1.1 本规范 2 涵盖用于高温使用的标称壁和最小壁无缝铁素体合金钢管。根据本规范订购的管道应适用于弯曲、翻边（vanstoning）和类似的成型操作，以及熔焊。选择将取决于设计、使用条件、机械性能和高温特性。 1.2 几种等级的铁素体钢（见 附注1 ）被覆盖。它们的组成见 表1 . 附注1: 在本说明书中，铁素体钢被定义为含有高达10%且包括10%铬的低合金钢和中合金钢。 1.3 提供了可选性质的补充要求（S1至S9）。补充要求S1至S6要求进行额外的测试，如果需要，应在订单中注明所需的此类测试的数量（如适用）。1.4 以SI单位或英寸-磅单位表示的值应单独视为标准值。在正文中，国际单位制单位显示在括号中。每个系统中陈述的值可能不完全等同；因此，每个系统应独立使用。合并两个系统的值可能导致不符合标准。除非订单中指定了本规范的“M”名称，否则应适用英寸-磅单位。 附注2: 在本标准中，无量纲符号NPS（标称管道尺寸）已取代诸如“标称直径”、“尺寸”和“标称尺寸”等传统术语。 1.5 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》中确立的国际公认的标准化原则制定的。

1.1 This specification 2 covers nominal wall and minimum wall seamless ferritic alloy-steel pipe intended for high-temperature service. Pipe ordered to this specification shall be suitable for bending, flanging (vanstoning), and similar forming operations, and for fusion welding. Selection will depend upon design, service conditions, mechanical properties, and high-temperature characteristics. 1.2 Several grades of ferritic steels (see Note 1 ) are covered. Their compositions are given in Table 1 . Note 1: Ferritic steels in this specification are defined as low- and intermediate-alloy steels containing up to and including 10 % chromium. 1.3 Supplementary requirements (S1 to S9) of an optional nature are provided. Supplementary requirements S1 through S6 call for additional tests to be made, and when desired, shall be so stated in the order together with the number of such tests required as applicable. 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 2: 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.