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Wrought copper-nickel alloys and Nickel Silvers

Dr. Dmitri Kopeliovich

According to the Unified Numbering System (UNS):

Copper-Nickel Alloys (Copper-Nickels, Cupro-nickels) are copper alloys, containing 1.5-45% of nickel (Ni) as the major alloying element. Wrought Copper-Nickel alloys are designated with the numbers from C70000 through C73499.

Wrought Copper-Nickel alloys may contain up to 8% of tin (Sn), up to 4.5% of manganese (Mn), up to 2% of iron (Fe), up to 2.5% of chromium (Cr) and up to 1% of silicon (Si) as additional alloying elements.

Copper-nickel-zinc alloys form a separate group called nickel silvers.

Copper-Nickel-Zinc Alloys (Nickel Silvers) are copper alloys containing 8-25% of nickel (Ni) and 17-45% of zinc (Zn) as the major alloying elements. Wrought Copper-Nickel-Zinc alloys are designated with the numbers from C73500 through C79999.

Wrought Copper-Nickel-Zinc alloys may contain up to 6% of manganese (Mn) as additional alloying element.

Copper-Nickel alloys and most of Copper-Nickel-Zinc alloys have mono-phase structure (α-phase) and possess very good formability in cold and hot states.

Wrought Copper-Nickel alloys have moderate mechanical strength and high ductility combined with very good corrosion resistance (particularly in sea water).

Iron, manganese and chromium are added to the wrought Copper-Nickel alloys for increasing their hardness and strength.

The alloys are strengthened by cold work (strain hardening). Ductility of the alloys decreases as a result of cold work.

Separate group of copper-nickel alloys is Spinodal Bronzes: copper-nickel-tin alloys possessing high mechanical strength due to a controlled heat treatment called Spinodal decomposition.

Copper-Nickel alloys are used for manufacturing coins, sea water equipment, evaporators, heat exchanger tubes, automotive hydraulic and cooling systems.

Copper-Nickel alloys (Nickel Silvers) are used in decorative applications and for manufacturing resistance wire, optical parts, screws, rivets, clips, tableware, electrical contacts.

Chemical compositions of some wrought copper-nickel alloys and Nickel Silvers

UNS Designation Trade mark Ni,% Zn,% Mn,% Fe,% Cu,%
C70400 Copper-Nickel 5% 4.8-6.2 1.0 max. 0.3-0.8 1.3-1.7 balance
C70600 Copper-Nickel 10% 9.0-11.0 1.0 max. 1.0 max. 1.0-1.8 balance
C71000 Copper-Nickel 20% 19-23 1.0 max. 1.0 max. 1.0 max. balance
C71500 Copper-Nickel 30% 29-33 1.0 max. 1.0 max. 0.4-1.0 balance
C74500 Nickel Silver 65-10 9.0-11.0 balance 0.5 max. 0.25 max. 63.5-66.5
C75200 Nickel Silver 65-18 16.5-19.5 balance 0.5 max. 0.25 max. 63.0-66.5
C75400 Nickel Silver 65-15 14.0-16.0 balance 0.5 max. 0.25 max. 63.5-66.5
C75700 Nickel Silver 65-12 11.0-13.0 balance 0.5 max. 0.25 max. 63.5-66.5
C77000 Nickel Silver 55-18 16.5-19.5 balance 0.5 max. 0.25 max. 53.5-56.5

Properties of some wrought copper-nickel alloys and Nickel Silvers

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wrought_copper-nickel_alloys_and_nickel_silvers.txt · Last modified: 2013/04/06 by dmitri_kopeliovich
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