O-Ring 100x5.68 NBR 70

What Is the O-Ring 100x5.68 NBR 70 Shore A?

The O-Ring 100x5.68 NBR 70 Shore A is a technical sealing ring manufactured from NBR (Nitrile Butadiene Rubber, Buna-N). The dimensions 100x5.68 mm indicate an inside diameter of 100 mm and a cross-section of 5.68 mm. Its 70 Shore A hardness provides a practical balance of elasticity, mechanical strength and sealing performance. This O-ring is particularly suitable for industrial systems operating with compatible mineral oils, lubricating greases and hydraulic fluids.

Technical Specification

Product Type: O-Ring

Material: NBR (Nitrile Butadiene Rubber, Buna-N)

Hardness: 70 Shore A

Inside Diameter: 100 mm

Cross Section: 5.68 mm

Colour: Black

Operating Temperature: Approximately -30°C to +100°C

Chemical Resistance:

• Mineral oils
• Mineral-based hydraulic oils
• Lubricating greases
• Selected petroleum-based fuels
• Industrial lubricants
• Compatible mineral oil-based technical fluids

Applications of the O-Ring 100x5.68 NBR

The 100x5.68 mm NBR O-Ring can be used in:

• Hydraulic systems
• Pneumatic systems
• Industrial pumps
• Valves
• Hydraulic cylinders
• Compressors
• Gearboxes
• Industrial machinery
• Agricultural machinery
• Manufacturing equipment
• Technical fittings
• Machine service and repair

Material compatibility with the operating medium, temperature, pressure and groove design should always be verified before installation.

Why Choose NBR 70 Shore A?

NBR 70 Shore A is one of the most commonly used elastomer compounds in industrial sealing technology. Nitrile rubber is particularly valued for its resistance to mineral oils and lubricating greases.

Its key properties include:

• Excellent resistance to mineral oils
• Good resistance to lubricating greases
• High abrasion resistance
• Good mechanical strength
• Good elasticity
• Reliable sealing performance
• Suitability for many static and dynamic applications
• Stable performance under typical industrial conditions

The 70 Shore A hardness provides a useful balance between flexibility and resistance to deformation.

Hydraulic and Pneumatic Applications

The O-Ring 100x5.68 NBR 70 Shore A can be used in hydraulic systems operating with compatible mineral oil-based fluids. NBR O-rings are also widely used in pneumatic cylinders, valves, fittings and other compressed-air equipment.

Reliable sealing depends not only on the elastomer but also on correct groove dimensions, compression, surface condition, pressure and operating temperature.

Machine Service and Maintenance

The 100x5.68 mm O-ring is suitable for maintenance, repair and replacement of sealing components in industrial machinery and equipment.

For maintenance departments, accurate identification of the 100 mm inside diameter, 5.68 mm cross-section and NBR 70 Shore A material is important when selecting a replacement seal.

NBR is particularly useful where the sealing element is exposed to compatible oils or greases and the operating conditions do not require a specialized elastomer such as FKM or EPDM.

Installation Recommendations

Before installation:

• Clean the sealing groove
• Check the condition of mating surfaces
• Remove or protect sharp installation edges
• Avoid excessive stretching
• Use only assembly lubricants compatible with NBR
• Ensure the O-ring is not twisted during installation

Cuts, scratches or excessive stretching during assembly may cause premature leakage or seal failure.

Frequently Asked Questions (FAQ)

What does the size 100x5.68 mean?
The first dimension is the 100 mm inside diameter, while the second dimension is the 5.68 mm cross-section thickness.

Is the O-Ring 100x5.68 NBR suitable for oil?
Yes. NBR provides very good resistance to many mineral oils and is widely used in oil-lubricated machinery.

Can this O-ring be used in hydraulic systems?
Yes, provided that the hydraulic fluid is compatible with NBR and the groove, pressure and temperature conditions are suitable.

Is 70 Shore A suitable for industrial machinery?
Yes. 70 Shore A is one of the most widely used hardness levels for NBR O-rings and provides a good balance between elasticity and mechanical resistance.

Is NBR suitable for prolonged outdoor exposure?
NBR is not the preferred elastomer for prolonged exposure to ozone, UV radiation and weathering. Another material may be more suitable depending on the operating medium and temperature.

Frequently Asked Questions from Service Technicians and Mechanics

Can a 100x5.68 O-ring be replaced with a different cross-section?
Not without checking the groove design. Changing the cross-section alters O-ring compression and may result in leakage or premature seal damage.

Can an NBR O-ring be used with gear oil?
In many applications, yes. However, compatibility with the specific gear oil formulation and operating temperature should be verified.

Is this O-ring suitable for static sealing?
Yes. NBR O-rings are widely used for static sealing when the groove dimensions and compression are correctly selected.

How can I identify a worn O-ring?
Typical signs include flattening, cracking, hardening, cuts, loss of elasticity or visible surface damage.

Can the O-ring be lubricated before installation?
Yes. A thin layer of a suitable lubricant can reduce installation friction, provided it is compatible with both NBR and the operating medium.