Table of Properties - O-Rings

  Nomenclature
Nitrile
(Buna N)
Silicone Fluorocarbon
(Viton, Fluorel)
Fluorosilicone Ethylene-
Propylene
ASTM D2000 Prefix

BG, BK, CH

FG, FE, GE

HK

FK

CA

ASTM D1418 Designation

NBR

PVMO, VMO

FKM

FYMO

EPDM, EPM

Properties
Compression set resistance Very Good Excellent Very Good Very Good Very Good
Continuous high temp. limit 250°F, 121°C 450°F, 232°C 400°F, 204°C 400°F, 204°C 300°F, 149°C
Dyanmic service/abrasion resistance Excellent Poor Very Good Poor Very Good
Hardness range, "A" scale 40-90 40-80 70-90C 60-80 50-90
Low temp. capability -40°F, -40°C -75°F, -59.5°C -20°F, -29°C -75°F, -59.5°C -70°F, -57°C
Relative o-ring cost Low

Moderate

Moderate/High High Low
Fluid Compatability Summary
Acid, inorganic Fair Good Excellent Good Good
Acid, organic Good Excellent Good Good Very Good
Aging (oxygen, ozone, weather) Fair/Poor Excellent Very Good Excellent Very Good
Air Fair Excellent Very Good Very Good Very Good
Alcohols Very Good Very Good Fair Very Good Excellent
Aldehydes Fair/Poor Good Poor Poor Very Good
Alkalis Fair/Good Very Good Good Good Excellent
Amines Poor Good Poor Poor Very Good
Animal oils Excellent Good Very Good Excellent Good
Esters, Alkyl Phosphate (Skydrol) Poor Good Poor Fair/Poor Excellent
Esters, Aryl Phosphate Fair/Poor Good Excellent Very Good Excellent
Esters, Silicate Good Poor Excellent Very Good Poor
Ethers Poor Poor Poor Fair Fair
Gasoline Poor Poor Good Good Poor
Hydrocarbon fuels, Aliphatic Excellent Fair Excellent Excellent Poor
Hydrocarbon fuels, Aromatic Good Poor Excellent Very Good Poor
Hydorcarbon fuels, Halogenated Fair/Poor Poor Excellent Very Good Poor

Hydrocarbon oils, High Aniline

Excellent

Very Good Excellent Excellent Poor
Hydrocarbon oils, Low Aniline Very Good Fair Excellent Very Good Poor
Impermeability to gases Good Poor Very Good Poor Good
Ketones Poor Poor Poor Fair/Poor Excellent
Silicone oils Excellent Good Excellent Excellent Excellent
Vegetable oils Excellent Excellent Excellent Excellent Good
Water/steam Good Fair Fair Fair Excellent
 
Material Advantages Disadvantages
Nitrile (Buna)(NBR)
Nitrile is the most widel used elastomer for general purpose sealing. Nitrile has excellent resistance to petroleum products and is superior to most elastomers with regard to compression set (cold flow), tear and abrasion resistance.
•Excellent general sealing characteristics
•Excellent resistance to petroleum oils and fluids
•Good cold water resistance
•Can service a wide variety of temps.
•Low Cost
•Poor weather resistance
•Poor resistance to ozone
•Moderate heat resistance
•Poor resistance to strong acids
Silicone Rubber (Si)
Silicone possesses excellent resistance to temperature extremes. Silicone's retention of it's properties at extremely high temperatures is superior to other eleastic materials.
•Excellent high/low temp resistance
•Excellent resistance to dry heat
•Excellent compression set (cold flow) resistance
•Poor physical strength
•Poor resistance to petroleum products
•Poor dynamic sealing
Fluorocarbon Rubber (Viton)(FKM)
Fluorocarbon rubber is recommended for seal use in aircraft, automobile and other mechanical devices requiring maximum resistance to elevated temperature and to a wide variety of function fluids.
•Excellent resistance to petroleum products
•Excellent resistance to organic acids
•Excellent high temp. resistance
•Good compression set resistance
•Moderately low temperature resistance
•High cost
Fluorosilicone (FSi)
Fluorosilicone combines the good high and low temperatures of silicone with basic fuel and oil resistance. Its primary use is in high temperature fuel systems or where the dry heat resistance of silicone is required.

•Good heat resistance
•Good resistance to petroleum products
•Good low temp. resistance

•Poor physical strength ans abrasion resistance
•High cost

Ethylene-Propylene (EP)
Ethylene-Propylene is very effective in break systems and for sealing hot water and steam. Etylene-Propylene performs in a wide temperature range and is ver weather resistant.
•Excellent weather resistance
•Good hig/low temp. resistance
•Good abrasion resistance
•Relatively low cost
•Good chemical resistance
•Poor resistance to petroleum products

This data has been obtained from numerous sources. While it is believed to be correct, we cannot assume responsibility for its use

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