This specification covers steel tubes, carbon and carbon manganese, fusion welded, for boiler, superheater, heat exchanger and condenser application. After welding, all tubes shall be heat treated and followed by cooling in air or in the cooling chamber of a controlled atmosphere furnace. The steel shall conform to the required chemical compositions. The tensile and hardness test requirements to all tube prior to cutting are presented. Mechanical testing requirements indicates that, one flattening test shall be made on specimens from each of two tubes from each lot or fraction thereof, one flange test shall be made on specimens from each of two tubes from each lot or fraction thereof, one crush test shall be made on specimens from each of two tubes from each lot or fraction thereof, and one reverse flattening test shall be made on each 1500 ft [450 m] of finished tubing. Finally, each tube shall be subjected to either the hydrostatic or the non-destructive electric test.

1.1 This specification covers minimum wall thickness welded tubes made from carbon and carbon manganese steels listed in Table 1, with various grades intended for use in boiler, superheater, heat exchanger, or condenser applications.

1.2 The tubing sizes and thicknesses usually furnished to this specification are ¼ to 5 in. [6.3 to 127 mm] in outside diameter and 0.015 to 0.375 in. [0.4 to 9.5 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 Mechanical property requirements do not apply to tubing smaller than ¹/₈ in. [3.2 mm] in inside diameter or 0.015 in. [0.4 mm] in thickness.

1.4 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 are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the “M” designation of the specification is specified in the order.

1.5 Optional supplementary requirements are provided and when desired, shall be so stated on the purchase order.

1.6 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 and health practices and determine the applicability of regulatory requirements prior to use.