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
0.34
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
Density
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.
| Cu | 85.2 to 89.7 | |
| Ni | 8.5 to 10.5 | |
| Sn | 1.8 to 2.8 | |
| Fe | 0 to 0.6 | |
| Zn | 0 to 0.5 | |
| Mn | 0 to 0.2 | |
| Pb | 0 to 0.050 | |
| res. | 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