O-ring NBR 40.2x3 70 Shore A

O-ring NBR 40.2x3 mm 70 Shore A - Pack of 100 Pieces

O-ring NBR 40.2x3 mm 70 Shore A is an elastomeric sealing ring with a nominal inner diameter of 40.2 mm and a cross-sectional diameter of 3 mm. Manufactured from nitrile butadiene rubber (NBR) with a nominal hardness of 70 Shore A, it is primarily intended for static sealing applications and appropriately designed hydraulic and pneumatic systems. Each package contains 100 O-rings for industrial maintenance, technical servicing and B2B supply.

Characteristics of the NBR 70 Shore A O-ring 40.2x3 mm

The NBR 40.2x3 mm O-ring is a circular elastomeric sealing element designed to prevent or reduce fluid and gas leakage between mating components.

Its round cross-section allows the material to deform under controlled compression, creating sealing contact pressure against the surrounding surfaces.

NBR is widely used in industrial sealing applications because of its compatibility with many mineral oil-based lubricants, greases and selected industrial fluids.

Key product characteristics:

• Inner diameter: 40.2 mm - nominal internal diameter of the sealing ring in its free condition.

• Cross-sectional diameter: 3 mm - nominal thickness of the circular elastomer profile.

• Nominal outer diameter: 46.2 mm - calculated from the inner diameter and cross-section.

• Material: NBR - nitrile butadiene rubber.

• Hardness: 70 Shore A - nominal elastomer hardness.

• Circular cross-section - enables sealing contact pressure when compressed in a correctly designed groove.

• Packaging: 100 pieces per pack for industrial supply, maintenance and repair operations.

Technical Specifications

The nominal outer diameter of 46.2 mm is calculated from the inner diameter and twice the cross-sectional diameter.

Actual dimensions are subject to manufacturing tolerances. A specific dimensional tolerance class has not been established for this product.

No product-specific operating temperature range or maximum working pressure has been confirmed.

What Does O-ring 40.2x3 mm NBR 70 Shore A Mean?

40.2 mm - Inner Diameter

The nominal inner diameter of the O-ring measured in its free, uninstalled condition.

This dimension is important when selecting the correct ring for the shaft, component or sealing groove.

3 mm - Cross-Sectional Diameter

The nominal diameter of the circular elastomer cross-section.

The cross-sectional diameter affects compression, groove filling and the sealing contact pressure developed during installation.

NBR - Nitrile Butadiene Rubber

NBR is a synthetic elastomer produced from acrylonitrile and butadiene.

It is commonly used in sealing systems exposed to compatible mineral oils, lubricating greases and hydraulic fluids.

Its chemical resistance depends on the specific rubber compound, fluid composition, temperature and duration of exposure.

70 Shore A - Elastomer Hardness

70 Shore A specifies the nominal hardness of the rubber compound.

This hardness is commonly used in industrial O-rings because it provides a practical balance between elastic deformation and resistance to mechanical loading.

The hardness designation alone does not determine the maximum permissible operating pressure.

100 Pieces - Packaging Quantity

Each commercial package contains 100 O-rings with nominal dimensions of 40.2x3 mm and hardness of 70 Shore A.

Construction and Operating Principle

The NBR 40.2x3 mm O-ring consists of a continuous elastomeric ring with a circular cross-section.

When installed in a correctly dimensioned groove, the ring is compressed between the mating surfaces.

This compression creates initial contact pressure, helping prevent fluid or gas from passing through the sealed connection.

When system pressure is applied, the O-ring may deform toward the low-pressure side of the groove, increasing contact with the sealing surfaces.

Effective sealing depends on several factors:

• Groove dimensions and geometry.

• O-ring compression ratio.

• Groove filling.

• Extrusion gap.

• Surface finish.

• Operating pressure and temperature.

• Chemical compatibility with the sealing medium.

• Static or dynamic operating conditions.

The O-ring should not be selected solely on the basis of its inner diameter.

Chemical Compatibility of NBR

Nitrile butadiene rubber is commonly selected for industrial sealing applications involving compatible mineral oil-based fluids.

These characteristics describe the NBR elastomer family and do not represent verified chemical resistance test results for the specific compound used in this product.

Compatibility with a particular operating medium should be confirmed before installation.

NBR 70 Shore A Compared with Other O-ring Materials

O-rings with identical nominal dimensions but different materials or hardness values are not automatically interchangeable.

Material selection must account for chemical compatibility, temperature, pressure, groove design and operating conditions.

Selection and Interchangeability of the 40.2x3 mm O-ring

Before selecting a replacement O-ring, verify the technical requirements of the sealing assembly.

Important selection criteria include:

1. Inner diameter: 40.2 mm.

2. Cross-sectional diameter: 3 mm.

3. Material: NBR.

4. Nominal hardness: 70 Shore A.

5. Groove dimensions.

6. Required compression ratio.

7. Operating fluid or gas.

8. Working pressure and temperature.

9. Extrusion clearance.

10. Static or dynamic operating conditions.

11. Required dimensional tolerances.

Changing the cross-sectional diameter from 3 mm to 3.5 mm can significantly affect compression and groove filling.

Therefore, a 40.2x3 mm O-ring should not automatically be replaced with a 40.2x3.5 mm O-ring.

Typical Applications of NBR 70 Shore A O-rings

NBR O-rings with a hardness of 70 Shore A are widely used in appropriately designed industrial sealing systems.

Typical applications may include:

• Static hydraulic connections.

• Pneumatic assemblies.

• Valve bodies and control components.

• Equipment covers and housings.

• Industrial fittings and connectors.

• Lubrication systems.

• Industrial machinery maintenance.

• Mechanical assemblies requiring sealing against compatible fluids or gases.

These examples describe general applications of NBR O-rings and do not establish compatibility with any specific machine, vehicle or OEM component.

Installation and Storage Recommendations

Before installation, clean the sealing groove and mating surfaces.

Remove dirt, burrs, sharp edges and contaminants that could damage the elastomer.

Install the O-ring without excessive stretching, twisting or cutting.

Where installation lubrication is required, use a lubricant compatible with NBR and the operating medium.

Avoid sharp metal tools that could damage the sealing surface.

Store unused O-rings in clean, dry conditions away from direct sunlight, ozone-generating equipment, excessive heat and chemicals that may degrade the rubber.

Alternative Designations and Search References

The product may be identified using the following dimensional and material descriptions:

• O-ring NBR 40.2x3 mm 70 Shore A

• NBR 70 O-ring 40.2x3

• O-ring 40.2x3 NBR 70

• Nitrile rubber O-ring 40.2x3 mm

• 40.2 mm ID 3 mm CS NBR O-ring

• Metric O-ring 40.2x3 mm NBR

• O-ring NBR 70 Shore A 40.2x3 mm - 100 pcs

• NBR O-ring 40.2x3 mm - Pack of 100

These are alternative identification formats, not independently verified manufacturer part numbers or OEM cross-references.

FAQ - NBR 70 Shore A O-ring 40.2x3 mm

1. What are the dimensions of the NBR 40.2x3 mm O-ring?

The nominal inner diameter is 40.2 mm, and the cross-sectional diameter is 3 mm. The calculated nominal outer diameter is 46.2 mm.

2. What does NBR 70 Shore A mean?

NBR identifies nitrile butadiene rubber, while 70 Shore A indicates the nominal hardness of the elastomer.

3. Is the NBR 40.2x3 mm O-ring suitable for hydraulic systems?

It may be suitable for hydraulic applications using compatible fluids and correctly designed sealing grooves. Operating pressure, temperature and groove geometry must be verified.

4. Is NBR resistant to engine oil?

NBR is generally compatible with many mineral oil-based lubricants. Compatibility with a particular engine oil formulation and its additives depends on the rubber compound and operating conditions.

5. Can a 40.2x3 mm O-ring be replaced with a 40x3 mm O-ring?

Not without verifying the application requirements. The difference in inner diameter may affect installation stretch and groove fit.

6. Are NBR 70 Shore A and NBR 90 Shore A interchangeable?

Not automatically. Different hardness values affect deformation, sealing contact pressure and resistance to extrusion.

7. Can this O-ring be used in dynamic sealing applications?

It may be used in selected dynamic applications when groove design, lubrication, movement speed and operating conditions are appropriate.

8. How many O-rings are included in one package?

Each package contains 100 NBR O-rings with nominal dimensions of 40.2x3 mm and hardness of 70 Shore A.

NBR 70 Shore A O-ring 40.2x3 mm - Key Technical Information

The NBR 70 Shore A O-ring 40.2x3 mm is an elastomeric sealing ring with a 40.2 mm inner diameter, 3 mm cross-section and calculated 46.2 mm outer diameter. Manufactured from nitrile butadiene rubber, it is suitable for properly designed sealing assemblies using compatible media. Each package contains 100 pieces for industrial maintenance, technical servicing and B2B procurement.

The product is available from simmering.pl, a specialist supplier of industrial seals, O-rings and rolling bearings.

With warehouse operations in Lublin, Poland, simmering.pl supplies industrial customers, maintenance departments, repair workshops and international B2B buyers, with worldwide shipping options.