1.1 本规范涵盖主要用作输电应用焊接管状结构底板的高强度低合金钢环和空心锻件。然而，本说明书的使用不限于这样的应用，并且其可以用于由本说明书定义的材料的属性适合的其它应用中。 1.2 在大多数环境中，A级、B级和C级的耐大气腐蚀性明显优于添加或不添加铜的碳结构钢（见 附注1 ).当暴露在大气中时，这些等级适用于裸露（未上漆）条件下的许多应用。 附注1: 参见指南 G101 用于评估低耐大气腐蚀性的方法-合金钢。 1.3 锻件的厚度仅受成分满足规定机械性能要求的能力的限制；然而，目前的实践通常将本规范下提供的锻件厚度限制在2英寸的范围内。到6英寸。[51mm至152mm]。 附注2: 当焊接钢材时，应使用适合钢材等级和预期用途或服务的焊接程序。参见质量标准附录X3 A6/A6M 有关可焊性的信息。 1.4 本规范的文本包含提供解释材料的注释、脚注或两者。该等附注及脚注（表格及数字除外）并无载有任何强制性规定。 1.5 补充要求是可用的，但仅适用于买方在订购时指定的情况。1.6 以SI单位或英寸-磅单位表示的值应单独视为标准值。每个系统中陈述的值不一定完全等同；因此，为确保符合标准，每个系统应独立使用，两个系统的数值不得合并使用。 1.7 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.8 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》中确立的国际公认的标准化原则制定的。

1.1 This specification covers high-strength, low-alloy steel ring and hollow forgings intended primarily for use as base plates in welded tubular structures for power transmission applications. However, use of this specification is not restricted to such applications and it may be used in other applications for which the attributes of the materials, as defined by this specification, are appropriate. 1.2 The atmospheric corrosion resistance of Grades A, B, and C in most environments is substantially better than that of carbon structural steel with or without copper addition (see Note 1 ). When exposed to the atmosphere, these grades are suitable for many applications in the bare (unpainted) condition. Note 1: See Guide G101 for methods of estimating the atmospheric corrosion resistance of low-alloy steels. 1.3 The thickness of forgings is limited only by the capacity of the composition to meet the specified mechanical property requirements; however, current practice normally limits the thickness of forgings furnished under this specification to a range of 2 in. to 6 in. [51 mm to 152 mm]. Note 2: When the steel is to be welded, a welding procedure suitable for the grade of steel and intended use or service should be used. See Appendix X3 of Specification A6/A6M for information on weldability. 1.4 The text of this specification contains notes, footnotes, or both, that provide explanatory material. Such notes and footnotes, excluding those in tables and figures, do not contain any mandatory requirements. 1.5 Supplementary requirements are available but shall apply only when specified by the purchaser at the time of ordering. 1.6 The values stated in either SI units or inch-pound 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. 1.7 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. 1.8 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.