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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.

Copper (Cu) 86 to 89
Tin (Sn) 9.0 to 11
Zinc (Zn) 1.0 to 3.0
Phosphorus (P) 0 to 1.5
Nickel (Ni) 0 to 1.0
Lead (Pb) 0 to 0.3
Iron (Fe) 0 to 0.2
Antimony (Sb) 0 to 0.2
Sulfur (S) 0 to 0.050
Silicon (Si) 0 to 0.0050
Aluminum (Al) 0 to 0.0050
Residuals 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