1.1 This specification covers average or minimum-wall thickness welded tubes made from various grades of austenitic, ferritic, martensitic and duplex stainless steel materials in which the (1) external tube surface, (2) internal tube surface, or (3) both internal and external tube surfaces have a textured configuration for improved heat transfer or fluid flow or both. Texture surface(s) are produced by cold forming a specified configuration on the surface(s) of base strip material, prior to welding. The produced welded textured tubes may be used in boilers, superheaters, condensers, evaporators, heat exchangers, and other similar heat transfer apparatus in diameters up to and including 1.5 in. [38 mm] for various wall thicknesses up to and including 0.079 in. [2 mm].

1.2 The tubing sizes and thicknesses usually furnished to this specification are 0.375 in. [10 mm] inside diameter (ID) to 1.5 in. [38 mm] outside diameter and 0.020 to 0.079 in. [0.5 to 2 mm], inclusive, in wall thickness. Tubing having other dimensions may be furnished provided such tubes comply with all other requirements of this specification.

1.3 Optional supplementary requirements are provided and, when one or more of these are desired, each shall be so stated in the order.

1.4 Several grades of austenitic, ferritic, martensitic and duplex stainless steels are included in this specification. Not all alloys are suitable for all conditions. Selection will depend upon design and service requirements.

1.5 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 non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

1.6 The following safety hazards statement pertains only to the test method and the Supplementary Requirements of this specification. A specific warning statement is given in the Supplementary Requirements. 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.

1.7 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.