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UNS C68800 Aluminum Brass

C68800 brass is a brass formulated for primary forming into wrought products. C68800 is the UNS number for this material. Additionally, the EN chemical designation is CuZn23Al3Co. It can have the highest tensile strength and has a moderately low thermal conductivity among wrought brasses.

The properties of C68800 brass include six 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 C68800 brass to: wrought brasses (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

110 GPa 16 x 106 psi

Elongation at Break

2.0 to 36 %

Poisson's Ratio

0.32

Rockwell B Hardness

81 to 99

Rockwell Superficial 30T Hardness

71 to 83

Shear Modulus

41 GPa 5.9 x 106 psi

Shear Strength

380 to 510 MPa 55 to 74 x 103 psi

Tensile Strength: Ultimate (UTS)

570 to 890 MPa 82 to 130 x 103 psi

Tensile Strength: Yield (Proof)

390 to 790 MPa 57 to 110 x 103 psi

Thermal Properties

Latent Heat of Fusion

190 J/g

Maximum Temperature: Mechanical

160 °C 320 °F

Melting Completion (Liquidus)

960 °C 1770 °F

Melting Onset (Solidus)

950 °C 1740 °F

Specific Heat Capacity

400 J/kg-K 0.1 BTU/lb-°F

Thermal Conductivity

40 W/m-K 23 BTU/h-ft-°F

Thermal Expansion

19 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

18 % IACS

Electrical Conductivity: Equal Weight (Specific)

20 % IACS

Otherwise Unclassified Properties

Base Metal Price

26 % relative

Density

8.2 g/cm3 510 lb/ft3

Embodied Carbon

2.8 kg CO2/kg material

Embodied Energy

48 MJ/kg 21 x 103 BTU/lb

Embodied Water

350 L/kg 42 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

16 to 180 MJ/m3

Resilience: Unit (Modulus of Resilience)

710 to 2860 kJ/m3

Stiffness to Weight: Axial

7.3 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

19 to 30 points

Strength to Weight: Bending

19 to 25 points

Thermal Diffusivity

12 mm2/s

Thermal Shock Resistance

19 to 30 points

Alloy Composition

Among wrought copper alloys, the composition of C68800 brass is notable for including cobalt (Co) and aluminum (Al). Cobalt is used to improve strength. Aluminum is used to add strength and oxidation resistance.

Copper (Cu) 70.8 to 75.5
Zinc (Zn) 21.3 to 24.1
Aluminum (Al) 3.0 to 3.8
Cobalt (Co) 0.25 to 0.55
Iron (Fe) 0 to 0.2
Lead (Pb) 0 to 0.050
Residuals 0 to 0.5

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

Followup Questions

Similar Alloys

Further Reading

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