UNS C90300 (Alloy 1B) Navy-G Tin Bronze
C90300 bronze is a bronze formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. C90300 is the UNS number for this material. Additionally, the common industry name is 88-8-0-4. Older literature may refer to this material as ASTM Alloy 1B, but this is now discouraged.
It has a fairly high thermal conductivity and a moderately high ductility among cast bronzes.
The graph bars on the material properties cards below compare C90300 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
Elastic (Young's, Tensile) Modulus
110 GPa 16 x 106 psi
Elongation at Break
22 %
Poisson's Ratio
0.34
Shear Modulus
41 GPa 5.9 x 106 psi
Tensile Strength: Ultimate (UTS)
330 MPa 48 x 103 psi
Tensile Strength: Yield (Proof)
150 MPa 22 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
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
12 % IACS
Electrical Conductivity: Equal Weight (Specific)
12 % IACS
Otherwise Unclassified Properties
Base Metal Price
33 % relative
Density
8.7 g/cm3 540 lb/ft3
Embodied Carbon
3.4 kg CO2/kg material
Embodied Energy
56 MJ/kg 24 x 103 BTU/lb
Embodied Water
370 L/kg 45 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
59 MJ/m3
Resilience: Unit (Modulus of Resilience)
110 kJ/m3
Stiffness to Weight: Axial
7.0 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
11 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 C90300 bronze 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 | 7.5 to 9.0 | |
| Zn | 3.0 to 5.0 | |
| 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 0.6 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
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
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001