O-ring 4.48x1.78 NBR 70 ShA

O-ring 4.48x1.78 NBR 70 ShA - 100 pcs

O-ring 4.48x1.78 NBR 70 ShA is an elastomeric sealing ring with a nominal inside diameter of 4.48 mm and a cross-section of 1.78 mm, supplied in a pack of 100 pcs. The O-ring is manufactured from NBR nitrile rubber with a nominal hardness of 70 ShA. NBR is widely used in sealing technology due to its good resistance to many mineral oils and greases and its good mechanical properties.

Technical data - O-ring 4.48x1.78 NBR 70 ShA

What does O-ring 4.48x1.78 NBR 70 ShA mean?

The designation identifies the main dimensions, material and hardness of the O-ring.

4.48 - nominal inside diameter of 4.48 mm.

1.78 - nominal cross-section diameter of 1.78 mm.

NBR - nitrile rubber used to manufacture the sealing ring.

70 ShA - nominal elastomer hardness measured on the Shore A scale.

100 pcs - number of O-rings supplied in the package.

The nominal O-ring size is:

4.48x1.78 mm

The first value represents the inside diameter, while the second represents the cross-section diameter.

Dimensions of the 4.48x1.78 O-ring

The nominal dimensions are:

Inside diameter d1: 4.48 mm

Cross-section d2: 1.78 mm

Nominal size:

4.48x1.78 mm

The approximate outside diameter of the uncompressed O-ring is:

8.04 mm

This results from:

4.48 mm + 2 x 1.78 mm = 8.04 mm

The primary size used to identify the product remains 4.48x1.78 mm.

NBR - nitrile rubber

NBR, or acrylonitrile-butadiene rubber, is one of the most widely used elastomers in sealing technology.

Typical properties of NBR include:

• good resistance to many mineral oils

• good resistance to many mineral greases

• good mechanical properties

• good abrasion resistance

• good elasticity for many technical applications

• widespread use in industrial sealing systems

The exact properties depend on the formulation of the specific NBR compound.

What does 70 ShA mean?

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

O-ring hardness influences factors including:

• deformation under compression

• behaviour in the sealing groove

• required compression

• response to pressure

• resistance to extrusion

When selecting an equivalent O-ring, check not only the 4.48x1.78 mm dimensions but also the NBR material and required hardness of 70 ShA.

Operating temperature of NBR

The exact operating temperature range depends on the specific NBR compound and actual operating conditions.

Factors affecting permissible operating temperature include:

• NBR compound formulation

• operating medium

• exposure time

• pressure

• static or dynamic operation

• seal design

If temperature is a critical selection parameter, the operating limits of the specific elastomer compound should be verified.

Chemical resistance of NBR

NBR is particularly associated with applications involving many mineral oils and greases.

However, NBR should not be considered universally resistant to every fluid or chemical.

Compatibility should be checked for the specific:

• oil

• grease

• fuel

• hydraulic fluid

• solvent

• chemical

• concentration

• operating temperature

Chemical resistance can vary depending on the formulation of the NBR compound.

O-ring design and sealing principle

An O-ring is a closed elastomeric sealing ring with a circular cross-section.

When installed in a correctly designed groove, the O-ring is compressed between mating surfaces. Controlled deformation of the elastomer generates sealing contact pressure.

Effective sealing depends on factors including:

• groove geometry

• O-ring compression

• installation clearance

• pressure

• temperature

• operating medium

• mating surface quality

• static or dynamic movement

The 4.48x1.78 mm dimensions alone do not define the complete operating capability of the sealing system.

O-ring 4.48x1.78 NBR vs VMQ

A 4.48x1.78 NBR O-ring and a 4.48x1.78 VMQ O-ring may have identical nominal dimensions but are manufactured from different elastomers.

NBR is nitrile rubber and is commonly selected for applications involving many mineral oils and greases.

VMQ is silicone rubber and is particularly valued for low-temperature flexibility and resistance to ozone, UV radiation and atmospheric ageing.

Identical 4.48x1.78 mm dimensions do not make NBR and VMQ automatically interchangeable.

O-ring 4.48x1.78 NBR vs FKM

NBR and FKM have different chemical structures and operating characteristics.

FKM is a fluoroelastomer with a different chemical and thermal resistance profile from NBR.

Selection between NBR and FKM should consider:

• operating medium

• temperature

• pressure

• static or dynamic operation

• groove geometry

• required hardness

• requirements of the specific application

A 4.48x1.78 FKM O-ring should not be considered a direct replacement for an NBR version solely because the dimensions are identical.

Typical applications of NBR O-rings

NBR O-rings are widely used in technical and industrial sealing systems.

Depending on the compound, operating medium and seal design, NBR O-rings can be used in applications such as:

• hydraulic systems

• pneumatic systems

• industrial machinery and equipment

• mechanical components

• technical connections

• static sealing arrangements

• appropriately designed dynamic sealing arrangements

• applications involving compatible oils and greases

Suitability for a specific application should always be evaluated according to the actual operating conditions.

Alternative designations and reference formats

Natural designation and search variants include:

O-ring 4.48x1.78 NBR 70 ShA

O-ring 4.48x1.78 NBR

NBR O-ring 4.48x1.78

NBR O-ring 4.48x1.78 70 ShA

O-ring NBR 4.48x1.78

O-ring 4.48x1.78 70 Shore A

O-ring 4.48x1.78 NBR 70 Shore

O-ring 4.48x1.78 NBR - 100 pcs

NBR O-ring 4.48x1.78 - 100 pcs

NBR O-ring 4.48x1.78 70 ShA - 100 pcs

4.48 mm ID x 1.78 mm CS NBR O-ring

Selection and interchangeability

Before purchasing or selecting an equivalent O-ring, check:

• inside diameter 4.48 mm

• cross-section 1.78 mm

• NBR material

• hardness 70 ShA

• operating medium

• required temperature range

• pressure

• static or dynamic operation

• groove geometry

• required compression

• requirements of the specific sealing system

An O-ring with identical dimensions manufactured from VMQ, FKM, EPDM or another elastomer is not automatically interchangeable with the NBR version.

Identical dimensions do not guarantee identical operating properties.

Installation

Before installation, make sure that the groove and mating surfaces are clean and free from contaminants.

During installation, avoid:

• cutting the O-ring

• twisting the ring

• excessive stretching

• pulling the O-ring across sharp edges

• contact with burrs

• damaging the elastomer surface

If an assembly lubricant is required, it should be compatible with both the NBR material and the operating medium.

Storage

NBR O-rings should be stored under conditions that minimise contamination, deformation and mechanical damage.

Avoid storing O-rings permanently stretched or strongly deformed.

Before installation, inspect the O-ring surface for cuts, cracks or other visible damage.

FAQ - O-ring 4.48x1.78 NBR 70 ShA

What are the dimensions of the O-ring 4.48x1.78?

The O-ring has a nominal inside diameter of 4.48 mm and a cross-section diameter of 1.78 mm. Its nominal size is 4.48x1.78 mm.

How many O-rings are included in the package?

The package contains 100 pcs of 4.48x1.78 NBR 70 ShA O-rings.

What is the outside diameter of a 4.48x1.78 O-ring?

Based on the nominal dimensions, the approximate uncompressed outside diameter is 8.04 mm. The primary product size remains 4.48x1.78 mm.

What does NBR mean?

NBR stands for acrylonitrile-butadiene rubber, commonly known as nitrile rubber. It is widely used for technical sealing elements.

What does 70 ShA mean?

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

Is NBR resistant to oil?

NBR provides good resistance to many mineral oils and greases. Compatibility should nevertheless be checked for the specific fluid, temperature and NBR compound.

Can a 4.48x1.78 VMQ O-ring replace an NBR O-ring?

Not automatically. VMQ silicone rubber and NBR nitrile rubber have different chemical, thermal and mechanical properties even when their nominal dimensions are identical.

Can a 4.48x1.78 FKM O-ring replace an NBR O-ring?

Replacement should not be based on dimensions alone. The operating medium, temperature, pressure, hardness and requirements of the sealing system should also be considered.

O-ring 4.48x1.78 NBR 70 ShA - key information

O-ring 4.48x1.78 NBR 70 ShA is an elastomeric sealing ring with a 4.48 mm inside diameter and 1.78 mm cross-section, supplied in a pack of 100 pcs. NBR identifies nitrile rubber, while 70 ShA specifies its nominal Shore A hardness. NBR is widely used in industrial sealing systems, including applications involving many compatible mineral oils and greases.

Available from simmering.pl, a specialist supplier of industrial sealing solutions. Stock in Poland with worldwide shipping.