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UNS C72500 (CW351H) Tin-Bearing Copper-Nickel

C72500 copper-nickel is a copper-nickel alloy formulated for primary forming into wrought products. CW351H is the EN numeric designation for this material. C72500 is the UNS number. Additionally, the EN chemical designation is CuNi9Sn2. And the common industry name is 89-9-2.

The properties of C72500 copper-nickel include eight 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 C72500 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

Poisson's Ratio


Rockwell B Hardness

75 to 100

Rockwell Superficial 30T Hardness

62 to 89

Shear Modulus

45 GPa 6.6 x 106 psi

Tensile Strength: Ultimate (UTS)

420 to 780 MPa 60 to 110 x 103 psi

Thermal Properties

Latent Heat of Fusion

210 J/g

Maximum Temperature: Mechanical

210 °C 410 °F

Melting Completion (Liquidus)

1130 °C 2060 °F

Melting Onset (Solidus)

1060 °C 1940 °F

Specific Heat Capacity

390 J/kg-K 0.093 BTU/lb-°F

Thermal Conductivity

54 W/m-K 31 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

11 % IACS

Electrical Conductivity: Equal Weight (Specific)

11 % IACS

Otherwise Unclassified Properties

Base Metal Price

35 % relative


8.9 g/cm3 560 lb/ft3

Embodied Carbon

3.6 kg CO2/kg material

Embodied Energy

55 MJ/kg 24 x 103 BTU/lb

Embodied Water

320 L/kg 38 gal/lb

Common Calculations

Stiffness to Weight: Axial

7.6 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

13 to 24 points

Strength to Weight: Bending

14 to 21 points

Thermal Diffusivity

16 mm2/s

Thermal Shock Resistance

14 to 27 points

Alloy Composition

Among wrought copper alloys, the composition of C72500 copper-nickel is notable for including manganese (Mn) and tin (Sn). Manganese is used to improve strength without a proportional reduction in ductility. Tin is used to improve strength, bearing properties, and corrosion resistance against certain types of media.

Copper (Cu)Cu 85.2 to 89.7
Nickel (Ni)Ni 8.5 to 10.5
Tin (Sn)Sn 1.8 to 2.8
Iron (Fe)Fe 0 to 0.6
Zinc (Zn)Zn 0 to 0.5
Manganese (Mn)Mn 0 to 0.2
Lead (Pb)Pb 0 to 0.050
Residualsres. 0 to 0.2

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

Followup Questions

Similar Alloys

Further Reading

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