Ring creep.

False brinelling

Also described as: Standstill marks.

Where fretting sits on the raceway, the wear looks like brinell dents. It forms when a stationary bearing vibrates or rocks.

What you see	Likely causes	What to do
Dents on the track at the rolling-element pitch	Vibration and rocking while the bearing is stopped	Improve how the shaft and housing are fixed Give the bearing some preload

Worth knowing: Shiny, flat-bottomed marks on the track at rolling-element spacing, with rust-coloured wear debris, suggest false brinelling, not true brinelling.

Full profiles: False brinelling.

Struck dents

Also described as: Hammer marks, handling damage.

A hammer blow or other strike leaves a dent where it hit.

What you see	Likely causes	What to do
Dents on the track, on rolling elements or on the cage	Poor handling	Improve assembly work Improve handling

Worth knowing: Use the right fitting tool, and apply force only to the ring that is being pressed on.

Full profiles: Handling damage.

Questions about bearing damage names

What is the difference between smearing and scuffing?

Both are sliding damage where the oil film failed. Scuffing is torn, roughened metal on surfaces that slide under high contact pressure, such as roller ends and ribs. Smearing is a smeared, glazed patch on the rolling surface where elements slid instead of rolling, often on lightly loaded, fast bearings.

What is the difference between flaking and spalling?

They describe the same thing: small pieces of the raceway or rolling element breaking away. Flaking at the end of calculated life is normal fatigue. Flaking early points to clearance, lubrication, load or alignment.

What does temper colour on a bearing mean?

The steel got hot enough to tint, usually straw, brown or blue. Look for too little internal clearance, the wrong or too little lubricant, or aged lubricant.

What causes fretting on the bore of a bearing?

A fit that is too loose, with vibration, lets the ring move slightly against the seat and grind off rust-coloured powder.

How do I tell false brinelling from true brinelling?

False brinelling is fretting wear at rolling-element spacing caused by vibration at standstill, so it is shiny with rust-coloured debris. True brinelling is plastic dents from overload or impact. Open the full profiles to compare.

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