Buna-N (Nitrile) O-Rings
Buna is one of the most widely used O-Ring elastomer compounds. Buna is a Nitrile compound. The actual name is Acrylonitrile-Butadiene and can be referred to as Buna, Nitrile or NBR. Standard durometer, or hardness, is 70 or 90, but can be made in other durometers, and comes in Black. The temperature range is generally -30°to 250°F. These are generally the least expensive and most readily available material in the widest range of sizes.
Buna-N o-rings are recommended for use with silicone greases and oils, water, petroleum oils and fuels.
Buna is not recommended for ketones, halogenated hydrocarbons, auto, and aircraft glycol-based brake fluids, strong acids, and is not resistant to sunlight, ozone or weathering.
Buna has good wear resistance, good compression set resistance, good short-term resilience, and good permeation resistance. It is used with hydraulic oils and fuels, extreme service-life, pneumatic and vacuum applications.
Our extensive inventory of Buna includes O-Rings in standard and metric sizes, quad-rings and backup rings, and parts. If your application requires unique or hard-to-find sizes or shapes, we will work with our manufacturing partners to source the seal you need.
You can find additional technical information related to buna-n o-rings and other materials regarding chemical compatibility, resistance to abrasion, suitability for dynamic or static applications, temperature operating ranges, longevity, and other factors on our Technical Information pages.