For o-ring seal in PTFE, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for PTFE (polytetrafluoroethylene (thermoplastic, not an elastomer)) is summarized below together with every size supplied.
Why Choose PTFE for O-Ring Seal — ISO / DIN (Series 160)
Chosen for chemical service and low friction rather than for elastic sealing. For o-ring seal — iso / din (series 160), 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 |
Corrosion Behavior in Service
Carbon and alloy steel o-ring seal — iso / din (series 160) 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 o-ring seal — iso / din (series 160) 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.
Sizes of O-Ring Seal — ISO / DIN (Series 160) Available in PTFE
| Inner diameter d1 (mm) | Outer diameter d2 (mm) | Wire dia (mm) | Material | Working temp range | Reference standard |
|---|---|---|---|---|---|
| 5 | 9 | 2 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 8 | 12 | 2 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 10 | 16 | 3 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 15 | 21 | 3 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 20 | 26 | 3 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 25 | 33 | 4 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 30 | 38 | 4 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 40 | 50 | 5 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 50 | 60 | 5 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 60 | 72 | 6 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 80 | 92 | 6 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
| 100 | 114 | 7 | NBR 70 | -30 to +110 C | ISO 3601 / GB/T 3452 |
