UNS C83600 (Alloy 4A, SAE 40) Ounce Metal
C83600 ounce metal is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 40 is the SAE designation for this material. C83600 is the UNS number. Additionally, the EN chemical designation is CuZn5P5Pb5. And the common industry name is 85-5-5-5. Older literature may refer to this material as ASTM Alloy 4A, but this is now discouraged.
It has a fairly high electrical conductivity among cast bronzes. In addition, it has a moderately high thermal conductivity and a moderately low embodied energy.
The graph bars on the material properties cards below compare C83600 ounce metal to: cast bronzes (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
21 %
Poisson's Ratio
0.34
Shear Modulus
39 GPa 5.7 x 106 psi
Tensile Strength: Ultimate (UTS)
250 MPa 36 x 103 psi
Tensile Strength: Yield (Proof)
120 MPa 18 x 103 psi
Thermal Properties
Latent Heat of Fusion
190 J/g
Maximum Temperature: Mechanical
160 °C 320 °F
Melting Completion (Liquidus)
1010 °C 1850 °F
Melting Onset (Solidus)
850 °C 1570 °F
Specific Heat Capacity
370 J/kg-K 0.088 BTU/lb-°F
Thermal Conductivity
72 W/m-K 42 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
15 % IACS
Electrical Conductivity: Equal Weight (Specific)
15 % IACS
Otherwise Unclassified Properties
Base Metal Price
31 % relative
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
3.1 kg CO2/kg material
Embodied Energy
50 MJ/kg 21 x 103 BTU/lb
Embodied Water
350 L/kg 42 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
43 MJ/m3
Resilience: Unit (Modulus of Resilience)
70 kJ/m3
Stiffness to Weight: Axial
6.7 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
7.9 points
Strength to Weight: Bending
10 points
Thermal Diffusivity
22 mm2/s
Thermal Shock Resistance
9.3 points
Alloy Composition
Among cast copper alloys, the composition of C83600 ounce metal 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 | 84 to 86 | |
| Sn | 4.0 to 6.0 | |
| Pb | 4.0 to 6.0 | |
| Zn | 4.0 to 6.0 | |
| P | 0 to 1.5 | |
| Ni | 0 to 1.0 | |
| Fe | 0 to 0.3 | |
| Sb | 0 to 0.25 | |
| S | 0 to 0.080 | |
| Si | 0 to 0.0050 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 0.7 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B62: Standard Specification for Composition Bronze or Ounce Metal Castings
ASTM B271: Standard Specification for Copper-Base Alloy Centrifugal Castings
ASTM B505: Standard Specification for Copper Alloy Continuous Castings
Copper: Its Trade, Manufacture, Use, and Environmental Status, Gunter Joseph, 2001
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001