ASTM A973/A973M-21

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A973/A973M − 07 (Reapproved 2012) A973/A973M − 21
Standard Specification for
Grade 100 Alloy Steel Chain
This standard is issued under the fixed designation A973/A973M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers Grade 100 heat-treated alloy steel chain for such applications as slings, lifting assemblies, and load
binding. For overhead lifting applications, only alloy chain should be used.
NOTE 1—This specification does not cover alloy steel chain for pocket wheel applications.
1.2 This specification is a performance standard for Grade 100 chain used between −20−20 °F and 400°F [−29400 °F [−29 °C and
205°C].205 °C]. The chain manufacturer should be contacted for use at temperatures outside this range.
1.3 The Grade designationchain grade is ⁄10 of the minimum breaking strength in newtons dividedbased on the nominal stress in
the link at the design breaking force strength. It is calculated by taking the minimum breaking force load and dividing by two times
the nominal cross-sectional area of the chain in square millimetres. link.
1.4 The values stated in either SI units or in other units shall are to be regarded separately as standard. The values stated in each
system mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system mustshall be
used independently of the other, without combining values in any way.and values from the two systems shall not be combined.
1.4.1 Metric Units—Grade = ⁄10 of the minimum breaking force in kilonewtons divided by two times the nominal cross-sectional
area in square millimeters.
= (MBF)/(0.005)(π)(d)2
1.4.2 English Units—Grade = 0.000689 of the minimum breaking force in pounds divided by two times the nominal
cross-sectional area in square inches.
= (0.000689)(MBF)/(0.5)(π)(d)2
1.4.3 MBF = minimum breaking force (lb or kN); d = chain diameter (in. or mm).
NOTE 2—The above formulas are for round diameter links only. If different cross sections are used, the actual cross section of the link would need to be
calculated and used.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.27
on Steel Chain.
Current edition approved Nov. 1, 2012Jan. 1, 2021. Published November 2012January 2021. Originally approved in 1997. Last previous edition approved in 20072012
as A973/A973M – 07.A973/A973M – 07 (2012). DOI: 10.1520/A0973_A0973M-07R12.10.1520/A0973_A0973M-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A973/A973M − 21
2. Referenced Documents
2.1 ASTM Standards:
A29/A29M Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
A751 Test Methods and Practices for Chemical Analysis of Steel Products
A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
2.2 SAE Standard:
SAE J422 Microscopic Determination of Inclusions in Steels
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 breaking force, minimum, n—minimum force in pounds or newtons at which the chain, during manufacture, has been found
by testing to break when a constantly increasing force is applied in direct tension.
3.1.1.1 Discussion—
This test is a manufacturer’smanufacturer’s attribute acceptance test and shall not be used as criteria for service.
3.1.2 date code, n—series of letters, numbers, or both embossed on the chain which enables its manufacturing history to be traced.
3.1.3 lot, n—for the purpose of acceptance testing, a lot shall consist of 3000 ft [1000 m], or fraction thereof, of the same size
chain. If a continuous length of chain exceeds 3000 ft [1000 m], it shall also be considered a lot.
3.1.4 proof test, n—quality control tensile test applied to chain for the purpose of verifying weld and material quality.
3.1.4.1 Discussion—
It is the minimum force in pounds or newtons which the chain has withstood at the time it left the producer, under a test in which
a constantly increasing force has been applied in direct tension to a straight length of chain. Proof test loads are a manufacturing
integrity test and shall not be used as criteria for service or design purposes.
3.1.5 traceability code, n—series of letters, numbers, or both embossed on the chain which enables its manufacturing history,
including the identity of the steel heat, to be traced.
3.1.6 working load limit (WLL), n—maximum combined static and dynamic load in pounds or kilograms that shall be applied in
direct tension to an undamaged straight length of chain.
4. Ordering Information
4.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for material ordered under this
specification. Such requirements include, but are not limited to, the following:
4.1.1 Product to conform to Specification A973/A973M and date of issue,
4.1.2 Nominal size of chain (in. or mm),
4.1.3 Quantity of chain (ft or m),
4.1.4 Length of each piece, if required,
4.1.5 Finish, if required,
4.1.6 Certification of test(s), if required,
4.1.7 Acceptance of inspection by purchaser, if required, and
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A973/A973M − 21
4.1.8 Supplementary requirements, if required.
5. Manufacturing
5.1 Melting Process—The alloy steel shall be fully killed and have an austenitic grain size of five or finer.
5.2 Welding Process—Alloy steel chain may be made by the electric welding or gas welding process.
5.3 Heat Treatment—After welding, alloy steel chain shall be heat treated before applying the proof test. Heat treatment shall
include quenching and tempering as defined by Terminology A941.
6. Material Requirements
6.1 Heat Analysis—The selection and amounts of the alloying elements in the steel are left to the judgment of the individual chain
manufacturer provided the steel meets the following criteria: carbon = 0.35 % max; phosphorous = 0.025 % max; sulfur = 0.025 %
max. The following elements must all be present in alloying amounts, nickel (0.40% min), chromium (0.40% min), and
molybdenum (0.15% min). The steel shall have oxide and silicate inclusions of 4 or less as determined by SAE J422.
6.2 Product Analysis—The steel used may be analyzed by the purchaser and shall conform to the requirements of 6.16.1 subject
to the product analysis tolerances specified in Specification A29/A29M. Test samples may be taken from rods, bars, or finished
chain. Samples for analysis shall be so taken as to represent the full cross section of the specimen.
6.3 Test Methods, Practices, and Terminology A751 shall be used for referee purposes.
7. Mechanical Requirements
7.1 Proof Test—All Every link of chain shall be tested to at least the proof load prescribed in Table 1 for the appropriate size chain.
When so tested it shall withstand these loads without loss of chain integrity. Links or chain segments not withstanding the proof
test load shall be removed from the chain.
7.2 Breaking Force—The breaking force test specimen shall consist of a length from the lot containing at least the number of links
in Table 2. All chain shall be in the quenched and tempered condition before the breaking force is measured.
7.2.1 Fixtures for securing chain in a testing machine shall be properly designed to support securely the shoulder of the link (see
Note 23). The opening in the fixture shall not be more than 125 % of the stock diameter being tested. Links engaged in the testing
fixture shall not be considered part of the test specimen.
NOTE 3—“U” bolts of the same or larger diameter and the same or greater strength may be used to secure the chain to the jaws of the testing machine.
7.2.2 Test results shall meet or exceed the minimum breaking force values given in Table 1 for the appropriate size chain.
7.3 Elongation:
TABLE 1 Grade 100 Alloy Chain Mechanical and Dimensional Requirements
Nominal Chain Material Diameter Working Load Limit Proof Test (min) Minimum Breaking Inside Length (max) Inside Width Range
Size (max) Force
in. mm in. mm lb kg lb kN lb kN in. mm in. mm
⁄32 5.5 0.217 5.5 2700 1220 5400 23.8 10 800 47.6 0.69 17.6 0.281 to 0.325 7.14 to 8.25
⁄32 7 0.276 7.0 4300 1950 8600 38.5 17 200 77 0.90 22.9 0.375 to 0.430 9.53 to 10.92
⁄16 8 0.315 8
...