O-ring 20x3 NBR 70 ShA

O-ring 20x3 NBR 70 ShA - 100 pcs

O-ring 20x3 NBR 70 ShA - 100 pcs is a technical sealing ring made of nitrile rubber (NBR), with an inside diameter of 20 mm, a cross-section of 3 mm and a hardness of 70 Shore A. The nominal outside diameter is 26 mm. NBR 70 ShA is one of the most widely used material and hardness combinations for technical O-rings, providing a practical balance between flexibility, sealing performance and mechanical stability.

Package quantity: 100 pcs.

Technical Specifications - O-ring 20x3 NBR 70 ShA

O-ring 20x3 NBR 70 ShA - Dimensions

The designation:

20x3

defines the two principal dimensions of the O-ring:

20 mm - inside diameter, ID

3 mm - cross-section diameter, CS

The nominal outside diameter can be calculated using:

OD = ID + 2 x CS

Therefore:

20 mm + 2 x 3 mm = 26 mm

The nominal dimensions are:

ID = 20 mm

CS = 3 mm

OD = 26 mm

These dimensions should always be checked when selecting an O-ring for an existing groove or replacing a previously installed seal.

NBR 70 ShA - Material and Hardness

The O-ring 20x3 NBR 70 ShA - 100 pcs is manufactured from NBR, also known as nitrile rubber or nitrile butadiene rubber.

NBR is one of the most commonly used elastomers in technical sealing applications.

It is widely used in environments involving many:

mineral oils

lubricating greases

selected petroleum-based products

compatible industrial fluids

The exact chemical compatibility should always be checked for the specific medium and operating conditions.

What Does 70 ShA Mean?

70 ShA indicates the hardness of the elastomer measured on the Shore A scale.

NBR 70 ShA is a widely used hardness for technical O-rings because it provides a useful balance between elasticity and mechanical stability.

Compared with harder NBR compounds, 70 ShA material is more flexible and can conform more easily to mating surfaces.

However, the correct hardness should always be selected according to the design and operating conditions of the sealing system.

NBR 70 ShA vs NBR 90 ShA

O-rings with the same 20x3 dimensions can be manufactured in different hardness grades.

NBR 70 ShA is more flexible and more easily conforms to mating surfaces.

NBR 90 ShA is harder and less susceptible to deformation.

Higher hardness does not automatically mean better sealing performance.

The correct choice depends on:

operating pressure

extrusion gap

groove geometry

O-ring compression

type of movement

temperature

operating medium

For this reason, an O-ring 20x3 NBR 70 ShA should not automatically be replaced by an O-ring 20x3 NBR 90 ShA solely because the dimensions are identical.

How Does an O-ring 20x3 NBR 70 ShA Work?

An O-ring creates a seal by controlled compression of the elastomer between mating components.

When installed in a correctly designed groove, the O-ring is compressed and creates sealing contact with the surrounding surfaces.

Effective sealing depends on several factors, including:

O-ring dimensions

groove dimensions

compression

groove fill

extrusion gap

pressure

temperature

operating medium

surface finish

static or dynamic operation

The dimensions 20x3 mm alone are therefore not sufficient to determine whether an O-ring is suitable for a particular sealing system.

NBR Resistance to Oils and Greases

Nitrile rubber is widely used for technical seals because of its good compatibility with many mineral-based oils and lubricating greases.

This makes NBR a common material for sealing systems used in industrial machinery, mechanical equipment, hydraulic and pneumatic components.

However, compatibility depends on the exact composition of the medium and operating conditions.

Before using an O-ring, the following should be considered:

type of oil or fluid

chemical composition

operating temperature

pressure

duration of exposure

NBR should not be treated as a universal elastomer suitable for every chemical medium.

Typical Applications of O-ring 20x3 NBR 70 ShA

NBR O-rings are widely used in:

industrial machinery

maintenance and repair

hydraulic systems

pneumatic systems

mechanical assemblies

pumps and valves

technical equipment

industrial sealing systems

The O-ring 20x3 NBR 70 ShA can be considered for static sealing and appropriately designed dynamic applications when the material, dimensions and hardness meet the requirements of the system.

A specific application should always be confirmed from technical documentation or by checking the dimensions and operating requirements of the sealing groove.

Static and Dynamic Sealing

O-rings are widely used in static sealing arrangements, where there is no relative movement between the sealing surfaces.

They can also be used in certain dynamic applications when the groove, lubrication, surface finish, speed and operating conditions have been designed for O-ring operation.

The same O-ring should not automatically be considered suitable for both static and dynamic operation without checking the application requirements.

How to Select O-ring 20x3 NBR 70 ShA

Before selecting this O-ring, verify:

• inside diameter ID = 20 mm
• cross-section CS = 3 mm
• nominal outside diameter OD = 26 mm
• NBR material
• 70 ShA hardness
• operating medium
• operating temperature
• pressure
• groove dimensions
• required compression
• groove fill
• extrusion gap
• static or dynamic operation

An O-ring with the same 20x3 dimensions but manufactured from FKM/FPM, EPDM, VMQ or another elastomer can have significantly different chemical and thermal properties.

Identical dimensions do not automatically mean complete interchangeability.

O-ring 20x3 NBR 70 ShA vs FKM/FPM

NBR and FKM/FPM are different elastomer families.

An O-ring 20x3 NBR 70 ShA should therefore not automatically be replaced with an FKM/FPM O-ring of the same dimensions.

Material selection depends on the operating medium, temperature, pressure and environmental conditions.

The correct elastomer should be selected according to the requirements of the application rather than dimensions alone.

O-ring Installation

Before installation, clean the groove and mating surfaces.

The O-ring should not be pulled across sharp edges, burrs or unprotected threads that could cut or damage the elastomer.

During installation, avoid:

cutting the O-ring

scratching the sealing surface

excessive stretching

twisting the O-ring

contamination

contact with sharp edges

If an assembly lubricant is used, its compatibility with NBR and the operating medium should be verified.

Package of 100 pcs - Industrial and B2B Supply

O-ring 20x3 NBR 70 ShA - 100 pcs is supplied as a package containing:

100 pcs

This package format is particularly suitable for:

industrial companies

maintenance departments

machinery manufacturers

repair services

workshops

technical wholesalers

B2B customers

A 100-piece package provides a practical stock quantity for companies that regularly use O-rings for production, maintenance or servicing.

FAQ - O-ring 20x3 NBR 70 ShA - 100 pcs

What are the dimensions of O-ring 20x3 NBR 70 ShA?

The O-ring has an inside diameter of 20 mm and a cross-section of 3 mm. Its nominal outside diameter is 26 mm.

What does NBR mean?

NBR stands for nitrile rubber, a widely used elastomer for industrial and technical sealing applications.

What does 70 ShA mean?

70 ShA indicates elastomer hardness measured on the Shore A scale. It is a widely used hardness for general-purpose technical O-rings.

What is the outside diameter of O-ring 20x3?

The nominal outside diameter is 26 mm.

It is calculated as:

20 mm + 2 x 3 mm = 26 mm

Is NBR 70 ShA suitable for oil?

NBR has good compatibility with many mineral-based oils and lubricating greases. Compatibility should always be verified for the exact medium and operating temperature.

Is NBR 70 ShA softer than NBR 90 ShA?

Yes. NBR 70 ShA is softer and more flexible than NBR 90 ShA. The correct hardness depends on the design and operating conditions of the sealing system.

Can an NBR O-ring be replaced with an FKM O-ring?

Not automatically. NBR and FKM/FPM have different material characteristics and chemical resistance. Material substitution should be based on the requirements of the application.

How many O-rings are included?

O-ring 20x3 NBR 70 ShA - 100 pcs contains 100 O-rings in the package.

O-ring 20x3 NBR 70 ShA - Key Information

O-ring 20x3 NBR 70 ShA - 100 pcs is a technical nitrile rubber sealing ring with an inside diameter of 20 mm, cross-section of 3 mm and nominal outside diameter of 26 mm. The 70 Shore A hardness provides a practical balance between flexibility and mechanical stability for many standard technical sealing applications.

Available from simmering.pl, stock in Poland with worldwide shipping.

simmering.pl supplies NBR, FKM/FPM, EPDM and VMQ O-rings and other technical seals for industry, maintenance departments, repair services, machinery manufacturers and B2B customers worldwide.