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 Tube fitting boss seals are included in AS568 as 900 series O-ring sizes, and are intended for use in MS33649 (now superseded by SAE-AS5202) straight thread tube fitings.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. | 30.000mm | |
| O.D. | 0.000mm | |
| C/S | 4.500mm | |
| Volume | 1.724cm3 | |
Gland Charts
MATERIALS
Carboxylated Nitrile
Non-Stock Material
Other Designations
XNBR; CNBR
Composition
Medium density terpolymer of acrylonitrile, butadiene, and a diene monomer containing carboxylic acid
Temperature Range
-30 to 250 °F
Description
Carboxylated Nitrile, or XNBR, is produced by adding a carboxylic acid side group to nitrile rubber, thereby adding more crosslinking sites than traditional NBR. As a result, solvent swell and abrasion resistance are significantly improved, as well as modulus, tensile strength and tear resistance. However, XNBRs give a higher hardness (up to 12 to 16 durometer points in most recipes) than comparable non-carboxylated NBRs, so care must be taken during the compounding and mixing stages in order to achieve the desired hardness. Water resistance, resilience and some low temperature properties are somewhat diminished.
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 | |
| Amines | • | |||
| Dilute acids and bases | • | |||
| Esters | • | |||
| LP Gas | • | |||
| Oxidation | • | |||
| Petroleum oils and fuels | • | |||
| Silicone Fluids | • | |||
| Solvents | • | |||
| Steam | • | |||
| Water | • | |||
| 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.