O-Ring 40x3 mm MVQ/VMQ 70 Shore A - Silicone Rubber Sealing Ring

O-Ring 40x3 mm MVQ/VMQ 70 Shore A - Silicone Rubber Sealing Ring

O-Ring 40x3 mm MVQ/VMQ 70 Shore A is an industrial silicone rubber sealing ring with a nominal inside diameter of 40 mm, a cross-sectional diameter of 3 mm and a nominal outside diameter of 46 mm. Manufactured from VMQ/MVQ silicone elastomer with a nominal hardness of 70 Shore A, this O-ring is primarily designed for static sealing applications in industrial equipment, mechanical housings and technical assemblies. Silicone rubber offers favorable temperature-related properties and flexibility. Correct seal selection requires consideration of the sealed medium, operating temperature, pressure and groove geometry.

Technical Specifications - O-Ring 40x3 MVQ/VMQ 70 Shore A

The nominal outside diameter is calculated as follows:

46 mm = 40 mm + 2 x 3 mm

The value of 46 mm represents the nominal geometric outside diameter of the undeformed O-ring, excluding manufacturing tolerances.

Exact dimensional tolerances, operating temperature limits, chemical resistance, mechanical properties and permissible operating pressure must be verified against the technical documentation for the specific silicone compound.

What Does O-Ring 40x3 MVQ/VMQ 70 Shore A Mean?

The product designation identifies the essential technical characteristics:

• 40 - nominal inside diameter of 40 mm.

• 3 - nominal cross-sectional diameter of 3 mm.

• MVQ / VMQ - designations used for silicone rubber in elastomeric sealing products.

• 70 Shore A - nominal elastomer hardness measured on the Shore A scale.

The designation 40x3 mm does not refer to the inside and outside diameters. It identifies the inside diameter and cross-sectional diameter of the O-ring.

VMQ and MVQ - Are They the Same Material?

VMQ is the standardized designation for silicone rubber. MVQ is an alternative designation encountered in commercial descriptions of sealing products.

Both designations refer to the silicone elastomer family, but they do not define the complete compound formulation.

Different silicone compounds may exhibit different:

• Mechanical properties.

• Chemical resistance.

• Operating temperature ranges.

• Compression set characteristics.

• Aging resistance.

• Compatibility with specific media.

Therefore, two 40x3 mm VMQ O-rings with nominal hardness of 70 Shore A are not necessarily interchangeable in every application.

Construction and Operating Principle of the 40x3 Silicone O-Ring

The 40x3 mm MVQ/VMQ 70 Shore A O-ring is a one-piece elastomeric sealing ring with a circular cross-section.

When installed in a correctly designed sealing groove, it is elastically compressed between two mating surfaces.

The resulting contact pressure helps prevent liquids or gases from passing through the sealing interface.

The O-ring does not require metal reinforcement, a spring or an additional sealing lip.

Effective sealing depends on:

• Correct groove dimensions.

• Appropriate compression of the 3 mm cross-section.

• Groove fill.

• Surface finish.

• Extrusion gap dimensions.

• Operating temperature.

• Operating pressure.

• Chemical compatibility.

• Compression set.

Why Is the 3 mm Cross-Section Important?

The 3 mm cross-sectional diameter determines the amount of elastomer occupying the groove and influences its behavior under compression.

A 40x3 mm O-ring should not automatically be replaced with a 40x2.5 mm or 40x3.5 mm O-ring.

Changing the cross-sectional diameter may result in insufficient sealing contact pressure or excessive groove fill.

Either condition can cause leakage or damage to the sealing element.

Silicone Rubber VMQ 70 Shore A - Material Properties

Resistance to Temperature Changes

VMQ silicone rubber is commonly used in sealing applications requiring flexibility at low temperatures and resistance to elevated temperatures.

Its favorable temperature-related characteristics are among the reasons silicone is used in industrial sealing technology.

However, the exact minimum and maximum operating temperatures depend on the compound formulation, exposure duration, sealed medium and mechanical loading.

Specific operating temperature limits should not be assigned to this O-ring without verified material documentation.

Hardness of 70 Shore A

A nominal hardness of 70 Shore A describes the elastomer's resistance to indentation.

This parameter influences:

• Force required to compress the sealing ring.

• Contact pressure against the sealing surfaces.

• O-ring behavior inside the groove.

• Deformation under mechanical loading.

• Risk of elastomer extrusion into a clearance gap.

A hardness value of 70 Shore A does not independently determine the maximum permissible operating pressure.

Pressure capability also depends on the joint design, extrusion gap and mechanical properties of the specific silicone compound.

Chemical Resistance of VMQ Silicone

VMQ silicone rubber is not universally resistant to all chemicals.

Before installation, compatibility should be verified for:

• Mineral oils.

• Fuels.

• Solvents.

• Cleaning agents.

• Industrial process fluids.

• Gases.

• Other substances present in the system.

Elastomer performance also depends on temperature, medium concentration and exposure duration.

Aging Resistance

Silicone rubber is used in applications requiring favorable aging characteristics and flexibility under changing temperature conditions.

However, the service life of a particular O-ring depends on the material formulation, operating conditions and installation method.

Mechanical Limitations

Compared with certain elastomers designed for intensive dynamic operation, silicone rubber may exhibit lower abrasion and tear resistance.

For this reason, the 40x3 mm VMQ O-ring should be protected from sharp edges, excessive stretching and twisting during installation.

VMQ vs NBR, FKM and EPDM O-Rings

O-rings measuring 40x3 mm can be manufactured from different elastomeric materials, but identical dimensions do not mean identical performance.

Elastomer selection should be based on the sealed medium, temperature, pressure and operating conditions rather than dimensions alone.

Alternative Designations and Search References

The product may appear under the following commercial designations:

• O-Ring 40x3 MVQ 70 Shore A

• O-Ring 40x3 VMQ 70 Shore A

• Silicone O-Ring 40x3 mm

• Silicone O-Ring 40x3 70 Shore A

• Silicone Sealing Ring 40x3 mm

• Silicone Rubber Seal 40x3 mm

• VMQ O-Ring 40x3

• MVQ O-Ring 40x3

• O-Ring 40x3 Silicone 70 ShA

• Silicone Rubber O-Ring 40x3 70 Shore A

• VMQ O-Ring 40 mm ID x 3 mm CS

• Metric Silicone O-Ring 40x3 mm

These are alternative commercial names and technical descriptions of the same nominal sealing ring type.

They are not verified OEM part numbers or manufacturer-specific cross-references.

Selecting the Correct 40x3 mm VMQ 70 Shore A O-Ring

Before purchasing and installing the O-ring, verify:

• Inside diameter: 40 mm.

• Cross-sectional diameter: 3 mm.

• Nominal outside diameter: 46 mm.

• Material: VMQ / MVQ.

• Nominal hardness: 70 Shore A.

• Groove dimensions and tolerances.

• Required compression.

• Installation stretch.

• Type of sealed medium.

• Operating temperature and pressure.

• Static or dynamic sealing conditions.

• Surface finish.

• Extrusion gap dimensions.

How Should the Groove Be Designed for a 40x3 O-Ring?

The groove must allow appropriate elastic compression of the 3 mm cross-section while providing sufficient space for elastomer deformation.

The groove depth should not simply be assumed to equal 3 mm.

Insufficient compression may result in leakage, while excessive compression may damage the ring or accelerate permanent deformation.

Groove dimensions must be selected according to the requirements of the specific sealing arrangement.

Can a 40x3 mm O-Ring Be Replaced with a 40x3.5 mm O-Ring?

Not automatically.

The difference in cross-sectional diameter is 0.5 mm and may significantly affect compression and groove fill.

Interchangeability requires verification of the installation geometry.

Can a 40x3 mm O-Ring Be Replaced with a 39x3 mm O-Ring?

Not automatically.

The nominal inside diameter differs by 1 mm, which may affect installation stretch and positioning inside the groove.

Can VMQ 70 Shore A Be Replaced with NBR 70 Shore A?

Not always.

Despite identical nominal hardness, the two elastomers differ in chemical, thermal and mechanical properties.

Material substitution requires verification of operating conditions.

Typical Applications of Silicone O-Rings 40x3 mm

The 40x3 mm VMQ 70 Shore A silicone O-ring may be used in correctly designed sealing arrangements where the material is compatible with the sealed medium and operating conditions.

Potential applications include:

• Static sealing of mechanical housings.

• Covers of industrial equipment.

• Mechanical assemblies.

• Technical connections requiring elastomeric sealing rings.

• Components with correctly designed O-ring grooves.

• Static sealing of compatible liquids and gases.

• Industrial equipment repair and maintenance.

These are general applications of silicone O-ring technology, not verified OEM applications for this specific product.

Is a Silicone O-Ring Suitable for Dynamic Sealing?

Certain silicone O-rings may be used in appropriately engineered dynamic sealing systems.

However, such applications require consideration of friction, movement speed, lubrication, temperature and wear resistance.

Not every VMQ 70 Shore A O-ring is suitable for intensive dynamic operation.

Food Contact and Medical Applications

Silicone rubber is used in certain products intended for food contact and medical applications.

However, this does not mean that every VMQ O-ring has the required approvals.

Regulated applications require documentation confirming the compliance of the specific compound and finished product.

The VMQ 70 Shore A designation does not automatically indicate FDA compliance or food-contact certification.

Installation and Maintenance of the 40x3 O-Ring

Preparing the Sealing Surfaces

Before installation, clean the groove and mating surfaces.

Remove burrs, sharp edges and contaminants that could damage the elastomer.

Correct Installation

During installation:

• Position the O-ring evenly inside the groove.

• Avoid twisting the cross-section.

• Do not stretch the ring excessively.

• Avoid sharp installation tools.

• Use only assembly lubricants compatible with silicone and the sealed medium.

• Check that the O-ring is not pinched during assembly.

Inspection During Service

During scheduled maintenance, inspect the sealing ring for:

• Cracking and tearing.

• Permanent cross-sectional flattening.

• Elastomer swelling.

• Loss of elasticity.

• Abrasion.

• Other mechanical damage.

Replace the O-ring if damage or deterioration is detected.

Storage

Store silicone O-rings in a clean, dry environment without excessive stretching or permanent compression.

Protect them from contamination and mechanical damage.

Frequently Asked Questions - O-Ring 40x3 MVQ/VMQ 70 Shore A

1. What are the dimensions of the 40x3 MVQ 70 Shore A O-ring?

The nominal inside diameter is 40 mm, the cross-sectional diameter is 3 mm and the nominal outside diameter is 46 mm.

2. What material is the 40x3 MVQ O-ring made from?

It is manufactured from silicone rubber, designated VMQ or MVQ.

3. What does 70 Shore A mean?

It indicates the nominal hardness of the elastomer, measured as 70 on the Shore A scale.

4. Do VMQ and MVQ both refer to silicone rubber?

Yes. VMQ is the standardized designation for silicone rubber, while MVQ is an alternative designation encountered in commercial product descriptions.

5. Is the 40x3 mm silicone O-ring suitable for high temperatures?

VMQ silicone rubber is commonly used in sealing applications operating across a broad temperature range. Exact limits must be verified for the specific compound.

6. Can a 40x3 mm VMQ O-ring replace an NBR O-ring?

Not automatically. The materials differ in chemical resistance, thermal behavior and mechanical properties.

7. Can a 40x3 mm O-ring replace a 40x2.5 mm O-ring?

Not automatically. The cross-sectional difference is 0.5 mm, affecting compression and groove fill.

8. Is the 40x3 mm silicone O-ring suitable for food contact?

Food-contact suitability cannot be confirmed from the VMQ designation alone. Appropriate material and product documentation is required.

9. Is the 40x3 mm VMQ O-ring resistant to oils?

Resistance depends on the type of oil, operating temperature and specific silicone compound. Compatibility must be verified.

10. What is the outside diameter of a 40x3 mm O-ring?

The nominal outside diameter is 46 mm, calculated as 40 mm + 2 x 3 mm.

O-Ring 40x3 MVQ/VMQ 70 Shore A - Key Product Information

The 40x3 mm MVQ/VMQ 70 Shore A O-ring is a silicone rubber sealing ring with a 40 mm inside diameter, 3 mm circular cross-section and 46 mm nominal outside diameter. Manufactured from silicone elastomer with nominal hardness of 70 Shore A, it is primarily intended for correctly designed static sealing applications. Before installation, material compatibility, operating temperature, pressure and groove geometry must be verified.

The O-Ring 40x3 MVQ 70 Shore A - VMQ Silicone Rubber Seal is available from simmering.pl, a specialist supplier of industrial sealing components and bearings operated by TG Ersatzteile Polska Sp. z o.o. The company maintains a warehouse in Lublin, Poland, serving industrial customers, maintenance departments, repair services and technical procurement teams with shipping across Poland and other European Union countries.