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UNS C79200 (CW404J) Leaded Nickel Silver

C79200 nickel silver is a copper-nickel alloy formulated for primary forming into wrought products. CW404J is the EN numeric designation for this material. C79200 is the UNS number. Additionally, the EN chemical designation is CuNi12Zn25Pb1.

It has a moderately high electrical conductivity and a moderately low melting temperature among wrought copper-nickels.

The properties of C79200 nickel silver include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C79200 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

Shear Modulus

44 GPa 6.4 x 106 psi

Tensile Strength: Ultimate (UTS)

480 to 540 MPa 70 to 79 x 103 psi

Thermal Properties

Latent Heat of Fusion

190 J/g

Maximum Temperature: Mechanical

170 °C 340 °F

Melting Completion (Liquidus)

950 °C 1750 °F

Melting Onset (Solidus)

910 °C 1660 °F

Specific Heat Capacity

390 J/kg-K 0.093 BTU/lb-°F

Thermal Conductivity

42 W/m-K 24 BTU/h-ft-°F

Thermal Expansion

19 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

28 % IACS

Electrical Conductivity: Equal Weight (Specific)

30 % IACS

Otherwise Unclassified Properties

Base Metal Price

30 % relative

Density

8.4 g/cm3 520 lb/ft3

Embodied Carbon

3.6 kg CO2/kg material

Embodied Energy

56 MJ/kg 24 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

16 to 18 points

Strength to Weight: Bending

16 to 18 points

Thermal Diffusivity

13 mm2/s

Thermal Shock Resistance

16 to 18 points

Alloy Composition

Among wrought copper alloys, the composition of C79200 nickel silver is notable for including manganese (Mn) and containing a comparatively high amount of lead (Pb). Manganese is used to improve strength without a proportional reduction in ductility. Lead is used to improve machinability and bearing properties, at the cost of toxicity.

Copper (Cu) 59 to 66.5
Zinc (Zn) 17.9 to 29.2
Nickel (Ni) 11 to 13
Lead (Pb) 0.8 to 1.4
Manganese (Mn) 0 to 0.5
Iron (Fe) 0 to 0.25
Residuals 0 to 0.5

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

Followup Questions

Similar Alloys

Further Reading

ASTM B151: Standard Specification for Copper-Nickel-Zinc Alloy (Nickel Silver) and Copper-Nickel Rod and Bar

ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001