C90700
Tin Bronze (Gear Bronze)
High-tin bronze with excellent wear resistance and low friction. The standard alloy for gears, worm wheels, and heavy-duty bearing applications. Also known as "Gear Bronze" per ASTM B427.
Tensile Strength
35-55 ksi
Yield Strength
17-30 ksi
Machinability
20 / 100
Density
0.317 lb/in³
Chemical Composition
| Element | Min % | Max % |
|---|---|---|
| Copper (Cu) | 88 | 90 |
| Tin (Sn) | 10 | 12 |
| Lead (Pb) | — | 0.5 |
| Zinc (Zn) | — | 0.5 |
| Nickel (Ni) | — | 0.5 |
| Iron (Fe) | — | 0.15 |
| Phosphorus (P) | — | 0.3 |
| Aluminum (Al) | — | 0.005 |
| Sulfur (S) | — | 0.05 |
| Antimony (Sb) | — | 0.2 |
| Silicon (Si) | — | 0.005 |
Physical Properties
| Density | 0.317 lb/cu in |
|---|---|
| Specific Gravity | 8.77 |
| Melting Point (Solidus) | 1528°F |
| Melting Point (Liquidus) | 1830°F |
| Electrical Conductivity | 10% IACS |
Mechanical Properties
| Tensile Strength | 35-55 ksi |
|---|---|
| Yield Strength | 17-30 ksi |
| Elongation | 10-20% |
| Hardness | 65-102 BHN |
| Machinability Rating | 20 |
Thermal Properties
| Thermal Conductivity | 41 Btu/ft·hr·°F |
|---|---|
| Coefficient of Expansion | 10.2 × 10⁻⁶ /°F |
| Specific Heat | 0.09 Btu/lb·°F |
Fabrication Properties
Soldering
Brazing
Oxyacetylene Welding
Gas Shielded Arc
Coated Metal Arc
Cold Working
Hot Forming
Typical Applications
- Gears and worm gears
- Speed reducers and gear boxes
- Heavy-duty bearings
- Valve bodies
- Piston rings
- Pump impellers
- Marine hardware
Applicable Specifications
- ASTM B427
- ASTM B505
- ASTM B30
- SAE J461
- SAE J462
Frequently Asked Questions
Technical details about C90700 composition, properties, and applications.