1.1 本规范涵盖适用于一般工程用途的双壁铜焊钢管，特别是在汽车、制冷和炉灶行业中，用于燃料管路、制动管路、油管、加热和冷却装置等。管子有两种类型，单条或双条，如所示 图1 . 图1 钎焊管，双壁，360度钎焊结构 1.2 单位- 本规范以英寸-磅单位和国际单位制表示； 但是，除非采购订单或合同规定了适用的M规格名称（国际单位制），否则英寸-磅单位应适用。以英寸-磅单位或国际单位表示的数值应单独视为标准值。在文本中，国际单位显示在括号中。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 在本规范中，硬转换或合理转换适用于直径、长度和拉伸性能。软转换适用于其他SI测量。 1.3 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 double-wall, copper-brazed steel tubing suitable for general engineering uses, particularly in the automotive, refrigeration, and stove industries for fuel lines, brake lines, oil lines, heating and cooling units, and the like. The tubing is available in either of two types, single strip or double strip as shown in Fig. 1 . FIG. 1 Brazed Tubing, Double-Wall, 360-deg Brazed Construction 1.2 Units— This specification is expressed in both inch-pounds units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the inch-pound units shall apply. 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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. In this specification hard or rationalized conversions apply to diameters, lengths, and tensile properties. Soft conversion applies to other SI measurements. 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.