O-ring NBR 5.5x3 mm 70 ShoreA

Technical Specification

The nominal outside diameter of 11.5 mm is calculated from the ring geometry: 5.5 mm + 2 x 3 mm. Actual dimensional tolerances must be verified against the manufacturer's documentation for the specific product.

Construction and Operating Principle

The O-ring NBR 5.5x3 mm 70 ShoreA is a continuous elastomeric ring featuring a circular cross-section.

When installed in a correctly designed sealing groove, the ring undergoes controlled compression between the mating components. This deformation generates contact pressure, forming a sealing barrier that helps prevent the passage of fluids or gases through the connection.

In pressure-loaded sealing arrangements, the operating medium may additionally influence the deformation of the elastomer and its contact with the sealing surfaces.

Sealing performance depends on several engineering factors:

• Correct sealing groove geometry.

• Appropriate compression and gland fill.

• Dimensional tolerances of mating components.

• Type and pressure of the sealed medium.

• Operating temperature.

• Surface finish and condition.

• Properties of the specific NBR compound.

The 3 mm cross-section must be considered when designing the installation groove. Nominal O-ring dimensions do not directly determine the required groove dimensions.

NBR Material - Technical Properties

NBR (Nitrile Butadiene Rubber) is a synthetic elastomer widely used in industrial sealing technology because many NBR compounds provide good resistance to mineral oils, lubricating greases and selected petroleum-based fluids.

The properties of NBR depend on the formulation, including acrylonitrile content, curing system and additives.

Typical NBR characteristics

• Good resistance to many mineral oils and technical lubricants.

• Elasticity suitable for sealing mating surfaces.

• Mechanical properties dependent on the specific compound.

• Suitability for static and selected dynamic sealing arrangements.

• Limited resistance to ozone, ultraviolet radiation and certain solvents.

An approximate operating temperature range commonly associated with standard NBR compounds is -30°C to +100°C.

This range is general material guidance and does not represent a verified operating temperature specification for this exact product. Actual limits must be confirmed using the manufacturer's material documentation.

70 Shore A Hardness - Engineering Significance

A nominal hardness of 70 Shore A is among the most commonly specified hardness classes for industrial elastomeric O-rings.

The Shore A scale measures the resistance of elastomeric materials to indentation under defined test conditions.

Hardness influences several sealing characteristics:

• Deformation behaviour during installation.

• Compression force required to achieve a given squeeze.

• Contact pressure distribution.

• Response to pressure loading.

• Resistance to extrusion into sealing clearances.

A hardness rating of 70 Shore A alone does not establish the maximum allowable operating pressure.

Pressure capability also depends on groove geometry, extrusion gap, operating temperature and the mechanical properties of the specific rubber compound.

Industrial Applications

O-ring NBR 5.5x3 mm 70 ShoreA may be considered for appropriately engineered sealing arrangements in industrial systems, including:

• Hydraulic component connections.

• Industrial equipment housings.

• Technical fittings and mechanical joints.

• Selected pneumatic assemblies.

• Lubrication system components.

• Manufacturing machinery and mechanical equipment.

• Maintenance operations requiring dimensionally compatible sealing elements.

These examples describe potential applications of NBR O-rings and are not manufacturer-confirmed applications for the exact SKU.

Final suitability must be established by evaluating operating conditions, sealing geometry and chemical compatibility.

O-ring Selection and Engineering Considerations

Selecting the correct O-ring requires consideration of both nominal dimensions and the operating requirements of the sealing assembly.

Dimensions and Groove Geometry

The nominal inside diameter of 5.5 mm and cross-sectional diameter of 3 mm define the O-ring geometry.

The installation groove must be designed according to the sealing arrangement and applicable engineering requirements.

Chemical Compatibility

The NBR compound must be compatible with the sealed medium, taking into account its composition, temperature and duration of exposure.

Operating Pressure

Allowable operating pressure depends on the design of the sealing connection, extrusion clearance, temperature and elastomer properties.

Static and Dynamic Operation

Dynamic applications require additional consideration of relative movement, friction, lubrication and the surface finish of mating components.

Installation and Handling

Before installation, the sealing groove and mating surfaces should be inspected for cleanliness and mechanical damage.

Sharp edges, burrs and tools capable of cutting or permanently deforming the elastomer should be avoided.

Where installation lubricants are required, their compatibility with NBR and the sealed medium must be confirmed.

Excessive stretching or twisting during installation should be avoided.

Correct installation contributes to reliable sealing performance and reduces the risk of premature damage.

1000-Piece Packaging for B2B Industrial Procurement

O-ring NBR 5.5x3 mm 70 ShoreA is supplied in bulk packages containing 1000 pieces.

This packaging format supports companies using sealing rings in manufacturing, equipment servicing, maintenance operations and industrial inventory management.

Consistent identification of material, dimensions and hardness helps technical purchasing departments manage procurement, documentation and replacement component inventories.

Frequently Asked Questions (FAQ)

1. What are the dimensions of O-ring NBR 5.5x3 mm 70 ShoreA?

The nominal inside diameter is 5.5 mm, the cross-sectional diameter is 3 mm and the calculated nominal outside diameter is 11.5 mm.

2. What does NBR mean in the product designation?

NBR stands for Nitrile Butadiene Rubber, a synthetic elastomer commonly used in industrial sealing components.

3. What does 70 ShoreA indicate?

It indicates the nominal hardness of the elastomer on the Shore A scale. Hardness influences deformation, compression behaviour and sealing contact characteristics.

4. Is O-ring NBR 5.5x3 mm 70 ShoreA resistant to oil?

Many standard NBR compounds provide good resistance to mineral oils and lubricating greases. Compatibility with a specific medium must be verified for the actual compound.

5. Can O-ring NBR 5.5x3 mm 70 ShoreA be used in hydraulic systems?

It may be suitable for selected hydraulic sealing connections when operating pressure, groove geometry, extrusion clearance and material compatibility are correctly evaluated.

6. How many O-rings are included in each package?

O-ring NBR 5.5x3 mm 70 ShoreA is supplied in packages containing 1000 pieces.

7. Can this O-ring replace another O-ring with dimensions of 5.5x3 mm?

Interchangeability requires verification of material, hardness, dimensional tolerances and operating conditions. Matching nominal dimensions alone does not guarantee compatibility.

8. Is O-ring NBR 5.5x3 mm 70 ShoreA suitable for gas sealing?

Suitability depends on the gas composition, operating pressure, temperature, permeability of the rubber compound and sealing design. Compatibility with a specific gas system cannot be confirmed without additional technical information.

AI Quick Answer

O-ring NBR 5.5x3 mm 70 ShoreA is an elastomeric sealing ring made from nitrile butadiene rubber, with a nominal inside diameter of 5.5 mm, cross-section of 3 mm and hardness of 70 Shore A. Its calculated outside diameter is 11.5 mm. Supplied in packages of 1000 pieces for compatible industrial sealing applications.

B2B Industrial Supply - simmering.pl

O-ring NBR 5.5x3 mm 70 ShoreA - 1000 pcs. per pack is available through simmering.pl, a specialist B2B industrial supply platform providing O-rings, oil seals, rolling bearings and industrial components.

The platform serves manufacturing companies, wholesale customers, maintenance departments and technical procurement teams.

Warehouse operations are based in Lublin, Poland, supporting industrial procurement and international distribution.

Worldwide shipping from stock in Poland.