FKM / Viton O-Rings | High Temperature & Chemical Resistant Seals

What is an FKM / Viton O-ring?

FKM (fluoroelastomer, Viton) is a fluorocarbon elastomer delivering superior chemical and heat resistance. As FKM O-rings / Viton O-rings, they outlast NBR/EPDM in fuels, solvents, lubricants, and aggressive media.

Typical window: -20°C to +200°C (up to ~+230°C for some grades). They are the go-to chemical resistant o-rings and fuel resistant o-rings for demanding service.

Composition & Properties

Compared to NBR, Viton O-rings handle heat/chemicals better while sacrificing some low-temp elasticity. For extreme media and heat, step up to FFKM.

• Hardness: 65–95 Shore A; common 75/80/90A for pressure and extrusion control.
• Mechanical: strong tensile and wear performance with low compression set at high temperature.
• Formulations: higher fluorine boosts chemical resistance; low-temp FKM improves flexibility near -40°C.

Temperature Range

For intermittent high heat, tune compression ratios and monitor set. For cold dynamic fits, use low-temp FKM and lubrication to avoid cracking.

• Continuous: about -20°C to +200°C; short-term to ~+230°C (grade-dependent).
• Low-temp: standard ~-20°C; low-temp types down to ~-40°C for cold starts/dynamics.
• Steam: brief/light steam can be acceptable; prolonged hot steam prefers steam-rated EPDM/FFKM.

Chemical Compatibility

Share MSDS for aggressive blends; otherwise consider FFKM. Compared to NBR/EPDM, Viton O-rings maintain sealing in harsh fuels/solvents and outdoor/UV exposure.

• Good for: fuels, lubricants, many solvents, acids/bases, gases, vacuum—classic chemical resistant o-rings.
• Avoid/verify: ketones, low-molecular esters/ethers (grade-dependent), prolonged hot water/steam.
• Ozone/outdoor: strong ozone/weather resistance; verify for aggressive blends or amine/ketone media.

Advantages

• High-temp capable: sustained ~200°C with low compression set.
• Chemical resistance: excellent vs fuels, lubricants, many solvents/acids/bases.
• Aging resistance: ozone/UV/weather strength superior to NBR/EPDM.
• Traceable: color/batch labels, compatible with backup rings for high pressure or rotary use.

Applications

• Automotive/aerospace: fuel systems, engine hot zones, exhaust/turbo accessories—high temperature o-rings that survive fuels.
• Chemical/solvent handling: pumps, valves, lines, samplers for organic solvents and aggressive fluids.
• Oil & gas/energy: valves, frac equipment, high-temp oil circuits—fuel resistant o-rings with backup rings.
• Vacuum/semiconductor: auxiliary seals in chemical/vacuum environments (FFKM for extreme chemistries).

Size Coverage (AS568 / Metric)

• AS568 000–475 available; common 75/90A stocked with batch labels; low-temp grades on request.
• Metric/large/custom profiles available; compression/extrusion guidance to stabilize Viton O-rings.
• Color/batch coding supported for traceability and warehouse control.

Ordering & Traceability

• Mixed MOQ 1 across AS568/metric, all batch-labeled.
• Submit size tables to lock batches and ship dates; packing photos/barcodes offered.
• Share media/temp/pressure/motion for alternatives; engineer responds within 24h.
• FDA/NSF FKM or special colors available with lead-time confirmation.

FAQs

• FKM vs NBR: pick FKM for heat/chemicals/fuels; NBR/HNBR for low-temp/cost.
• Steam? Avoid prolonged hot steam—use steam-rated EPDM/FFKM.
• Low-temp? Choose low-temp FKM (~ -40°C) or HNBR/silicone.
• Food/NSF? Use dedicated compounds; confirm color/hardness/lead time.

Installation & Selection Tips

• Compression: static 15–25%, dynamic 10–20%; chamfer + lubrication prevent nicks.
• High-temp/high-pressure: backup rings, controlled extrusion gaps; groove Ra 0.8–1.6 μm.
• Storage: avoid heat/ozone/UV; sealed bags, FIFO to preserve fluorocarbon o-rings elasticity.