Leaded Commercial

Leaded Commercial Bronze, also known as C31400, is a type of bronze alloy that contains lead as an alloying element. The addition of lead improves the machinability of the alloy, making it easier to work with compared to other bronzes. This type of bronze is widely used in various industrial applications due to its good mechanical properties and excellent machinability.

Composition:

Copper (Cu): Approximately 86-89%
Lead (Pb): Approximately 1-2%
Zinc (Zn): Approximately 9-11%
Other elements: Small amounts of iron (Fe), tin (Sn), and other trace elements.

Grades

ASTM B 140 C31400:

ASTM standard specifying the composition and mechanical properties for leaded commercial bronze alloys.

Properties:

Corrosion Resistance:
- Good resistance to corrosion in various environments, including industrial atmospheres.
- Not as resistant to seawater corrosion compared to other bronzes.
Mechanical Properties:
- Tensile Strength: Typically around 310-380 MPa.
- Yield Strength: Approximately 110-220 MPa.
- Elongation: Generally around 20-35%, indicating good ductility.
- Hardness: Moderate hardness, with a typical Brinell hardness number (HB) of around 80-120.
Wear Resistance:
- Moderate wear resistance, suitable for applications involving moderate friction and mechanical stress.
Machinability:
- Excellent machinability due to the presence of lead, which acts as a lubricant and reduces friction during machining.
- Can be easily cast, forged, and worked to various shapes.
Thermal and Electrical Conductivity:
- Good thermal conductivity, suitable for heat exchangers and electrical applications.
- Moderate electrical conductivity, sufficient for many industrial uses but lower than pure copper.

Applications:

Bushings and Bearings: Extensively used in the production of bushings and bearings due to its good machinability and moderate wear resistance.
Automotive Parts: Commonly used in automotive parts such as gears, connectors, and fasteners due to its ease of machining and good mechanical properties.
Valves and Fittings: Suitable for manufacturing valves and fittings that require good machinability and moderate corrosion resistance.
Industrial Equipment: Used in various industrial equipment parts, including pump components, gears, and machine parts.