The table below provides detailed information on the symptoms of leaf chain wear, the probable causes and the corrective measures that should be taken. This table is a useful reference point for service technicians conducting leaf chain inspections.

Symptom

Appearance

Probable cause

Correction

Worn contour

Chain Worn contour

Normal wear on sheave

Abnormal wear rubbing on guides

Replace leaf chain when 5% worn

Check Leaf chain alignment or increase clearance

Worn surfaces on outer plates or pin heads

Worn surfaces on outer plates or pin heads

Misalignment, rubbing on side flanges

Check leaf chain alignment and correct clearance as necessary

Tight joints

Chain Tight joints

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

Clean & re-lubricate leaf chain

Replace leaf chain

Replace leaf chain

Missing parts

Chain Missing parts

Missing at original assembly

Replace leaf chain

Abnormal protrusion or turned pins

Chain Abnormal protrusion or turned pins

Excessive internal friction caused by high loading and inadequate lubrication

Replace leaf chain, improve lubrication and eliminate overload conditions

Cracked plates (fatigue)

Cracked Chain plates

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 leaf chain of larger dynamic capacity or eliminate high load condition or dynamic (impulse) overloading

 

Symptom Appearance Probable cause Correction
Fractured plates (tension mode)

Fractured chain plates

Note material distortion

High overload Replace leaf chain and correct cause of overload
Arc like cracked plates (stress corrosion) Arc like cracked plates 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 leaf chain and protect from hostile environment.
Enlarged holes Enlarged chain holes High overload Replace leaf chain and correct cause of overload
Corrosion pitting   Exposure to corrosive environment Replace leaf chain and protect from hostile environment.
Worn leaf chain anchor bolt connecting pin   Normal wear Replace worn leaf chain components and always when fitting new leaf chains