1.1 本规范涵盖了可锻铸铁法兰、管道配件和阀门零件，包括用于铁路、海洋和其他重型服务应用的组装零件，其中根据美国国家标准150和300级可锻铸铁螺纹配件（ANSI B16.3）提供的配件被视为不充分。 1.2 服务应包括多达650个 华氏度（345 °C）。 2. 1.3 以英寸-磅单位表示的数值视为标准值。括号中给出的值是数学转换为SI单位，仅供参考，不被视为标准单位。 1.4 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 malleable iron flanges, pipe fittings, and valve parts, including parts to be assembled for use in railroad, marine, and other heavy-duty service applications where fittings furnished in accordance with American National Standard for Malleable Iron Threaded Fittings, Classes 150 and 300 (ANSI B16.3) are not considered adequate. 1.2 Service shall include up to 650 °F (345 °C). 2 1.3 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. 1.4 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.