Silicone is an excellent material for o-rings in static sealing applications, due to its outstanding resistance to extreme temperatures and retention of compression and flexibility. Additionally silicone exhibits excellent resistance to ozone, oxygen, moisture and water swell. Finally, silicone is a very low odor and taste elastomer making it a prime choice for the medical, and food and beverage industries. Limiting factors of silicone are its low tear strength and poor abrasion resistance which limit silicone o-rings to static sealing applications. Silicone o-rings are sometimes referred to as VMQ o-rings.
The silicone AS216-70S o-ring can be reference in one of four ways:
The final consideration for an o-ring after size and material type is the durometer. Durometer is an industry standard measurement for a material’s hardness. Most often for rubber seals, durometer is measured and listed in accordance with the “Shore A” scale. Typical durometers for standard rubber seals are 70, 75 and 90, depending on the material. A higher number indicates a harder material. Durometer is also generally stated and accepted with a “+/- 5” tolerance. For silicone o-rings, the standard nominal durometer is 70.
O-Rings, rubber seals and custom molded rubber components for:
|-75`F / -59`C||450`F / 232`C|
|Oils & Grease|
|Heat Ozone & Aging Resistance|
|Water Swell Resistance|
AS568-216 (Durometer 70) cross reference sizes