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.

RUBBER O RINGS Chemical Comptatibility

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