UNS C87800 Silicon Brass
C87800 brass is a brass formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. It has a moderately low thermal conductivity among cast brasses. In addition, it has a fairly low electrical conductivity and a very high tensile strength.
The graph bars on the material properties cards below compare C87800 brass to: cast 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
25 %
Poisson's Ratio
0.33
Rockwell B Hardness
86
Shear Modulus
42 GPa 6.1 x 106 psi
Tensile Strength: Ultimate (UTS)
590 MPa 85 x 103 psi
Tensile Strength: Yield (Proof)
350 MPa 50 x 103 psi
Thermal Properties
Latent Heat of Fusion
260 J/g
Maximum Temperature: Mechanical
170 °C 340 °F
Melting Completion (Liquidus)
920 °C 1680 °F
Melting Onset (Solidus)
820 °C 1510 °F
Specific Heat Capacity
410 J/kg-K 0.1 BTU/lb-°F
Thermal Conductivity
28 W/m-K 16 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
6.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
7.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
27 % relative
Density
8.3 g/cm3 520 lb/ft3
Embodied Carbon
2.7 kg CO2/kg material
Embodied Energy
44 MJ/kg 19 x 103 BTU/lb
Embodied Water
300 L/kg 36 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
130 MJ/m3
Resilience: Unit (Modulus of Resilience)
540 kJ/m3
Stiffness to Weight: Axial
7.4 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
20 points
Strength to Weight: Bending
19 points
Thermal Diffusivity
8.3 mm2/s
Thermal Shock Resistance
21 points
Alloy Composition
Among cast copper alloys, the composition of C87800 brass is notable for including arsenic (As). Arsenic is used to protect the alloy against dezincification.
| Cu | 80 to 84.2 | |
| Zn | 12 to 16 | |
| Si | 3.8 to 4.2 | |
| Sn | 0 to 0.25 | |
| Ni | 0 to 0.2 | |
| Mn | 0 to 0.15 | |
| Fe | 0 to 0.15 | |
| Al | 0 to 0.15 | |
| Pb | 0 to 0.15 | |
| S | 0 to 0.050 | |
| Sb | 0 to 0.050 | |
| As | 0 to 0.050 | |
| P | 0 to 0.010 | |
| Mg | 0 to 0.010 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B176: Standard Specification for Copper-Alloy Die Castings
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001