SEAL SPECIFICATION GUIDE
SEAL SPECIFICATION GUIDE
SEAL SPECIFICATION GUIDE
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MATERIAL SELECTION<br />
General Elastomer Information<br />
BASE POLYMER NITRILE POLYACRYLATE SILICONE FLUOROELASTOMER<br />
TEMPERATURE* -50˚F ~ 250˚F -20˚F ~ 300˚F -80˚F ~ 400˚F -30˚F ~ 400˚F<br />
RANGE -45˚C ~ 125˚C -30˚C ~ 150˚C -60˚C ~ 200˚C -35˚C ~ 200˚C<br />
Oil Resistance l l n l<br />
Acid Resistance n s s s<br />
Alkali Resistance n v v s<br />
Water Resistance n s n n<br />
Heat Resistance n l l l<br />
Cold Resistance n s n s<br />
Wear Resistance l l n l<br />
Ozone Resistance n l l l<br />
lVery good n Good for most applications s Fair, can be used if no other materials available but otherwise not recommended v Not recommended<br />
MATERIALS ADVANTAGES DISADVANTAGES<br />
NITRILE • Commonly referred to as Buna-N and a • Poor resistance to ozone and weather aging<br />
S Copolymerof Butadiene and Acryonitrile<br />
• Low cost<br />
• Good resistance to petroleum oils, water,<br />
silicone oils,greases, glycol base fluids<br />
• Good abrasion resistance, cold flow, tear<br />
resistance<br />
POLYACRYLATE • Polymerised acrylic acidesters • Fair cold temperature limit<br />
N • Good resistance to mineral oils, hypoid gear oils, • Lower mechanical strength<br />
E.P. additives, greases, aging and flex cracking • Costs slightly higher than Nitrile<br />
• Higher temperature limit than Nitrile • Poor dry running ability, water resistant<br />
SILICONE • Broad temperature range • Low resistance to hydrocarbon fluids like<br />
H • Good ozone resistance gasoline or paraffin fluids or steam above 50 psi<br />
• Resistant to compression set • Cost is higher than Polyacrylate<br />
FLUOROELASTOMER • Good temperature resistance • Fair resistance to water, dry running<br />
V • Compatible with wide range of fluids • Low temperature resistance is fair<br />
• Commonly chosen as high temperature<br />
replacement for Nitrile or Polyacrylate<br />
• Cost is high<br />
ETHYLENE ACRYLIC • Good resistance to lubricating oils, greases, • Poor steam resistance<br />
(Vamac ® ) transmission fluids, power steering fluids and • Fair cold temperature limit<br />
E diesel fuel<br />
• Higher temperature limit than NBR<br />
• High/Consistent vibration damping capability<br />
• Cost is higher than NBR<br />
FKM & ACM BLEND • Better fluids resistance than ACM • Cost is higher than ACM<br />
X • Better high temperature performance than ACM • Properties tend to be closer to ACM<br />
than FKM<br />
FKM & VMQ BLEND • Better low temperature properties than FKM • Cost is higher than VMQ<br />
Y • Better oil resistance than VMQ • Properties tend to be closer to VMQ than<br />
FKM<br />
Felt (F) - Adequate seal for heavier lubricants, commonly used as a wiper seal.<br />
Urethane (U) - Good lubricant resistance, good ozone resistance, good abrasion resistance<br />
Tetrafluoro-Ethylene Propylene (Aflas ® ) (A) - Compatible with range of hydraulic fluids, fair abrasion resistance<br />
P.T.F.E. (Teflon ® ) (T) - Low friction properties, good heat and chemical resistance<br />
TEFLON ® , VAMAC ® and VITRON ® are registered trademarks of E.I. Dupont.<br />
AFLAS ® is a registered trademark of the 3M Company.<br />
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