How to Chose O-Ring Material

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O-ring are one of the most commonly used fluid power seals. These seals have a simple donut-shaped ring (technically called a toroid) and are manufactured using pliable material such as elastomers like silicone, Buna-N and Ethylene-Propylene. O-rings are installed in order to seal off connections between connectors, pipes, tubes, etc. via mechanical deformation. Once installed, O-rings make sure that no liquid or air sweep through the designated area.

Since O-rings are crucial to perform effectively after being installed, selecting the right O-ring material is crucial. The crash of space shuttle Challenger in 1986 is a well-documented case of what failure of O-rings can do. Today O-rings are manufactured using thousands of different materials and every material perform differently under several conditions. The following sections includes the most commonly materials used for the O-rings, their working temperature, the shore A hardness scores, the standard colors as well as the limitations of that materials.