What Is a Lifting Chain Strength Test?
How Is an Alloy Steel Lifting Chain Strength Test Performed?
What Other Tests Verify Lifting Chain Quality?
G80 vs. G100 Lifting Chain Strength Test: What Is the Difference?
Which Standards Apply to Lifting Chain Strength Testing?
How Can Buyers Verify a Lifting Chain Strength Test Report?
Frequently Asked Questions About Lifting Chain Strength Tests
Conclusion
A lifting chain strength test is an essential part of verifying whether an alloy steel chain meets the mechanical requirements for industrial lifting. Chains used for lifting heavy machinery, steel structures, and equipment assemblies must provide more than high tensile strength. They also need adequate toughness, ductility, consistent dimensions, and reliable welded links.
But how do manufacturers test the strength of a lifting chain? What is the difference between a proof load test and a breaking force test? And how can buyers confirm that a Grade 80 or Grade 100 chain meets the required specifications?
This guide explains the main testing methods, equipment, acceptance criteria, and international standards used to evaluate alloy steel lifting chains.
A lifting chain strength test is a controlled mechanical examination used to verify the performance of a lifting chain against a defined specification.
The process may involve applying tensile force to a finished chain or representative sample, measuring deformation, examining chain links, and recording the results.
The exact requirements depend on the chain grade, size, applicable manufacturing standard, and intended application.
Lifting chains experience tensile forces during normal operation. The chain links and welded sections must maintain their structural integrity under the loading conditions covered by their approved rating.
Testing helps manufacturers verify that a chain meets requirements for:
Mechanical strength
Manufacturing consistency
Weld integrity
Resistance to permanent deformation
Minimum breaking force
Ductility and elongation
Applicable dimensional tolerances
However, a successful strength test does not mean that a chain can safely withstand any load.
The chain must still be used within its marked Working Load Limit (WLL), with compatible lifting components and an approved lifting arrangement.
Three important terms appear frequently in lifting chain test reports.
Term | Meaning | Main Purpose |
Working Load Limit (WLL) | Maximum permitted working load under specified conditions | Safe equipment selection |
Manufacturing Proof Force (MPF) | Specified force applied during a non-destructive manufacturing test | Verify chain integrity |
Minimum Breaking Force (MBF) | Specified minimum force that a test specimen must withstand before failure | Verify mechanical strength |
For many Grade 80 and Grade 100 lifting chain specifications, the minimum breaking force is approximately four times the WLL.
However, the exact relationship must be verified against the applicable chain standard and the manufacturer's approved ratings.
A chain with a 4:1 design factor is not permitted to lift four times its WLL.
Manufacturers use different testing methods to assess different mechanical characteristics.
The most important are proof force testing, breaking force testing, elongation measurement, and applicable bend testing.
The proof load test, also known as a manufacturing proof force test, is a non-destructive tensile test.
A specified tensile force is applied to the chain to verify that it can withstand the required manufacturing test load without losing its structural integrity.
Typical procedure:
Identify the chain grade, size, and applicable test specification.
Position the chain in suitable testing equipment.
Apply the specified manufacturing proof force using a controlled procedure.
Monitor the chain and testing equipment.
Examine the chain for relevant defects or failure.
Record the test result and identification details.
Under relevant standards such as ASTM A391/A391M and ASTM A973/A973M, finished chain is required to undergo proof testing.
The exact proof force and acceptance criteria depend on the product specification.
Important: A proof test is not intended to break the chain, and the proof force must never be treated as the permissible working load.
A breaking force test is a destructive tensile test performed on a representative chain specimen.
Unlike the proof test, the applied force is increased until the specimen fractures.
The objective is to determine whether the chain meets or exceeds its specified minimum breaking force.
Typical procedure:
Select a representative specimen according to the applicable sampling requirements.
Verify the specimen's grade, diameter, and identification.
Secure it using suitable tensile testing fixtures.
Apply tensile force at the rate specified by the test procedure.
Continue loading until the specimen breaks.
Record the maximum force, specimen behavior, and test result.
The measured breaking force is compared with the minimum requirement for the relevant chain size and grade.
The test may also provide information about fracture behavior and the location of failure.
Because this is a destructive test, manufacturers test representative specimens according to the applicable sampling plan rather than intentionally breaking every finished chain.
A lifting chain must provide adequate strength without becoming excessively brittle.
Elongation testing helps assess the chain's capacity to deform under tensile loading.
During the specified tensile test, the original gauge length of the specimen is compared with the length measured under the relevant test conditions.
For total elongation at fracture, the result may be expressed as:
Elongation (%) = [(Final Length − Original Length) ÷ Original Length] × 100
The measurement method must follow the applicable standard, including its definition of gauge length and final length.
Higher elongation is not automatically better. The chain must meet the required combination of strength and ductility for its grade.
A chain that meets its breaking-force requirement but fails the specified elongation requirement may still be nonconforming.
Some lifting chain standards also require a bend test.
For example, EN 818-2 includes a bend deflection requirement for Grade 8 lifting chains.
In this test, an individual chain link is subjected to a specified bending deformation under controlled conditions.
The link is then examined according to the applicable acceptance criteria.
The purpose is to help verify that the material and welded link possess sufficient deformation capacity without unacceptable cracking or failure.
Bend test requirements must be taken from the governing chain specification rather than assumed to be identical for every chain grade.
A tensile test alone cannot fully describe the quality of an alloy steel lifting chain.
Material composition, heat treatment, link dimensions, and weld quality all influence the finished product.
Grade 80 and Grade 100 lifting chains are manufactured from specified heat-treated alloy steels.
The material's chemical composition affects hardenability, strength, toughness, and manufacturing performance.
Depending on the applicable specification, material verification may include:
Chemical composition analysis
Material identification
Heat or batch traceability
Review of steel mill certificates
Verification against the approved steel specification
Alloy steel does not automatically meet Grade 80 or Grade 100 strength requirements.
The finished chain must achieve the mechanical properties required by its approved grade.
Quenching and tempering play an important role in developing the required mechanical properties of alloy steel lifting chains.
Manufacturers must control the heat treatment process to achieve an appropriate balance of strength, toughness, and ductility.
Depending on the product specification and quality plan, verification may include hardness measurements, heat treatment records, and related mechanical testing.
For a deeper explanation of the metallurgical process, read TOPONE's The Science of Heat Treatment: Why It Matters for Lifting Chain Strength.
A hardness result alone does not establish a lifting chain's WLL or demonstrate that it has passed all required strength tests.
Lifting chains may experience repeated loading during industrial service.
Fatigue testing helps evaluate how a chain or sample performs under controlled cyclic loading.
A test procedure may specify:
Minimum and maximum cyclic forces
Loading frequency
Number of cycles
Specimen preparation
Failure or acceptance criteria
Fatigue test requirements vary according to the chain standard, product design, and purchaser's specification.
A published fatigue cycle result must not be interpreted as a guaranteed service life.
Actual chain life depends on load conditions, maintenance, wear, corrosion, and the complete lifting arrangement.
Mechanical performance also depends on consistent link geometry.
Important dimensional checks include nominal chain diameter, pitch, inside width, outside width, and applicable welding dimensions.
Welded sections are examined according to the required manufacturing inspection procedure.
A chain with excellent material strength may still be unsuitable if its dimensions or welds do not satisfy the approved specification.
Grade 80 and Grade 100 are two common strength classifications for alloy steel lifting chains.
Both require verified mechanical performance, but their rated capacities and specified test forces differ.
Grade 80 lifting chains are commonly manufactured from quenched and tempered alloy steel.
Applicable specifications include EN 818-2, ISO 3076, and ASTM A391/A391M, depending on the product and market.
These standards address relevant dimensional, mechanical, manufacturing, and testing requirements within their respective scopes.
For model specifications and corresponding reference test loads, see TOPONE's Grade 80 Lifting Chain.
Grade 100 lifting chains generally provide approximately 25% higher nominal WLL than comparable Grade 80 chains of the same diameter under equivalent rating conditions.
Achieving this higher strength classification requires suitable material selection, manufacturing control, heat treatment, and mechanical verification.
ASTM A973/A973M provides a relevant product specification for Grade 100 alloy steel chains.
The chain must meet its own approved proof force, breaking force, elongation, and other applicable requirements.
TOPONE publishes reference specifications for its G100 Lifting Chain range.
The following table illustrates how grade affects rated capacity and specified test forces for selected 10 × 30 mm lifting chains.
Parameter | 10 mm G80 Chain | 10 mm G100 Chain |
Nominal Chain Diameter | 10 mm | 10 mm |
Nominal Chain Pitch | 30 mm | 30 mm |
Reference WLL | 3.15 t | 4.00 t |
Reference Proof Force | 78.5 kN | 98.1 kN |
Reference Minimum Breaking Force | 126 kN | 157 kN |
Main Material | Heat-Treated Alloy Steel | Heat-Treated Alloy Steel |
Values are based on selected TOPONE reference specifications. Final acceptance criteria must follow the applicable standard and approved product documentation.
These values illustrate three important points.
First, both chains have the same nominal diameter and pitch, but their strength classifications differ.
Second, the Grade 100 chain has higher rated and specified test-force values in the selected configuration.
Third, neither proof force nor minimum breaking force can be used as a substitute for the chain's marked WLL.
The complete lifting assembly must also be evaluated separately.
Different standards address different aspects of alloy steel lifting chain manufacturing, testing, and completed sling assemblies.
The correct standard depends on the chain grade, intended application, and market requirements.
Standard | Main Scope | Relevance to Testing |
EN 818-1 | General acceptance requirements for short-link lifting chains | General manufacturing and verification requirements |
EN 818-2 | Grade 8 medium-tolerance lifting chains | Proof force, breaking force, elongation and bend requirements |
ISO 3076 | Grade 8 medium-tolerance chains for chain slings | Grade-specific performance and acceptance |
ASTM A391/A391M | Grade 80 heat-treated alloy steel chain | Material, dimensional and mechanical requirements |
ASTM A973/A973M | Grade 100 heat-treated alloy steel chain | Material, proof testing, breaking force and elongation |
EN 818-4 | Grade 8 chain sling assemblies | Assembly ratings, testing and safety requirements |
ASME B30.9 | Slings | Selection, use, inspection and other sling safety requirements |
These standards must be applied according to their actual scopes.
EN 818-2 is a Grade 8 chain standard and must not automatically be cited as a complete Grade 100 product specification.
Likewise, ASME B30.9 addresses slings and should not be presented as a standalone manufacturing specification for every individual chain grade.
Yes.
Testing an individual chain and testing an assembled chain sling are related but distinct activities.
A completed chain sling may contain master links, hooks, connecting links, and multiple chain legs.
The finished assembly must meet the applicable requirements for its configuration and rated capacity.
For example, OSHA 29 CFR 1910.184 requires proof testing of new, repaired, or reconditioned alloy steel chain slings before use under its applicable provisions.
The assembly must also have appropriate identification and be inspected according to the relevant requirements.
For examples of complete lifting assemblies, explore TOPONE's Chain Lifting Slings range.
A successful strength test on the chain alone does not establish the WLL of a complete multi-leg sling.
Not necessarily.
Precision load chains used in manual or electric chain hoists have different dimensional and equipment compatibility requirements from ordinary lifting sling chains.
For example, EN 818-7 addresses fine-tolerance Grade T hoist chains, including Types T, DAT, and DT.
A chain that passes a Grade 80 sling-chain test is not automatically approved for use in an electric hoist.
The actual hoist manufacturer's approved chain specification must govern replacement and equipment compatibility.
A credible test report should provide enough information to identify the tested product and determine whether the required acceptance criteria were met.
Depending on the applicable specification and contractual requirements, buyers may request the following information.
Inspection Item | Information to Verify |
Manufacturer | Company or manufacturing source |
Product Description | Chain grade, size and type |
Applicable Standard | Standard designation and edition |
Batch Identification | Heat number, lot number or traceability code |
Material Information | Approved steel grade and material records |
Proof Force | Required force and test result |
Breaking Force | Specified minimum and measured result |
Elongation | Measured value and acceptance limit |
Dimensional Inspection | Chain diameter, pitch and other relevant dimensions |
Additional Tests | Bend, hardness or fatigue results where applicable |
Inspection Status | Acceptance result and authorized verification |
The exact report format varies by manufacturer, product standard, and buyer requirements.
Not every test listed above is mandatory for every chain or order.
Buyers should request clarification when a supplier provides:
A test report without a corresponding chain grade or diameter
Breaking force values without an identified testing standard
Proof test claims without traceable records
A generic certificate that cannot be linked to the ordered product
Inconsistent WLL, proof force, and breaking force values
Certification claims that do not identify the actual product or scope
For replacement or repeat orders, maintaining consistent product identification and batch traceability can simplify technical verification.
Manufacturing testing verifies the product against its specified acceptance requirements at production.
It does not eliminate the need for inspection during use.
A chain can become unsuitable for lifting because of wear, deformation, overload, cracks, corrosion, or excessive elongation.
For practical measurement methods, see TOPONE's How to Measure Lifting Chain Wear and Elongation.
In-service inspection must use the appropriate rejection criteria. A used chain should not be subjected to an arbitrary overload test to determine whether it is still safe.
Both proof force testing and breaking force testing are important, but they serve different purposes.
Proof testing verifies chain integrity under a specified non-destructive load. Breaking force testing verifies that representative specimens meet the minimum ultimate strength requirement.
No. A correctly performed manufacturing proof load test is intended to be non-destructive.
If a chain fails the specified proof test or shows an unacceptable defect, it cannot simply be accepted for service.
Proof load is a specified manufacturing verification load.
Breaking load refers to the force measured when a test specimen fails, while minimum breaking force is the required acceptance threshold.
Neither is the approved working load.
No. Breaking tests are destructive and are performed on representative specimens according to the applicable sampling requirements.
Finished chain is proof tested according to the governing product specification.
Grade 100 chain is evaluated according to its approved manufacturing specification, including required proof testing, minimum breaking force, elongation, and other applicable verification.
ASTM A973/A973M is one relevant specification for Grade 100 alloy steel chain.
Not automatically.
A higher specified breaking force may reflect a higher chain grade or larger chain diameter, but safe lifting depends on the approved WLL, equipment condition, compatible fittings, lifting geometry, and operating procedures.
No.
A test certificate demonstrates compliance with specified requirements at the time of testing. It cannot guarantee performance under every future loading or environmental condition.
A lifting chain strength test is a critical part of verifying the mechanical performance of Grade 80 and Grade 100 alloy steel lifting chains.
The principal testing methods include manufacturing proof force testing, breaking force testing, elongation measurement, and applicable bend tests. Material verification, heat treatment control, dimensional inspection, and other specified tests provide additional evidence of product quality.
The most important distinction is between WLL, proof force, and minimum breaking force. These values have different purposes and must never be treated as interchangeable.
For industrial buyers, selecting a lifting chain should involve checking its grade, dimensions, applicable standard, rated capacity, and traceable testing documentation.
Looking for Tested Alloy Steel Lifting Chains?
TOPONE supplies Grade 80 and Grade 100 alloy steel lifting chains for industrial lifting and rigging applications.
When requesting a quotation, provide your required chain grade, diameter, length, WLL, order quantity, and applicable testing or documentation requirements.
Contact TOPONE CHAIN to discuss available chain specifications, testing documentation requirements, and bulk purchasing options.
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