UNS C31400 Leaded Hardware Bronze
C31400 bronze is a bronze formulated for primary forming into wrought products. It can have a moderately low tensile strength among wrought bronzes. In addition, it has a moderately low embodied energy and a moderately high electrical conductivity.
The properties of C31400 bronze include three 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 C31400 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 16 x 106 psi
Elongation at Break
6.8 to 29 %
Poisson's Ratio
0.33
Shear Modulus
42 GPa 6.1 x 106 psi
Shear Strength
180 to 240 MPa 26 to 35 x 103 psi
Tensile Strength: Ultimate (UTS)
270 to 420 MPa 40 to 60 x 103 psi
Tensile Strength: Yield (Proof)
78 to 310 MPa 11 to 45 x 103 psi
Thermal Properties
Latent Heat of Fusion
200 J/g
Maximum Temperature: Mechanical
180 °C 350 °F
Melting Completion (Liquidus)
1040 °C 1900 °F
Melting Onset (Solidus)
1010 °C 1850 °F
Specific Heat Capacity
380 J/kg-K 0.091 BTU/lb-°F
Thermal Conductivity
180 W/m-K 100 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
42 % IACS
Electrical Conductivity: Equal Weight (Specific)
43 % IACS
Otherwise Unclassified Properties
Base Metal Price
29 % relative
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
2.6 kg CO2/kg material
Embodied Energy
42 MJ/kg 18 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
26 to 59 MJ/m3
Resilience: Unit (Modulus of Resilience)
28 to 420 kJ/m3
Stiffness to Weight: Axial
7.1 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
8.7 to 13 points
Strength to Weight: Bending
11 to 14 points
Thermal Diffusivity
54 mm2/s
Thermal Shock Resistance
9.6 to 15 points
Alloy Composition
Among wrought copper alloys, the composition of C31400 bronze is notable for containing a comparatively high amount of lead (Pb) and including nickel (Ni). Lead is used to improve machinability and bearing properties, at the cost of toxicity. Nickel is used to improve strength (particularly at elevated temperatures) and corrosion resistance.
| Cu | 87.5 to 90.5 | |
| Zn | 5.8 to 11.2 | |
| Pb | 1.3 to 2.5 | |
| Ni | 0 to 0.7 | |
| Fe | 0 to 0.1 | |
| res. | 0 to 0.4 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B140: Standard Specification for Copper-Zinc-Lead (Red Brass or Hardware Bronze) Rod, Bar, and Shapes
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001