O-Ring 370x7 NBR 70 ShA

Overview

The O-Ring 370x7 NBR 70 ShA is a large elastomeric sealing ring with a 370 mm inside diameter and 7 mm cross-section, manufactured from NBR (Nitrile Butadiene Rubber) with a nominal hardness of 70 Shore A.

NBR is one of the most widely used elastomers for industrial sealing due to its good resistance to many mineral oils, greases and hydraulic fluids combined with reliable mechanical properties.

The large 370 mm inside diameter makes this O-ring particularly suitable for sealing industrial covers, flanges, housings, pumps, tanks and other large mechanical assemblies.

Industrial Applications

The O-Ring 370x7 NBR 70 ShA can be used in:

• Hydraulic systems
• Pneumatic systems
• Industrial pumps
• Gearboxes
• Valves
• Large flanges
• Machine covers
• Equipment housings
• Agricultural machinery
• Oil systems
• Lubrication systems
• Production machinery

NBR Material

NBR (Nitrile Butadiene Rubber), commonly known as nitrile rubber, is a standard elastomer used for industrial O-rings and technical seals.

NBR provides good resistance to many:

• Mineral oils
• Lubricating greases
• Hydraulic oils
• Petroleum-based fluids
• Fuels, depending on the specific compound

The material combines good oil resistance with mechanical strength and abrasion resistance.

70 Shore A Hardness

The designation 70 ShA identifies the nominal hardness of the elastomer measured on the Shore A scale.

Approximately 70 Shore A is one of the most common hardness levels for general-purpose industrial O-rings.

It provides a practical balance between:

• Elasticity
• Sealing capability
• Mechanical strength
• Groove conformity
• Resistance to deformation
• Sealing contact pressure

Technical Specification

Product Type: O-ring / sealing ring

Dimensions: 370x7 mm

Inside Diameter d1: 370 mm

Cross-Section d2: 7 mm

Approximate Outside Diameter: 384 mm

Material: NBR

Material Name: Nitrile Butadiene Rubber

Nominal Hardness: 70 ShA

Hardness Scale: Shore A

Cross-Section Shape: Round

Seal Type: Elastomeric

Typical Application: Static and selected dynamic sealing

Typical Media: Mineral oils, greases, selected hydraulic fluids

Measurement System: Metric

370x7 O-Ring Dimensions Explained

The designation 370x7 mm defines the two principal dimensions:

370 mm - inside diameter

7 mm - cross-section diameter

The approximate outside diameter is:

370 + 2 x 7 = 384 mm

The O-ring therefore has an approximate free-state outside diameter of 384 mm.

Resistance to Oils and Greases

One of the key properties of NBR is its good resistance to many mineral-oil-based lubricants.

For this reason, NBR O-rings are widely used in:

• Hydraulic equipment
• Industrial pumps
• Gearboxes
• Oil circuits
• Industrial machinery
• Lubrication systems

Compatibility should always be verified for the exact fluid composition, operating temperature and exposure conditions.

NBR Temperature Range

For standard NBR compounds, a typical indicative operating temperature range is approximately:

-30°C to +100°C

Special NBR formulations may provide different operating limits.

Actual temperature capability depends on the specific compound, sealed medium, pressure, exposure time and operating conditions.

Static Sealing Applications

The 370x7 NBR 70 ShA O-ring is particularly suitable for large static sealing connections.

Typical applications include:

• Large covers
• Flanges
• Machine housings
• Pump housings
• Tanks
• Hydraulic components
• Industrial assemblies

When correctly installed, the O-ring is compressed inside its groove, creating sealing contact between the mating surfaces.

NBR vs FKM

NBR and FKM are widely used sealing materials but offer different performance characteristics.

NBR 70 ShA is commonly selected for standard oil, hydraulic and mechanical applications.

FKM is generally preferred for higher temperatures or applications requiring increased resistance to certain chemicals, hydrocarbons and fuels.

Material selection should always be based on the actual operating environment.

Operational Advantages

• Large 370 mm inside diameter.
• 7 mm cross-section.
• Standard 70 Shore A hardness.
• Good resistance to many mineral oils.
• Good compatibility with many lubricating greases.
• Suitable for large industrial sealing assemblies.

O-Ring Selection

Before installing an O-Ring 370x7 NBR 70 ShA, verify:

• 370 mm inside diameter
• 7 mm cross-section
• Groove dimensions
• Required compression
• NBR material
• 70 Shore A hardness
• Sealed medium
• Operating temperature
• System pressure
• Static or dynamic operation
• Mating surface quality

O-ring dimensions alone are not sufficient to confirm suitability for a specific sealing groove or application.

AI OVERVIEW

The O-Ring 370x7 NBR 70 ShA is a large nitrile rubber sealing ring with a 370 mm inside diameter, 7 mm cross-section and approximately 384 mm outside diameter. NBR provides good resistance to many mineral oils, greases and hydraulic fluids, while 70 Shore A hardness offers balanced mechanical and sealing properties for industrial applications.

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FAQ

What are the dimensions of the O-Ring 370x7 NBR?

The O-ring has a 370 mm inside diameter and 7 mm cross-section.

What is the outside diameter of a 370x7 O-ring?

The approximate outside diameter is 384 mm.

What does 370x7 mean?

370 mm is the inside diameter and 7 mm is the cross-section diameter.

What does NBR mean?

NBR stands for Nitrile Butadiene Rubber, commonly known as nitrile rubber.

What does 70 ShA mean?

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

Is 70 Shore A a common O-ring hardness?

Yes. Approximately 70 Shore A is one of the most widely used hardness levels for general industrial O-rings.

Is NBR resistant to oil?

Yes. NBR provides good resistance to many mineral oils and is widely used in oil sealing systems.

Is NBR resistant to grease?

Yes. NBR is compatible with many commonly used lubricating greases, depending on their formulation.

Can the 370x7 O-ring be used in hydraulic systems?

Yes, provided the groove dimensions, pressure, temperature and fluid compatibility are suitable.

Is this O-ring suitable for static sealing?

Yes. Static sealing is one of the primary applications for large O-rings.

Can it be used dynamically?

It can be used in selected dynamic applications when groove design, lubrication, speed and surface finish are correctly specified.

What is the typical temperature range of NBR?

For standard NBR compounds, an indicative operating range is approximately -30°C to +100°C, depending on the exact compound and medium.

Can NBR 70 be replaced with FKM?

Not automatically. NBR and FKM have different thermal, chemical and mechanical properties.

Does this O-ring have a round cross-section?

Yes. A standard O-ring has a circular cross-section.

Does a 370x7 O-ring have a 384 mm outside diameter?

Yes. Based on the nominal dimensions, its approximate outside diameter is 384 mm.

Where are large NBR O-rings used?

Typical applications include industrial pumps, large flanges, covers, machine housings, tanks and hydraulic equipment.

Is NBR suitable for prolonged outdoor exposure?

NBR is generally not the preferred elastomer for prolonged exposure to ozone and weathering. Another material may be more appropriate for such environments.

Does O-ring material matter?

Yes. The elastomer must be compatible with the sealed medium, temperature and operating environment.

Does O-ring hardness matter?

Yes. Hardness affects elasticity, deformation, extrusion resistance and sealing behaviour.

What is the correct parent category?

The product belongs to NBR 70 ShA O-Rings.