UNS C65400 Silicon Bronze
C65400 bronze is a bronze formulated for primary forming into wrought products. It has a moderately low electrical conductivity among wrought bronzes. In addition, it can have the highest tensile strength and has a moderately low thermal conductivity.
The properties of C65400 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 C65400 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
110 GPa 17 x 106 psi
Elongation at Break
2.6 to 47 %
Poisson's Ratio
0.34
Rockwell B Hardness
82 to 120
Rockwell Superficial 30T Hardness
71 to 92
Shear Modulus
43 GPa 6.2 x 106 psi
Shear Strength
350 to 530 MPa 51 to 77 x 103 psi
Tensile Strength: Ultimate (UTS)
500 to 1060 MPa 73 to 150 x 103 psi
Tensile Strength: Yield (Proof)
170 to 910 MPa 25 to 130 x 103 psi
Thermal Properties
Latent Heat of Fusion
260 J/g
Maximum Temperature: Mechanical
200 °C 380 °F
Melting Completion (Liquidus)
1020 °C 1860 °F
Melting Onset (Solidus)
960 °C 1750 °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
17 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
31 % relative
Density
8.7 g/cm3 540 lb/ft3
Embodied Carbon
2.8 kg CO2/kg material
Embodied Energy
45 MJ/kg 19 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
10 to 480 MJ/m3
Resilience: Unit (Modulus of Resilience)
130 to 3640 kJ/m3
Stiffness to Weight: Axial
7.3 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
16 to 34 points
Strength to Weight: Bending
16 to 27 points
Thermal Diffusivity
10 mm2/s
Thermal Shock Resistance
18 to 39 points
Alloy Composition
Among wrought copper alloys, the composition of C65400 bronze is notable for including chromium (Cr) and silicon (Si). Chromium additions permits certain types of heat treatment to improve mechanical strength. Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy.
| Cu | 93.8 to 96.1 | |
| Si | 2.7 to 3.4 | |
| Sn | 1.2 to 1.9 | |
| Zn | 0 to 0.5 | |
| Cr | 0.010 to 0.12 | |
| Pb | 0 to 0.050 | |
| res. | 0 to 0.2 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B96: Standard Specification for Copper-Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes and Pressure Vessels
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015