FKM / Viton (Fluorocarbon Elastomer)
cao su fluoro FKM Viton
Also known as: Viton · fluorocarbon rubber · fluoroelastomer · FPM
FKM (fluorocarbon elastomer, trade name Viton) is a high-performance O-ring material with 66–70% fluorine content, resisting oils, fuels, and chemicals from –20°C to +200°C.
Technical Detail
FKM is standardised as fluoroelastomer per ISO 1629 / ASTM D1418. The fluorine content determines chemical resistance: Viton A (66% F) covers mineral oils and aromatic fuels; Viton GF/GBL (70% F) adds resistance to methanol blends, polar solvents (MEK, acetone), and concentrated acids. Temperature range: –20°C to +200°C continuous; short peak to +230°C. Low-temperature FKM (LT-FKM, TR-10 ≤ –30°C) available for cold-climate duty. Compression set: ≤20% at 200°C/70h with peroxide-cured compounds; bisphenol-cured grades are cheaper but show higher set. FKM costs 5–10× NBR. Standard specification: 70 Shore A, peroxide cure, low-compression-set grade for static flange seals in refinery, chemical plant, and offshore applications. Size to AS568 or JIS B2401 — same groove dimensions as NBR.
Reference Standards
- ASTM D1418 FK class
- ISO 1629 FKM
- ASTM D2000 HK grade
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