UNS C92900 Leaded Gear Bronze
C92900 bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C92900 is the UNS number for this material. Older literature may refer to this material as ASTM Gear Bronze Type D, but this is now discouraged.
It has a fairly high embodied energy among cast bronzes. In addition, it has a moderately high base cost and a moderately low electrical conductivity.
The graph bars on the material properties cards below compare C92900 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
84
Elastic (Young's, Tensile) Modulus
110 GPa 16 x 106 psi
Elongation at Break
9.1 %
Poisson's Ratio
0.34
Shear Modulus
40 GPa 5.8 x 106 psi
Tensile Strength: Ultimate (UTS)
350 MPa 51 x 103 psi
Tensile Strength: Yield (Proof)
190 MPa 28 x 103 psi
Thermal Properties
Latent Heat of Fusion
190 J/g
Maximum Temperature: Mechanical
170 °C 340 °F
Melting Completion (Liquidus)
1030 °C 1890 °F
Melting Onset (Solidus)
860 °C 1570 °F
Specific Heat Capacity
370 J/kg-K 0.088 BTU/lb-°F
Thermal Conductivity
58 W/m-K 34 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
9.0 % IACS
Electrical Conductivity: Equal Weight (Specific)
9.2 % IACS
Otherwise Unclassified Properties
Base Metal Price
35 % relative
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
3.8 kg CO2/kg material
Embodied Energy
61 MJ/kg 26 x 103 BTU/lb
Embodied Water
390 L/kg 46 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
27 MJ/m3
Resilience: Unit (Modulus of Resilience)
170 kJ/m3
Stiffness to Weight: Axial
6.8 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
11 points
Strength to Weight: Bending
13 points
Thermal Diffusivity
18 mm2/s
Thermal Shock Resistance
13 points
Alloy Composition
Among cast copper alloys, the composition of C92900 bronze is notable for containing comparatively high amounts of lead (Pb) and nickel (Ni). Lead is used to improve machinability and bearing properties, at the cost of toxicity. It also adds pressure tightness to castings. Nickel is used to improve strength (particularly at elevated temperatures) and corrosion resistance. It also creates the need for additional care during casting.
| Cu | 82 to 86 | |
| Sn | 9.0 to 11 | |
| Ni | 2.8 to 4.0 | |
| Pb | 2.0 to 3.2 | |
| P | 0 to 1.5 | |
| Zn | 0 to 0.25 | |
| Sb | 0 to 0.25 | |
| Fe | 0 to 0.2 | |
| S | 0 to 0.050 | |
| Si | 0 to 0.0050 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 0.7 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B427: Standard Specification for Gear Bronze Alloy Castings
ASTM B505: Standard Specification for Copper Alloy Continuous Castings
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001