1.1 本规范涵盖了用于铁路车辆、建筑、工业用途、负载约束和除高架起重以外的一般用途的碳钢链。 注1: 本规范不包括链轮应用的碳钢链条。 1.2 涵盖三类碳钢链: 1.2.1 30级- 验证线圈链。 1.2.2 43年级- 高测试链。 1.2.3 70级- 运输链。 1.3 链条等级基于链环在设计断裂力强度下的标称应力。通过取最小断裂力载荷并除以连杆标称横截面积的两倍来计算。 1.4 以国际单位或其他单位表示的数值应单独视为标准值。每个系统中规定的值不一定是精确的等价物；因此，为确保符合本标准，每个系统应独立使用，且两个系统的值不得组合。 1.4.1 公制单位- 等级= 1. / 10 最小破断力（千牛顿）除以标称横截面积（平方毫米）的两倍（MBF）/（0.005）（π）（d）（d） 1.4.2 英制单位- 等级=最小破断力（磅）的0.000689除以标称横截面积（平方英寸）的两倍（0.000689）（MBF）/（0.5）（π）（d）（d） 1.4.3 MBF=最小破断力（lb或kN）；d=链条直径（in.或mm）。 注2: 以上公式仅适用于圆直径连杆。如果使用不同的横截面，则需要计算和使用链路的实际横截面。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。

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.