PTFE Metric O-Rings (ISO 3601) combine the dimensional form of ISO 3601-1 (fluid power — O-rings, inside diameters and cross-sections) with the material properties of grade polytetrafluoroethylene (thermoplastic, not an elastomer): near-universal chemical resistance; no elastic recovery, so it is used as a back-up or energised seal, non-magnetic, service range approx. -200 °C to +260 °C. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose PTFE for Metric O-Rings (ISO 3601)
Chosen for chemical service and low friction rather than for elastic sealing. For metric o-rings (iso 3601), this matters when near-universal chemical resistance; no elastic recovery, so it is used as a back-up or energised seal is the primary requirement.
Mechanical & Physical Properties
| Grade designation | polytetrafluoroethylene (thermoplastic, not an elastomer) |
|---|---|
| Magnetic response | Non-magnetic |
| Service temperature | approx. -200 °C to +260 °C |
| Corrosion characteristic | Near-universal chemical resistance; no elastic recovery, so it is used as a back-up or energised seal |
Galvanic & Galling Considerations
Galvanic and galling behavior do not apply to metric o-rings (iso 3601) in PTFE — 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.
Comparable Grades
For metric o-rings (iso 3601), consider an energised or spring-loaded PTFE seal where recovery is required, or FKM where the chemistry allows an elastomer. 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 PTFE
| Cross-section (mm) | Typical inside-diameter range (mm) | Common compounds | Notes |
|---|---|---|---|
| 1.0 | 1.0 – 20 | NBR, FKM, EPDM, silicone | miniature and pneumatic |
| 1.5 | 2.0 – 40 | NBR, FKM, EPDM, silicone | small pneumatic and instrument |
| 1.78 | 1.78 – 50 | NBR, FKM, EPDM | nearest metric equivalent to the 1/16 in section |
| 2.0 | 3.0 – 100 | NBR, FKM, EPDM, silicone | general hydraulic and pneumatic |
| 2.5 | 5.0 – 150 | NBR, FKM, EPDM | general hydraulic |
| 3.0 | 6.0 – 200 | NBR, FKM, EPDM | general hydraulic |
| 3.5 | 10 – 250 | NBR, FKM | hydraulic |
| 4.0 | 12 – 300 | NBR, FKM | hydraulic and larger flanges |
| 5.0 | 20 – 400 | NBR, FKM | large flanges and covers |
| 5.33 | 20 – 400 | NBR, FKM | nearest metric equivalent to the 3/16 in section |
| 6.0 | 25 – 500 | NBR, FKM | large covers and housings |
Dimensions are independent of the material: every size above is available in PTFE.
Custom manufacturing · Made to drawing
Need this seal in a grade that is not listed?
Ptfe 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.
