O-Ring Material Selection Guide

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

HPU

Polyurethane

Also referred to as:

Urethane, HPU, PUR

95

N/A

Honey

(could also be Natural Milky White or Red Coloured)

-30 to 110°C

-22 to 230°F

Use in: Hydraulic cylinders as rod seals and piston seals.  This material is most commonly used as hydraulic u-cups, rod wipers and packings.

Description:  This is a high performance material with improved resistance to hot water (up to 200°F) makes it ideally suited for mining applications where water based hydraulic fluids are being used.  Can be used for pressures to 6000psi.  It is excellent in oil based hydraulic fluids.  Great abrasion resistance.  Resistant to most oils, fuels and gases.  Can be used successfully as a drive belt of various shapes.

Characteristics:  Plastic-like.  Shiny surface finish.  Difficult to stretch.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

NBR

Nitrile Rubber

Also referred to as:

NBR, Buna-N, Buna

85

70

70FDA

70NSF

90

Black

-30 to 100°C

-22 to 210°F

Use in: Pneumatic seals, O-Rings, oil seal lips, gaskets, washers and low pressure hydraulic seals.  Can be used with a back-up ring in higher pressure applications.  This is the most popular O-Ring material.

Description:  General purpose elastomer for use as seal energizer or low pressure applications such as hydraulics and pneumatics.  Resistant to oils, hydraulic fluids, water fuels and gases.  Not suited for use in brake fluids.  Good abrasion resistance.  Good resistance to compression set.  High tensile strength.

Characteristics:  Rubber-like elastomer.  Dull, matte finish.  Some NBR O-Rings have a very shiny surface.

HNBR Hydrogenated Nitrile O-Ring 

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

HNBR

Highly Saturated

Nitrile Rubber

Also referred to as:

HNBR, Hydrogenated Nitrile

Hydrogenated NBR

Hydrogenated

Buna-N

85

70

90

Black

-25 to 150°C

-13 to 300°F

Use in: Seal and gasket application requiring additional resistance to chemicals and slightly higher temperatures than can be handled with NBR.  O-Rings, washers, rod and piston seals, back-up rings and gaskets.

Description:  HBNR is achieved by hydrogenated NBR.  Greatly improved wear and extrusion resistance over standard NBR.  Good chemical compatibility and can be used with oils which have aggressive additives.  Has an extended high temperature range

Characteristics:  Rubber-like elastomer.  Dull finish.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

VIT

Fluroelastomer

- Viton® -

Also referred to as:

VIT, Viton®, FKM, Flurocarbon

85

75

90

Black

(could also be Brown, Green - molded O-Rings)

-20 to 200°C

-4 to 392°F

Use in: Tough sealing applications requiring extreme chemical resistance.  O-Rings, Hydraulic seals.  Pneumatic seals.

Description:  An excellent elastomer for use in high temperature applications.  Also exhibits excellent chemical resistance for use in harsh environments such as phosphate esters.  Widely used in applications dealing with extreme temperature and/or extreme chemicals.  It is suitable to use with all chemicals (exception - Skydrol, certain esters and ethers) makes it a popular elastomer in chemical processing, paper/pulp mills, various chemical, acid and solvent applications.

Characteristics:  Rubber-like elastomer.  Noticeably heavier than NBR.  Dull, Non-Glossy finish.  Smells like cinnamon.

EPDM O-Ring  

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

EPD

EPDM Rubber

Also referred to as:

EPD, EPR, EP,

Ethylene Propylene

85

70

Black

-45 to 150°C

-49 to 300°F

Use in: Sealing lips of special oil seals, u-cups, wiper rings, O-Rings, gaskets, washers and rollers.

Description:  For use in high temperature water, steam and brake fluids.  This elastomer must not come in contact with mineral oils or grease.  It is used in applications that deal with acids, weak alkalis.  EPD is sometimes an acceptable FDA material.

Characteristics:  Rubber-like elastomer.  Strong rubber smell.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

TFES

Teflon®

Encapsulated

Silicone Core

Also referred to as:

Teflex® Encapsulated Silicone O-Rings,

PTFE Encapsulated Silicone O-Rings,

PTFE-FEP Encapsulated Silicone O-Rings

N/A

70

(core)

Orange

with

opaque

shell

-40 to 205°C

-75 to 401°F

Use in: To improve O-Ring performance in difficult applications where silicone       O-Rings alone fail.

Description:

 Teflon® Encapsulated

TFES are produced using a thin PTFE shielded tubing fully encasing a silicone rubber core.  The outer jacket protects the resilient silicone core from fluids the O-Ring contacts.

Characteristics:  Semi-rigid PTFE-FEP tubing fully encapsulating the silicone core material.

Material:  PTFE-FEP jacket with a minimum thickness of .008" over a silicone core.

Teflon® Encapsulated-Viton® Core 

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

TFEV

Teflon®

Encapsulated

Viton® Core

Also referred to as:

Teflex® Encapsulated Viton® O-Rings, PTFE Encapsulated Viton®

O-Rings, PTFE-FEP Encapsulated Viton®

O-Rings

N/A

75

(core)

Black

with

opaque

shell

-73 to 205°F

-99 to 401°C

Use in: To improve O-Ring performance in difficult applications where Viton® alone fails.

Description: 

Teflon® Encapsulated

TFEV are produced using a thin PTFE shielded tubing fully encasing a Viton® elastomeric core.  The outer jacket protects the resilient Viton® core from the fluids which the O-Ring contacts.

Characteristics:  Semi-rigid PTFE-FEP tubing fully encapsulating the Viton® core material.  Endless.  No joints.

Material:  PTFE-FEP jacket with a minimum thickness of .008" over a Viton® core.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

SIL

Silicone Rubber

Also referred to as:

SIL, Silicone, Silastic

85

70

Blue

Sometimes

White

-60 to 200°C

-75 to 392°F

Use in:  O-Rings, special low pressure seals, gaskets.

Description:  An excellent material generally used for static seals with excellent low and high temperature stability and good resistance to aging.  Generally not suited for dynamic applications due to poor tensile strength and abrasion resistance.  Does exhibit excellent resistance to extreme temperature and is an acceptable FDA material.  Typical use for silicone is in dry heat applications and food processing applications.

Characteristics:  Very springy - like rubber-type material.

Orange

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

TFV

Virgin PTFE

Also referred to as:

Teflon®, Virgin Teflon®, PTFE, TFE, TFV, Polytertra-fluroethlene

Solid

Solid

White

-200 to 260°F

-328 to 500°C

Use in:  Packings, gaskets, seals, washers, spacers, insulators, wheels, rollers, bearings, guide rings.

Description:  An extremely low friction material which remains stable at both low and high temperatures.  The chemical resistance of this material is outstanding.  Can be used in applications with extreme temperatures, extreme pressures and extreme chemicals.  Since Teflon® TFV has a tendency to cold flow and has no memory.  It can be filled or mixed with glass, bronze and nickel to enhance its properties.

Characteristics:  Semi-rigid plastic material.  Most of the time it is finished by machining.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

FSI

Fluorosilicone

Also referred to as:

Silastic L.S.®

N/A

70

Blue

-62 to 177°C

-80 to 350°F

Use in: Common applications include, aircraft fuel systems, jet fuel/gasoline, petroleum oils, and synthetic jet oil.

Description:  Fluorosilicone is a mix of Fluorocarbon (Viton®) and Silicone.  Wide range of fluid and chemical resistance.  Large temperature range.

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

AFL

Aflas®

Also referred to as:

Tetrafluoroethylene Propylene

Check with EPM for avail-ability

75

Black

-28 to 204°C

-20 to 400°F

Use in:  Common applications include, O-Rings for various fluid seals.  Not readily available in other seal forms.  Petroleum fluids and steam amines, brake fluids or phosphate esters.

Description:  Excellent resistance to petroleum products, steam, phosphate esters, amines and brake fluids.  Broad range media resistance similar to EPD and Viton®.  Elastomeric form makes it low in gas permeability.

Characteristics:  Superior heat and wear resistance.  Non-abrasive.

Coef. Friction:  .15

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

NEO

Neoprene®

Also referred to as:

Chloroprene

N/A

70

Black

-65 to 250°F

-54 to 121°C

Use in: Common applications include, refrigeration seals, Freon/air conditioning, motor mounts, engine coolants.

Description:  Good resistance to petroleum oils.  Low compression set and good tear and abrasion strength.  Good resistance to weathering, sunlight and ozone.

PFR  Kalrez® O-Ring

Seal

Material

Hardness

Colour

Temperature

Limits

Information

Machined

O-Ring

Molded

O-Ring

PFR

Perfluoro-

lastomer

Also referred to as:

Kalrez®

N/A

70

75

90

Black with Brown Hue

-20 to 570°F

-30 to 300°C

Use in: Most likely application environments are for aggressive acids, solvents and steam.  Could be suited for many non-oxidizing dry process chemicals.

Description:  Broad resistance to chemicals.  Low compression set, strong tear resistance.  Virtually indestructive.  Above average outgassing performance in vacuums.