O-Rings
Additional Information
There are several different standards to choose from when it comes to O-ring dimensions. The most popular in the United States is the AS568 standard for O-ring sizes and tolerances. Maintained by the Society of Automotive Engineers, this standard allows the user to choose from five different cross-sections with inside diameters ranging from 1/32" to 26". Tube fitting boss seals are included in AS568 as 900 series O-ring sizes, and are intended for use in MS33649 (now superseded by SAE-AS5202) straight thread tube fitings. RT/Dygert also offers a wide array of metric sizes, in both standard and non-standard dimensions. As a subset of the metric sizes offered, we also stock many Japanese Industrial Standard (JIS B2401) sizes. If an O-ring with special size or fluid resistance is required, RT/Dygert can provide custom O-rings, specially made to your demanding requirements.
SIZES
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| AS568A | ||
| Dash No. | ||
| Metric | Nominal | |
| I.D. | 14.990mm | |
| O.D. | 0.000mm | |
| C/S | 2.620mm | |
| Volume | 0.298cm3 | |
Gland Charts
MATERIALS
Highly Saturated Nitrile
RT/Dygert Stock Material
Other Designations
HNBR; HSN; Therban® (Bayer)
Composition
Formed by hydrogenating the nitrile copolymer of butadiene and acrylonitrile
Temperature Range
-40 to 300 °F
Description
Hydrogenation of nitrile rubber removes most of the residual unsaturation in the polymer to make it far less vulnerable to attack by heat, ozone, and oxygen. In fact, due to superior oil and temperature resistance, Highly Saturated Nitrile can sometimes be substituted for more costly fluorocarbon rubber. It is frequently used in automotive air conditioning systems employing R-134a refrigerants. HNBR can be can be either peroxide or sulfur cured, depending on the degree of unsaturation achieved by the hydrogenation process, but peroxide is almost always used due to the good heat stabiIity properties of the peroxide crosslinks. It can be compounded for both low and high temperature use.
Information above applies to the generic material. Specific compounds may exhibit different properties.
Physical Properties*
| Excellent | Good | Fair | Poor | |
| Abrasion resistance | • | |||
| Compression Set | • | |||
| Elongation | • | |||
| Flame resistance | • | |||
| Gas permeability | • | |||
| Low temperature flexibility | • | |||
| Tear resistance | • | |||
| Tensile strength | • |
Chemical Resistance*
| Excellent | Good | Fair | Poor | |
| Automatic transmission fluid | • | |||
| Automotive refrigerants | • | |||
| Oxygenated fuels | • | |||
| Ozone | • | |||
| Petroleum oils | • | |||
| Sour crude oil | • | |||
| Weather | • |
*Excellent, good, fair and poor are intended to serve as general guidelines only. Actual testing in the application environment is always recommended.
Information above applies to the generic material. Specific compounds may exhibit different properties.