UNS C67500 (CW721R) Manganese Bronze
C67500 bronze is a bronze formulated for primary forming into wrought products. CW721R is the EN numeric designation for this material. C67500 is the UNS number. Additionally, the EN chemical designation is CuZn40Mn1Pb1AlFeSn. And the British Standard (BS) designation is CZ114. Older literature may refer to this material as ASTM Manganese Bronze Type A, but this is now discouraged.
It has a moderately low base cost and a moderately low melting temperature among wrought bronzes.
The properties of C67500 bronze include five common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C67500 bronze to: wrought 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
100 GPa 15 x 106 psi
Elongation at Break
14 to 33 %
Poisson's Ratio
0.3
Shear Modulus
40 GPa 5.8 x 106 psi
Shear Strength
270 to 350 MPa 40 to 51 x 103 psi
Tensile Strength: Ultimate (UTS)
430 to 580 MPa 63 to 84 x 103 psi
Tensile Strength: Yield (Proof)
170 to 370 MPa 24 to 54 x 103 psi
Thermal Properties
Latent Heat of Fusion
170 J/g
Maximum Temperature: Mechanical
120 °C 250 °F
Melting Completion (Liquidus)
890 °C 1630 °F
Melting Onset (Solidus)
870 °C 1590 °F
Specific Heat Capacity
390 J/kg-K 0.092 BTU/lb-°F
Thermal Conductivity
110 W/m-K 61 BTU/h-ft-°F
Thermal Expansion
21 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
24 % IACS
Electrical Conductivity: Equal Weight (Specific)
27 % IACS
Otherwise Unclassified Properties
Base Metal Price
23 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
2.8 kg CO2/kg material
Embodied Energy
47 MJ/kg 20 x 103 BTU/lb
Embodied Water
330 L/kg 39 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
61 to 130 MJ/m3
Resilience: Unit (Modulus of Resilience)
130 to 650 kJ/m3
Stiffness to Weight: Axial
7.3 points
Stiffness to Weight: Bending
20 points
Strength to Weight: Axial
15 to 20 points
Strength to Weight: Bending
16 to 19 points
Thermal Diffusivity
34 mm2/s
Thermal Shock Resistance
14 to 19 points
Alloy Composition
Among wrought copper alloys, the composition of C67500 bronze is notable for including aluminum (Al) and containing a comparatively high amount of iron (Fe). Aluminum is used to add strength and oxidation resistance. Iron is used to increase strength inexpensively.
| Cu | 57 to 60 | |
| Zn | 35.1 to 41.7 | |
| Fe | 0.8 to 2.0 | |
| Sn | 0.5 to 1.5 | |
| Mn | 0.050 to 0.5 | |
| Al | 0 to 0.25 | |
| Pb | 0 to 0.2 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B138: Standard Specification for Manganese Bronze Rod, Bar, and Shapes
ASTM B124: Standard Specification for Copper and Copper Alloy Forging Rod, Bar, and Shapes
ASTM B283: Standard Specification for Copper and Copper-Alloy Die Forgings (Hot-Pressed)
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001