Bushing materials come in a wide variety, and the choice of material determines key performance characteristics such as load-carrying capacity, wear resistance, self‑lubrication, and corrosion resistance. In practical engineering applications, selecting the appropriate material requires a comprehensive assessment of multiple factors, including load, speed, temperature, and the surrounding service environment. The following is a classification of mainstream bushing materials along with recommendations for material selection:

1. Metal‑based bushings: A classic choice for load bearing and heat dissipation

Metallic materials are the most traditional choice for bushings, primarily including copper alloys, cast iron, and steel.

Copper alloys (such as bronze and brass): These are the most widely used materials for metal bushings. For example, tin bronze (e.g., ZCuSn5Pb5Zn5) offers excellent overall performance and is well suited to general‑purpose applications involving moderate speeds and loads; aluminum bronze (e.g., ZCuAl10Fe3), on the other hand, exhibits exceptionally high strength and hardness, making it ideal for severe service conditions characterized by heavy loads, low speeds, and impact. Copper‑based materials possess good thermal conductivity, effectively dissipating heat generated by friction, but they typically require an external oil‑lubrication system.

Cast Iron vs. Steel: Gray cast iron is cost-effective and offers excellent vibration damping, making it suitable for low-speed, light-load applications; in contrast, carbon steel or stainless steel is used in situations demanding very high strength or specific corrosion resistance—such as 304 stainless steel, which is commonly employed in food-processing machinery.

Selection recommendation: If your equipment operates under heavy loads and high-temperature conditions, and has adequate lubrication, metal bushings are the preferred choice.

2. Engineering Plastics and Polymer Composites: Pioneers in Maintenance-Free and Corrosion-Resistant Performance

With the advancement of materials science, polymer‑based bearing sleeves—such as those made from PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), and POM (polyoxymethylene)—are increasingly replacing traditional metal bearings.

Self-lubricating properties: These materials typically contain solid lubricants internally, enabling long-term operation under completely oil-free (dry friction) conditions with an extremely low coefficient of friction.

Corrosion Resistance and Lightweight Design: These materials exhibit exceptional resistance to aggressive chemicals such as strong acids and strong bases, while weighing significantly less than metals. They are ideally suited for applications in food packaging, medical devices, chemical processing equipment, and new‑energy vehicles—sectors that demand stringent cleanliness and lightweight construction.

Selection recommendation: If your equipment must be protected from oil contamination, operates in a corrosive environment, or requires “maintenance-free operation after installation,” high-performance plastic composite bushings are the optimal choice.

3. Powder Metallurgy (Oil-Impregnated) Bushings: An Economical and Practical Self-Lubricating Solution

It is produced by mixing metal powders—such as iron‑based or copper‑based powders—with graphite, followed by compaction and sintering, resulting in a material with interconnected microscopic pores.

Oil‑retention function: During manufacturing, the component is pre‑impregnated with lubricant; during operation, oil from the pores migrates to lubricate the friction surfaces, and upon shutdown, capillary action draws it back in. This type of bushing is low‑cost and enables long‑term, maintenance‑free operation, making it well suited for light‑load, low‑speed household appliances or small motors.

4. Special Ceramic Bushings: The Ultimate Solution for Extreme Operating Conditions

Advanced ceramic materials, exemplified by silicon carbide, exhibit extremely high hardness and wear resistance—5 to 20 times that of metals—and possess outstanding high-temperature and corrosion‑resistance properties.

Extreme‑environment adaptation: It can operate reliably at temperatures exceeding 1,300°C, in highly acidic or alkaline media, and in slurries containing solid particles. However, ceramic materials are relatively brittle, have poor impact resistance, and incur high processing and procurement costs.

Selection recommendation: Recommended only for critical components in pumps and other applications subjected to extreme wear, severe corrosion, or ultra‑high temperatures.

Summary of selection considerations: In practical decision‑making, first calculate the PV value (pressure × velocity) for the operating conditions and verify that it falls within the material’s allowable range. For heavy loads with impact, prioritize high‑strength metals such as aluminum bronze; for high speeds requiring fatigue resistance, lead bronze or tin bronze are more suitable; for low‑speed oscillating applications in dusty or submerged environments, self‑lubricating engineering‑plastic bushings can significantly reduce maintenance costs; and under extreme conditions involving severe corrosion or ultra‑high temperatures, special ceramic bushings should be selected.