.Seals Gaskets Metric Oil Hydraulic Shaft Mechanical O-ring MSO

O Rings Backups

We can manufacture any o-ring up to 2 meters in diameter fast including NBR, HNBR, Silicone, EPDM, Viton®, Aflas, Teflon® and polyurethane.

Standard O Rings

Fabric Reinforced Vee Packings are recommended for liquid and gas service on all heavy-duty equipment where operating pressures and clearances exceed the recommended pressures for the homogeneous packings. They are used in hydraulic cylinder and pump applications and are available in a number of compositions covering an exceptionally wide range of operating conditions. Fabric Reinforced Vee Packings are usually constructed of cotton duck or asbestos cloth, coated with various elastomers and molded under heat and pressure. click here for more details

Metric O-ring

American standard size o-ring (Inch Sizes)

O-RINGS & BACK-UPS

O-ring cord

O-ring kit and assortment

Encapsulated o-rings

Square cut ring

Four-sided rings

WE HAVE A MOUNTAIN OF O-RINGS!!

Round cross sections

Back-ups available in standard sizes or machined to your specification.

Square cross sections

O-RING MATERIAL

Back-ups available in standard sizes or machined to your specification.

SPECIAL O-RINGS Manufactured or CNC Lathe

HNBR - 90 Durometer

Polyurethane - 92 Durometer Teflon®® - Glass filled Teflon®® - Virgin

Silicone - 85 Durometer

Viton® - 90 Durometer

Water Resistant Polyurethane

NBR - 90 Durometer

EPDM - 85 Durometer

O-Rings



*Transeals has over 2 million metric & imperial O-rings in our inventory.*
Sizing In a world where virtually nothing is absolutely standard, O-rings sizes by convention are always stated as Inside Diameter x Cross Section.

Materials
Nitrile (NBR) 70	The most common elastomer used for industrial grade O-rings. Compatible with most mineral based hydraulic fluids with a working temperature range from -40°C to 110°C.
Nitrile (NBR) 90	Harder than Nitrile 70 and hence suitable for use as a high pressure O-ring or back up washer.
Viton® 75	Possessing the broadest chemical compatibility of any mainstream elastomer, its broad working temperature range of -35°C to 205°C and excellent mechanical properties make this an excellent high performance compound for use in hydraulic systems.
Silicone, EPDM, Neoprene	..and other specialty compounds are available in many sizes or to order.

O-Ring Failure Analysis

COMMON SEAL FAILURES

	ABRASION
	Description: The seal or parts of the seal exhibit a flat surface parallel to the direction or motion. Loose particles and scrapes may be found on the seal surface.
	Contributing Factors: Rough sealing surfaces. Excessive temperature. Process environment containing abrasive particles. Dynamic motion. Poor elastomer surface finish.
	Suggested Solutions: Use recommended gland surface finishes. Consider internally lubed elastomers. Eliminate abrasive components.

	COMPRESSION SET
	Description: The seal exhibits a flat-sided cross-section, the flat sides correspoding to the mating seal surfaces.
	Contributing Factors: Excessive compression. Excessive temperature. Incompletely cured elastomer. Elastomer with high compression set. Excessive volume swell in chemical.
	Suggested Solutions: Low compression set elastomer. Proper gland design for the specific elastomer. Confirm material compatibility.

	CHEMICAL DEGRADATION
	Description: The seal may exhibit many signs of degradation including blisters, cracks, voids or discoloration. In some cases, the degradation is observable only by measurement of physical properties.
	Contributing Factors: Contributing Factors: Incompatibility with the chemical and/or thermal environment.
	Suggested Solutions: Selection of more chemically resistant elastomer.

	EXPLOSIVE DECOMPRESSION
	Description: The seal exhibits blisters, pits or pocks on its surface. Absorption of gas at high pressure and the subsequent rapid decrease in pressure. The absorbed gas blisters and ruptures the elastomer surface as the pressure is rapidly removed.
	Contributing Factors: Rapid pressure changes. Low-modulus/hardness elastomer.
	Suggested Solutions: Higher-modulus/hardness elastomer. Slower decompression (release of pressure).

	EXTRUSION
	Description: The seal develops ragged edges (generally on the low-pressure side) which appear tattered.
	Contributing Factors: Excessive clearances. Excessive pressure. Low-modulus/hardness elastomer. Excessive gland fill. Irregular clearance gaps. Sharp gland edges. Improper sizing.
	Suggested Solutions: Decrease clearances. Higher-modulus/hard-ness elastomer. Proper gland design. Use of polymer backup rings.

	INSTALLATION DAMAGE
	Description: The seal or parts of the seal may exhibit small cuts, nicks or gashes.
	Contributing Factors: Sharp edges on glands or components. Improper sizing of elastomer. Low-modulus/hardness elastomer. Elastomer surface contamination.
	Suggested Solutions: Remove all sharp edges. Proper gland design. Proper elastomer sizing. Higher-modulus/hardness elastomer.

	OUTGASSING / EXTRACTION
	Description: This failure is often very difficult to detect from examination of the seal. The seal may exhibit a decrease in cross-sectional size.
	Contributing Factors: Improper or improperly cured elastomer. High vacuum levels. Low hardness/plasticized elastomer.
	Suggested Solutions: Avoid plasticized elastomers. Ensure all seals are properly post-cured to minimize outgassing.

	OVERCOMPRESSION
	Description: The seal exhibits parallel flat surfaces (corresponding to the contact areas) and may develop circumferential splits within the flattened surfaces.
	Contributing Factors: Improper design—failure to account for thermal or chemical volume changes, or excessive compression.
	Suggested Solutions: Gland design should take into account material responses to chemical and thermal environments.

	PLASMA DEGRADATION
	Description: The seal often exhibits discoloration, as well as powdered residue on the surface and possible erosion of elastomer in the exposed areas.
	Contributing Factors: Chemical reactivity of the plasma. Ion bombardment (sputtering). Electron bombardment (heating). Improper gland design. Incompatible seal material.
	Suggested Solutions: Plasma-compatible elastomer and compound. Minimize exposed area. Examine gland design.

	SPIRAL FAILURE
	Description: The seal exhibits cuts or marks which spiral around its circumference.
	Contributing Factors: Difficult or tight installation (static). Slow reciprocating speed. Low-modulus/hardness elastomer. Irregular O-ring surface finish (including excessive parting line). Excessive gland width. Irregular or rough gland surface finish. Inadequate lubrication.
	Suggested Solutions: Correct installation procedures. Higher-modulus elastomer. Internally-lubed elastomers. Proper gland design. Gland surface finish of 8–16 microinch RMS. Possible use of polymer backup rings.

	THERMAL DEGRADATION
	Description: The seal may exhibit radial cracks located on the highest temperature surfaces. In addition, certain elastomers may exhibit signs of softening—a shiny surface as a result of excessive temperatures.
	Contributing Factors: Elastomer thermal properties. Excessive temperature excursions or cycling.
	Suggested Solutions: Selection of an elastomer with improved thermal stability. Evaluation of the possibility of cooling sealing surfaces.

O-RING FAILURE ANALYSIS

Prevention of seal failures through proper design, material selection and maintenance certainly minimizes the risk of failure. Attention to the condition of replaced seals, as well as the equipment performance over time, will result in improved process reliability, reduced operating costs and a safer work environment.

O-ring seals often fail prematurely in applications because of improper design or compound selection. This section is designed to provide the user with examples of common failure modes. By correctly identifying the failure mode, changes in the design or seal material can lead to improved seal performance.

From the end-user’s point of view, a seal can fail in three (3) general ways:

Leaking
Contamination
Change in Appearance

These three effects are demonstrated as Ishikawa (fishbone) diagrams with special emphasis on the following three analysis areas.

ENVIRONMENT ANALYSIS

One major factor in possible seal failure is the extreme and harsh environment in which seals are expected to perform. The sealing environment can consist of virtually anything from inert gases at room temperatures to aggressive chemicals at very high temperatures. The sealing environment may result in chemical degradation or swelling of the sealing components. Elevated temperatures may cause seal degradation, swelling or outgassing. And the pressure—or more often, the vacuum environments—can cause outgassing and weight loss.

Contributing factors to seal failure in the sealing environment include:

Chemical— the type of chemical(s) in service
Thermal— the operating ranges of the seal (also any thermal cycling)
Pressure/Vacuum— the range of pressures or vacuum levels in the process

SEAL DESIGN ANALYSIS

Analysis of the seal application is crucial to the understanding of possible failure. Most seal design is performed by component suppliers and equipment manufacturers. The designs are refined as experience is gained. As quickly as process technology changes, however, the experience gained with seal design may not be relevant to the latest process technology. Vacuum applications have historically relied on high levels of compression and gland fill to reduce permeation and trapped gases. These techniques, when applied to new materials, or at higher operating temperatures, can result in premature seal failure.

The seal design and application can provide information about the cause of failure:

Static Seals— axial and radial, confined or unconfined
Dynamic Seals— axial (open-close) or radial (reciprocating or rotary)

Sealing Gland Dimensions—
- shape (square, trapezoidal, etc.)
- compression
- gland fill
- stretch
Installation Procedures— stretch

Standard O Rings

Standard O-Ring Sizing Chart

Back to the O-Ring Page

AS568A-
Dash #

Actual
I.D.
Inches

Actual
C.S.
Inches

Actual
I.D.
Millimeters

Actual
C.S.
Millimeters

Nominal
Reference
I.D.

Nominal
Reference
C.S.

Nominal
Reference
O.D.

-001

-002

-003

-004

-005

-006

-007

-008

-009

-010

-011

-012

-013

-014

-015

-016

-017

-018

-019

-020

-021

-022

-023

-024

-025

-026

-027

-028

-029

-030

-031

-032

-033

-034

-035

-036

-037

-038

-039

-040

-041

-042

-043

-044

-045

-046

-047

-048

-049

-050

.029±.004

.042±.004

.056±.004

.070±.005

.101±.005

.114±.005

.145±.005

.176±.005

.208±.005

.239±.005

.301±.005

.364±.005

.426±.005

.489±.005

.551±.007

.614±.009

.676±.009

.739±.009

.801±.009

.864±.009

.926±.009

.989±.010

1.051±.010

1.114±.010

1.176±.011

1.239±.011

1.301±.011

1.364±.013

1.489±.013

1.614±.013

1.739±.015

1.864±.015

1.989±.018

2.114±.018

2.239±.018

2.364±.018

2.489±.018

2.614±.020

2.739±.020

2.864±.020

2.989±.024

3.239±.024

3.489±.024

3.739±.027

3.989±.027

4.239±.030

4.489±.030

4.739±.030

4.989±.037

5.239±.037

.040±.003

.050±.003

.060±.003

.070±.003

0.74±0.10

1.07±0.10

1.42±0.10

1.78±0.13

2.57±0.13

2.90±0.13

3.68±0.13

4.47±0.13

5.28±0.13

6.07±0.13

7.65±0.13

9.25±0.13

10.82±0.13

12.42±0.13

14.00±0.18

15.60±0.23

17.17±0.23

18.77±0.23

20.35±0.23

21.95±0.23

23.52±0.23

25.12±0.25

26.70±0.25

28.30±0.25

29.87±0.28

31.47±0.28

33.05±0.28

34.65±0.33

37.82±0.33

41.00±0.33

44.17±0.38

47.35±0.38

50.52±0.46

53.70±0.46

56.87±0.46

60.05±0.46

63.22±0.46

66.40±0.51

69.57±0.51

72.75±0.51

75.92±0.61

82.27±0.61

88.62±0.61

94.97±0.69

101.32±0.69

107.67±0.76

114.02±0.76

120.37±0.76

126.72±0.94

133.07±0.94

1.02±0.08

1.27±0.08

1.52±0.08

1.78±0.08

1/32

3/64

1/16

5/64

3/32

1/8

5/32

3/16

7/32

1/4

5/16

3/8

7/16

1/2

9/16

5/8

11/16

3/4

13/16

7/8

15/16

1-1/16

1-1/8

1-3/16

1-1/4

1-5/16

1-3/8

1-1/2

1-5/8

1-3/4

1-7/8

2-1/8

2-1/4

2-3/8

2-1/2

2-5/8

2-3/4

2-7/8

3-1/4

3-1/2

3-3/4

4-1/4

4-1/2

4-3/4

5-1/4