Standard Dimensions
● JISB 2401 “O-rings,”
● AS 568B “Aerospace size standards for O-rings”
● JIS B 8365 “Dimensions of Clamped- type Vacuum Couplings”
Advantages of Rubber O Rings
O-ring selection is based on chemical compatibility, application temperature, sealing pressure, lubrication requirements, durometer, size and cost.
Chemical Compatibility:
- Air, 200 – 300 °F – Silicone
- Beer – EPDM
- Chlorine Water – Viton (FKM)
- Gasoline – Buna-N or Viton (FKM)
- Hydraulic Oil (Petroleum Base, Industrial) – Buna-N
- Hydraulic Oils (Synthetic Base) – Viton
- Water – EPDM
- Motor Oils – Buna-N
Service temperature and basic physical properties
Product name | Nitrile rubber | Chloroprene rubber | Ethylene-propylene rubber | Silicone rubber | Fluorine rubber FA | Fluorine rubber FB | |
Material symbol | NBR | CR | EP | SI | FA | FB | |
Features | Mineral oil-resistant | Weather-resistant and oil-resistant | Weather-resistant and water-resistant | Heat-resistant | Heat-resistant | Acid-resistant and vapor-resistant | |
JIS class | Class 1A | ─ | Class 3 | Class 4C | Class 4D | ─ | |
Color tone | Black | Black | Black | Reddish brown | Black | Black | |
Service temperature range (rough guide)[℃] | -30~120 | -30~120 | -40~150 | -50~200 | -15~200 | 0~200 | |
Physical properties in normal state |
Hardness measured using a type A durometer | 73 | 70 | 71 | 72 | 70 | 70 |
Tensile strength [Mpa] | 16.1 | 11.0 | 14.8 | 6.8 | 13.6 | 23.9 | |
Elongation [%] | 270 | 270 | 250 | 200 | 240 | 320 | |
Tensile stress [at 100% elongation] | 4.2 | ─ | 4.6 | 2.4 | 4.5 | 3.1 | |
Compression permanent deformation | Temperature × Time[℃]×[hrs] | 120×70 | 100×70 | 100×70 | 175×22 | 175×22 | 175×22 |
Compression permanent deformation[%] | 20 | 31 | 9 | 20 | 8 | 20 | |
Aging resistance |
Temperature × Time[℃]×[hrs] | 120×70 | 100×70 | 100×70 | 230×24 | 230×24 | 230×24 |
Change of hardness measured using a type A durometer | +1 | +9 | 0 | +4 | +2 | 0 | |
Tensile strength rate of change[%] | +6.5 | +16.3 | +6.6 | -5.9 | +12.5 | -13 | |
Elongation rate of change[%] | -25.9 | -35 | 0 | 0 | -16.6 | -6 |