EN CC491K (CuSn5Zn5Pb5-C) Leaded Tin Bronze
CC491K bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. CC491K is the EN numeric designation for this material. CuSn5Zn5Pb5-C is the EN chemical designation.
It has a fairly high electrical conductivity among cast bronzes. In addition, it has a moderately high thermal conductivity and a moderately low tensile strength.
The graph bars on the material properties cards below compare CC491K 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
Brinell Hardness
73
Elastic (Young's, Tensile) Modulus
110 GPa 16 x 106 psi
Elongation at Break
13 %
Poisson's Ratio
0.34
Shear Modulus
40 GPa 5.8 x 106 psi
Tensile Strength: Ultimate (UTS)
260 MPa 37 x 103 psi
Tensile Strength: Yield (Proof)
120 MPa 17 x 103 psi
Thermal Properties
Latent Heat of Fusion
190 J/g
Maximum Temperature: Mechanical
160 °C 330 °F
Melting Completion (Liquidus)
980 °C 1790 °F
Melting Onset (Solidus)
900 °C 1650 °F
Specific Heat Capacity
370 J/kg-K 0.087 BTU/lb-°F
Thermal Conductivity
71 W/m-K 41 BTU/h-ft-°F
Thermal Expansion
19 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
8.9 g/cm3 550 lb/ft3
Embodied Carbon
3.1 kg CO2/kg material
Embodied Energy
51 MJ/kg 22 x 103 BTU/lb
Embodied Water
350 L/kg 42 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
27 MJ/m3
Resilience: Unit (Modulus of Resilience)
67 kJ/m3
Stiffness to Weight: Axial
6.7 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
8.1 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 CC491K bronze 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 | 81 to 87 | |
| Sn | 4.0 to 6.0 | |
| Pb | 4.0 to 6.0 | |
| Zn | 4.0 to 6.0 | |
| Ni | 0 to 2.0 | |
| Fe | 0 to 0.3 | |
| Sb | 0 to 0.25 | |
| P | 0 to 0.1 | |
| S | 0 to 0.1 | |
| Si | 0 to 0.010 | |
| Al | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 1982: Copper and copper alloys - Ingots and castings