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UNS C82400 (Alloy 165C) Beryllium Copper

C82400 copper is a lightly alloyed grade of copper, formulated for casting. C82400 is the UNS number for this material. Older literature may refer to this material as ASTM Alloy 165C or ASTM Alloy 165CT.

It has a fairly low thermal conductivity among cast coppers. In addition, it has a fairly low electrical conductivity and a fairly low melting temperature.

The properties of C82400 copper 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 C82400 copper to: cast coppers (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

Elongation at Break

1.0 to 20 %

Poisson's Ratio


Shear Modulus

45 GPa 6.5 x 106 psi

Tensile Strength: Ultimate (UTS)

500 to 1030 MPa 72 to 150 x 103 psi

Tensile Strength: Yield (Proof)

260 to 970 MPa 37 to 140 x 103 psi

Thermal Properties

Latent Heat of Fusion

230 J/g

Maximum Temperature: Mechanical

270 °C 520 °F

Melting Completion (Liquidus)

1000 °C 1820 °F

Melting Onset (Solidus)

900 °C 1650 °F

Specific Heat Capacity

380 J/kg-K 0.092 BTU/lb-°F

Thermal Conductivity

130 W/m-K 77 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

25 % IACS

Electrical Conductivity: Equal Weight (Specific)

26 % IACS

Otherwise Unclassified Properties


8.8 g/cm3 550 lb/ft3

Embodied Carbon

8.9 kg CO2/kg material

Embodied Energy

140 MJ/kg 60 x 103 BTU/lb

Embodied Water

310 L/kg 37 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

10 to 83 MJ/m3

Resilience: Unit (Modulus of Resilience)

270 to 3870 kJ/m3

Stiffness to Weight: Axial

7.6 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

16 to 33 points

Strength to Weight: Bending

16 to 26 points

Thermal Diffusivity

39 mm2/s

Thermal Shock Resistance

17 to 36 points

Alloy Composition

Among cast copper alloys, the composition of C82400 copper is notable for including cobalt (Co) and beryllium (Be). Cobalt is used to improve strength. Beryllium is used to permit precipitation hardening (which increases strength) without much effect on electrical conductivity, but at the cost of substantial toxicity.

Copper (Cu)Cu 96 to 98.2
Beryllium (Be)Be 1.6 to 1.9
Cobalt (Co)Co 0.2 to 0.65
Nickel (Ni)Ni 0 to 0.2
Iron (Fe)Fe 0 to 0.2
Aluminum (Al)Al 0 to 0.15
Titanium (Ti)Ti 0 to 0.12
Chromium (Cr)Cr 0 to 0.1
Tin (Sn)Sn 0 to 0.1
Zinc (Zn)Zn 0 to 0.1
Lead (Pb)Pb 0 to 0.020
Residualsres. 0 to 0.5

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

Followup Questions

Similar Alloys

Further Reading

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