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.
| Cu | 70.8 to 75.5 | |
| Zn | 21.3 to 24.1 | |
| Al | 3.0 to 3.8 | |
| Co | 0.25 to 0.55 | |
| Fe | 0 to 0.2 | |
| Pb | 0 to 0.050 | |
| res. | 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