UNS C68400 Silicon-Manganese Brass
C68400 brass is a brass formulated for primary forming into wrought products. Cited properties are appropriate for the M30 (as hot extruded) condition.
It has the highest electrical conductivity among wrought brasses. In addition, it has a moderately low melting temperature and a moderately low thermal conductivity.
The graph bars on the material properties cards below compare C68400 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
Brinell Hardness
150
Elastic (Young's, Tensile) Modulus
110 GPa 15 x 106 psi
Elongation at Break
18 %
Poisson's Ratio
0.31
Shear Modulus
41 GPa 5.9 x 106 psi
Shear Strength
330 MPa 48 x 103 psi
Tensile Strength: Ultimate (UTS)
540 MPa 78 x 103 psi
Tensile Strength: Yield (Proof)
310 MPa 45 x 103 psi
Thermal Properties
Latent Heat of Fusion
210 J/g
Maximum Temperature: Mechanical
130 °C 270 °F
Melting Completion (Liquidus)
840 °C 1540 °F
Melting Onset (Solidus)
820 °C 1520 °F
Specific Heat Capacity
400 J/kg-K 0.1 BTU/lb-°F
Thermal Conductivity
66 W/m-K 38 BTU/h-ft-°F
Thermal Expansion
20 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
87 % IACS
Electrical Conductivity: Equal Weight (Specific)
99 % IACS
Otherwise Unclassified Properties
Base Metal Price
23 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
2.7 kg CO2/kg material
Embodied Energy
47 MJ/kg 20 x 103 BTU/lb
Embodied Water
320 L/kg 38 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
81 MJ/m3
Resilience: Unit (Modulus of Resilience)
460 kJ/m3
Stiffness to Weight: Axial
7.5 points
Stiffness to Weight: Bending
20 points
Strength to Weight: Axial
19 points
Strength to Weight: Bending
19 points
Thermal Diffusivity
21 mm2/s
Thermal Shock Resistance
18 points
Alloy Composition
Among wrought copper alloys, the composition of C68400 brass is notable for including aluminum (Al) and silicon (Si). Aluminum is used to add strength and oxidation resistance. Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy.
| Cu | 59 to 64 | |
| Zn | 28.6 to 39.3 | |
| Si | 1.5 to 2.5 | |
| Mn | 0.2 to 1.5 | |
| Fe | 0 to 1.0 | |
| Ni | 0 to 0.5 | |
| Al | 0 to 0.5 | |
| Sn | 0 to 0.5 | |
| P | 0.030 to 0.3 | |
| Pb | 0 to 0.090 | |
| B | 0.0010 to 0.030 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.