Cu85Sn5Pb5Zn5 Sliding Plate

Graphite Bronze Bearing Material: Tin Bronze Cu85Sn5Pb5Zn5

The Cu85Sn5Pb5Zn5 alloy, often referred to as a type of tin bronze, is an excellent material for bearings, particularly when enhanced with graphite inserts. This combination provides superior performance in a variety of industrial applications due to its excellent mechanical properties, self-lubricating nature, and durability. Below is a detailed overview of this material.

Chemical Composition

• Copper (Cu): 85%
• Tin (Sn): 5%
• Lead (Pb): 5%
• Zinc (Zn): 5%

Physical Properties

• Density: 8.8 g/cm³
• Melting Point: Approximately 1020°C

Mechanical Properties

• Tensile Strength: 250 MPa (minimum)
• Yield Strength: 130 MPa (minimum)
• Elongation: 12% (minimum)
• Hardness: 75-90 HB
• Compressive Strength: 380 MPa (minimum)

Thermal Properties

• Thermal Conductivity: 55 W/m·K
• Coefficient of Thermal Expansion: 18 x 10⁻⁶ /K

Friction and Wear Properties

• Coefficient of Friction (dry): 0.25 (with graphite inserts)
• Wear Rate: Very low, especially when enhanced with graphite inserts

Corrosion Resistance

• Corrosion Resistance: Excellent, particularly in seawater and other corrosive environments.

Key Features and Benefits

1. High Load-Bearing Capacity: Cu85Sn5Pb5Zn5 alloy can support significant mechanical loads without significant wear or deformation.
2. Excellent Wear Resistance: The alloy’s composition, combined with graphite inserts, significantly reduces wear and extends the lifespan of the bearings.
3. Self-Lubricating Properties: Graphite inserts provide continuous lubrication, reducing maintenance needs and ensuring smoother operation.
4. Good Corrosion Resistance: Resistant to corrosion in various environments, making it suitable for marine and industrial applications.
5. Thermal Stability: Maintains performance and structural integrity at high temperatures.

Applications

Graphite-enhanced Cu85Sn5Pb5Zn5 bronze bearings are ideal for use in:

• Heavy Machinery: Bearings and bushings subjected to high loads and continuous operation.
• Automotive Industry: Components requiring low friction and high durability, such as engine parts and transmission systems.
• Aerospace: High-stress applications where reliability and performance are critical.
• Marine Industry: Bearings and other components exposed to corrosive environments.
• Construction Equipment: High-wear applications requiring robust and reliable materials.

Fabrication and Machining

• Casting: Suitable for sand casting, centrifugal casting, and continuous casting.
• Machinability: Good, due to the presence of lead and zinc, which act as internal lubricants during machining processes.
• Welding: Generally not recommended due to the lead content.

Maintenance and Care

• Lubrication: Graphite inserts reduce the need for frequent lubrication, but periodic maintenance can further enhance bearing life.
• Inspection: Regular inspection for wear and tear can prevent unexpected failures and extend the operational lifespan of the bearings.

Conclusion

The Cu85Sn5Pb5Zn5 bronze alloy, enhanced with graphite inserts, represents a high-performance solution for bearing materials in demanding industrial environments. Its combination of mechanical strength, wear resistance, self-lubricating properties, and corrosion resistance makes it a preferred choice for applications requiring reliable and efficient performance under challenging conditions.