FKM & Viton™ B flat gaskets and cut components
Precision-cut flat gaskets, seals and custom components in fluorocarbon elastomer (FKM) and Viton™ B. CNC die-cut from premium sheet stock for superior chemical resistance to fuels, oils, solvents and hydraulic fluids at continuous service temperatures from –20°C to +200°C.
Manufacturing principle and process
FKM and Viton™ B flat gaskets are manufactured by precision cutting from fluoroelastomer sheet with 68% fluorine content, ensuring chemical and mechanical stability in demanding industrial service.
The process begins with selection of certified sheet stock per ASTM D1418 (FKM) or DuPont™ specification for Viton™ B, with batch validation of Shore A hardness, tensile strength and compression set.
Cutting is performed via 3-axis CNC routing with ±0.05 mm positional accuracy for standard circular and rectangular geometries, abrasive waterjet for complex contours without thermal stress, or progressive die-cutting for high-volume repeatability to DIN 7715 tolerances.
Each gasket undergoes dimensional inspection using digital callipers and profile projectors. Critical batches include Shore A hardness verification per AQL 1.5 sampling, visual inspection for surface defects (voids, inclusions, tooling marks) and laser or pad-print traceability marking where required.
Packaging is carried out in individual heat-shrink film for delicate geometries or interleaved stacking with protective liner for high-volume gaskets, with labelling that identifies material, dimensions, production batch and applicable certifications (ASTM, FDA, ISO 9001).
Materials and formulations
| Property | Viton™ B | Generic FKM | Standard |
|---|---|---|---|
| Fluorine content | 68% | 66–68% | — |
| Shore A hardness | 70 ±5 | 70 ±5 | ASTM D2240 |
| Tensile strength | 10 MPa typical | 9–13 MPa | ASTM D412 |
| Elongation at break | 150% | 125–200% | ASTM D412 |
| Compression set (70h/200°C) | <25% | <25% | ASTM D395 |
| Fuel resistance (ASTM Oil #3) | Excellent (<10% swell) | Excellent (<10%) | ASTM D471 |
| Continuous service temperature | –20 to +200°C | –20 to +200°C | — |
| Batch traceability | DuPont™ certificate available | ASTM certificate available | — |
| Aerospace OEM certification | AMS 7276 available | Limited | AMS 7276 |
| Relative cost | Premium (+30–40%) | Standard | — |
When to specify Viton™ B
- OEM specification requiring DuPont™ trademarked compound
- Aerospace application with traceable material certificate requirement
- Critical process validation where batch-to-batch variability must be minimised
- Regulated environment (pharmaceutical, nuclear) with documented quality audits
When to specify generic FKM
- Industrial application without brand or specific certification requirement
- Cost optimisation where ASTM D1418/D2000 specification is sufficient
- Replacement of existing component with open FKM specification
- Pilot project or prototyping where sourcing flexibility is a priority
Both materials comply with ASTM D1418 (FKM), ASTM D2000, SAE J200 classification and European fluorocarbon elastomer standards. Viton™ B can additionally be certified to AMS 7276 for aerospace applications.
Available configurations
Circular gaskets
Flat annular gaskets from Ø20 mm to Ø600 mm OD, with proportional bore diameter based on required wall thickness (typically 10–40% of OD), thickness 0.5 mm to 10 mm. DIN 7715 tolerances: ±0.2 mm for Ø<100 mm, ±0.5 mm for Ø>100 mm.
Multi-port gaskets
Multi-port gaskets (4, 6, 8 or custom bolt pattern) for flanged mounting on hydraulic manifolds, heat exchangers or filter housings. Bore diameter from Ø3 mm with minimum centre-to-centre spacing of 8 mm. CNC or waterjet cut depending on complexity.
Rectangular gaskets
Rectangular and square gaskets from 20×20 mm to 500×300 mm with corner radii R2–R5 to prevent stress concentration. Thickness 0.5–10 mm with tolerance ±0.15 mm (<3 mm) or ±0.25 mm (>3 mm).
Diaphragms
Circular and rectangular diaphragms in controlled thickness 0.5–3 mm for pneumatic actuators, diaphragm valves or pressure regulation systems. Burr-free surface with flatness control <0.3 mm/100 mm.
Metal insert gaskets
Gaskets with bonded metal insert (brass, 304/316 stainless steel) for high-pressure applications (>100 bar) or assemblies where radial stiffness is critical. Metal-to-FKM adhesion validated by peel test >15 N/mm.
Die-cut components
High-volume components (>1000 pcs/year) manufactured by progressive die-cutting with dedicated tooling. Tighter tolerances (±0.1 mm) and high throughput (up to 600 parts/hour depending on geometry).
Colours
Black as standard (approx. RAL 9017), green, brown or custom RAL on request. Note: pigments may affect FDA certifications — consult prior to specifying non-standard colour.
Marking
Laser marking or pad printing with traceability code, customer part number, corporate logo or material specification (e.g. "FKM 70 ShA") available on request. Minimum marking area: 10×10 mm.
Production environment
Quality
Manufactured under ISO 9001:2015 certified quality management system with annual third-party audits. Sheet stock suppliers approved with ASTM and FDA certificates of conformity where applicable.
Environmental control
Sheet storage under controlled conditions (18–25°C, RH <60%) to prevent ozone or UV degradation. Climate-controlled cutting area for dimensional stability during precision machining.
Equipment
- 3-axis CNC router with polycrystalline diamond cutter for clean, burr-free edges, positional accuracy ±0.05 mm
- Abrasive waterjet with 80-mesh garnet, 3800 bar operating pressure, kerf width <0.8 mm for complex geometries
- 50-tonne hydraulic die press with ground hardened-steel tooling for high-volume production runs
Validation
Dimensional inspection by sampling per AQL 1.5 plan (acceptable quality level: 1.5% defective). Shore A hardness verification on every production batch. Full sheet-to-finished-part traceability via QR code.
Technical specifications
| Property | Value | Standard |
|---|---|---|
| Hardness (Shore A) | 70–80 | ASTM D2240 |
| Tensile strength | 9–13 MPa | ASTM D412 |
| Elongation at break | 125–200% | ASTM D412 |
| Tear resistance | 20–35 kN/m | ASTM D624 |
| Density | 1.85–1.95 g/cm³ | ASTM D297 |
| Continuous service temperature | –20…+200 °C | — |
| Peak temperature (short duration) | +230 °C | — |
| Compression set (70h/200°C) | <25% | ASTM D395 |
| Volume swell in ASTM Oil No. 3 (70h/150°C) | <10% | ASTM D471 |
| Flame resistance | Self-extinguishing (UL94 V-0 available) | UL94 |
| Fluorine content | 66–68% | — |
Tolerances and dimensional control
- CNC cutting
- ±0.2 mm (<100 mm) · ±0.5 mm (>100 mm)
- Waterjet cutting
- ±0.3 mm (all dimensions)
- Die-cutting
- ±0.1 mm (repetitive geometries with dedicated tooling)
- Thickness
- ±0.15 mm (<3 mm) · ±0.25 mm (>3 mm)
- Flatness
- <0.3 mm/100 mm (diaphragms and critical components)
Chemical compatibility
Excellent
- Petrol
- Diesel fuel
- Kerosene
- Mineral oils
- Synthetic oils
- Hydraulic fluids (phosphate ester, HFA, HFB, HFC)
- Aromatic solvents (toluene, xylene)
- Aliphatic solvents (hexane, heptane)
- Dilute acids (H₂SO₄ <30%, HCl <20%)
Limited
- Ketones (acetone, MEK) — moderate swelling >20%
- Aliphatic amines — progressive chemical attack
- Superheated steam (>180°C) — accelerated hydrolysis
- Glycol-based brake fluids (DOT 3/4) — reduced compatibility
- Alcohols (methanol, ethanol) — slight swelling 10–15%
Not recommended
- Concentrated acids (H₂SO₄ >70%, HNO₃ >50%)
- Strong bases (NaOH >10%, KOH >10%)
- Aromatic amines
- Chlorinated solvents (trichloroethylene, perchloroethylene)
- Polar ketones (neat acetone, neat MEK)
- Ammonia refrigerants (NH₃)
Chemical resistance guide
Indicative chemical compatibility guide for FKM/Viton™ B based on ASTM D471 immersion swell testing, accumulated industrial field data and compound manufacturer datasheets. Values represent typical behaviour at ambient temperature (23°C) under continuous exposure.
Classification based on percentage volumetric swell after 168 h immersion: Excellent (<10%), Limited (10–25%), Not recommended (>25% or visible chemical degradation)
Values are indicative — compatibility testing recommended for critical applications
Elevated temperature increases chemical aggressiveness — derate maximum temperature by 20–30°C for aggressive media
Fluid mixtures may exhibit negative synergies not predicted by individual immersion tests
Consult engineering department before specifying for unlisted fluids or extreme service conditions
ProSilicones64 accepts no liability for incorrect material selection. The customer is responsible for validating chemical compatibility under actual operating conditions prior to specifying production components.
Service limitations
Not recommended for continuous steam exposure >150°C (accelerated hydrolysis of polymer chains)
Not recommended for concentrated strong bases (NaOH >10%, KOH >10%) — progressive chemical degradation
Not recommended for chlorinated solvents (trichloroethylene, perchloroethylene) — severe swelling >40%
Not recommended for cryogenic applications (<–20°C) — loss of flexibility and embrittlement
Not recommended for aromatic amines (aniline, toluidine) — direct attack on fluorinated groups
Not recommended for concentrated acids (H₂SO₄ >70%, HNO₃ >50%) — oxidation and degradation
Not recommended for neat polar ketones (pure acetone, pure MEK) — swelling >30%
Not recommended for food-contact applications without specific validation — consult for FDA-certified formulations
Certifications
Material standards
Applications by sector
Automotive
- Fuel injector gaskets
- Fuel pump seals
- Rocker cover gaskets
- Sump and valve train seals
- Intake and turbo system gaskets
- Fuel pressure regulator diaphragms
- Oil-water heat exchanger gaskets
- Coolant and antifreeze circuit seals
- EGR (exhaust gas recirculation) system gaskets
- Variable geometry turbo (VGT) actuator diaphragms
- Fuel and oil filter gaskets
- Engine pressure and temperature sensor seals
Aerospace
- Landing gear hydraulic system gaskets
- Turbine fuel pump seals
- APU flow control valve gaskets
- Flight control surface hydraulic actuator diaphragms
- Fuel-oil heat exchanger gaskets
- Jet engine lubrication system seals
- In-flight refuelling connector gaskets
- Fuel tank and auxiliary tank seals
Oil Gas
- Crude and natural gas pipeline flange gaskets
- Wellhead valve seals
- Submersible pump housing gaskets
- Pressure regulator valve diaphragms
- Refinery heat exchanger gaskets
- Gas-liquid separation equipment seals
- Natural gas compressor gaskets
- Chemical injection system seals
Chemical
- Reactor and autoclave gaskets
- Aromatic solvent pump seals
- Process filter housing gaskets
- Chemical dosing valve diaphragms
- Corrosive fluid heat exchanger gaskets
- Mixer and agitator seals
- Chemical transfer line gaskets
- Distillation and evaporation equipment seals
Energy
- Gas turbine gaskets (lubrication systems)
- Primary and secondary circuit pump seals
- Combined-cycle heat exchanger gaskets
- Control valve hydraulic actuator diaphragms
- Genset fuel system gaskets
- Instrument air compressor seals
- Transformer cooling system gaskets (oil)
Hydraulic
- Piston pump gaskets
- Proportional and servo valve seals
- Manifold and distribution block gaskets
- Hydraulic accumulator diaphragms
- Hydraulic cylinder gaskets (end caps and chambers)
- Hydraulic motor seals
- High-pressure filter gaskets
Pharmaceutical
- Organic solvent synthesis reactor gaskets
- API (active pharmaceutical ingredient) pump seals
- Solvent filtration system gaskets
- Purification process control valve diaphragms
- Centrifuge and dryer gaskets
- CIP/SIP equipment seals with aggressive cleaning chemicals
Water treatment
- Chlorine and chemical dosing pump gaskets
- Treatment plant valve seals
- Reverse osmosis membrane gaskets
- Aeration air compressor seals
- Process chemical flow meter gaskets
Quick selection guide
- Fuel and oil resistance to +200°C
- FKM or Viton™ B gaskets
- Fuel resistance + low-temperature flexibility
- Fluorosilicone profiles (Series 13)
- Aerospace OEM certified application
- Viton™ B with traceable material certificate
- Cost optimisation without brand requirement
- Generic FKM to ASTM specification
- Chlorinated solvent or amine contact
- Consult for FFKM alternatives
- High temperature (>200°C) without oil contact
- High-temperature silicone gaskets (Series 9)
Production and delivery
- Minimum order
- Minimum order quantity dependent on reference and geometry. Contact us for bespoke requirements.
- Lead times
- Lead times variable depending on order volume and destination (UK/EU/international). Contact us for project-specific timescales.
- Customisation
- Custom RAL colour, laser marking or pad printing, bespoke packaging and technical documentation (certificates of conformity, dimensional reports, inspection protocols) available on request.
- Logistics
- UK, EU and international shipping with protective packaging. Customs documentation and transport insurance available on request.
Technical summary
FKM and Viton™ B flat gaskets and cut components deliver the superior chemical resistance required in systems exposed to fuels, oils, solvents and hydraulic fluids where conventional elastomers fail.
Fluoroelastomer sheet with 68% fluorine content ensures dimensional stability and mechanical performance under continuous exposure to aggressive media across a service temperature range of –20°C to +200°C with short-term peaks to +230°C.
Each gasket is precision-cut by CNC, waterjet or die-cutting to suit the required geometry, with batch traceability and material certification available on request for applications with documented quality requirements.
A proven technical solution for design engineers, specifiers and procurement teams requiring sealing components with extended chemical resistance and long-term in-service durability.
Complimentary technical assessment
Our engineering team evaluates fluid, temperature, pressure and geometry before recommending the optimum material and manufacturing process for your application.
- Chemical compatibility review with your process fluids
- Service temperature and working pressure validation
- Cutting process selection based on geometry and tolerances
- Viton™ B vs generic FKM recommendation based on certification requirements