Roller inspection check-list

 

Symptom Appearance Probable cause Correction

Worn contour

chain-1

Abnormal wear rubbing on guides

Replace roller chain when 5% worn. Check roller chain alignment or increase clearance.

Pin galling

 

Inadequate lubrication

Reduce load or roller chain drive speed. Provide proper roller chain lubrication.

Tight joints

chain-3

Dirt or foreign substance packed in joints or corrosion or rust or bent pins

Clean & re-lubricate roller chain. Replace roller chain.

Hooked sprocket teeth

 

Excessive roller chain wear

Replace roller chain and roller chain sprocket.

Abnormal protrusion or turned pins

chain-5

Excessive internal friction caused by high loading and inadequate lubrication

Replace roller chain, improve lubrication and eliminate overload conditions.

Cracked plates (fatigue)

chain-6

Crack from aperture towards edge of linkplate at 90º to line of pull. Note there is no linkplate distortion.

Loading beyond chain's dynamic capacity (above fatigue endurance limit)

Replace chain with roller chain of larger dynamic capacity or eliminate high load condition or dynamic (impulse) overloading.

 

Symptom Appearance Probable cause Correction

Fractured plates (tension mode)

chain-7

Note material distortion

High overload

Replace roller chain and correct cause of overload.

Arc like cracked plates (stress corrosion)

 chain-8

Severe rusting or exposure to acidic or caustic medium, plus static pressure at press fit (between pin and pin linkplate). No cyclic stress is necessary for this phenomenon to occur.

Replace roller chain and protect from hostile environment.

Enlarged holes

chain-9

High overload

Replace roller chain and correct cause of overload.

Corrosion pitting

 

Exposure to corrosive environment

Replace roller chain and protect from hostile environment.

Broken, cracked or deformed rollers

 

Speed too high. Sprockets too small

Replace roller chain and reduce speed. Replace roller chain and use larger roller chain sprockets/

Broken pins

 

Extreme overload

Replace roller chain. Eliminate cause of overload or redesign roller chain drive/

Rusted chain

 

Exposed to moisture. Water in lubricant. Inadequate lubrication

Replace roller chain and protect from moisture. Change roller chain lubricant. Replace roller chain and improve roller chain lubrication.