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EN CC497K (CuSn5Pb20-C) High-Leaded Tin Bronze

CC497K bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. CC497K is the EN numeric designation for this material. CuSn5Pb20-C is the EN chemical designation.

It has a very low heat capacity among cast bronzes. In addition, it has a very low tensile strength and a very low melting temperature.

The graph bars on the material properties cards below compare CC497K 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


Elastic (Young's, Tensile) Modulus

93 GPa 13 x 106 psi

Elongation at Break

6.7 %

Poisson's Ratio


Shear Modulus

34 GPa 5.0 x 106 psi

Tensile Strength: Ultimate (UTS)

190 MPa 27 x 103 psi

Tensile Strength: Yield (Proof)

91 MPa 13 x 103 psi

Thermal Properties

Latent Heat of Fusion

160 J/g

Maximum Temperature: Mechanical

130 °C 260 °F

Melting Completion (Liquidus)

870 °C 1600 °F

Melting Onset (Solidus)

800 °C 1480 °F

Specific Heat Capacity

330 J/kg-K 0.078 BTU/lb-°F

Thermal Conductivity

53 W/m-K 31 BTU/h-ft-°F

Thermal Expansion

20 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

9.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.7 % IACS

Otherwise Unclassified Properties

Base Metal Price

29 % relative


9.3 g/cm3 580 lb/ft3

Embodied Carbon

3.0 kg CO2/kg material

Embodied Energy

48 MJ/kg 21 x 103 BTU/lb

Embodied Water

370 L/kg 44 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

10 MJ/m3

Resilience: Unit (Modulus of Resilience)

45 kJ/m3

Stiffness to Weight: Axial

5.5 points

Stiffness to Weight: Bending

16 points

Strength to Weight: Axial

5.6 points

Strength to Weight: Bending

7.8 points

Thermal Diffusivity

17 mm2/s

Thermal Shock Resistance

7.2 points

Alloy Composition

Among cast copper alloys, the composition of CC497K bronze is notable for containing a comparatively high amount of lead (Pb). Lead is used to improve machinability and bearing properties, at the cost of toxicity. It also adds pressure tightness to castings.

Copper (Cu)Cu 67.5 to 77.5
Lead (Pb)Pb 18 to 23
Tin (Sn)Sn 4.0 to 6.0
Nickel (Ni)Ni 0.5 to 2.5
Zinc (Zn)Zn 0 to 2.0
Antimony (Sb)Sb 0 to 0.75
Iron (Fe)Fe 0 to 0.25
Manganese (Mn)Mn 0 to 0.2
Phosphorus (P)P 0 to 0.1
Sulfur (S)S 0 to 0.1
Silicon (Si)Si 0 to 0.010
Aluminum (Al)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