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UNS C65500 (CW116C) Silicon Bronze

C65500 bronze is a bronze formulated for primary forming into wrought products. CW116C is the EN numeric designation for this material. C65500 is the UNS number. Additionally, the EN chemical designation is CuSi3Mn1. The British Standard (BS) designation is CS101. And the common industry name is High-Silicon Bronze A.

It has a moderately low electrical conductivity among wrought bronzes. In addition, it can have the highest ductility and has a moderately low embodied energy.

The properties of C65500 bronze include eleven 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 C65500 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

120 GPa 17 x 106 psi

Elongation at Break

4.0 to 70 %

Poisson's Ratio


Rockwell B Hardness

62 to 97

Shear Modulus

43 GPa 6.3 x 106 psi

Shear Strength

260 to 440 MPa 38 to 63 x 103 psi

Tensile Strength: Ultimate (UTS)

360 to 760 MPa 52 to 110 x 103 psi

Tensile Strength: Yield (Proof)

120 to 430 MPa 17 to 62 x 103 psi

Thermal Properties

Latent Heat of Fusion

260 J/g

Maximum Temperature: Mechanical

200 °C 390 °F

Melting Completion (Liquidus)

1030 °C 1880 °F

Melting Onset (Solidus)

970 °C 1780 °F

Specific Heat Capacity

400 J/kg-K 0.1 BTU/lb-°F

Thermal Conductivity

36 W/m-K 21 BTU/h-ft-°F

Thermal Expansion

18 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

7.3 % IACS

Otherwise Unclassified Properties

Base Metal Price

29 % relative

Calomel Potential

-270 mV


8.6 g/cm3 540 lb/ft3

Embodied Carbon

2.7 kg CO2/kg material

Embodied Energy

42 MJ/kg 18 x 103 BTU/lb

Embodied Water

300 L/kg 36 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

11 to 450 MJ/m3

Resilience: Unit (Modulus of Resilience)

62 to 790 kJ/m3

Stiffness to Weight: Axial

7.5 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

12 to 24 points

Strength to Weight: Bending

13 to 21 points

Thermal Diffusivity

10 mm2/s

Thermal Shock Resistance

12 to 26 points

Alloy Composition

Among wrought copper alloys, the composition of C65500 bronze is notable for including silicon (Si) and manganese (Mn). Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy. Manganese is used to improve strength without a proportional reduction in ductility.

Copper (Cu)Cu 91.5 to 96.7
Silicon (Si)Si 2.8 to 3.8
Manganese (Mn)Mn 0.5 to 1.3
Zinc (Zn)Zn 0 to 1.5
Iron (Fe)Fe 0 to 0.8
Nickel (Ni)Ni 0 to 0.6
Lead (Pb)Pb 0 to 0.050
Residualsres. 0 to 0.5

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM B98: Standard Specification for Copper-Silicon Alloy Rod, Bar and Shapes

ASTM B96: Standard Specification for Copper-Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes and Pressure Vessels

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)

Copper: Its Trade, Manufacture, Use, and Environmental Status, Gunter Joseph, 2001

Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011

Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993