Wear-resistance properties improved in PAI grades

Wear resistance has been significantly boosted in a pair of new Torlon polyamide-imide (PAI) grades from Solvay Advanced Polymers (Alpharetta, GA) over the previous wear-resistant Torlon materials. Ideal for use in applications including bushings, bearings, sliding elements, and needle bearing replacements in industrial, aerospace, and automotive industries, Torlon 4630 and 4645 provide an alternative to metal-based designs used in high-temperature and wear applications.

“We’ve improved the wear properties of Torlon PAI to an unprecedented level in response to OEMs who seek better performance over a range of pressures and velocities,” says Brian Stern, senior global automotive market manager for Solvay.  At operating temperatures of up to 527°F, the material is said to offer excellent mechanical properties, compressive strength, sealing capability, and resistance to creep, strong acids, and most organics.

Of the two available injection molding grades, Torlon 4630 is a graphite/PTFE-filled grade for nonlubricated environments. This grade offers a reported wear factor improvement of 50% over previous grades in both high-pressure/low-speed applications and low-pressure/high-speed applications. The coefficient of linear thermal expansion (CLTE) is 40% lower than previous materials, and the limiting PV (contact pressure times velocity) is 150,000 psi x fpm.

For lubricated environments, the carbon-fiber/PTFE Torlon 4645 grade improves the wear factor over previous grades by 100%. Suitable for high-pressure/low-speed applications, this grade has a low coefficient of friction of 0.05-0.1, a limiting PV value of 750,000 psi x fpm, and a low CLTE of 3 ppm per degree Fahrenheit for tight-tolerance molding. Both injection molding grades are manufactured at Solvay’s Greenville, SC facility and are also available in stock shapes. —[email protected]