This specification covers carbon steel chain for such applications as railroad cars, construction, industrial uses, load binding, and general purposes other than overhead lifting. The three classes of carbon steel chains covered here include Grade 30 (proof coil chain), Grade 43 (high test chain), and Grade 70 (transport chain). The dimensional requirements of the chain with respect to the appropriate grade and size are presented. The mechanical testing requirements for the steel includes, proof testing, breaking force testing, and elongation testing. One test for breaking strength and elongation shall be made from each lot. The elongation and breaking force tests may be performed at the same time on the same test specimen.

1.1 This specification covers carbon steel chain for such applications as railroad cars, construction, industrial uses, load binding, and general purposes other than overhead lifting.

Note 1: This specification does not cover carbon steel chain for sprocket applications.

1.2 Three classes of carbon steel chain are covered:

1.2.1 Grade 30—Proof coil chain.

1.2.2 Grade 43—High test chain.

1.2.3 Grade 70—Transport chain.

1.3 The chain grade is based 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 link.

1.4 The values stated in either SI units or in other units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.4.1 Metric Units—Grade = ¹/₁₀ of the minimum breaking force in kilonewtons divided by two times the nominal cross-sectional area in square millimeters. = (MBF)/(0.005)(π)(d)(d)

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)(d)

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.