The OnlineMetals Guide to Bronze


The term Bronze is applied to alloys of metal that are copper-based where tin is the main additive. This is not a hard and fast rule, however - some bronzes have phosphorus, manganese, aluminum or silicon as the main alloying ingredient.


The primary traits of Bronze alloys are that of toughness, strength, corrosion resistance, electrical conductivity, and thermal conductivity. Depending on the alloy, there is a bronze for just about every application. currently stocks four types of bronze in various shapes and sizes:
C932 / SAE 660 - Bearing Bronze (available in HollowBar, Round)
C954 - Aluminum Bronze (available in HollowBar, Rectangle, Round, Square)
C655 - Silicon Bronze (available in Round)
C863 - Manganese Bronze (available in HollowBar, Round)


Bearing Bronze
As the name implies, this is the most commonly used bronze in bushing and bearing applications. It is comparably easy to machine, and provides long life in applications where wear is a consideration.


Bearing Bronze (C932), a/k/a SAE 660
Minimum Properties Ultimate Tensile Strength, psi 35,000
Yield Strength, psi 20,000
Elongation in 2" 10%
Brinell Hardness 65
Chemistry Copper (Cu) 81.0 - 85.0%
Tin (Sn) 6.3 - 7.5%
Lead 6.0 - 8.0%
Zinc 2.0 - 4.0%


Aluminum Bronze
Aluminum bronzes are most valued for their higher strength and corrosion resistance as compared to other bronze alloys. These alloys are tarnish-resistant and show low rates of corrosion in atmospheric conditions, low oxidation rates at high temperatures, and low reactivity with sulfurous compounds and other exhaust products of combustion. They are also resistant to corrosion in sea water. Finally, they prevent colonization by marine organisms including algae, barnacles, and mussels.

Aluminum bronzes are most commonly used in applications where their resistance to corrosion makes them preferable to other engineering materials.

Aluminum Bronze, C954
Minimum Properties Ultimate Tensile Strength, psi 85,000
Yield Strength, psi 32,000
Elongation in 2" 12%
Brinell Hardness 170
Chemistry Copper (Cu) 83.0% min
Iron (Fe) 3.0 - 5.0%
Aluminum (Al) 10.0 - 11.5%


Silicon Bronze
Silicon Bronze is a high-strength, highly corrosion resistant material with nonmagnetic properties. It is generally as strong as steel. Because of its composition, it is more difficult to machine. However, it is excellent for use in general marine applications, as well as pumps and boilers.
Silicon Bronze, C655
Minimum Properties Ultimate Tensile Strength, psi 85,000
Yield Strength, psi 55,000
Elongation in 2" 20%
Rockwell Hardness B90
Chemistry Copper (Cu) 97.0% min
Iron (Fe) 0.8% max
Manganese (Mn) 1.5% max
Nickel (Ni) 0.6% max
Lead (Pb) 0.5% max
Silicon (Si) 2.8 - 3.8%
Zinc (Zn) 1.5% max



Manganese Bronze
Manganese Bronze is a high-strength bronze alloy primarily used in heavy-duty applications.
Manganese Bronze (C863)
Minimum Properties Ultimate Tensile Strength, psi 119,000
Yield Strength, psi 66,700
Hardness, Brinell 225
Elongation at break 18%
Machinability 8%
Chemistry Copper (Cu) 60.0 - 68.0%
Aluminum (Al) 3 - 7.5%
Iron (Fe) 2.0 - 4.0%
Manganese (Mn) 2.50 - 5.0%
Zinc (Zn) 25.0%