O-ring 40x3.5 NBR 70 Shore A

O-ring 40x3.5 NBR 70 Shore A - 100 pcs

O-ring 40x3.5 NBR 70 Shore A is a technical sealing ring manufactured from nitrile butadiene rubber (NBR), with an inside diameter of 40 mm and a cross-section of 3.5 mm. The nominal elastomer hardness is 70 Shore A. NBR is widely used for seals operating with many mineral oils and lubricating greases. The product is supplied in packs of 100 pieces.

Technical Data

O-ring 40x3.5 - What Do the Dimensions Mean?

The designation:

40x3.5 mm

specifies the inside diameter and cross-section of the O-ring:

• 40 mm - inside diameter

• 3.5 mm - cross-section diameter

The calculated outside diameter is:

40 mm + 2 x 3.5 mm = 47 mm

The principal dimensions are therefore:

• inside diameter d1: 40 mm

• cross-section d2: 3.5 mm

• calculated outside diameter: 47 mm

For technical O-ring selection, the standard dimensional format is inside diameter x cross-section.

NBR - Nitrile Butadiene Rubber

This O-ring is manufactured from NBR - nitrile butadiene rubber.

NBR is one of the most widely used elastomers in technical sealing applications. It is particularly valued for its good resistance to many:

• mineral oils

• lubricating greases

• mineral-oil-based fluids

For this reason, NBR O-rings are widely used in industrial machinery, mechanical systems, hydraulic equipment and many other technical applications.

NBR does not provide universal chemical resistance. Compatibility with the specific operating medium and temperature should always be verified before use.

Oil-Resistant 40x3.5 NBR O-ring

The term oil-resistant NBR O-ring refers to the good resistance of nitrile rubber to many common mineral oils and lubricating greases.

It does not mean that NBR is resistant to every oil, fuel or chemical substance.

Before selecting an O-ring, consider:

• type of oil or grease

• chemical composition of the medium

• operating temperature

• pressure

• static or dynamic operating conditions

Correct material selection has a direct influence on sealing performance and service life.

70 Shore A Hardness

The nominal hardness of this O-ring is:

70 Shore A

This is a commonly used hardness for standard NBR O-rings intended for a broad range of technical sealing applications.

Hardness influences the way the elastomer deforms inside the sealing groove.

However, Shore A hardness alone does not determine chemical resistance, temperature capability or permissible operating pressure.

Applications of the 40x3.5 NBR O-ring

The 40x3.5 NBR O-ring can be used in appropriately designed sealing systems in:

• industrial machinery

• mechanical equipment

• hydraulic systems

• pneumatic systems

• pumps

• valves

• gearboxes

• lubrication systems

• automotive applications

• agricultural machinery

• workshop equipment

• maintenance and repair operations

Suitability for a specific application depends on the complete sealing system and its operating conditions.

Static and Dynamic Sealing

O-rings can be used in both static connections and appropriately designed dynamic sealing arrangements.

Static Sealing

In a static application, the O-ring seals surfaces without relative movement between the mating components during normal operation.

Dynamic Sealing

In suitable designs, an O-ring can also operate with moving components.

Dynamic applications require particular attention to:

• friction

• lubrication

• movement speed

• surface finish

• temperature

• groove geometry

An O-ring suitable for a static connection is not automatically the optimum solution for a dynamic application.

How to Select a 40x3.5 O-ring

Before use, verify:

1. Inside diameter 40 mm.

2. Cross-section 3.5 mm.

3. Sealing groove dimensions and design.

4. NBR material.

5. Nominal hardness 70 Shore A.

6. Operating medium.

7. Operating temperature.

8. Pressure.

9. Type of movement or static operation.

10. Environmental conditions.

Matching the 40x3.5 mm dimensions alone does not confirm suitability for every application.

NBR vs FKM/FPM vs EPDM

O-rings with dimensions of 40x3.5 mm can be manufactured from different elastomers.

NBR

A widely used choice for many sealing applications involving mineral oils and lubricating greases.

FKM / FPM

A fluoroelastomer with a different chemical and thermal resistance profile compared with NBR. Viton® is a well-known trademark associated with fluoroelastomer materials.

EPDM

An elastomer with different chemical resistance characteristics, selected for applications where the properties of NBR or FKM may not be appropriate.

NBR, FKM/FPM and EPDM O-rings should not automatically be considered interchangeable simply because their dimensions are identical.

Pack of 100 Pieces

O-ring 40x3.5 NBR 70 Shore A is supplied in a package containing:

100 pcs

The 100-piece pack is particularly suitable for:

• industrial companies

• maintenance departments

• repair services

• workshops

• machine manufacturers

• purchasing departments

• B2B customers

Alternative Search Terms

The product may also be searched as:

• O-ring 40x3.5 NBR

• O-ring 40x3.5 NBR 70 Shore A

• O-ring 40x3.5

• NBR O-ring 40x3.5

• 40x3.5 NBR O-ring

• oil-resistant O-ring 40x3.5

• nitrile O-ring 40x3.5

• nitrile rubber seal 40x3.5

• sealing ring 40x3.5

• technical seal 40x3.5

• O-ring 40x3.5 70 ShA

• O-ring 40x3.5 100 pcs

• 40 mm ID O-ring

• 40 mm ID 3.5 mm CS O-ring

• 40x3.5 industrial O-ring

FAQ

What are the dimensions of the 40x3.5 O-ring?

The O-ring has an inside diameter of 40 mm and a cross-section of 3.5 mm.

What is the outside diameter of a 40x3.5 O-ring?

The calculated outside diameter is 47 mm.

What material is the O-ring made from?

The product is manufactured from NBR - nitrile butadiene rubber.

What is the hardness of the O-ring?

The nominal elastomer hardness is 70 Shore A.

Is the 40x3.5 NBR O-ring oil resistant?

NBR provides good resistance to many mineral oils and lubricating greases. This does not mean resistance to every medium, so compatibility should be checked for the specific fluid and operating temperature.

Can the 40x3.5 NBR O-ring be used in hydraulic systems?

NBR O-rings are widely used in hydraulic equipment. Suitability for a particular system depends on factors such as groove design, pressure, medium, temperature and operating conditions.

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

Not automatically. NBR and FKM/FPM have different chemical and thermal properties. The elastomer should be selected according to the specific application.

How many O-rings are included in the package?

The package contains 100 pieces.

Does 40 mm indicate the inside diameter?

Yes. In the 40x3.5 designation, 40 mm is the inside diameter and 3.5 mm is the cross-section diameter.

O-ring 40x3.5 NBR 70 Shore A - Quick Technical Answer

O-ring 40x3.5 NBR 70 Shore A is a technical nitrile rubber sealing ring with a 40 mm inside diameter and 3.5 mm cross-section. Its calculated outside diameter is 47 mm. NBR provides good resistance to many mineral oils and lubricating greases. The product is supplied in packs of 100 pieces.

O-ring 40x3.5 NBR at simmering.pl

O-ring 40x3.5 NBR 70 Shore A is available from simmering.pl, a specialist B2B supplier of O-rings, rotary shaft seals, V-rings, bearings and industrial sealing solutions.

The product is supplied in packs of 100 pieces.

Stock and technical service are located in Lublin, Poland, with worldwide shipping available.