UNS C71000 Copper-Nickel
C71000 copper-nickel is a copper-nickel alloy formulated for primary forming into wrought products. C71000 is the UNS number for this material. Additionally, the EN chemical designation is CuNi20. The British Standard (BS) designation is CN104. And the common industry name is Cupronickel 20.
It has a moderately high melting temperature among the wrought copper-nickels in the database.
The properties of C71000 copper-nickel include seven common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C71000 copper-nickel to: wrought copper-nickels (top), all copper alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
130 GPa 19 x 106 psi
Poisson's Ratio
0.33
Rockwell B Hardness
59 to 85
Rockwell Superficial 30T Hardness
56 to 73
Shear Modulus
49 GPa 7.1 x 106 psi
Tensile Strength: Ultimate (UTS)
320 to 560 MPa 47 to 82 x 103 psi
Thermal Properties
Latent Heat of Fusion
230 J/g
Maximum Temperature: Mechanical
240 °C 460 °F
Melting Completion (Liquidus)
1200 °C 2190 °F
Melting Onset (Solidus)
1150 °C 2100 °F
Specific Heat Capacity
400 J/kg-K 0.1 BTU/lb-°F
Thermal Conductivity
43 W/m-K 25 BTU/h-ft-°F
Thermal Expansion
15 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
6.5 % IACS
Electrical Conductivity: Equal Weight (Specific)
6.6 % IACS
Otherwise Unclassified Properties
Base Metal Price
37 % relative
Density
8.9 g/cm3 560 lb/ft3
Embodied Carbon
4.3 kg CO2/kg material
Embodied Energy
63 MJ/kg 27 x 103 BTU/lb
Embodied Water
290 L/kg 35 gal/lb
Common Calculations
Stiffness to Weight: Axial
8.2 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
10 to 18 points
Strength to Weight: Bending
12 to 17 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
12 to 20 points
Alloy Composition
Among wrought copper alloys, the composition of C71000 copper-nickel is notable for including manganese (Mn) and nickel (Ni). Manganese is used to improve strength without a proportional reduction in ductility. Nickel is used to improve strength (particularly at elevated temperatures) and corrosion resistance.
| Cu | 73.5 to 80.5 | |
| Ni | 19 to 23 | |
| Fe | 0.5 to 1.0 | |
| Mn | 0 to 1.0 | |
| Zn | 0 to 1.0 | |
| Pb | 0 to 0.050 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B111: Standard Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock
ASTM B122: Standard Specification for Copper-Nickel-Tin Alloy, Copper-Nickel-Zinc Alloy (Nickel Silver), and Copper-Nickel Alloy Plate, Sheet, Strip, and Rolled Bar
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001