1.1 本规范涵盖结构用三种等级的缝焊圆形锥形钢管。A级和B级为低碳钢或高强度低合金钢成分，C级为耐候钢成分。 1.1.1 产品可以从圆形横截面改为其他形状，无需随后重新测试。 1.2 这种管子是以焊接尺寸生产的，直径范围为2 3. / 8. 至30英寸。[60至762 mm]（含）。壁厚范围为0.1046至0.375英寸。[2.66至9.53毫米]。锥度须经制造商同意。 1.3 以国际单位或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不完全相等；因此，每个系统应独立于其他系统使用。组合两个系统的值可能会导致- 符合标准。 1.4 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 three grades of seam-welded, round, tapered steel tubes for structural use. Grades A and B are of low-carbon steel or high-strength low-alloy steel composition and Grade C is of weather-resistant steel composition. 1.1.1 The product may be modified from its round cross section into other shapes without subsequent retesting. 1.2 This tubing is produced in welded sizes in a range of diameters from 2 3 / 8 to 30 in. [60 to 762 mm] inclusive. Wall thicknesses range from 0.1046 to 0.375 in. [2.66 to 9.53 mm]. Tapers are subject to agreement with the manufacturer. 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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. 1.4 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.