This guide establishes requirements for seamless and welded copper-nickel tubes for use in heat exchangers in water desalting plants. Seamless tubes shall be manufactured by hot extrusion or piercing, and subsequent cold working and annealing as to produce a uniform, seamless wrought structure in the finished product. The welded tubes shall be manufactured from flat rolled strip which is subsequently formed and welded by a forge-weld process or a fusion-weld process. For forged-welded tube, the edges of the strip shall be heated to a required welding temperature, usually by high-frequency electric current, and be pressed firmly together causing a forged-type joint to be formed with internal and external flash or bead. On the other hand, fusion-welded tube shall be mechanically worked to produce a smooth external and internal surface without the application of scarfing or other removal of the weld bead. The product shall be cold worked and annealed as necessary to meet properties of the temper specified. The test specimen shall be free of defects, but blemishes of a nature that do not interfere with the intended application are acceptable for the following tests: expansion test, flattening test, and reverse-bend test. Forged-welded and annealed tubes shall have a completely recrystallized grain structure, and the weld zone shall have a structure typical of hot-forged welds. Fusion-welded and annealed tube shall have a structure typical of a fusion weld on its weld zone. The product shall be clean and free from defects, but blemishes of a nature that do not interfere with the intended application are acceptable.

1.1 This specification establishes requirements for seamless and welded copper-nickel tubes from 0.250 to 2.125 in. (6.35 to 54.0 mm) in diameter for use in heat exchangers in water desalting plants. The following alloys are involved:

Copper or
Copper Alloy UNS No.

Type of Metal

C70600

90-10 copper-nickel

C70620

90-10 copper-nickel
(Modified for Welding)

C71500

70-30 copper-nickel

C71520

70-30 copper-nickel
(Modified for Welding)

C71640

copper-nickel-iron-manganese

C72200

copper-nickel

1.2 Units—Values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 The following safety hazard caveat pertains only to the test methods of Section 16 described in this specification: 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 limitations prior to its use.