UNS C90500 (Alloy D, SAE 62) Gun Metal
C90500 gun metal is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 62 is the SAE designation for this material. C90500 is the UNS number. Additionally, the EN chemical designation is CuSn10Zn2. And the common industry name is 88-10-0-2. Older literature may refer to this material as ASTM Alloy D or ASTM Alloy 1A.
It has a fairly high thermal conductivity among cast bronzes. In addition, it has a moderately high base cost and a moderately high embodied energy.
The graph bars on the material properties cards below compare C90500 gun metal 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
280 MPa 40 x 103 psi
Elastic (Young's, Tensile) Modulus
110 GPa 16 x 106 psi
Elongation at Break
20 %
Fatigue Strength
90 MPa 13 x 103 psi
Poisson's Ratio
0.34
Shear Modulus
40 GPa 5.8 x 106 psi
Tensile Strength: Ultimate (UTS)
320 MPa 46 x 103 psi
Tensile Strength: Yield (Proof)
160 MPa 23 x 103 psi
Thermal Properties
Latent Heat of Fusion
190 J/g
Maximum Temperature: Mechanical
170 °C 340 °F
Melting Completion (Liquidus)
1000 °C 1830 °F
Melting Onset (Solidus)
850 °C 1570 °F
Solidification (Pattern Maker's) Shrinkage
1.6 %
Specific Heat Capacity
370 J/kg-K 0.089 BTU/lb-°F
Thermal Conductivity
75 W/m-K 43 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
11 % IACS
Electrical Conductivity: Equal Weight (Specific)
11 % IACS
Otherwise Unclassified Properties
Base Metal Price
35 % relative
Density
8.7 g/cm3 540 lb/ft3
Embodied Carbon
3.6 kg CO2/kg material
Embodied Energy
59 MJ/kg 25 x 103 BTU/lb
Embodied Water
390 L/kg 46 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
54 MJ/m3
Resilience: Unit (Modulus of Resilience)
110 kJ/m3
Stiffness to Weight: Axial
6.9 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
10 points
Strength to Weight: Bending
12 points
Thermal Diffusivity
23 mm2/s
Thermal Shock Resistance
12 points
Alloy Composition
Among cast copper alloys, the composition of C90500 gun metal is notable for containing a comparatively high amount of tin (Sn) and including sulfur (S). Tin is used to improve strength, bearing properties, and corrosion resistance against certain types of media. It also places certain constraints on cast part design, so as to avoid porosity problems. Sulfur is used to improve machinability at the cost of a decrease in electrical conductivity.
| Cu | 86 to 89 | |
| Sn | 9.0 to 11 | |
| Zn | 1.0 to 3.0 | |
| P | 0 to 1.5 | |
| Ni | 0 to 1.0 | |
| Pb | 0 to 0.3 | |
| Fe | 0 to 0.2 | |
| Sb | 0 to 0.2 | |
| S | 0 to 0.050 | |
| Si | 0 to 0.0050 | |
| Al | 0 to 0.0050 | |
| res. | 0 to 0.3 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B22: Standard Specification for Bronze Castings for Bridges and Turntables
ASTM B271: Standard Specification for Copper-Base Alloy Centrifugal Castings
ASTM B505: Standard Specification for Copper Alloy Continuous Castings
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