1.1 本规范 2. 涵盖最小壁厚的低合金钢管，用于承压零件，如省煤器或其他耐腐蚀性很重要的应用。 1.2 通常根据本规范提供的管道尺寸和厚度为 1. / 2. 至5英寸。外径[12.7至127 mm]和0.035至0.500 in。[0.9至12.7 mm]，包括最小壁厚。可提供其他尺寸的管子，前提是此类管子符合本规范的所有其他要求。 1.3 机械性能要求不适用于小于 1. / 4. 在里面内径[3.2 mm]或0.015 in。厚度为[0.4 mm]。 1.4 本规范涵盖三个等级、两种类型和两种制造饰面: 1.4.1 等级1、2和3在 表1 （化学要求），以及 表3 （拉伸要求）， 1.4.2 类型（无缝或电阻焊）， 1.4.3 制造（热加工或冷加工）。 1.5 提供了可选补充要求S1和S2，如需要，应在订单中说明。 1.6 以国际单位制或英寸-磅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。除非订单中规定了本规范的“M”名称，否则英寸-磅单位应适用。 1.7 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 2 covers minimum-wall-thickness, low-alloy steel tubes for pressure containing parts such as economizers or other applications where corrosion resistance is important. 1.2 The tubing sizes and thicknesses usually furnished to this specification are 1 / 2 to 5 in. [12.7 to 127 mm] in outside diameter and 0.035 to 0.500 in. [0.9 to 12.7 mm] inclusive, in minimum wall thickness. Tubing having other dimensions may be furnished, provided such tubes comply with all other requirements of this specification. 1.3 Mechanical property requirements do not apply to tubing smaller than 1 / 4 in. [3.2 mm] in inside diameter or 0.015 in. [0.4 mm] in thickness. 1.4 This specification covers three grades, two types, and two manufacture finishes: 1.4.1 Grades 1, 2, and 3 are identified in Table 1 (Chemical Requirements), and Table 3 (Tensile Requirements), 1.4.2 Type (seamless or electric-resistance welded), 1.4.3 Manufacture (hot finished or cold finished). 1.5 Optional supplementary requirements S1 and S2 are provided and, when desired, shall be so stated in the order. 1.6 The values stated in either SI units or inch-pound 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. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order. 1.7 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.