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Seals · ISO 3601-1 (fluid power — O-rings, inside diameters and cross-sections)

FKM (Viton®-type) Metric O-Rings (ISO 3601)

Temperature range, chemical and fluid compatibility, hardness and the full dimensional range for this compound.

FKM (Viton®-type) Metric O-Rings (ISO 3601) are supplied to fluoroelastomer, typically 75 Shore A. Corrosion behaviour is excellent resistance to heat, fuels, and most chemicals; poor with ketones and hot water/steam, the material is non-magnetic, and the usable service range is approx. -20 °C to +200 °C. In practice this grade is specified where temperature or chemical exposure exceeds nitrile.

Grade
fluoroelastomer, typically 75 Shore A
Corrosion resistance
Excellent resistance to heat, fuels, and most chemicals; poor with ketones and hot water/steam
Magnetic response
Non-magnetic
Service temperature
approx. -20 °C to +200 °C

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

FKM (Viton®-type) Metric O-Rings (ISO 3601) reference image

Metric O-Rings (ISO 3601) manufactured in FKM (Viton®-type) (fluoroelastomer, typically 75 Shore A) are dimensioned to ISO 3601-1 (fluid power — O-rings, inside diameters and cross-sections). The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.

Why Choose FKM (Viton®-type) for Metric O-Rings (ISO 3601)

Specified where temperature or chemical exposure exceeds nitrile. For metric o-rings (iso 3601), this matters when excellent resistance to heat, fuels, and most chemicals; poor with ketones and hot water/steam is the primary requirement.

Mechanical & Physical Properties

Grade designationfluoroelastomer, typically 75 Shore A
Magnetic responseNon-magnetic
Service temperatureapprox. -20 °C to +200 °C
Corrosion characteristicExcellent resistance to heat, fuels, and most chemicals; poor with ketones and hot water/steam

Corrosion Behavior in Service

Carbon and alloy steel metric o-rings (iso 3601) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.

Comparable Grades

For metric o-rings (iso 3601), consider NBR where the service is ordinary mineral oil and the cost matters, or EPDM for hot water and steam, which attacks FKM. Elastomer selection is decided by the medium, the temperature range and whether the seal is static or dynamic — not by strength.

Sizes of Metric O-Rings (ISO 3601) Available in FKM (Viton®-type)

Cross-section (mm)Typical inside-diameter range (mm)Common compoundsNotes
1.01.0 u2013 20NBR, FKM, EPDM, siliconeminiature and pneumatic
1.52.0 u2013 40NBR, FKM, EPDM, siliconesmall pneumatic and instrument
1.781.78 u2013 50NBR, FKM, EPDMnearest metric equivalent to the 1/16 in section
2.03.0 u2013 100NBR, FKM, EPDM, siliconegeneral hydraulic and pneumatic
2.55.0 u2013 150NBR, FKM, EPDMgeneral hydraulic
3.06.0 u2013 200NBR, FKM, EPDMgeneral hydraulic
3.510 u2013 250NBR, FKMhydraulic
4.012 u2013 300NBR, FKMhydraulic and larger flanges
5.020 u2013 400NBR, FKMlarge flanges and covers
5.3320 u2013 400NBR, FKMnearest metric equivalent to the 3/16 in section
6.025 u2013 500NBR, FKMlarge covers and housings

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (ISO 3601-1 (fluid power — O-rings, inside diameters and cross-sections))

Cross-section (mm)Typical inside-diameter range (mm)Common compoundsNotes
1.01.0 u2013 20NBR, FKM, EPDM, siliconeminiature and pneumatic
1.52.0 u2013 40NBR, FKM, EPDM, siliconesmall pneumatic and instrument
1.781.78 u2013 50NBR, FKM, EPDMnearest metric equivalent to the 1/16 in section
2.03.0 u2013 100NBR, FKM, EPDM, siliconegeneral hydraulic and pneumatic
2.55.0 u2013 150NBR, FKM, EPDMgeneral hydraulic
3.06.0 u2013 200NBR, FKM, EPDMgeneral hydraulic
3.510 u2013 250NBR, FKMhydraulic
4.012 u2013 300NBR, FKMhydraulic and larger flanges
5.020 u2013 400NBR, FKMlarge flanges and covers
5.3320 u2013 400NBR, FKMnearest metric equivalent to the 3/16 in section
6.025 u2013 500NBR, FKMlarge covers and housings

Applications & Industries

Where Metric O-Rings are used, and what decides the specification in each case. Stocked from 1.0 to 6.0 (inside diameter).

Industries that specify Metric O-Rings

  • Hydraulics Port, cover and piston seals.
  • Pneumatics Cylinder and valve seals.
  • Food and beverage EPDM and silicone compounds.
  • Chemical plant FKM for aggressive media.
  • Hydraulics & pneumatics Static and dynamic sealing in cylinders and valve bodies.
  • Process & food equipment Sealing at joints that are cleaned and inspected.

Typical applications

  • specifying inside diameter, cross-section and compound together
  • matching the compound to the fluid and the temperature
  • checking the groove dimensions give the right squeeze
  • using a back-up ring at high pressure
  • sealing a joint against fluid or air pressure
  • excluding dust and moisture from a housing

Service conditions to specify against

Sealed joints
Used where the fixing has to keep water or air out as well as hold — the elastomer, not the fastener, decides service life.

Where to use something else

  • Do not substitute an NBR ring for an FKM one because the dimensions match; the size fits and the compound fails, which looks like a leak with no cause.

Full application guide: where Metric O-Rings are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

What's the service temperature limit for FKM (Viton®-type)?

The practical service range is approx. -20 °C to +200 °C.

Can FKM (Viton®-type) replace stainless steel structurally?

No — stainless A2/A4 cannot match class 10.9 / 12.9 strength. Stainless is selected for corrosion, not raw strength.

Are FKM (Viton®-type) Metric O-Rings (ISO 3601) magnetic?

FKM (Viton®-type) Metric O-Rings (ISO 3601) are non-magnetic.

What corrosion resistance do FKM (Viton®-type) Metric O-Rings (ISO 3601) offer?

FKM (Viton®-type) Metric O-Rings (ISO 3601) provide excellent resistance to heat, fuels, and most chemicals; poor with ketones and hot water/steam with a service range of approx. -20 °C to +200 °C.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.