This specification covers metal-arc-welded steel pipe for use with high pressure transmission systems. The pipe is intended for fabrication of fittings and accessories for compressor or pump-station piping. The required chemical compositions for carbon steel, and the tensile properties of finished pipes are presented. Mechanical testing requirements namely transverse body tension test and transverse weld tension test shall be performed on each length of pipe from each lot of 100 lengths, and transverse guided-bend weld test cut from a length of pipe from each lot of 50 length, also hydrostatic test from each length of pipes shall be performed. A radiographic examination shall also be performed to ensure that the welding equipment is consistently producing the required quality.

1.1 This specification covers straight seam, double-submerged-arc-welded carbon or high-strength low-alloy steel pipe (Note 1) suitable for high-pressure service, 16 in. [400 mm] and larger in outside diameter, with wall thicknesses from ⁵/₁₆ to 1¹/₂ in. [8 to 40 mm]. The pipe is intended for fabrication of fittings and accessories for compressor or pump-station piping. Pipe ordered to this specification shall be suitable for bending, flanging, corrugating, and similar operations.

Note 1: A comprehensive listing of standardized pipe dimensions is contained in ANSI B36.10.

Note 2: The term “double welded” is commonly used in the gas and oil transmission industry, for which this pipe is primarily intended, to indicate welding with at least two weld passes, of which one is on the outside of the pipe and one on the inside. For some sizes of the pipe covered by this specification, it becomes expedient to use manual welding, in which case the provisions of Note 3 shall be followed.

1.2 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the applicable inch-pound units shall apply. 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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

1.3 Eleven classes of pipe, based on minimum yield point requirements, are covered as indicated in Table 1.

1.4 This specification identifies various thermal treatments (3.1.9, 5.5, and 5.6).

1.5 The following caveat applies to the test methods portion, Sections 9, 10, and 11, only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

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.