UNS C86500 Manganese Bronze
C86500 bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C86500 is the UNS number for this material. Additionally, the common industry name is No. 1 Manganese Bronze. Older literature may refer to this material as ASTM Alloy 8A, but this is now discouraged.
It has a very low base cost among cast bronzes. In addition, it has a very high electrical conductivity and a fairly high thermal conductivity.
The graph bars on the material properties cards below compare C86500 bronze 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
25 %
Poisson's Ratio
0.3
Shear Modulus
40 GPa 5.8 x 106 psi
Tensile Strength: Ultimate (UTS)
530 MPa 76 x 103 psi
Tensile Strength: Yield (Proof)
190 MPa 28 x 103 psi
Thermal Properties
Latent Heat of Fusion
170 J/g
Maximum Temperature: Mechanical
120 °C 250 °F
Melting Completion (Liquidus)
880 °C 1620 °F
Melting Onset (Solidus)
860 °C 1580 °F
Specific Heat Capacity
390 J/kg-K 0.093 BTU/lb-°F
Thermal Conductivity
86 W/m-K 50 BTU/h-ft-°F
Thermal Expansion
21 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
22 % IACS
Electrical Conductivity: Equal Weight (Specific)
25 % IACS
Otherwise Unclassified Properties
Base Metal Price
23 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
2.8 kg CO2/kg material
Embodied Energy
48 MJ/kg 21 x 103 BTU/lb
Embodied Water
330 L/kg 39 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
110 MJ/m3
Resilience: Unit (Modulus of Resilience)
180 kJ/m3
Stiffness to Weight: Axial
7.4 points
Stiffness to Weight: Bending
20 points
Strength to Weight: Axial
19 points
Strength to Weight: Bending
18 points
Thermal Diffusivity
28 mm2/s
Thermal Shock Resistance
17 points
Alloy Composition
Among cast copper alloys, the composition of C86500 bronze is notable for containing a comparatively high amount of iron (Fe) and including manganese (Mn). Iron is used to increase strength inexpensively. Manganese is used to improve strength without a proportional reduction in ductility.
| Cu | 55 to 60 | |
| Zn | 36 to 42 | |
| Fe | 0.4 to 2.0 | |
| Al | 0.5 to 1.5 | |
| Mn | 0.1 to 1.5 | |
| Ni | 0 to 1.0 | |
| Sn | 0 to 1.0 | |
| Pb | 0 to 0.4 | |
| res. | 0 to 1.0 |
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
ASTM B505: Standard Specification for Copper Alloy Continuous Castings
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001