1.1 This specification covers laser or laser-hybrid welded stainless steel square, rectangular, or custom shape structural tubing for welded, riveted, or bolted construction. This tube has either a sharp-cornered profile (SCP) or is built-up tube with rounded corners. This product is used in, but not limited to, the following applications: buildings and structures, including architecturally exposed steel structures (AESS); architectural steel profiles such as curtain wall, staircases, and others; industrial; and general structural applications.

1.2 This tubing is manufactured from multiple pieces of plate, bar, sheet, strip, or shapes, potentially in different thicknesses by laser or laser-hybrid welding in accordance with the requirements of Specification A1069/A1069M. It is available in sizes up to 36 in. (914 mm) outside dimension, and the wall thickness tolerance is ±5 % of the specified wall thickness. Corner welds are permissible.

1.3 This specification establishes the minimum requirements for manufacturing of laser and laser hybrid welded stainless steel tube and requires the welds to, at a minimum, match the tensile and yield strength of the base metal. If base metals of different strengths are used, the lower strength base metal shall be matched.

1.4 This specification refers to Specifications A240/A240M, A276/A276M or A479/A479M for chemical requirements, but the mechanical test requirements are determined by the mechanical properties section of this standard. This standard includes four strength grades. The default strength grade 1 is determined by the base metal standard. Grades 2 through 4 are for specification of higher strength levels.

1.5 Supplementary requirements (S1 Charpy V- notch, S2 Corrosion, S3 Tensile, and S4 Bend) of an optional nature are provided. They shall apply only when specified by the purchaser.

1.6 The text of this specification contains notes and footnotes that provide explanatory material. Such notes and footnotes, excluding those in tables and figures, do not contain any mandatory requirements.

1.7 Units—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 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.

1.8 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.

1.9 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.