FKM O Ring

Wholesale FKM O-Rings Manufacturer & Factory

Direct factory supply of premium fluoroelastomer seals engineered for demanding industrial environments. We manufacture standard and custom FKM O-rings with stable chemical resistance, high temperature performance, and consistent dimensional accuracy for global OEM customers.

Premium Compound: 100% virgin material available from 50 to 90 Shore A with FDA, RoHS and REACH compliant options.

Extreme Endurance: Designed for operating temperatures from −45°C to +300°C with excellent resistance to fuels, oils and chemicals.

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Working Temperature

−45°C to +300°C

Hardness Range

50 Shore A – 90 Shore A

Certifications

FDA • RoHS • REACH

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Product Overview

Industrial fluid systems working under high temperatures and harsh chemicals need reliable seals. FKM (Fluorocarbon Elastomer) O-rings are designed for static and dynamic uses exposed to acids, fuels, oils, and temperatures up to 250°C.

Product Types

Standard AS568 and Metric O-Rings: Molded to international sizes including AS568 (USA), ISO 3601, and JIS B 2401, fitting standard groove dimensions.

Custom Molded O-Rings: Made for special housing designs, with non-standard inner diameters (ID) and cross-sections (CS) built using custom tooling to match your CAD drawings.

Square and Rectangular Rings: Cut or molded shapes used in static flange joints where higher resistance to extrusion is needed compared to round profiles.

Bonded and Spliced Seals: Extruded cord stock joined by vulcanization for large equipment maintenance where standard molds are too costly.

Metal-Inserted Seals: Elastomer bonded to metal parts for specialized automotive and hydraulic manifold blocks.

Materials and Performance

FKM seal performance depends on the polymer type, fluorine content (66% to 70% plus), and the curing system used. We provide four main material types:

Type 1 (Bisphenol Cured / General Purpose): Standard copolymer (similar to Viton A) with about 66% fluorine. Good resistance to general fuels and mineral oils. Working range: -20°C to +200°C.

Type 2 and 3 (Low Temperature / Terpolymers): Terpolymers (similar to Viton B and F) with 68% to 70% fluorine. Better resistance to broader chemicals and polar fluids. Working range: -30°C to +200°C.

Peroxide-Cured FKM (GLT and GFLT series): Cured with organic peroxides. Offers high resistance to amine lubricants, steam, sour gas (H2S), and polar solvents, with low-temperature flexibility down to -40°C.

FEPM (AFLAS type): Special elastomer with high resistance to steam, hot water, phosphate esters, and strong alkaline liquids where standard FKM fails.

Performance Comparison

Material Grade	Fluorine Content (%)	Curing System	Low Temp Limit (C)	High Temp Limit (C)	Key Fluid Resistance
FKM Copolymer	~66%	Bisphenol	-20°C	+200°C	Fuels, mineral oils, aliphatic hydrocarbons
FKM Terpolymer	~68 to 70%	Bisphenol	-15°C	+200°C	Broad chemicals, aromatic hydrocarbons
Peroxide FKM	~67 to 70%	Peroxide	-40°C	+220°C	Acids, steam, amines, sour oil and gas
FEPM	N/A	Peroxide	-10°C	+200°C	Steam, strong bases, sour fluids

Technical Specifications

Parameter	Specification	Test Standard / Note
Hardness Range	60 to 90 Shore A	Plus or minus 5 tolerance; ASTM D2240
Tensile Strength	12.0 to 18.0 MPa minimum	ASTM D412
Elongation at Break	150% to 300%	Depending on hardness and filler type
Compression Set	25% to 35% maximum at 200 °C for 72 h	ASTM D395 Method B
Specific Gravity	1.80 to 2.15 g/cm3	Depending on compound formula
Dimensional Tolerances	ISO 3601-1 Grade S (Precision); RMA A2/A3	According to applicable size and tolerance requirements

Applications

Oil and Gas: Downhole tools, wellhead valves, and mud pumps exposed to high-pressure sour crude and chemicals.

Automotive and Heavy Duty: Fuel injection systems, diesel particulate filter lines, turbocharger oil seals, and transmission valves.

Chemical Processing: Mechanical seals, valve seats, chemical pumps, and pipe flange gaskets handling strong acids and solvents.

Aerospace: Hydraulic actuators, fuel systems, and auxiliary power unit interface seals.

Vacuum Equipment: Vacuum chamber fittings and process equipment gaskets with low outgassing under heat.

How to Select FKM O-Rings

Check Chemical Exposure

List all liquids, cleaners, and chemicals touching the seal. Match them with the correct fluorine content and curing system.

Determine Temperature Limits

Check both continuous working temperature and peak heat spikes. High heat past the limit will harden the rubber and cause permanent set deformation.

Calculate Groove Size

Follow standard gland design tables to get the recommended squeeze percentage (15% to 30%) and fill volume (70% to 85%).

Choose Shore A Hardness

Use 75 Shore A for general static and dynamic seals for easy fitting. Use 90 Shore A for high-pressure systems to prevent seal extrusion into metal gaps.

Verify Compliance Standards

Confirm if regulations like FDA 21 CFR 177.2600, REACH, RoHS, or NACE MR0175 are required for your market.

Manufacturing and Quality Control

Our factory uses internal batch mixing, vacuum compression molding, and post-cure ovens to build stable rubber parts.

Compound Batching

Raw polymers and fillers are mixed in internal machines with digital weight controls.

Molding and Curing

Multi-cavity molds on hydraulic presses ensure clean edges and uniform density. Post-curing removes excess gas and improves heat resistance.

Dimensional Inspection

Optical scanners and vision systems check parts for size errors and surface flaws.

Lab Testing

In-house labs test physical properties per ASTM standards, including hardness, tensile strength, weight, and fluid swelling.

Custom and OEM Manufacturing

We support custom manufacturing based on your technical drawings, 3D CAD files (STEP or IGES), or sample parts.

Compound Adjustments

Formulas can be adjusted for special needs, such as low-temperature flexibility or custom color coding.

Tooling Development

In-house mold making allows fast samples and trial runs within 7 to 10 business days.

OEM Services

Custom packaging, barcode labeling, lot numbers printed on bags, and vendor-managed inventory agreements.

Packaging and Delivery

Packaging

O-rings are packed in sealed anti-static plastic bags sorted by size to prevent sticking or damage during shipping. Each bag shows batch numbers, material grades, dimensions, and production dates.

Global Shipping

Packed in double-wall cardboard boxes or fumigation-free wooden pallets with moisture barriers. We work with reliable international courier and freight forwarders for air and ocean shipping.

Our Certifications

FAQ

Q: What is the difference between Bisphenol-cured and Peroxide-cured FKM?

A: Bisphenol-cured FKM is standard for general fuel and oil uses with easy processing. Peroxide-cured FKM offers better resistance to polar solvents, steam, acids, and amine lubricants, plus better high-temperature compression set performance.

Q: Should I choose 75 Shore A or 90 Shore A hardness?

A: 75 Shore A is standard for general sealing and fits groove surfaces easily under moderate pressure. 90 Shore A is chosen for high-pressure hydraulic systems above 15 MPa to stop the seal from pushing into the clearance gap.

Q: What quality documents come with shipments?

A: Every shipment includes a Material Test Report (MTR) showing lot test results for hardness, tensile strength, elongation, and specific gravity, giving full trace history back to raw polymer batches.

Q: Can you make O-rings in non-standard sizes without high mold costs?

A: We first check our existing mold inventory. If a new mold is needed, our in-house tooling team makes custom mold plates quickly to lower setup costs for OEM clients.

Q: What is the shelf life of FKM O-rings in storage?

A: FKM rubber resists ozone and weathering very well. When stored in cool, dark, and dry rooms away from direct sunlight per ISO 2230 guidelines, FKM O-rings stay usable for over 10 to 15 years.

Q: Are your FKM compounds compliant with FDA standards for food contact?

A: We formulate specific white and black FKM compounds that meet FDA 21 CFR 177.2600 standards for rubber parts used repeatedly in food processing machinery. Please request compliance letters before ordering.

Q: How does extreme heat affect FKM O-ring lifespan?

A: Working near the maximum limit of 200°C to 250°C for a long time breaks down the rubber structure, causing hardening and loss of elasticity. For continuous high heat, use a high-fluorine terpolymer or peroxide-cured grade.

Q: What file types do you accept for custom seal inquiries?

A: We accept 2D PDF technical drawings with clear dimensions, and 3D CAD files including STEP, IGES, and SolidWorks formats for engineering review and mold design.

As one of the most professional fkm o ring manufacturers and suppliers in China, we offer a wide range of products with superior quality. Please feel free to wholesale high quality fkm o ring made in China here from our factory. Also, custom service is available.

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