1.1 本规范 2. 涵盖管式换热器、冷凝器和类似传热设备的最小壁厚无缝冷拔低碳钢管。 1.2 本规范涵盖管子 1. / 8. 外径为3英寸[3.2至76.2毫米]（含）。 注1: 可提供外径小于本规范所示且壁厚较薄的管道。机械性能要求不适用于小于 1. / 8. 外径为0.015英寸[3.2mm]或壁厚小于0.015英寸[0.4mm]。 1.3 以英寸磅单位或国际单位制表示的数值应单独视为标准。在正文中，国际单位制显示在括号中。每个系统中规定的数值并不完全相等；因此，每个系统都必须独立使用。将两个系统的值组合在一起可能会导致不符合规范。英寸磅单位应适用，除非订单中规定了本规范的“M”名称。 1.4 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 2 covers minimum-wall-thickness, seamless cold-drawn low-carbon steel tubes for tubular heat exchangers, condensers, and similar heat transfer apparatus. 1.2 This specification covers tubes 1 / 8 to 3 in. [3.2 to 76.2 mm], inclusive, in outside diameter. Note 1: Tubing smaller in outside diameter and having a thinner wall than indicated in this specification is available. Mechanical property requirements do not apply to tubing smaller than 1 / 8 in. [3.2 mm] in outside diameter or with a wall thickness under 0.015 in. [0.4 mm]. 1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. 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 specification. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order. 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.