When should I use a resin- or metal-impregnated blank?

Impregnation reduces open porosity, improves sealing, and can increase wear resistance. Resin is common for seals and EDM; metal impregnation adds conductivity and hardness for demanding mechanical uses.

What graphite material is used for mechanical seals?

Faces and rings are typically machined from carbon-graphite or impregnated graphite for sealing and controlled wear. We complement with GRAFOIL for monoblock gaskets and packing.

Do you manufacture build-to-print?

Yes. From drawing or sample we make graphite/carbon parts: bushings, electrodes, crucibles, seals, molds, and special components, with dimensional control and traceability.

Why are mechanical seal faces made from carbon-graphite?

Because the face needs low friction and the ability to work with very little lubricant film. Carbon-graphite is self-lubricating, holds flatness at temperature, and chemically resists many process media, which lets it be paired with a hard counterface such as silicon carbide, tungsten carbide, or ceramic.

What impregnation is used in seal faces?

It depends on the service. Impregnation closes the open porosity of carbon-graphite so the seal does not leak through the material itself: resins, metals, or inorganic salts are used depending on temperature, chemical compatibility with the fluid, and application requirements. ESGRAF confirms the impregnation available in each grade.

Can a graphite seal run dry?

It tolerates starts, stops, and momentary loss of film better than most metal combinations, but continuous dry service is not its design condition. If the equipment can be left without fluid for sustained periods, the seal design needs review, not only the material.

Can seal faces be replaced from a sample?

Yes. With the reference part or the drawing, ESGRAF machines the face to the required tolerances, flatness, and finish, and recommends an equivalent grade when the original material is not identified.

Graphite and carbon-graphite mechanical seal rings and faces

Mechanical applications

Pump mechanical seals

They guarantee efficient sealing in mechanical systems subjected to high pressures and temperatures.

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Dynamic seal face

Also known as: Graphite seal faces · Carbon-graphite mechanical seal rings · Carbon mechanical seals · Carbon-graphite primary faces

[ Technical summary ]

Graphite seal faces and rings form the friction pair that contains the fluid where the shaft passes through the housing. Carbon-graphite, usually impregnated, provides self-lubrication of the face, thermal stability, and chemical resistance, so the seal can run against a hard counterface without depending on an external lubricant. They appear in pumps, compressors, and chemical-process and power-generation equipment.

[ Problem it solves ]

Contain leakage at a rotating shaft when the friction pair must lubricate itself with the process fluid, or run dry for short periods, without resorting to a lubricant that would contaminate the medium.

Processes

Dynamic sealing

Operating conditions

High pressure
High temperature
Corrosive or clean media

When it is suitable

The friction pair must lubricate itself with the process fluid
The pumped medium is corrosive or must stay clean
The seal works at temperatures above the elastomer range
A brief dry start or stop is acceptable
A flat, stable face is required throughout the duty cycle

When it may not be suitable

The service carries suspended abrasive solids without filtration
There is prolonged rather than occasional dry running
There are impact or repeated shock loads
There is severe oxidation in air at high temperature without protection or impregnation

Process challenges

Leakage in dynamic seals
Friction-face wear
Incompatibility with liquid lubricants

Advantages

Seal-face self-lubrication
Thermal stability
Good chemical resistance in suitable grades

Limitations

Oxidation in air at high temperature without protection
Lower mechanical strength than structural metals
Requires grade selection by load and environment

[ Critical selection variables ]

These variables define the grade and the geometry. Actual values are confirmed against the grade datasheet.

Differential pressureDecisive
Operating temperatureDecisive
Fluid or medium in contactDecisive
Rotational speedDecisive
Flatness and surface finishDecisive
Type of impregnationDecisive
Counterface material and finishRelevant
Risk of dry runningRelevant

[ Required material properties ]

Properties that guide selection. Numerical values come from each grade's datasheet.

Critical properties

Friction coefficient
Wear resistance
Compressive strength
Flexural strength

Secondary properties

Impermeability
Self-lubrication
Chemical resistance
Dimensional stability

[ Related ]

[ Frequently asked questions ]

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Technical content reviewed by ESGRAF — Last reviewed: September 8, 2026

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