Viton™ B is a terpolymer formulated at approximately 68% fluorine content — a step up from Viton A's dipolymer chemistry — giving noticeably better resistance to inorganic acids, caustics and harsh industrial process fluids. FITCO specifies Viton B when Viton A has shown signs of chemical attack but the fluid list doesn't yet justify moving to Viton F or a specialty grade.
| Temperature range | -20°C to +200°C |
|---|---|
| Hardness range | 60–90 Shore A |
| Relative cost | $$$ |
| Resists | Inorganic acids, caustics, harsher industrial fluids than Viton A, ozone, weathering |
| Avoid with | Strong bases at high concentration, ketones, amines |
| Standards | AS568 / ISO 3601 / BS 4518 |
General-purpose seal for mineral oils, fuels and hydraulic fluids.
-20°C to +200°CHigh-temperature, chemical-resistant sealing for oil & gas and process industries.
-15°C to +327°CNear-universal chemical resistance for the most demanding process seals.
FEP encapsulated O-rings use standard Silicone or standard Viton FKM as the elastomer core — not specialty sub-grades. If you need FEP encapsulation, the core is standard FKM, not this specific grade.
Standard FKM details → Specialty ProductThin PTFE coating on the FKM O-ring surface — reduced assembly friction, anti-stick, dry lubrication for production line assembly without grease.
PTFE Coated O-Rings → Custom SizesNon-standard ID or cross-section? FITCO manufactures custom O-rings in all Viton grades to any dimension — send your drawing or ID × CS in mm.
Custom O-Ring sizes →Send us your fluid, temperature and pressure — our engineers will confirm the compound.
