1.1 本规范涵盖了主要用于环境温度较低地区的石油和天然气管道的承压和其他应用的碳钢和合金钢铸件。铸件应通过正火和回火或液体淬火和回火进行热处理。所有等级均可在适当条件下焊接。某些等级的淬透性可能会限制可用截面尺寸。 1.2 以英寸磅单位或国际单位制表示的数值应单独视为标准值。每个系统中规定的值并非完全相等；因此，每个系统必须独立使用。将两个系统的值合并可能导致不符合标准。 1.2.1 除非订单中指定了“M”，否则材料应以英寸磅单位提供。 1.3 本标准并不旨在解决与其使用相关的所有安全问题（如有）。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，并确定监管限制的适用性。 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。

1.1 This specification covers carbon and alloy steel castings for pressure-containing and other applications intended primarily for petroleum and gas pipelines in areas subject to low-ambient temperatures. Castings shall be heat treated by normalizing and tempering or liquid quenching and tempering. All classes are weldable under proper conditions. Hardenability of some grades may limit usable section size. 1.2 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.2.1 Unless the order specifies an “M” designation, the material shall be furnished to inch-pound units. 1.3 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. 1.4 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.