What is the 125x5 mm NBR 70 O-Ring?

The 125x5 mm NBR 70 O-ring is a high-quality metric sealing ring manufactured from NBR (Nitrile Butadiene Rubber) with a hardness of 70 Shore A. Designed to create a reliable seal between two mating surfaces, it effectively prevents leakage of liquids and gases in both static and dynamic sealing applications.

NBR 70 is one of the world's most widely used elastomers for industrial sealing thanks to its excellent resistance to mineral oils, greases, hydraulic fluids and petroleum-based lubricants, combined with outstanding mechanical properties and wear resistance.

The 125 mm internal diameter and 5 mm cross-section make this O-ring suitable for a wide range of industrial, hydraulic, pneumatic and automotive applications.

Technical Specifications

*Temperature range may vary depending on the rubber compound and operating conditions.

Key Features

The 125x5 NBR 70 O-ring offers:

• Excellent sealing performance
• High resistance to mineral oils
• Excellent grease resistance
• Good resistance to hydraulic fluids
• High abrasion resistance
• Good mechanical strength
• Reliable elasticity
• Long service life
• Easy installation
• Cost-effective sealing solution

Typical Applications

This O-ring is commonly used in:

• Hydraulic cylinders
• Pneumatic systems
• Pumps
• Valves
• Compressors
• Hydraulic power units
• Industrial machinery
• Agricultural equipment
• Automotive applications
• Gearboxes
• Fluid handling systems
• General mechanical engineering

NBR Material Properties

NBR (Nitrile Butadiene Rubber) is one of the most widely used sealing materials because it provides:

• Excellent resistance to mineral oils
• Excellent resistance to greases
• Good resistance to hydraulic oils
• Good wear resistance
• High tensile strength
• Reliable sealing performance
• Long operational life

What Does 70 Shore Mean?

70 Shore A is the standard hardness used for most industrial O-rings.

It provides an excellent balance between:

• Flexibility
• Compression resistance
• Wear resistance
• Ease of installation
• Long-term sealing reliability

FAQ

What are the O-ring dimensions?

The O-ring has an inside diameter of 125 mm and a cross-section of 5 mm.

What material is used?

It is manufactured from NBR (Nitrile Butadiene Rubber) with a hardness of 70 Shore A.

Is NBR resistant to oil?

Yes. NBR provides excellent resistance to mineral oils, greases and many petroleum-based lubricants.

Can this O-ring be used in hydraulic systems?

Yes. NBR 70 O-rings are widely used in hydraulic and pneumatic equipment.

Is it suitable for dynamic sealing?

Yes. When installed in a correctly designed groove, it is suitable for both static and many dynamic sealing applications.

Frequently Asked Questions from Mechanics and Engineers

Why is NBR the most popular O-ring material?

NBR combines excellent oil resistance, good mechanical strength, long service life and an economical price, making it suitable for most industrial sealing applications.

What are the most common causes of O-ring failure?

• Incorrect installation
• Incorrect groove dimensions
• Chemical incompatibility
• Excessive temperature
• Excessive pressure
• Twisting during installation
• Abrasion

How can O-ring service life be extended?

Use the correct groove dimensions, lubricate the seal during assembly, avoid twisting and select the appropriate material for the operating environment.