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UNS C72900 Tin-Bearing Copper-Nickel

C72900 copper-nickel is a copper-nickel alloy formulated for primary forming into wrought products. It can have a moderately high tensile strength among wrought copper-nickels. In addition, it has a moderately high base cost and a moderately high embodied energy.

The properties of C72900 copper-nickel 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 C72900 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

120 GPa 18 x 106 psi

Elongation at Break

6.0 to 20 %

Poisson's Ratio


Shear Modulus

45 GPa 6.6 x 106 psi

Shear Strength

540 to 630 MPa 79 to 92 x 103 psi

Tensile Strength: Ultimate (UTS)

870 to 1080 MPa 130 to 160 x 103 psi

Tensile Strength: Yield (Proof)

700 to 920 MPa 100 to 130 x 103 psi

Thermal Properties

Latent Heat of Fusion

210 J/g

Maximum Temperature: Mechanical

210 °C 400 °F

Melting Completion (Liquidus)

1120 °C 2040 °F

Melting Onset (Solidus)

950 °C 1740 °F

Specific Heat Capacity

380 J/kg-K 0.091 BTU/lb-°F

Thermal Conductivity

29 W/m-K 17 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.8 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.0 % IACS

Otherwise Unclassified Properties

Base Metal Price

39 % relative


8.8 g/cm3 550 lb/ft3

Embodied Carbon

4.6 kg CO2/kg material

Embodied Energy

72 MJ/kg 31 x 103 BTU/lb

Embodied Water

360 L/kg 43 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

49 to 210 MJ/m3

Resilience: Unit (Modulus of Resilience)

2030 to 3490 kJ/m3

Stiffness to Weight: Axial

7.6 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

27 to 34 points

Strength to Weight: Bending

23 to 27 points

Thermal Diffusivity

8.6 mm2/s

Thermal Shock Resistance

31 to 38 points

Alloy Composition

Among wrought copper alloys, the composition of C72900 copper-nickel is notable for including magnesium (Mg). Magnesium is used to improve strain hardenability. This increases strength but reduces the ability to form the alloy into complex shapes.

Copper (Cu)Cu 74.1 to 78
Nickel (Ni)Ni 14.5 to 15.5
Tin (Sn)Sn 7.5 to 8.5
Iron (Fe)Fe 0 to 0.5
Zinc (Zn)Zn 0 to 0.5
Manganese (Mn)Mn 0 to 0.3
Magnesium (Mg)Mg 0 to 0.15
Niobium (Nb)Nb 0 to 0.1
Lead (Pb)Pb 0 to 0.020
Residualsres. 0 to 0.3

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

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