Torlon bearings are high-performance solutions designed for extreme performance even under extreme loads, high temperatures, and aggressive wear conditions. In this blog post, learn why more and more engineers are opting for Torlon bearings based on Torlon’s properties, bearing performance characteristics, and diverse areas of applications.

Properties of Torlon Bearings

Chemical Structure and Material Classification

Torlon® (polyamide-imide, PAI) is a high-performance engineering polymer. It is a hybrid polymer that combines the characteristics of both polyamides and polyimides, offering excellent toughness, thermal resistance, and mechanical strength. Its aromatic monomers, which reduce molecular mobility, give it stiffness, creep resistance, and high-temperature capabilities. 

The imide linkages in Torlon give it a high bond strength, allowing it to resist chain scission at extremely high temperatures. In addition, the imide groups provide excellent resistance to oxidative degradation, extending their service life in oxygen-exposed environments.

This combination of aromatic monomers with imide linkages enables it to have a high continuous-use temperature of up to 500°F without losing its key mechanical properties. Torlon’s combined imide and aromatic bonding networks also enhance its wear resistance, which is critical in poor-lubrication or dry-running operating conditions.

Torlon’s molecular architecture enables bearings to provide reliable performance even under high PV loads and improves their compressive strength to support high-load-bearing applications. In addition, its chemical makeup enables Torlon to outperform many other engineering polymers in applications that demand dimensional stability under heavy mechanical cycling or extreme thermal spikes.

Thermal Properties

Torlon is known for its continuous-use temperatures approaching 260°C (500°F), as well as its excellent retention of mechanical strength at such elevated temperatures. Torlon also exhibits very low thermal expansion. Its primary thermal drawback lies in manufacturing: it is primarily limited to compression molding and machining because of its high melt processing temperature. 

Mechanical Properties

Torlon is known for its excellent strength and stiffness, including a high load capacity. Two of the bearing grades of Torlon are …

• Torlon 4435: high-temperature, low-friction, high-PV
• Torlon 4301: high strength, low friction, graphite-filled

Tribological Properties

Naturally low friction coefficients are another key property of Torlon. These values can be improved by using PTFE- or graphite-filled material. Moreover, Torlon has excellent wear resistance even in environments with minimal lubrication. Finally, it exhibits very low levels of deformation and creep even under sustained stress.

Chemical & Environmental Resistance

Torlon has excellent resistance to chemical attack, including automotive fluids, solvents, and hydraulic oils, and good resistance to hydrolysis.

Performance of Torlon Bearings

Load-Carrying Capacity

Its excellent compressive strength means that Torlon bearings can be used in high-load bearing applications, with PV ratings up to 100,000 for Torlon 4435.

Temperature Performance

Torlon bearings maintain excellent structural and wear performance even under continuous high temperatures. It is suitable for operating conditions where metal bearings seize.

PV (Pressure–Velocity) Capability

The high PV capability of these bearings makes them well suited for high-speed, high-load applications where heat generation is significant. For example …

• Torlon 4435
  • Max P (Pressure): 1,000 psi
  • Max V (Velocity): 850 sfm
  • Max PV: 100,000 (psi·ft/min)
  • Service Temperature: 500°F
• Torlon 4301
  • Max P (Pressure): 1,000 psi
  • Max V (Velocity): 900 sfm
  • Max PV: 50,000 (psi·ft/min)
  • Service Temperature: 500°F

Wear and Friction Behavior

Because these bearings have such a low coefficient of friction, startup wear and energy losses are very low, and they exhibit excellent dry-running performance. In addition, friction is stable across a wide range of loads and temperatures.

Dimensional Stability & Creep Resistance

Low thermal expansion and minimal creep make Torlon bearings an excellent option for precision applications, tight clearances, and long service life.

Applications for Torlon Bearings

Torlon bearings are used in aerospace systems such as flap actuators and landing gear, where low weight, high wear resistance, and the ability to withstand extreme thermal cycling are essential. In oil and gas equipment, Torlon provides reliable performance in HPHT environments for components like downhole tools, pumps, and valves. Industrial machinery relies on Torlon for bushings, wear rings, and thrust washers that offer low friction and long life, where metal bearings wear out quickly.

In automotive and transportation systems, Torlon supports transmissions, pumps, and electric motors with strong thermal resistance and low wear. Semiconductor and precision equipment benefit from Torlon’s low outgassing, chemical resistance, and dimensional stability in clean, tightly controlled environments. Automation and robotics use Torlon bearings in high-load joints and guides, where strength, low wear, and minimal lubrication improve system reliability.

Conclusion

Torlon bearings offer unique advantages for extreme mechanical, thermal, and environmental operating conditions. Their high load capacity, excellent wear behavior, superior PV performance, and broad industrial applicability have made them the choice for many bearing solutions across a range of industries and applications. If you are interested in bearing solutions for aggressive operating environments, contact Advanced EMC today for custom Torlon bearing design, material selection, and manufacturing guidance.