UNS C85200 Leaded Yellow Brass
C85200 brass is a brass formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C85200 is the UNS number for this material. Older literature may refer to this material as ASTM Alloy 6A, but this is now discouraged.
It has a moderately high ductility and a fairly high melting temperature among cast brasses.
The graph bars on the material properties cards below compare C85200 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 15 x 106 psi
Elongation at Break
28 %
Poisson's Ratio
0.32
Shear Modulus
40 GPa 5.8 x 106 psi
Tensile Strength: Ultimate (UTS)
270 MPa 39 x 103 psi
Tensile Strength: Yield (Proof)
95 MPa 14 x 103 psi
Thermal Properties
Latent Heat of Fusion
180 J/g
Maximum Temperature: Mechanical
140 °C 290 °F
Melting Completion (Liquidus)
940 °C 1730 °F
Melting Onset (Solidus)
930 °C 1700 °F
Specific Heat Capacity
380 J/kg-K 0.090 BTU/lb-°F
Thermal Conductivity
84 W/m-K 49 BTU/h-ft-°F
Thermal Expansion
20 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
18 % IACS
Electrical Conductivity: Equal Weight (Specific)
19 % IACS
Otherwise Unclassified Properties
Base Metal Price
26 % relative
Density
8.4 g/cm3 520 lb/ft3
Embodied Carbon
2.8 kg CO2/kg material
Embodied Energy
46 MJ/kg 20 x 103 BTU/lb
Embodied Water
330 L/kg 39 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
59 MJ/m3
Resilience: Unit (Modulus of Resilience)
42 kJ/m3
Stiffness to Weight: Axial
7.0 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
8.9 points
Strength to Weight: Bending
11 points
Thermal Diffusivity
27 mm2/s
Thermal Shock Resistance
9.3 points
Alloy Composition
Among cast copper alloys, the composition of C85200 brass is notable for containing a comparatively high amount of lead (Pb) and including sulfur (S). Lead is used to improve machinability and bearing properties, at the cost of toxicity. It also adds pressure tightness to castings. Sulfur is used to improve machinability at the cost of a decrease in electrical conductivity.
| Cu | 70 to 74 | |
| Zn | 20 to 27 | |
| Pb | 1.5 to 3.8 | |
| Sn | 0.7 to 2.0 | |
| Ni | 0 to 1.0 | |
| Fe | 0 to 0.6 | |
| Sb | 0 to 0.2 | |
| Si | 0 to 0.050 | |
| S | 0 to 0.050 | |
| P | 0 to 0.020 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 0.9 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B271: Standard Specification for Copper-Base Alloy Centrifugal Castings
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001