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UNS C91300 (Alloy A) Bell Metal

C91300 bell metal is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C91300 is the UNS number for this material. Additionally, the common industry name is 81-19 Tin Bronze.

It has the highest base cost among cast bronzes. In addition, it has the lowest ductility and the highest embodied energy.

The graph bars on the material properties cards below compare C91300 bell 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

190 MPa 27 x 103 psi

Elastic (Young's, Tensile) Modulus

100 GPa 15 x 106 psi

Elongation at Break

0.5 %

Poisson's Ratio

0.34

Shear Modulus

38 GPa 5.5 x 106 psi

Tensile Strength: Ultimate (UTS)

240 MPa 35 x 103 psi

Tensile Strength: Yield (Proof)

210 MPa 30 x 103 psi

Thermal Properties

Latent Heat of Fusion

180 J/g

Maximum Temperature: Mechanical

150 °C 300 °F

Melting Completion (Liquidus)

890 °C 1630 °F

Melting Onset (Solidus)

820 °C 1500 °F

Specific Heat Capacity

360 J/kg-K 0.085 BTU/lb-°F

Thermal Expansion

18 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

7.4 % IACS

Otherwise Unclassified Properties

Base Metal Price

39 % relative

Density

8.6 g/cm3 530 lb/ft3

Embodied Carbon

4.5 kg CO2/kg material

Embodied Energy

74 MJ/kg 32 x 103 BTU/lb

Embodied Water

460 L/kg 54 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

1.1 MJ/m3

Resilience: Unit (Modulus of Resilience)

210 kJ/m3

Stiffness to Weight: Axial

6.6 points

Stiffness to Weight: Bending

18 points

Strength to Weight: Axial

7.8 points

Strength to Weight: Bending

10 points

Thermal Shock Resistance

9.3 points

Alloy Composition

Among cast copper alloys, the composition of C91300 bell 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) 79 to 82
Tin (Sn) 18 to 20
Phosphorus (P) 0 to 1.5
Nickel (Ni) 0 to 0.5
Iron (Fe) 0 to 0.25
Lead (Pb) 0 to 0.25
Zinc (Zn) 0 to 0.25
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 0.6

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

ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015