For o-ring seal 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 O-Ring Seal — ISO / DIN (Series 159)
The water, steam and outdoor-weathering elastomer. For o-ring seal — iso / din (series 159), this matters when excellent in water, steam, brake fluid and weathering; unsuitable for mineral oil is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ethylene-propylene-diene rubber, typically 70 Shore A |
|---|---|
| Magnetic response | Non-magnetic |
| Service temperature | approx. -45 °C to +150 °C |
| Corrosion characteristic | Excellent in water, steam, brake fluid and weathering; unsuitable for mineral oil |
Corrosion Behavior in Service
Carbon and alloy steel o-ring seal — iso / din (series 159) 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 159) 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 O-Ring Seal — ISO / DIN (Series 159) Available in EPDM
| 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 |


