1.1 本规范涵盖了三类灰铸铁，用于阀门承压部件、管道配件和法兰的铸件。 1.2 以英寸-磅为单位的数值应视为标准。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 注1: 本标准的文本引用了提供解释性材料的注释和脚注。这些注释和脚注（不包括表和图中的注释和脚注）不应被视为本标准的要求。 1.3 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《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 three classes of gray iron for castings intended for use as valve pressure-retaining parts, pipe fittings, and flanges. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. Note 1: The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 1.3 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.