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Dr. Dmitri Kopeliovich
According to the Unified Numbering System (UNS):
Coppers are copper alloys, containing not less than 99.3% of copper. Cast coppers are designated with the numbers from C80000 through C81399.
High Copper Alloys are copper alloys, containing more than 96% but less than 99.3% of copper. Cast High Copper Alloys are designated with the numbers from C81400 through C83299.
Alloys from these groups have any major alloying elements but may contain small amounts of beryllium (Be), chromium (Cr), phosphorous (P), silver (Ag) and nickel (Ni) as minor alloying additives.
Coppers and High Copper Alloys have very high electric and heat conductivity, very high ductility and relatively low hardness and tensile strength.
Machinability of coppers and high copper alloys is low.
High Copper Alloys have better hardness and tensile strength, but lower ductility than coppers.
Some of the high copper alloys are heat-treatable (beryllium copper, chromium copper).
Solution treatment followed by either artificial or natural aging allows considerable increasing the yield strength (3-5 times). Ductility of the alloy decreases as a result of the heat treatment.
Coppers and High Copper Alloys have a good corrosion resistance provided by protection film of copper oxide formed on the metal surface.
Cast Coppers and High Copper Alloys are used for manufacturing electric conductors, connectors, electrodes.
| UNS Designation | Trade mark | Be,% | Ni,% | Cr,% | Cu,% min |
|---|---|---|---|---|---|
| C80100 | Copper | - | - | - | 99.95 |
| C80410 | Copper | - | - | - | 99.9 |
| C81500 | Chromium Copper | - | - | 0.4-1.5 | balance |
| C82700 | Beryllium Copper | 2.35-2.55 | 1.0-1.5 | 0.6-1.2 | balance |
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