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UNS C65100 (CW115C) Silicon Bronze

C65100 bronze is a bronze formulated for primary forming into wrought products. CW115C is the EN numeric designation for this material. C65100 is the UNS number. Additionally, the EN chemical designation is CuSi1. And the common industry name is Low-Silicon Bronze B.

It has the lowest embodied energy and can have a moderately low tensile strength among wrought bronzes.

The properties of C65100 bronze include nine 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 C65100 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

2.4 to 50 %

Poisson's Ratio


Shear Modulus

43 GPa 6.3 x 106 psi

Shear Strength

200 to 350 MPa 29 to 50 x 103 psi

Tensile Strength: Ultimate (UTS)

280 to 560 MPa 40 to 82 x 103 psi

Tensile Strength: Yield (Proof)

95 to 440 MPa 14 to 63 x 103 psi

Thermal Properties

Latent Heat of Fusion

230 J/g

Maximum Temperature: Mechanical

200 °C 390 °F

Melting Completion (Liquidus)

1060 °C 1940 °F

Melting Onset (Solidus)

1030 °C 1890 °F

Specific Heat Capacity

390 J/kg-K 0.094 BTU/lb-°F

Thermal Conductivity

57 W/m-K 33 BTU/h-ft-°F

Thermal Expansion

18 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

12 % IACS

Electrical Conductivity: Equal Weight (Specific)

12 % IACS

Otherwise Unclassified Properties

Base Metal Price

30 % relative

Calomel Potential

-280 mV


8.8 g/cm3 550 lb/ft3

Embodied Carbon

2.6 kg CO2/kg material

Embodied Energy

41 MJ/kg 18 x 103 BTU/lb

Embodied Water

300 L/kg 36 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

12 to 110 MJ/m3

Resilience: Unit (Modulus of Resilience)

39 to 820 kJ/m3

Stiffness to Weight: Axial

7.3 points

Stiffness to Weight: Bending

18 points

Strength to Weight: Axial

8.7 to 18 points

Strength to Weight: Bending

11 to 17 points

Thermal Diffusivity

16 mm2/s

Thermal Shock Resistance

9.5 to 19 points

Alloy Composition

Among wrought copper alloys, the composition of C65100 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 94.5 to 99.2
Silicon (Si)Si 0.8 to 2.0
Zinc (Zn)Zn 0 to 1.5
Iron (Fe)Fe 0 to 0.8
Manganese (Mn)Mn 0 to 0.7
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

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