C 932 Bronze (UNS C93200)


Bronze alloys consist primarily of copper, usually with tin as the main additive.  The lead content in bearing bronze bars are between 6 percent and 15 percent.  High leaded tin bronze alloys are free cutting and retain favorable thermal conductivity and good lubricity due to the lead content. Alloy C 932 or C93200 is considered the workhorse alloy and is widely used in many bearing applications.  Alloy C 932 is a general purpose bearing alloy possessing good anti-friction properties, ample strength and hardness, adequate ductility and excellent machinability. It is used as bearings, bushings, light duty gears and sprockets, impellers, wear strips, plates, automotive fittings and washers. It is used extensively in pumps, cylinders, machine tools, earth moving machinery and other general purpose applications.

Alloy C 932 has a wider range of applicability, and is more often specified, than all other bearing materials.  C 932 is a high-leaded tin bronze that is used for general utility applications under medium loads and speeds.  Strength and hardness are somewhat lower than those of the tin bronzes but C 932 excels in antifriction and machining properties.

Chemical Composition

Chemical Composition (wt%) limits as specified in ASTM B505*

Copper 81.0-85.0 Antimony 0.35
Tin 6.3-7.5 Phosphorus 1.50
Lead 6.0-8.0 Sulfur 0.08
Zinc 2.0-4.0 Aluminum 0.005
Iron 0.20 Silicon 0.005
Nickel 1.00    

*Maximum, unless range is indicated

Physical Properties

Physical properties for C 932 Bronze

Density, lb/in3 0.322
Modulus of Elasticity, psi 14,500
Coefficient of Thermal Expansion, 68-212˚F, /˚F 10 x 10-6
Thermal Conductivity, Btu/ft hr ˚F 33.6
Specific Heat, Btu/lb ˚F 0.09
Electrical Resistivity, Microhm-in 2.8

Mechanical Properties

Mechanical property requirements as specified in ASTM B505

Yield Strength, min (ksi) 20
Tensile Strength, min (ksi) 35
Elongation, min (%) 10


Typical standards for C 932 Bronze