Roller Chain inspection check-list
Symptom | Appearance | Probable cause | Correction |
---|---|---|---|
Worn contour |
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Abnormal wear rubbing on guides |
Replace roller chain when 5% worn. Check roller chain alignment or increase clearance. |
Pin galling |
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Inadequate lubrication |
Reduce load or roller chain drive speed. Provide proper roller chain lubrication. |
Tight joints |
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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 |
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Excessive roller chain wear |
Replace roller chain and roller chain sprocket. |
Abnormal protrusion or turned pins |
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Excessive internal friction caused by high loading and inadequate lubrication |
Replace roller chain, improve lubrication and eliminate overload conditions. |
Cracked plates (fatigue) |
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) |
Note material distortion |
High overload |
Replace roller chain and correct cause of overload. |
Arc like cracked plates (stress corrosion) |
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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 |
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High overload |
Replace roller chain and correct cause of overload. |
Corrosion pitting |
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Exposure to corrosive environment |
Replace roller chain and protect from hostile environment. |
Broken, cracked or deformed rollers |
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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 |
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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. |