O-ring 200x4 NBR 90 ShA

What is the 200X4 NBR 90 ShA O-Ring?

The 200X4 NBR 90 ShA O-Ring is a precision metric sealing ring manufactured from NBR (Nitrile Butadiene Rubber) with a hardness of 90 Shore A. Designed for demanding industrial applications, it provides reliable sealing in systems operating under higher pressures and increased mechanical loads compared to standard 70 Shore A seals. With an inside diameter of 200 mm and a 4 mm cross-section, this O-ring is commonly used in hydraulic systems, pneumatic equipment, industrial machinery and OEM assemblies where improved extrusion resistance and long service life are required.

Design and Construction

The O-ring features a precision-moulded circular cross-section designed to provide effective sealing when installed in a correctly engineered groove.

Key features include:

• Metric dimensions
• NBR (Nitrile Butadiene Rubber) material
• 90 Shore A hardness
• Round sealing profile
• Uniform elastomer structure
• High resistance to mechanical deformation

Compared with standard 70 Shore A O-rings, the 90 Shore A version offers greater resistance to extrusion in high-pressure applications while maintaining reliable sealing performance.

Technical Specification

Manufacturer: GRN

Product Type: Metric O-Ring

Part Number: 200X4 90NBR ShA

Material: NBR (Nitrile Butadiene Rubber)

Hardness: 90 Shore A

Inside Diameter: 200 mm

Cross Section: 4 mm

Profile: Round

Colour: Black

How Does an O-Ring Work?

An O-ring seals by elastic compression between two mating surfaces.

During installation, the seal is compressed within its groove, creating continuous contact pressure that prevents leakage of liquids or gases. As system pressure increases, the pressure further energizes the seal, improving its sealing capability.

The higher hardness of 90 Shore A reduces deformation under heavy loads, making these O-rings particularly suitable for demanding hydraulic and industrial applications.

Why Choose NBR 90 Shore A?

NBR 90 Shore A is selected when increased hardness and improved resistance to extrusion are required.

Key advantages include:

• Excellent resistance to mineral oils
• Good compatibility with lubricating greases
• Improved extrusion resistance
• High mechanical strength
• Good abrasion resistance
• Suitable for higher-pressure sealing applications
• Long service life under demanding operating conditions

Selecting the Correct O-Ring

Proper selection should consider:

• Inside diameter
• Cross-section
• Material
• Hardness
• Operating medium
• Working pressure
• Operating temperature
• Static or dynamic application
• Groove dimensions
• Equipment manufacturer's specifications

Using the correct hardness is just as important as selecting the correct dimensions.

Installation Recommendations

For reliable sealing performance:

• Clean the sealing groove thoroughly.
• Remove burrs and sharp edges.
• Lubricate the seal if recommended.
• Avoid twisting or overstretching during installation.
• Inspect mating surfaces before assembly.

Proper installation significantly extends seal life and reduces the risk of leakage.

Common Causes of O-Ring Failure

Typical causes of seal failure include:

• Incorrect hardness selection
• Wrong dimensions
• Mechanical damage during installation
• Excessive compression
• Chemical incompatibility
• Contaminated sealing surfaces
• Improper groove design
• Elastomer ageing

Selecting the correct material and hardness helps minimize premature failures.

Industrial Applications

The 200X4 NBR 90 ShA O-Ring is suitable for equipment designed for this specific metric size.

Typical applications include:

• Hydraulic cylinders
• Hydraulic valves
• Pumps
• Pneumatic systems
• Industrial machinery
• Gearboxes
• Manufacturing equipment
• Agricultural machinery
• OEM production
• Industrial MRO maintenance

Always verify compatibility with the equipment manufacturer's technical documentation.

OEM and Industrial Maintenance

O-rings with 90 Shore A hardness are frequently specified in applications requiring increased resistance to deformation under pressure.

They are widely used by:

• OEM manufacturers
• Hydraulic equipment builders
• Industrial maintenance departments
• Machine service companies
• Heavy industry
• MRO operations

Using the correct high-hardness seal helps improve reliability and reduce maintenance intervals.

Why Engineers Choose 90 Shore A O-Rings

• Increased hardness for demanding applications
• Improved extrusion resistance
• Excellent oil and grease resistance
• Reliable sealing under higher pressures
• Good wear resistance
• Suitable for OEM and industrial maintenance
• Standard metric dimensions
• Long operational service life

Frequently Asked Questions (FAQ)

What does 90 Shore A mean?

It is the hardness rating of the NBR material. Compared with 70 Shore A, it is significantly harder and offers better resistance to deformation and extrusion.

Can this O-ring be used with mineral oils?

Yes. NBR is widely used in systems operating with mineral oils and lubricating greases.

Why choose 90 Shore A instead of 70 Shore A?

90 Shore A is typically selected for applications involving higher pressures or where greater resistance to extrusion is required.

Is this O-ring suitable for hydraulic systems?

Yes, provided the dimensions and operating conditions match the equipment manufacturer's specifications.

Can it be used for dynamic sealing?

Yes, when the application is properly designed and operating parameters are appropriate.

Where are high-hardness O-rings commonly used?

They are commonly installed in hydraulic equipment, industrial machinery, heavy-duty systems and OEM applications requiring enhanced mechanical performance.