本规范涵盖了适用于石油和天然气行业管道运输系统的无缝和焊接复合钢管以及具有增强耐腐蚀性能的内衬钢管。本文规定的覆层和内衬钢管由外部（在某些情况下为内部和/或外部）的碳钢背衬或基材以及管道内部的耐腐蚀合金（CRA）层或内衬组成。母材符合API 5L（第45版）、产品规范等级（PSL）2和适用附件的要求，除非本文另有修改。 本规范涵盖的母材等级包括X42、X46、X52、X56、X60、X65、X70、X80以及这些等级的中间等级。CRA层的等级为LC 1812、2205、2506、2242、2262、统一编号系统（UNS）S31703、UNS N08904、UNS N10276、合金31（UNS N08031）、合金59（UNS N06059）、合金254 SMO-11（UNS S31254）、合金400（UNS N04400）、AL6NX（UNS N08367）和EN 1.4529（UNS N08926）。其他等级须经买方和制造商同意。交付的产品通常有方形端部，但其他特殊端部可通过买方和制造商之间的协议提供。 包括标称管道尺寸（NPS）25 mm（1 in.）通过2134毫米（84英寸）。尺寸大于2134毫米（84英寸）不在API 5L（第45版）的范围内，但可提供高达2500 mm（100 in.）根据协议，包括材料要求。

This specification covers seamless and welded clad steel line pipe and lined steel line pipe with enhanced corrosion-resistant properties suitable for use in pipeline transportation systems in the petroleum and natural gas industries. The clad and lined steel line pipe specified herein is composed of a carbon steel backing or base material outside (in some cases inside and/or outside) and a corrosion-resistant alloy (CRA) layer or lining inside of the pipe. The base material conforms to API 5L (45th Ed.), product specification level (PSL) 2 and applicable annex(es), except as modified herein.Grades of base material covered by this specification include X42, X46, X52, X56, X60, X65, X70, X80, and grades intermediate to these. Grades of the CRA layer are LC 1812, 2205, 2506, 2242, 2262, unified numbering system (UNS) S31703, UNS N08904, UNS N10276, Alloy 31 (UNS N08031), Alloy 59 (UNS N06059), Alloy 254 SMO-11 (UNS S31254), Alloy 400 (UNS N04400), AL6NX (UNS N08367), and EN 1.4529 (UNS N08926). Other grades are subject to agreement between the purchaser and the manufacturer.The delivered product usually has square ends, but other special ends may be furnished by agreement between the purchaser and manufacturer. Included are nominal pipe sizes (NPS) 25 mm (1 in.) through 2134 mm (84 in.). Sizes greater than 2134 mm (84 in.) are outside of the range of API 5L (45th Ed.) but may be supplied up to 2500 mm (100 in.) by agreement, including requirements for materials.