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

EPDM Metric O-Rings (ISO 3601)

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

EPDM Metric O-Rings (ISO 3601) are supplied to ethylene-propylene-diene rubber, typically 70 Shore A. Corrosion behaviour is excellent in water, steam, brake fluid and weathering; unsuitable for mineral oil, the material is non-magnetic, and the usable service range is approx. -45 °C to +150 °C. In practice this grade is the water, steam and outdoor-weathering elastomer.

Grade
ethylene-propylene-diene rubber, typically 70 Shore A
Corrosion resistance
Excellent in water, steam, brake fluid and weathering; unsuitable for mineral oil
Magnetic response
Non-magnetic
Service temperature
approx. -45 °C to +150 °C

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

EPDM Metric O-Rings (ISO 3601) reference image

For metric o-rings (iso 3601) in EPDM, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for EPDM (ethylene-propylene-diene rubber, typically 70 Shore A) is summarized below together with every size supplied.

Why Choose EPDM for Metric O-Rings (ISO 3601)

The water, steam and outdoor-weathering elastomer. For metric o-rings (iso 3601), this matters when excellent in water, steam, brake fluid and weathering; unsuitable for mineral oil is the primary requirement.

Mechanical & Physical Properties

Grade designationethylene-propylene-diene rubber, typically 70 Shore A
Magnetic responseNon-magnetic
Service temperatureapprox. -45 °C to +150 °C
Corrosion characteristicExcellent in water, steam, brake fluid and weathering; unsuitable for mineral oil

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.

Galvanic & Galling Considerations

Galvanic and galling behavior do not apply to metric o-rings (iso 3601) in EPDM — the relevant compatibility questions are chemical: confirm the elastomer against the fluid, the temperature and any cleaning agents in service, and check the gland or groove dimensions give the intended compression on the section.

Sizes of Metric O-Rings (ISO 3601) Available in EPDM

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

Dimensions are independent of the material: every size above is available in EPDM.

Custom manufacturing · Made to drawing

Need this seal in a grade that is not listed?

Epdm is one of the grades the catalog describes. A special seal is almost always a compound change rather than a size change — the same dimensions in a material that survives the medium.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

Custom seal manufacturingSend a drawing

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.

Dimensioned line drawing of 1.0 Metric O-Rings (ISO 3601) to ISO 3601-1 (fluid power — O-rings, inside diameters and cross-sections). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.
Typical inside-diameter range (mm)
1.0 – 20
Common compounds
NBR, FKM, EPDM, silicone
Notes
miniature and pneumatic
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 – 20NBR, FKM, EPDM, siliconeminiature and pneumatic
1.52.0 – 40NBR, FKM, EPDM, siliconesmall pneumatic and instrument
1.781.78 – 50NBR, FKM, EPDMnearest metric equivalent to the 1/16 in section
2.03.0 – 100NBR, FKM, EPDM, siliconegeneral hydraulic and pneumatic
2.55.0 – 150NBR, FKM, EPDMgeneral hydraulic
3.06.0 – 200NBR, FKM, EPDMgeneral hydraulic
3.510 – 250NBR, FKMhydraulic
4.012 – 300NBR, FKMhydraulic and larger flanges
5.020 – 400NBR, FKMlarge flanges and covers
5.3320 – 400NBR, FKMnearest metric equivalent to the 3/16 in section
6.025 – 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

Video: EPDM Metric O-Rings (ISO 3601)

Third-party video, selected automatically for this topic. It is not produced by Engineering Hardware and is not a specification source — use the tables on this page for dimensional data.

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

Does EPDM have a shelf life?

Yes. Elastomers age in storage as well as in service — keep them cool, dark, dry and away from ozone sources such as electric motors, and use stock in the order it arrived. PTFE is the exception and does not age this way.

How much compression should EPDM metric o-rings (iso 3601) see?

The groove or gland decides it, not the seal: a static radial seal is normally designed for roughly 15–30% compression on the section, and a dynamic one for less. Give us the groove dimensions and the pressure and we will confirm the section against them.

What's the service temperature limit for EPDM?

The practical service range is approx. -45 °C to +150 °C.

Are EPDM Metric O-Rings (ISO 3601) magnetic?

EPDM Metric O-Rings (ISO 3601) are non-magnetic.

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.