UNS C93200 (SAE 660) Bearing Bronze
C93200 bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 660 is the SAE designation for this material. C93200 is the UNS number. Additionally, the common industry name is 83-7-7-3. Older literature may refer to this material as ASTM Alloy 3B, but this is now discouraged.
It has a moderately low tensile strength among cast bronzes. In addition, it has a moderately low heat capacity and a moderately high ductility.
The graph bars on the material properties cards below compare C93200 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
Compressive (Crushing) Strength
320 MPa 46 x 103 psi
Elastic (Young's, Tensile) Modulus
100 GPa 15 x 106 psi
Elongation at Break
20 %
Fatigue Strength
110 MPa 16 x 103 psi
Poisson's Ratio
0.35
Rockwell B Hardness
65
Shear Modulus
38 GPa 5.5 x 106 psi
Tensile Strength: Ultimate (UTS)
240 MPa 35 x 103 psi
Tensile Strength: Yield (Proof)
130 MPa 18 x 103 psi
Thermal Properties
Latent Heat of Fusion
180 J/g
Maximum Temperature: Mechanical
160 °C 310 °F
Melting Completion (Liquidus)
980 °C 1790 °F
Melting Onset (Solidus)
850 °C 1570 °F
Solidification (Pattern Maker's) Shrinkage
1.8 %
Specific Heat Capacity
360 J/kg-K 0.086 BTU/lb-°F
Thermal Conductivity
59 W/m-K 34 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
32 % relative
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
3.2 kg CO2/kg material
Embodied Energy
52 MJ/kg 22 x 103 BTU/lb
Embodied Water
370 L/kg 44 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
40 MJ/m3
Resilience: Unit (Modulus of Resilience)
76 kJ/m3
Stiffness to Weight: Axial
6.5 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
7.5 points
Strength to Weight: Bending
9.7 points
Thermal Diffusivity
18 mm2/s
Thermal Shock Resistance
9.3 points
Alloy Composition
Among cast copper alloys, the composition of C93200 bronze is notable for containing a comparatively high amount of lead (Pb). Lead is used to improve machinability and bearing properties, at the cost of toxicity. It also adds pressure tightness to castings.
| Cu | 81 to 85 | |
| Pb | 6.0 to 8.0 | |
| Sn | 6.3 to 7.5 | |
| Zn | 2.0 to 4.0 | |
| P | 0 to 1.5 | |
| Ni | 0 to 1.0 | |
| Sb | 0 to 0.35 | |
| Fe | 0 to 0.2 | |
| S | 0 to 0.080 | |
| Si | 0 to 0.0050 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 1.0 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
Copper: Its Trade, Manufacture, Use, and Environmental Status, Gunter Joseph, 2001
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993