A Guide to O-Ring Materials

Courtesy of Gallagher Fluid Seals, here’s a guide to O-Ring materials, how they are used, and when to avoid using them:

Nitrile (Buna, HBR): A widely used, economical material that has strong wear resistance and mechanical properties. Temperature: -55 to 250 degrees Fahrenheit Applications: Petroleum based oils and fuels, dynamic applications Avoid: Break fluids and ozone Hydrogenated Nitrile (HNBR): Nitrile base with added chemical strength and resistance following hydrogenation.

Temperature: -50 to 300 degrees Fahrenheit Applications: Water and steam up to 300 degrees Fahrenheit, fuel systems, oil resistant and high abrasion applications Avoid: Strong acids and polar solvents such as ethers and ketones Polyacrylate (ACM): Widely used by auto makers in power steering and transmission systems.

Temperature: -15 to 350 degrees Fahrenheit Applications: Mineral oil, engines, gear boxes, power steering, transmissions Avoid: Cold temperatures, hot water, steam Ethylene-Propylene (EPDM): Strong ozone and chemical resistance

Temperature: -55 to 275 degrees Fahrenheit, 300 degrees Fahrenheit when used with peroxide curing agents Applications: Brake systems, glycol-based fluids, H20 steam Avoid: Mineral oil products and hydrocarbon fluids Chloroprene (Neoprene, CR): The first commercial synthetic rubber developed, chloroprene has good mechanical properties over a wide range of temperatures.

Temperature: -40 to 250 degrees Fahrenheit Applications: Refrigeration, due to its excellent ozone resistance, low-temp H20 Avoid: Esters, ketones and aromatic and chlorinated hydrocarbons. Butyl: An all-petroleum compound, butyl has low gas permeability and good resistance to sun exposure and ozone.

Temperature: -70 to 400 degrees Fahrenheit Applications: Life science and medical devices, FDA applications, numerous specialized compounds for specific material certifications Avoid: Highly abrasive applications and water and steam over 250 degrees Fahrenheit Fluorosilicone (FVMQ): Broad temperature performance and strong fuel and solvent resistance, but weak abrasion resistance due to high friction.

Temperature: -75 to 400 degrees Fahrenheit Applications: Aerospace, fuel and mineral oil Avoid: High temperature air, dynamic applications Flurocarbon (Vikton, FKM): The high fluorine levels in fluorocarbon rings give them excellent swelling and permeability resistance. They also feature high temperature and chemical resistance.

Temperature: -15 to 400 degrees Fahrenheit Applications: Broad chemical resistance, transmission and blended gasoline Avoid: Low temperatures, ketones and amines Tetrafluoroethylene-Propylene (AFLAS): Excellent chemical and temperature performance.

Temperature: 15 to 450 degrees Fahrenheit Applications: Aerospace, steam, hot water, oil fields Avoid: Chlorinated hydrocarbons, ketones, acetic acid Perfluoelastomer (FFKM): Of all elastomers, this one has the highest performing temperature and chemical properties, as well as low out-gassing and extractable properties.

Temperature: -15 to 600 degrees Fahrenheit Applications: Semiconductors, chemical processing, vacuum applications Avoid: Fluorinated solvents and perfluorinated lubricants If you have questions about O-Ring materials, contact Gallagher Fluid Seals, Inc. Our experts can answer any questions you might have about these small, yet crucial, sealing products.