What Are Lifting Chain Wear and Elongation?
Why Does Lifting Chain Elongation Matter?
How to Measure Lifting Chain Wear
How to Measure Lifting Chain Elongation
How Much Lifting Chain Elongation Is Allowed?
Other Damage to Check While Measuring the Chain
Lifting Chain Wear and Elongation Inspection Checklist
Measuring Lifting Chain Elongation: The Practical Rule
Lifting chains are designed for repeated load cycles, but they do not remain dimensionally unchanged throughout their service life. Wear can gradually reduce the cross-section of individual links, while overload, deformation, or accumulated service damage can increase link dimensions or the measured length of a chain section.
This makes lifting chain elongation and wear two of the most important conditions to check during inspection.
A chain that still looks intact may no longer meet its allowable dimensional limits. For this reason, inspection should not rely only on visual appearance. Measurements should be compared with the chain manufacturer's original dimensions and applicable removal criteria.
The basic inspection process is:
Clean the Chain → Identify Grade and Size → Inspect Visually → Measure Wear → Measure Elongation → Compare With Limits → Record the Result
This guide explains how to measure lifting chain wear and elongation correctly and how to recognize when dimensional changes require further evaluation or removal from service.
Wear and elongation are related inspection issues, but they are not the same type of damage.
Chain wear normally refers to a reduction in the material cross-section of a chain link. It commonly develops where links contact each other or where the chain bears against hooks, fittings, sheaves, pockets, or other surfaces.
Chain elongation refers to an increase in a specified link dimension or in the measured length over a defined number of links.
This distinction matters because a chain can experience significant local wear without showing obvious overall elongation. Conversely, abnormal dimensional increase can indicate deformation even when material loss appears limited.
Condition | What Changes | Typical Inspection Method |
Wear | Link material/cross-section | Diameter or section measurement |
Elongation | Link or chain length | Pitch/multi-link length measurement |
Deformation | Link shape or dimensions | Measurement + visual inspection |
Mechanical damage | Surface condition | Visual and dimensional inspection |
Both wear and elongation can affect whether a lifting chain remains suitable for service.
They should therefore be evaluated separately rather than using one measurement as a substitute for the other.
A lifting chain is manufactured to controlled dimensional tolerances. Its pitch, link dimensions, material cross-section, weld geometry, and mechanical properties are all part of the chain's rated design.
When these dimensions change significantly during service, the chain may no longer correspond to its original condition.
Elongation can result from several mechanisms.
If a chain experiences forces beyond its intended operating conditions, individual links can undergo permanent deformation.
This is different from normal elastic stretch.
All steel components deform elastically to some degree when loaded. When the load is removed within the elastic range, the component returns substantially to its original dimensions.
Permanent elongation means the material or link geometry does not fully return to its original condition after unloading.
Elongation measured over several links does not always mean the steel itself has simply “stretched.”
Material can gradually wear away at the contact surfaces between adjacent links. As those contact areas become thinner, the effective pitch or overall measured length of a chain section can change.
This is one reason inspectors should check both:
Link Cross-Section + Multi-Link Length
rather than relying on only one measurement.
Bent, twisted, stretched, or otherwise distorted links can also change the overall dimensions of the chain.
Visible deformation should therefore be treated seriously even if a multi-link elongation measurement has not yet reached a specified limit.
Before taking measurements, remove dirt, grease, and contamination that could hide the actual surface or interfere with measuring tools.
The chain should be unloaded and positioned so that individual links can be inspected properly.
Start by identifying:
Chain Grade → Nominal Diameter → Manufacturer → Applicable Standard → Original Dimensions
Do not compare a used chain with an assumed generic diameter if the manufacturer's dimensional data are available.
Wear frequently occurs at the bearing surfaces where adjacent links contact each other.
These areas may be more difficult to see than the outside surface of the chain.
A caliper or other suitable measuring instrument can be used to measure the remaining section according to the manufacturer's specified inspection method.
A simplified wear calculation is:
Wear (%) = (Original Dimension − Measured Dimension) ÷ Original Dimension × 100
For example, if an original reference dimension is 10.0 mm and the corresponding worn dimension measures 9.2 mm:
Wear = (10.0 − 9.2) ÷ 10.0 × 100 = 8%
This calculation tells you how much dimensional loss has occurred.
It does not automatically tell you whether the chain can remain in service.
The measured result must then be compared with the allowable wear limit specified for that particular chain and application.
One common inspection mistake is measuring only the easiest part of the link to reach.
The least-worn external surface may still appear close to nominal diameter while substantial wear exists at the interlink bearing surface.
Inspect the entire circumference and pay particular attention to:
Interlink contact areas · Weld area · Load-bearing surfaces · Areas contacting fittings or chain pockets
If the chain has uneven wear, measurements should focus on the most severely affected areas rather than an average of good and bad sections.
Elongation can be checked at individual-link level or over a specified number of consecutive links, depending on the chain type and manufacturer's inspection procedure.
Measuring several links can make small dimensional changes easier to detect because the change accumulates over a longer reference length.
You need a reliable original dimension before calculating elongation.
Depending on the product, this may come from:
Manufacturer dimensional specifications
Original inspection records
Applicable chain standard
An approved reference measurement
Do not assume that nominal chain diameter can be used to calculate the exact original multi-link length.
Pitch and dimensional tolerances must be considered.
The chain should be unloaded and arranged according to the measurement procedure.
Twisted links, contamination, or an inconsistent measuring position can affect the result.
When measuring multiple links, use the same reference points each time.
Consistency is essential if inspection records will be compared over the chain's service life.
Measure the required reference length across the specified number of consecutive links.
For example, if the inspection procedure calls for measurement over several links, record the complete reference length rather than trying to estimate elongation from visual appearance.
A basic percentage calculation is:
Elongation (%) = (Measured Length − Original Length) ÷ Original Length × 100
Suppose the original reference length is 500 mm and the current measured length is 510 mm:
Elongation = (510 − 500) ÷ 500 × 100 = 2%
Again, this is a measurement result—not automatically a pass/fail decision.
The calculated percentage must be compared with the removal criteria for the specific lifting chain.
Both methods can provide useful information, but they answer slightly different questions.
Individual-link inspection is particularly useful for finding local deformation, wear, bending, or damage.
Multi-link measurement helps detect accumulated dimensional changes across a section of chain.
For a thorough inspection, these methods should complement each other.
A chain could theoretically pass an overall length measurement while still containing one severely damaged link. Likewise, individual links may not immediately reveal gradual accumulated pitch changes across a longer chain section.
This is why lifting chain inspection should combine:
Visual Inspection + Local Measurement + Multi-Link Measurement
rather than relying on a single measurement.
This is where inspectors need to be careful.
There is no responsible reason to take one percentage from an unrelated chain type and apply it universally to every Grade 80, Grade 100, hoist, sling, or other lifting chain.
The allowable limit depends on factors such as:
Chain type · Chain grade · Applicable standard · Manufacturer · Measurement method · Intended application
For example, a Grade 80 chain sling and a calibrated hoist load chain do not necessarily use the same inspection procedure or dimensional removal criteria.
The correct process is therefore:
Identify Chain → Find Manufacturer/Standard Limit → Measure Using Specified Method → Compare Result → Remove From Service if Limit Is Exceeded
If the chain's identification is missing and its grade, specification, or original dimensions cannot be reliably established, it should not simply be assigned a capacity based on appearance or diameter.
Visible elongation is a poor inspection threshold.
By the time deformation becomes obvious to the naked eye, significant dimensional change may already have occurred.
Measurements provide objective evidence and allow results to be compared over time.
For frequently used lifting equipment, maintaining inspection records can also help identify progressive deterioration before it becomes severe.
Wear and elongation should never be inspected in isolation.
While measuring the chain, also look for:
Bent or twisted links that no longer maintain their original shape.
Cracks particularly around welds and highly stressed areas.
Nicks and gouges that remove material or create stress concentrations.
Heat damage including unusual discoloration or evidence of exposure beyond permitted temperature limits.
Corrosion that causes significant material loss or pitting.
Weld damage or abnormal conditions around the welded portion of the link.
Also inspect the complete chain sling assembly.
Hooks, master links, connecting links, shortening devices, and other load-bearing components can develop wear or deformation independently of the chain.
The condition of the strongest chain does not compensate for a damaged or lower-rated component elsewhere in the sling.
A practical inspection can follow this sequence:
Inspection Item | What to Check |
Identification | Grade, size, manufacturer and traceability |
Surface condition | Cracks, gouges, corrosion and heat damage |
Link shape | Bending, twisting or distortion |
Interlink area | Local material loss and wear |
Chain section | Remaining measured dimension |
Individual links | Abnormal dimensional change |
Multi-link length | Elongation over specified reference length |
Weld area | Damage or abnormal wear |
Components | Hooks, master links and connecting components |
Acceptance criteria | Manufacturer and applicable standard |
Inspection record | Measurements, date and result |
If a chain reaches or exceeds the applicable removal criteria, it should be removed from lifting service according to the relevant inspection procedure.
Do not attempt to restore stretched or distorted alloy steel lifting chain by hammering, heating, welding, or reshaping the damaged links.
The most useful principle is that lifting chain elongation cannot be judged by appearance alone.
A proper assessment requires a known reference dimension, consistent measurement method, suitable measuring equipment, and the correct acceptance criteria for the chain being inspected.
Use this sequence:
Identify → Clean → Inspect → Measure Wear → Measure Elongation → Compare With Limits → Record
And remember that wear and elongation are different.
Wear reduces the material cross-section.
Elongation increases a specified link or chain-section dimension.
Both can make a lifting chain unsuitable for continued service, and either condition may require removal even when the other measurement remains acceptable.
For Grade 80, Grade 100, and other lifting chains, the final decision should therefore be based on the manufacturer's dimensional limits and applicable inspection requirements, not on a universal percentage or a visual guess.
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