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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.

Copper (Cu) 92.7 to 97.5
Nickel (Ni) 2.2 to 4.2
Silicon (Si) 0.25 to 1.2
Zinc (Zn) 0 to 1.0
Magnesium (Mg) 0.050 to 0.3
Manganese (Mn) 0 to 0.1
Lead (Pb) 0 to 0.050
Residuals 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