1.1 本规范 2. 包括最小壁厚、无缝中碳钢、锅炉管和锅炉烟道，包括安全端（见 注1 )、拱形管和拉线管以及过热器管。 注1: 这种类型不适合通过锻造焊接安全结束。 1.2 通常根据本规范提供的管道尺寸和厚度为 1. / 2. 在里面至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. / 8. 在里面内径[3.2 mm]或0.015 in。厚度为[0.4 mm]。 1.4 本规范涵盖了具有不同化学和拉伸要求的A-1和C级无缝中碳锅炉和过热器管。( 表1 , 表3 ，和截面 11 .) 1.5 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不是精确的等价物；因此，每个系统必须相互独立使用。合并两个系统的值可能会导致不符合规范。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。 1.6 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, seamless medium-carbon steel, boiler tubes and boiler flues, including safe ends (see Note 1 ), arch and stay tubes, and superheater tubes. Note 1: This type is not suitable for safe ending by forge welding. 1.2 The tubing sizes and thicknesses usually furnished to this specification are 1 / 2 in. 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 / 8 in. [3.2 mm] in inside diameter or 0.015 in. [0.4 mm] in thickness. 1.4 This specification covers grades A-1 and C of Seamless Medium-Carbon Boiler and Superheater Tubes with different chemical and tensile requirements. ( Table 1 , Table 3 , and Section 11 .) 1.5 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. 1.6 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.