UNS C70250 (CW112C) Nickel-Silicon Copper
C70250 copper is a copper-nickel alloy formulated for primary forming into wrought products. CW112C is the EN numeric designation for this material. C70250 is the UNS number. Additionally, the EN chemical designation is CuNi3Si.
It can have a moderately high electrical conductivity among wrought copper-nickels. In addition, it has the highest thermal conductivity and a moderately low embodied energy.
The properties of C70250 copper include five 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 C70250 copper 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
120 GPa 17 x 106 psi
Poisson's Ratio
0.34
Shear Modulus
44 GPa 6.4 x 106 psi
Tensile Strength: Ultimate (UTS)
520 to 740 MPa 75 to 110 x 103 psi
Thermal Properties
Latent Heat of Fusion
220 J/g
Maximum Temperature: Mechanical
210 °C 400 °F
Melting Completion (Liquidus)
1100 °C 2000 °F
Melting Onset (Solidus)
1080 °C 1970 °F
Specific Heat Capacity
390 J/kg-K 0.094 BTU/lb-°F
Thermal Conductivity
170 W/m-K 98 BTU/h-ft-°F
Thermal Expansion
17 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
36 to 50 % IACS
Electrical Conductivity: Equal Weight (Specific)
37 to 51 % IACS
Otherwise Unclassified Properties
Base Metal Price
31 % relative
Density
8.9 g/cm3 550 lb/ft3
Embodied Carbon
2.9 kg CO2/kg material
Embodied Energy
45 MJ/kg 19 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Stiffness to Weight: Axial
7.4 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
16 to 23 points
Strength to Weight: Bending
16 to 21 points
Thermal Diffusivity
49 mm2/s
Thermal Shock Resistance
18 to 26 points
Alloy Composition
Among wrought copper alloys, the composition of C70250 copper is notable for including magnesium (Mg) and silicon (Si). Magnesium is used to improve strain hardenability. This increases strength but reduces the ability to form the alloy into complex shapes. Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy.
| Cu | 92.7 to 97.5 | |
| Ni | 2.2 to 4.2 | |
| Si | 0.25 to 1.2 | |
| Zn | 0 to 1.0 | |
| Mg | 0.050 to 0.3 | |
| Mn | 0 to 0.1 | |
| 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 B422: Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper- Nickel-Tin Alloy Sheet and Strip
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001