Viton (FKM) O-Rings.
Also known as Viton O-rings, FKM O-rings, fluoroelastomer O-rings and FPM O-rings.
Viton (FKM) O-rings are fluoroelastomer seals made for heat, fuels, oils and many chemicals, rated for continuous service to about 400 °F. They are the standard upgrade when nitrile (Buna-N) seals harden, crack or swell. All Industry Supplies supplies FKM O-rings by AS568 dash number or to your dimensions, with a quote within 1 business day.
Viton (FKM) O-Rings specifications
| Material | FKM (Viton) |
|---|---|
| Grade | standard compound |
| Also known as | Viton O-rings, FKM O-rings, fluoroelastomer O-rings, FPM O-rings |
| Forms | O-rings |
| Temperature range | About −15 °F to +400 °F (−26 °C to +204 °C) static; moving seals only to about 0 °F (−18 °C) |
| Hardness | 75 Shore A standard; 90 Shore A for higher pressure |
| Resists | Petroleum oils, fuels, mineral hydraulic fluids, many acids and solvents |
| Avoid | Ketones (acetone, MEK), hot water and steam, amines, glycol brake fluid, aviation phosphate-ester fluids |
| Common colors | Black or brown |
| Sizes and lead time | Sizes, tolerances and lead times are quoted on request. |
Typical applications
- Hydraulic and lubrication seals in hot service
- Fuel, oil and solvent pumps, valves and fittings
- Chemical-processing pumps and valves
- Engine, gearbox and compressor seals
- Vacuum seals, where low outgassing matters
- Replacing nitrile seals that harden or swell
Viton (FKM) O-Rings vs. the alternatives
Buna-N (nitrile) O-rings
Lower in cost and the default for petroleum oils and hydraulic fluid up to about 250 °F. Choose Viton when the temperature goes past that, or when fuels, solvents or chemicals attack nitrile.
EPDM O-rings
The choice for hot water, steam and glycol-based brake fluid, all things standard Viton handles poorly. EPDM must never see petroleum oil or fuel.
Silicone O-rings
A wider temperature range in dry service, about −65 °F to 450 °F, and common in food and medical equipment. Silicone tears and abrades easily and swells in fuels and oils, so keep it to static seals.
Machining and fabrication notes
Order by AS568 dash number when you can: the number fixes the inside diameter and cross-section, so a -214 is the same size in any material. Lubricate the ring at assembly with a grease compatible with the fluid it seals. Chamfer or deburr any edge the ring slides over, and avoid rolling or twisting it into the groove. Store spares sealed, away from sunlight, heat and electric motors, which produce ozone.
Common questions about Viton (FKM) O-Rings
What temperature can Viton O-rings handle?
Standard Viton (FKM) compounds are rated for continuous service up to about +400 °F (+204 °C). Static seals hold down to about −15 °F (−26 °C), but moving seals are limited to about 0 °F (−18 °C) because the rubber stiffens. Colder service needs a low-temperature FKM grade. Tell us the operating range when you request a quote.
Viton or Buna-N: which O-ring do I need?
Buna-N (nitrile) handles petroleum oils and hydraulic fluid up to about 250 °F at lower cost. Choose Viton when the seal runs hotter than that, or when it sees fuels, aromatic solvents or chemicals that make nitrile swell or harden.
What does an AS568 dash number mean?
AS568 is the standard size chart for inch O-rings. Each dash number fixes an inside diameter and a cross-section. A -214, for example, is about 0.984 in ID × 0.139 in cross-section. The same dash number fits the same groove in any material, so you can switch a nitrile -214 to a Viton -214.
Are Viton O-rings good for water and steam?
Standard Viton grades are not recommended for hot water or steam, where they swell and lose strength. EPDM is the usual choice for that service. Some specialty FKM compounds are rated for steam: describe the media and temperature on your quote request, and the quote confirms whether one can be supplied.
What durometer should I choose?
75 Shore A suits most static and dynamic seals. 90 Shore A resists extrusion at higher pressures and is common in hydraulic service, often paired with backup rings. If you are unsure, note the pressure and motion and we will confirm the grade on the quote.
Is FKM the same as Viton?
Viton is The Chemours Company's trademark for its fluoroelastomers. FKM is the ASTM D1418 name for the whole class (FPM in ISO 1629), so every Viton O-ring is FKM, but not every FKM O-ring is Viton. If your drawing or customer calls for brand-name Viton, say so in the notes and it is confirmed on the quote.
Request a quote for Viton (FKM) O-Rings
Enter the size and quantity you need. The line goes on your quote list with the full spec attached, next to any catalog parts, and we answer within 1 business day.
Supplied throughUSA Industrials