A bushing is a cylindrical component designed to reduce vibration, noise, and friction between two moving parts, one of which is usually a sliding, spinning, or rotating shaft. While metals, including bronze and steel, are traditional bushing materials, non-metallic polymers, including PTFE, PEEK, and high performance composite bushings are also highly effective. They can be used as alternative materials to cast iron or steel in corrosive environments, to reduce lubrication needs in pressing or drilling applications, or as wear- and weather-resistant materials for bushings in exposed or harsh operating conditions.

With decades of industry experience, WS Hampshire offers a comprehensive selection of industrial bushings in a wide range of shapes, sizes, and non-metallic materials.

This practical guide will help buyers and engineers select the most durable and reliable type of bushing material for different applications, including those with abrasive, corrosive, or high-temperature operating conditions.

PEEK Insulator

Factors That Influence Bushing Material Choice

Selecting an appropriate bushing material for an application has a significant effect on productivity, cycle times, and processing times, and lubrication and other maintenance needs.

To make the best material choice, it’s important to look at the operating conditions and material properties.

  • Chemical Exposure

    Bushings are used in many applications that involve chemicals, including drilling, manufacturing, food processing, vehicle systems, and tools. Chemical exposure can lead to reduced bushing performance or outright failure, both of which impact operational efficiency. Risks of chemical exposure include:

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    • Material degradation. Certain chemicals can alter a material’s structural properties, reducing its overall durability and strength. Even relatively weak chemicals can cause damage to bushings through long-term exposure.
    • Premature failure. Damage like surface pitting or cracking can trap abrasive particles or chemicals, accelerating the wear and tear of the component, leading to a shortened service life.
    • Rapid corrosion. Strong acids and bases can quickly corrode metal materials like steel, brass, and bronze. Polymers and composites often resist this damage better.
    • Swelling. Some non-metallic materials are prone to moisture absorption, which can lead to swelling and dimensional instability that increase heat and friction.

    It is essential to select a bushing material with adequate chemical resistance. Many metals may tend to degrade or corrode in extreme environments, while advanced thermoplastics can often stand up to solvents, alkalis, and acids.

  • Load Capacity
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    Bushings experience loading from whether they are used with static or dynamic components, operating pressures and temperatures, and the speed at which components move. Most bushings are subject to multiple of these forces at the same time, and if a material is not rated to withstand each type of loading, the bushing can become damaged or fail entirely. Thermoplastics and composite materials reinforced with fiber can often withstand high operating loads.

  • Operational Temperature Range
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    Using thermoplastics for heat-resistant bushings can help to conduct or insulate heat, depending on the application needs. High-performance materials, such as PTFE and PEEK, offer excellent thermal resistance and can withstand both high-heat and cryogenic conditions without deformation.

  • Lubrication Needs
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    Composite materials that include self-lubricating additives reduce the frequency of lubrication and the amount of lubricant needed. This increases productive uptime and cuts down on maintenance requirements. Industrial bushings made from these materials can also reduce the risk of mechanical failure due to improper lubrication or excessive friction.

  • Wear Characteristics
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    Bushings made from thermoplastics and composite laminates exhibit a low coefficient of friction, which helps protect mated parts made of soft metals, such as aluminum. They also help minimize wear on costly or labor-intensive components, protecting the parts with which they come into contact.

Pros and Cons of Common Industrial Bushing Materials

Industrial bushings can be made from many different materials, and each has advantages and disadvantages for specific applications. Here, we’ll compare some common materials.

Bronze

Bushings can be made from solid bronze, bronze alloys, and sintered powdered bronze. In general, bronze-based materials are durable, strong, corrosion-resistant, and support high loading and high speed operations. Solid bronze has excellent wear resistance, strength, and impact resistance; however, it requires lubrication, is difficult to machine, is heavy, and can be expensive. Many alloys are available with metals that enhance or improve bronze’s properties:

  • Aluminum bronze (especially for high-temperature applications).
  • Manganese bronze (especially for high-temperature applications).
  • Phosphor bronze.
  • Tin bronze.

Self-lubricating bronze bushings are also widely used. Sintered or oil-impregnated bronze bushings are made through powder metallurgy, in which bronze powder is blended with various fillers and binders, compacted in a mold, and sintered (i.e., heat treated), then filled with oil to create a self-lubricating component. Another option is bronze bushings cast with holes in a grid pattern. The holes are plugged with graphite or PTFE, which creates a self-lubricating surface.

Steel

Steel bushings are very strong and durable for heavy-duty applications, including extreme temperature environments. This material requires lubrication and non-stainless steel is susceptible to corrosion due to its iron content. Steel bushings may be prone to vibration and are not well-suited to high-speed operations.

Brass

Brass is an alloy of copper and zinc and is a softer material than bronze or steel, so it is easier to machine but less durable and may deform under heavy loading. Brass is a cost-effective choice for general-purpose applications, lower speeds, and lighter use. Brass also requires regular lubrication.

Thermoset Composites and Laminates

Thermoset laminates are made by layering epoxy, melamine, polyester, or silicone resins with a structural material such as carbon fiber or glass-based fabric. Because they are thermosets, once they are cured they retain their shape and composition permanently. They tend to be rigid, hard, structurally stable, and hard-wearing.

Ryertex Composite Laminates are a popular alternative to metal for industrial and commercial applications involving high heat (250° F to 572° F), load, and/or speed. They are an ideal alternative to metal components in high-speed, high-temperature, high-impact, and high-load applications.

Thermoplastics

Thermoplastics, including WS Hampshire’s line of Timco Technical Thermoplastics, are polymer composites that become soft and formable when heated. They can also be reheated and reformed multiple times. Some common examples used for bushing applications include:

  • Ultra high molecular weight polyethylene (UHMW): Extremely low coefficient of friction material; grades include ceramic filled for added compressive strength and dimensional stability, high-temperature to extend its properties to conditions over 250° F, and MoS2 filled to reduce its wear rate; generally has low compressive strength, heat resistance maximum of 160° F, and high rates of thermal expansion that can impact ability to hold tolerances in some applications.
  • Polyether Ether Ketone (PEEK): Very strong, highly workable, and resistant to high temperatures; can be extruded or compression molded and is available with glass or carbon reinforcement.
  • Nylon: lightweight, cost-effective material with high tensile strength and hardness; has a low coefficient of friction that eliminates the need for lubrication, and good abrasion resistance; excellent at noise dampening, can be cast or molded. MoS2 filled grade has increased crystallinity, improves load-bearing capacity and wear resistance.
  • Acetal: Also known by its DuPont tradename Delrin®; good dimensional stability in humid or wet conditions, resists most organic solvents, and has low water absorption; some grades may include micro-pinholes and tends to outgas formaldehyde fumes when exposed to temperatures above 150° F.
  • Polyethylene Terephthalate (PET-GL): Lubricant is dispersed throughout this material for improved operation with little to no additional lubrication required; (almost no moisture absorption; can overcome “stick-slip” and jerky movement as wear pads begin to move; does not wear on soft metals.

Learn More About Non-Metallic Bushings From WS Hampshire

The WS Hampshire team brings years of experience with industrial plastics to every project and product, including bushings, bearings, and wear plates. Our non-metallic alternatives to traditional metal for bushings can reduce lubrication and maintenance needs, improve corrosion resistance, and save money over traditional metal materials. All products are fabricated in-house for short lead times and continuity of workmanship and quality.

Contact us today to learn more about material selection for your next industrial bushing project!