O-ring 194.2x5.7 NBR 70 Shore A

O-ring 194.2x5.7 mm NBR 70 Shore A - Nitrile Rubber Sealing Ring

O-ring 194.2x5.7 mm NBR 70 Shore A is an elastomeric sealing ring with an inside diameter of 194.2 mm, a cross-section diameter of 5.7 mm and a nominal hardness of 70 Shore A. Manufactured from nitrile butadiene rubber (NBR), it is primarily designed to seal connections in machinery and industrial equipment operating with mineral oils, greases and other fluids compatible with the specific elastomer compound.

The 194.2x5.7 mm O-ring can be used in static sealing applications and, in appropriately designed systems, certain dynamic applications. Its suitability depends on groove dimensions, compression, operating pressure, temperature, fluid compatibility and service conditions.

Technical Specifications - O-ring 194.2x5.7 NBR 70 Shore A

Important: The operating temperature range, permissible pressure, chemical resistance and dimensional tolerances must be verified for the specific material compound and application. The designation NBR 70 Shore A alone does not define every property of the seal.

What Does 194.2x5.7 NBR 70 Shore A Mean?

194.2 mm - Inside Diameter

The first value identifies the nominal inside diameter of the O-ring.

In its free, uninstalled condition, the ring has an inside diameter of 194.2 mm.

5.7 mm - Cross-Section Diameter

The second value indicates the diameter of the circular elastomer cross-section.

The 5.7 mm cross-section is important when designing the sealing groove and determining the required compression.

NBR - Nitrile Butadiene Rubber

NBR is an elastomer widely used in technical sealing applications because of its resistance to many mineral oils and lubricating greases.

70 Shore A - Material Hardness

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

It does not specify the maximum operating pressure or temperature.

Dimensions of the 194.2x5.7 mm O-ring

The outside diameter is calculated using the following formula:

D = d1 + 2 × d2

D = 194.2 + 2 × 5.7 = 205.6 mm

This is the nominal geometric outside diameter of the O-ring in its free condition, without accounting for manufacturing tolerances.

How Does an O-ring Seal Work?

An O-ring seals a connection through controlled deformation of the elastomer between mating surfaces.

When installed in a correctly designed groove, the ring is compressed, generating contact pressure against the sealing surfaces.

During operation, fluid pressure may further influence the distribution of sealing contact pressure.

Sealing performance depends on:

• Groove geometry.

• Cross-section compression.

• Ring stretch during installation.

• Surface roughness.

• Installation clearances.

• Temperature.

• Pressure.

• Fluid type.

• NBR compound hardness and properties.

Incorrect selection can result in leakage even when a new O-ring is installed.

Properties of NBR 70 Shore A

Nitrile butadiene rubber is a widely used material in industrial sealing technology.

Resistance to Mineral Oils

NBR is frequently selected for contact with mineral oils used in hydraulic systems, lubrication systems and mechanical drives.

Actual resistance depends on oil composition, chemical additives and temperature.

Resistance to Greases

The material is used in seals operating with many industrial lubricating greases based on mineral oils.

Elasticity

Suitable elasticity allows the ring to conform to sealing surfaces within the designed deformation range.

Hardness of 70 Shore A

A nominal hardness of 70 Shore A is widely used in static seals and selected dynamic sealing applications.

Material Limitations

Standard NBR is not universally resistant to all chemical media.

Compatibility should be carefully verified for:

• Fuels with specific chemical compositions.

• Solvents.

• Ester-based fluids.

• Ozone and prolonged atmospheric exposure.

• Hot water and steam.

• Strongly oxidizing media.

Applications requiring different material properties may benefit from FKM, EPDM, VMQ or other elastomers, depending on the fluid and temperature.

Operating Temperature of NBR O-rings

Typical NBR compounds used in industrial sealing applications often operate within an approximate temperature range of -30°C to +100°C.

However, this is not a confirmed operating temperature range for the specific 194.2x5.7 mm NBR 70 Shore A O-ring.

The permissible temperature depends on:

• Compound formulation.

• Duration of exposure.

• Fluid type.

• Mechanical loading.

• Static or dynamic operating conditions.

For elevated-temperature applications, the material data sheet and chemical compatibility should be checked.

Static and Dynamic Sealing Applications

Static Sealing

The O-ring can be used between components that do not move relative to each other during operation.

Typical examples include:

• Covers.

• Flanges.

• Housings.

• Casings.

• Connections.

• Hydraulic system components.

Dynamic Sealing

In certain designs, O-rings are also used in systems involving relative movement.

These applications require particular attention to:

• Movement speed.

• Friction.

• Lubrication.

• Temperature.

• Pressure.

• Surface wear.

• Risk of O-ring twisting.

Not every O-ring suitable for static sealing is appropriate for dynamic operation.

O-ring 194.2x5.7 and Operating Pressure

Permissible operating pressure cannot be determined solely from the ring dimensions and 70 Shore A hardness.

It depends on:

• Type of sealing arrangement.

• Groove geometry.

• Clearance between components.

• Pressure direction.

• Temperature.

• Elastomer hardness.

• Resistance to extrusion.

• Use of backup rings.

In high-pressure systems, backup rings may be required to prevent the elastomer from being forced into the clearance gap.

NBR 70 Shore A vs NBR 90 Shore A O-rings

A hardness of 90 Shore A does not automatically provide better sealing performance.

Selection must account for the connection design and operating conditions.

NBR vs FKM and EPDM O-rings

This comparison is general. Final material compatibility depends on the specific compound and operating medium.

How to Select the Groove for a 194.2x5.7 O-ring

A correctly designed groove must provide controlled compression of the 5.7 mm cross-section.

The following factors should be considered:

1. Type of sealing application.

2. Direction of pressure.

3. Installation diameter.

4. Permissible O-ring stretch.

5. Groove depth.

6. Groove width.

7. Groove volume fill.

8. Dimensional tolerances.

9. Thermal expansion.

10. Elastomer swelling in the operating medium.

11. Surface roughness.

12. Required compression.

Groove dimensions should not be selected solely on the basis of the nominal cross-section diameter.

Installation of the 194.2x5.7 NBR 70 Shore A O-ring

Step 1. Clean the Surfaces

Remove contamination, remnants of the previous seal and particles that could damage the elastomer.

Step 2. Inspect the Groove

Check groove geometry, surface condition and the presence of sharp edges.

Step 3. Use a Suitable Assembly Lubricant

If required by the application, use a lubricant compatible with NBR and the operating medium.

Step 4. Avoid Twisting the Ring

The O-ring should be positioned evenly in the groove without localized twisting or excessive stretching.

Step 5. Control Compression

During assembly, prevent the ring from being pinched, cut or forced out of the groove.

Step 6. Check Sealing Performance

After installation, perform a sealing inspection according to the procedure applicable to the equipment.

Common Causes of O-ring Failure

Compression Set

Prolonged exposure to temperature and compression may reduce the elastomer's ability to return to its original shape.

Extrusion

Under pressure, the O-ring may be forced into the clearance gap between mating components.

Installation Damage

Sharp edges, unsuitable tools or twisting can cause cuts and localized deformation.

Swelling

Contact with an incompatible medium may change the dimensions and mechanical properties of the material.

Thermal Aging

Prolonged exposure to elevated temperatures may cause loss of elasticity and cracking.

Applications of the 194.2x5.7 NBR O-ring

The O-ring may be used in appropriately designed connections within:

• Hydraulic systems.

• Industrial housings.

• Mechanical gearboxes.

• Covers and casings.

• Lubrication equipment.

• Manufacturing machinery.

• Technical installations.

• Sealing assemblies.

• Equipment operating with mineral oils.

• Systems requiring large-diameter elastomeric sealing rings.

These are general application examples and do not confirm compatibility with specific machine models.

Alternative Designations and Search Terms

The product may also be identified using the following terms:

• O-ring 194.2x5.7 NBR 70 Shore A

• O-ring 194.2x5.7 mm

• NBR O-ring 194.2x5.7

• Nitrile rubber seal 194.2x5.7

• Sealing ring 194.2x5.7

• O-ring 194.2x5.7 NBR 70

• NBR 70 Shore A O-ring 194.2x5.7

• Rubber sealing ring 194.2x5.7

• O-ring 194.2 mm inside diameter

• NBR 70 sealing ring 194.2 mm

Frequently Asked Questions

What are the dimensions of the 194.2x5.7 O-ring?

The inside diameter is 194.2 mm and the cross-section diameter is 5.7 mm.

What is the outside diameter of the O-ring?

The nominal outside diameter is 205.6 mm.

What does NBR mean?

NBR stands for nitrile butadiene rubber, a material widely used in industrial seals, particularly in contact with many mineral oils and greases.

What does 70 Shore A mean?

It indicates the nominal elastomer hardness of 70 units on the Shore A scale.

Is the O-ring resistant to oil?

NBR is generally suitable for many mineral oils, but compatibility must be checked for the specific fluid and operating temperature.

Can this O-ring be used in hydraulic systems?

Yes, provided the groove design, pressure, temperature and fluid are compatible with the sealing material.

Is this O-ring suitable for hot water?

Standard NBR is generally not the preferred material for prolonged exposure to hot water. EPDM is often considered for such applications.

Can it be used in high-pressure applications?

Potentially, provided the system is correctly designed. Permissible pressure depends on groove geometry, clearances, temperature and any backup rings used.

Can the 194.2x5.7 O-ring be used for dynamic sealing?

Under suitable conditions, yes. Movement speed, friction, lubrication and sealing design must be evaluated.

Can NBR 70 be replaced with NBR 90?

Not automatically. The difference in hardness affects deformation, contact pressure and operating conditions.

Should the O-ring be lubricated before installation?

In many applications, a suitable assembly lubricant compatible with the elastomer and operating medium is recommended.

Does the 194.2 mm dimension indicate the groove diameter?

No. It is the nominal inside diameter of the O-ring in its free, uninstalled condition.

O-ring 194.2x5.7 NBR 70 Shore A - Quick Technical Answer

The 194.2x5.7 mm NBR 70 Shore A O-ring is an elastomeric sealing ring with an inside diameter of 194.2 mm, a cross-section diameter of 5.7 mm and a nominal outside diameter of 205.6 mm. Manufactured from nitrile butadiene rubber with a nominal hardness of 70 Shore A, it is designed for appropriately engineered sealing connections, particularly in systems operating with mineral oils and lubricating greases.

NBR O-rings at simmering.pl

simmering.pl supplies NBR, FKM, EPDM and other industrial sealing components for machine manufacturers, technical service providers and maintenance departments.

For accurate product identification, specify the complete designation O-ring 194.2x5.7 mm NBR 70 Shore A, including the inside diameter, cross-section diameter, material and hardness.

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