O-ring NBR 145x3.55 mm 70 Shore A

O-ring NBR 145x3.55 mm 70 Shore A is an elastomeric sealing ring made from nitrile rubber (NBR), with a nominal inside diameter of 145 mm, a 3.55 mm cross-section and a hardness of 70 Shore A. Its circular cross-section is designed for controlled compression in a correctly dimensioned sealing groove. The nominal outside diameter calculated from the dimensions is approximately 152.1 mm.

Technical data

The nominal outside diameter of approximately 152.1 mm is geometrically derived from the O-ring dimensions:

145 mm + 2 x 3.55 mm = 152.1 mm.

No exact operating temperature range, specific NBR compound formulation, certifications or material approvals are stated because these parameters cannot be determined from the product designation alone.

What does O-ring NBR 145x3.55 mm 70 Shore A mean?

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

NBR - nitrile rubber, an elastomer widely used for technical sealing elements.

145x3.55 mm - O-ring dimensions, where 145 mm is the nominal inside diameter and 3.55 mm is the nominal cross-section.

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

O-ring 145x3.55 mm dimensions

O-ring dimensions are specified as:

ID x CS

For this product:

145x3.55 mm

where:

• ID 145 mm - nominal inside diameter

• CS 3.55 mm - nominal circular cross-section

The nominal outside diameter can be calculated as:

OD = ID + 2 x CS

OD = 145 mm + 2 x 3.55 mm

OD = approximately 152.1 mm

The 152.1 mm value is a geometrically calculated nominal outside diameter and not a separate product size designation.

NBR - O-ring material

NBR, or nitrile rubber, is one of the most widely used elastomers in technical sealing applications.

Appropriately selected NBR compounds are commonly used in contact with many mineral oils and greases.

The actual resistance and performance of a specific NBR O-ring depend on the particular compound and operating conditions.

The NBR designation alone does not confirm:

• an exact operating temperature range

• compatibility with every oil or chemical

• food-contact approval

• a specific compound formulation

• particular certifications or approvals

These properties should be verified for the specific elastomer compound whenever they are critical to the application.

What does 70 Shore A mean?

70 Shore A specifies the nominal hardness of the elastomer on the Shore A scale.

Hardness is an important O-ring parameter because it influences deformation under load and the behaviour of the seal within its groove.

When selecting a replacement, hardness should not be ignored. An NBR 145x3.55 mm O-ring with a different hardness is not automatically equivalent to the 70 Shore A version simply because its dimensions are identical.

Construction of the NBR 145x3.55 mm O-ring

The O-ring is a closed sealing ring made from NBR elastomer with a nominal circular cross-section of 3.55 mm.

Its basic uninstalled dimensions are:

• inside diameter 145 mm

• cross-section 3.55 mm

• calculated outside diameter approximately 152.1 mm

When installed in a correctly designed groove, the O-ring cross-section is compressed between the mating surfaces.

This controlled deformation of the elastomer creates the sealing contact.

Sealing performance depends on several factors, including:

• groove geometry

• compression

• O-ring stretch

• pressure

• operating temperature

• sealed medium

• mating surface condition

• static or dynamic operation

O-ring NBR 145x3.55 70 Shore A vs FKM 145x3.55

NBR and FKM O-rings may have identical nominal dimensions of 145x3.55 mm but are made from different elastomer families.

NBR - nitrile rubber.

FKM/FPM - fluoroelastomer.

The material difference affects properties such as chemical compatibility and behaviour in different media and operating temperatures.

An NBR O-ring should therefore not be replaced with an FKM O-ring, or vice versa, solely because the dimensions are identical.

70 Shore A O-ring vs other hardness grades

Two NBR O-rings with identical 145x3.55 mm dimensions may have different hardness grades.

A change in elastomer hardness can affect:

• deformation characteristics

• sealing compression

• behaviour under pressure

• installation

• performance in the specific groove

If the application specifies NBR 70 Shore A, the suitability of a different hardness grade should be technically verified before substitution.

Alternative designations and search references

Natural reference formats for this product include:

• O-ring NBR 145x3.55 mm 70 Shore A

• O-ring 145x3.55 NBR 70 Shore A

• NBR O-ring 145x3.55 70 Shore A

• 145x3.55 NBR O-ring

• NBR sealing ring 145x3.55 mm

• O-ring seal NBR 145x3.55 mm

• O-ring 145x3.55 mm NBR

• NBR 145x3.55 mm 70 Shore A

No OEM or cross-reference numbers are provided because none have been confirmed for this product.

How to select an NBR 145x3.55 mm 70 Shore A O-ring

Before purchasing or replacing the O-ring, verify:

• inside diameter 145 mm

• cross-section 3.55 mm

• NBR material

• 70 Shore A hardness

• groove geometry

• required compression

• O-ring stretch

• sealed medium

• operating temperature

• pressure

• static or dynamic operation

• mating surface condition

Matching the 145x3.55 mm dimensions alone does not guarantee complete interchangeability. Material and hardness are also important selection parameters.

Applications

O-ring NBR 145x3.55 mm 70 Shore A is a sealing element designed for installation in an appropriately dimensioned groove.

NBR O-rings can be used in static sealing arrangements and in suitable dynamic sealing systems when the design and operating conditions permit.

The designation NBR 145x3.55 70 Shore A alone does not confirm suitability for a specific pump, valve, hydraulic system, machine, vehicle or other equipment.

Installation and operation

Before installation, thoroughly clean the groove and mating surfaces.

During installation, avoid:

• cutting the O-ring

• contact with sharp edges

• pulling the seal over unprotected threads

• twisting the ring

• excessive stretching

• contamination of the sealing surfaces

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

Store the O-ring in conditions that minimise exposure to light, ozone, excessive heat and permanent mechanical deformation.

FAQ

What are the dimensions of the NBR 145x3.55 O-ring?

The O-ring has a nominal inside diameter of 145 mm and a circular cross-section of 3.55 mm.

What is the outside diameter of a 145x3.55 O-ring?

The calculated nominal outside diameter is approximately 152.1 mm, based on 145 mm + 2 x 3.55 mm.

What does NBR mean?

NBR stands for nitrile rubber, an elastomer widely used for technical sealing elements.

What does 70 Shore A mean?

70 Shore A specifies the nominal hardness of the elastomer on the Shore A hardness scale.

Can an NBR 145x3.55 O-ring be replaced with an FKM 145x3.55 O-ring?

Not automatically. Although the dimensions may be identical, NBR and FKM have different material properties. Compatibility with the medium, temperature and other operating conditions must be checked.

Can I use an NBR 145x3.55 O-ring with a different hardness?

Not automatically. If the application specifies 70 Shore A, a different hardness should be verified against the groove design and operating conditions.

Does 145x3.55 mean the inside diameter?

Yes. The first value, 145 mm, is the nominal inside diameter. The second value, 3.55 mm, is the nominal cross-section.

Is the NBR 145x3.55 mm 70 Shore A O-ring sold individually?

Yes. This size is sold individually as 1 pc.

O-ring NBR 145x3.55 mm 70 Shore A - key information

O-ring NBR 145x3.55 mm 70 Shore A is a nitrile rubber sealing ring with a nominal inside diameter of 145 mm, a 3.55 mm circular cross-section and 70 Shore A hardness. Its calculated nominal outside diameter is approximately 152.1 mm. Dimensions, NBR material and hardness should all be verified when selecting a replacement.

O-ring NBR 145x3.55 mm 70 Shore A is available from the specialist industrial supplier simmering.pl, with stock in Poland and worldwide shipping. Assistance with O-ring identification and technical seal selection is also available.

PRESTA SUMMARY

O-ring NBR 145x3.55 mm 70 Shore A - nitrile rubber sealing ring with a nominal inside diameter of 145 mm and 3.55 mm cross-section. Hardness 70 Shore A and calculated nominal outside diameter approximately 152.1 mm. Sold individually as 1 pc. Available from simmering.pl with stock in Poland and worldwide shipping.