1.1 本规范涵盖小齿轮、齿轮和轴的正火和回火碳钢以及淬火和回火合金钢锻件。 1.2 包括以下几种钢种: 1.2.1 一级甲级， 为正火回火碳钢。 1.2.2 2级、B级、3级、C级、3A级、D级、4至7级、E、F、G和H级、8级、I级和9级、J级， 是液态淬火和回火的合金钢。 1.3 所有等级和类别均视为在适当条件下可焊接。焊接技术至关重要，前提是焊接工艺和检查应符合所用材料类别的批准方法。 1.4 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致- 符合标准。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 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 normalized and tempered carbon steel and quenched and tempered alloy steel forgings for pinions, gears, and shafts. 1.2 Several grades of steel are covered as follows: 1.2.1 Grade 1, Class A, is normalized and tempered carbon steel. 1.2.2 Grade 2, Class B, Grade 3, Class C, Grade 3A, Class D, Grades 4 to 7, Classes E, F, G, and H, Grade 8, Class I, and Grade 9, Class J, are liquid quenched and tempered alloy steel. 1.3 All grades and classes are considered weldable under proper conditions. Welding technique is of fundamental importance and it is presupposed that welding procedure and inspection shall be in accordance with approved methods for the class of material used. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 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.