1.1 本规范 2. 适用于腐蚀性或高温条件下的直缝或螺旋缝电熔焊、轻壁奥氏体铬镍合金钢管。所涵盖的尺寸为NPS 14至30，壁厚为额外的灯（附表5S）和灯（附表10S）。 表X1.1 显示了Schedule 5S和10S管道的壁厚。可提供其他尺寸的管道，前提是此类管道符合本规范的所有其他要求。 1.2 如中所示，涵盖了几种等级的合金钢 表1 . 1.3 提供了可选的补充要求。这些要求进行额外的测试，当需要时，应在订单中说明，以及所需的此类测试的数量。 1.4 以国际单位制或英寸表示的数值- 磅单位应单独视为标准单位。在正文中，国际单位制显示在括号中。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值合并可能导致不符合标准。英寸磅单位应适用，除非订单中规定了本规范的“M”名称。 注1: 无量纲指示符NPS（公称管道尺寸）在本标准中已被传统术语取代，如 公称直径 , 大小 和 标称尺寸 . 1.5 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 straight seam or spiral seam electric-fusion-welded, light-wall, austenitic chromium-nickel alloy steel pipe for corrosive or high-temperature service. The sizes covered are NPS 14 to 30 with extra light (Schedule 5S) and light (Schedule 10S) wall thicknesses. Table X1.1 shows the wall thickness of Schedule 5S and 10S pipe. Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification. 1.2 Several grades of alloy steel are covered as indicated in Table 1 . 1.3 Optional supplementary requirements are provided. These call for additional tests to be made, and when desired shall be stated in the order, together with the number of such tests required. 1.4 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. Note 1: The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as nominal diameter , size , and nominal size . 1.5 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.