UNS C74000 Nickel Silver
C74000 nickel silver is a copper-nickel alloy formulated for primary forming into wrought products. C74000 is the UNS number for this material. Additionally, the common industry name is 70-10-20. Older literature may refer to this material as ASTM Copper-Nickel Type 9, but this is now discouraged.
It has a moderately high electrical conductivity among the wrought copper-nickels in the database.
The properties of C74000 nickel silver 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 C74000 nickel silver 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
0.32
Rockwell B Hardness
70 to 88
Shear Modulus
44 GPa 6.5 x 106 psi
Tensile Strength: Ultimate (UTS)
380 to 590 MPa 55 to 85 x 103 psi
Thermal Properties
Latent Heat of Fusion
200 J/g
Maximum Temperature: Mechanical
180 °C 360 °F
Melting Completion (Liquidus)
990 °C 1820 °F
Melting Onset (Solidus)
950 °C 1730 °F
Specific Heat Capacity
390 J/kg-K 0.094 BTU/lb-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
40 % IACS
Electrical Conductivity: Equal Weight (Specific)
42 % IACS
Otherwise Unclassified Properties
Base Metal Price
30 % relative
Density
8.5 g/cm3 530 lb/ft3
Embodied Carbon
3.4 kg CO2/kg material
Embodied Energy
54 MJ/kg 23 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Stiffness to Weight: Axial
7.7 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
13 to 19 points
Strength to Weight: Bending
14 to 18 points
Thermal Shock Resistance
13 to 19 points
Alloy Composition
Among wrought copper alloys, the composition of C74000 nickel silver is notable for including manganese (Mn) and nickel (Ni). Manganese is used to improve strength without a proportional reduction in ductility. Nickel is used to improve strength (particularly at elevated temperatures) and corrosion resistance.
| Cu | 69 to 73.5 | |
| Zn | 14.2 to 22 | |
| Ni | 9.0 to 11 | |
| Mn | 0 to 0.5 | |
| Fe | 0 to 0.25 | |
| Pb | 0 to 0.1 | |
| res. | 0 to 0.5 |
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
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015