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UNS C97600 (Alloy 11A) Dairy Metal

C97600 dairy metal is a copper-nickel alloy formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C97600 is the UNS number for this material. Additionally, the common industry name is 20% Leaded Nickel Silver. Older literature may refer to this material as ASTM Alloy 11A, but this is now discouraged.

It has the lowest thermal conductivity among cast copper-nickels. In addition, it has a moderately low heat capacity and a moderately low electrical conductivity.

The graph bars on the material properties cards below compare C97600 dairy metal to: cast 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

11 %

Poisson's Ratio

0.33

Shear Modulus

46 GPa 6.6 x 106 psi

Tensile Strength: Ultimate (UTS)

310 MPa 45 x 103 psi

Tensile Strength: Yield (Proof)

140 MPa 21 x 103 psi

Thermal Properties

Latent Heat of Fusion

210 J/g

Maximum Temperature: Mechanical

210 °C 400 °F

Melting Completion (Liquidus)

1140 °C 2090 °F

Melting Onset (Solidus)

1110 °C 2030 °F

Specific Heat Capacity

380 J/kg-K 0.091 BTU/lb-°F

Thermal Conductivity

22 W/m-K 13 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

5.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

5.1 % IACS

Otherwise Unclassified Properties

Base Metal Price

37 % relative

Density

8.8 g/cm3 550 lb/ft3

Embodied Carbon

4.6 kg CO2/kg material

Embodied Energy

69 MJ/kg 30 x 103 BTU/lb

Embodied Water

330 L/kg 39 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

29 MJ/m3

Resilience: Unit (Modulus of Resilience)

85 kJ/m3

Stiffness to Weight: Axial

7.7 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

9.8 points

Strength to Weight: Bending

12 points

Thermal Diffusivity

6.5 mm2/s

Thermal Shock Resistance

11 points

Alloy Composition

Among cast copper alloys, the composition of C97600 dairy metal is notable for containing comparatively high amounts of nickel (Ni) and lead (Pb). Nickel is used to improve strength (particularly at elevated temperatures) and corrosion resistance. It also creates the need for additional care during casting. Lead is used to improve machinability and bearing properties, at the cost of toxicity. It also adds pressure tightness to castings.

Copper (Cu) 63 to 67
Nickel (Ni) 19 to 21.5
Zinc (Zn) 3.0 to 9.0
Lead (Pb) 3.0 to 5.0
Tin (Sn) 3.5 to 4.0
Iron (Fe) 0 to 1.5
Antimony (Sb) 0 to 0.25
Silicon (Si) 0 to 0.15
Sulfur (S) 0 to 0.080
Phosphorus (P) 0 to 0.050
Aluminum (Al) 0 to 0.0050
Residuals 0 to 0.3

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

Followup Questions

Similar Alloys

Further Reading

ASTM B271: Standard Specification for Copper-Base Alloy Centrifugal Castings

ASTM B505: Standard Specification for Copper Alloy Continuous Castings

Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993