Characteristics and Performance Advantages of Flanged Graphite Copper Bushings

I. Structural and Design Features

Flanged (Stop-Collar) Design

• Flanged copper bushings are equipped with a flange structure at the end, which restricts axial movement of the bushing, prevents displacement during operation, and enhances assembly stability. Some products also support the addition of positioning holes on the flange to ensure precise positioning.
• They are suitable for applications requiring axial load resistance or frequent start-stop cycles, such as injection molding machine screw injection mechanisms and metallurgical equipment guide rails.

Self-Lubrication Mechanism

• The base material is high-strength brass (e.g., ZCuZn25Al6, CuZn24Al6, or CuZn25Al6Fe3Mn3), embedded with graphite or molybdenum disulfide (MoS₂) solid lubricants (accounting for 20%-30% of the friction surface).
• During friction, the lubricant transfers to the shaft surface upon heating, forming a solid lubricating film that reduces direct metal contact. The high thermal conductivity of the brass base (approximately 109 W/m·K) aids in heat dissipation, maintaining lubrication effectiveness.

II. Material and Performance Parameters

Base Material

• High-strength brass: Contains 60-66% copper, with added strengthening elements such as aluminum, iron, and manganese. It has a hardness of HB210-290, an ultimate dynamic load capacity of 100-110 N/mm², and double the wear resistance compared to ordinary copper bushings.
• Some products adopt a composite structure (e.g., surface rolled with a mixture of PTFE and lead) to enhance self-lubrication.

Key Performance Parameters

• Coefficient of friction: <0.16 (dry friction).
• Operating temperature: Up to 300°C without oil, extendable to 320°C with regular lubrication.
• Sliding speed: 0.4 m/s for dry friction, 5 m/s with oil lubrication.
• Ultimate PV value: 3.8 N/mm²·m/s.

III. Performance Advantages

High Load Capacity and Wear Resistance

• An ultimate dynamic load capacity of 100-110 N/mm² makes them suitable for low-speed, heavy-load scenarios (e.g., mining machinery, rolling mill equipment).
• Wear life is twice that of traditional tin bronze bushings.

Maintenance-Free and Environmentally Friendly

• No external oil supply is required, avoiding oil contamination and making them suitable for clean environments such as food machinery and medical equipment.

Corrosion Resistance and Wide Temperature Range Adaptability

• Stable against water and weak acid-base media, suitable for long-term use in humid or chemically corrosive environments.
• Withstands temperatures from -40°C to 300°C, adapting to extreme conditions such as high-temperature injection molding and metallurgical continuous casting.

IV. Typical Application Scenarios

• Metallurgical equipment: Guide devices for continuous casting machines, roller bearings for rolling mill equipment.
• Heavy machinery: Transmission components for mining machinery, bearings for ship propulsion systems.
• Industrial equipment: Injection molding machine screw injection bushings, guide rails for automated production lines.
• Special environments: Transmission components for high-temperature furnaces, underwater equipment (e.g., ship propeller shafts).

V. Assembly and Usage Recommendations

Shaft Material Selection

• Recommended shaft materials are stainless steel or chrome-plated steel, with a hardness higher than that of the copper bushing (suggested shaft hardness ≥HRC45).

Assembly Methods

• Pre-lubrication: Apply lubricating oil to the friction surface before assembly to shorten the running-in period.
• Low-temperature assembly: Preferably use the freezing shrinkage method (-196°C liquid nitrogen treatment) to avoid deformation caused by hammering.

Maintenance Considerations

• The black graphite lubricating film formed on the surface does not need to be removed; normal use is sufficient.
• Regularly inspect the fit clearance in corrosive environments to prevent abnormal wear caused by foreign object intrusion.

VI. Market and Product Information

• Main Manufacturers: Mingxu Bearing: [email protected], offering customization services (e.g., size, positioning hole processing).
• Price Range: Varies based on size and batch quantity, with no minimum order quantity, but better pricing is available for bulk orders.