Resilient Metal Seals

Resilient metal seals from GFD have already proven themselves worldwide under the most diverse extreme operating conditions. They are used when conventional sealing products can no longer meet the parameters and requirements in new or existing applications.

For example, when the conventional seal is not suitable for the temperature range or the flat gasket cannot compensate for flange gaping or the required leakage rate cannot be achieved by the seal previously used.

Possible applications and advantages:

  • Seal for vacuum, gases and liquids under extreme operating conditions.
  • Applicable in pressure ranges from UHV up to 5000bar at service temperatures from -269°C to 750°C.
  • Resistant against radioactive radiation, chlorides, corrosion and other aggressive influences. No aging.
  • Can be optimally adjusted to parameters and requirements in the application through a variety of possible combinations
  • Achievement of lowest leakage rates through additional coating
  • Maintenance of tightness even when the flange is lifted off by elastic compensation behaviour of the seal
  • Resistant to explosive decompression
  • Simple force calculations, since ring works in force shunt.
Any questions? Contact us!

We are known as a problem solver in the field of resilient metal seals. Every application is tested and evaluated by our technical department on the basis of years of experience in order to provide the best possible solution for your application.

General information Materials Overview Metal O-Rings Metal C-Rings Metal U-Rings Customized designs

Resilient metal seals from GFD are available in a variety of different types, cross sections, wall thicknesses, materials, coatings, coating thicknesses and heat treatments.

Diameters can be defined by the customer starting with the minimum diameters, which depend on the seal type and cross section. Due to the resulting infinite combination possibilities, these sealing elements are manufactured by GFD order-related. For the selection of the most suitable sealing element for your application you are free to contact the technical support of GFD. Please let us know the relevant parameters, e.g. temperature, pressure, medium, surface quality, etc., as well as the requirements in the application, e.g. required leakage rate, load cycles, expected flange lift-off, etc.

By pressing the sealing element from the original cross section (A) to the required groove depth (C), the maximum press load (F max) is generated. In this process, the ring is not only deformed elastically (A-B) but also plastically (B-C). In the case of coated rings, the press load also causes the coating to flow. Microscopically small irregularities in the counter sealing surface of the groove are closed by this mechanism and the lowest possible leakage rates are ensured. Resilient metal seals have the ability to spring back in a defined manner (C-E) when relieved of load, this behavior is also known as Springback SB. The usable elastic springback (C-D) ensures that the tightness is maintained when flange lift-off occurs as a result of pressure and temperature application. In order to maintain the sealing performance, usually only a part of the total SB can be used, so that the sealing load F min SB is not undercut.

Typical applications / industries

  • Machine and plant constructions:
    Gas turbines, heat exchangers, plastic injection machines, pressure vessels, pump housings, internal combustion engines
  • Oil and gas industry:
    Fittings, valves, cryogenic applications
  • Chemical and process technology:
    High vacuum, heat exchangers, pressure vessels, fittings, valves, cryogenic applications
  • Sealing Technology
  • Laser and sensor technology
  • Aerospace industry:
    mechanics, modules, fuel system, engines



With this recommendation, we would like to give all those responsible for the components advice on how to design the construction in order to implement a successful sealing solution. Appropriate dimensioning and material selection depending on the parameters and requirements contribute as much to the reliable functioning of the sealing solution as the sealing element itself.
Contrary to complex calculations, e.g. when using flat gaskets, in the case of resilient metal seals the press load of the seal must essentially be added to the operating forces of the application.
Especially for high-temperature applications, knowledge of the strength curve of the construction materials for the stiffness of flanges as well as the design and number of bolted connections is of great importance. If a flange gap can be expected from calculations on the behaviour of the construction, please provide us with exact numerical values. We are able to support you in the selection of a suitable GFD sealing element.

Furthermore the surface quality of the counter sealing surface is of elementary importance. The tightness is the result of the successful interaction between the sealing element and the surface quality of the counter sealing surface.

The necessity of a coating and, if necessary, the determination of the coating thickness depends on the desired leakage rate . Rougher surfaces can be compensated within limits by a higher coating thickness in order to meet the leakage requirement.

For rings in internal and external pressure applications:
The processing marks caused by machining must be concentric with the line of contact of the seal.
Avoid radial scoring and scratches.
Processing marks on the groove or flange surface must be free of dirt, grinding dust or other foreign matter.

The following applies to rings in axial pressure applications:
Processing marks caused by machining must be concentric with the line of contact of the seal.
Avoid axial scoring and scratches.
Processing marks on the inside and outside of the groove must be free of dirt, grinding dust or other foreign matter.

Permissible eccentricity:
- up to bore Ø 85mm = max. 0.015mm
- from bore Ø 85mm = max. 0.03mm
Surface hardness 60 HRC

  • The seals should be kept in their original packaging until the time of installation to avoid damage.
  • When opening the packaging, make sure that the seal is not damaged by sharp objects, e.g. a knife or scissors, as even the smallest scratches can have a negative effect on the sealing performance.
  • After unpacking, check the seal for possible damage or other defects.
  • Use only suitable tools for assembly, if at all necessary.
  • Wear suitable gloves if required by the specification.
  • Handle the seal with the utmost care.

  • The condition of the counter sealing surfaces plays a decisive role in the subsequent sealing effect. In addition to the points mentioned in the design recommendations, it must be ensured that grooves and flanges are free of dirt, foreign particles, scratches and other damage and deformation, as any of the above-mentioned conspicuous features can lead to leakage. Cleaning, e.g. with a dust-free cloth and acetone, immediately before installation is recommended.
  • Wear suitable gloves if required by the specification.
  • Carry out the above mentioned tests and cleaning with the utmost care.

  • When installing the seal in the groove, make sure that no scratches or other damage is caused.
  • When using tools, if at all necessary, ensure that neither the seal nor the surrounding construction, especially the counter sealing surfaces, are damaged in any way.
  • Do not use any auxiliary materials such as oil, grease or other products
  • Wear suitable gloves if the specification requires it.
  • After placing the seal, carefully guide the adjacent structural parts towards each other. In the case of multiple fittings, gradually tighten the flanges crosswise to achieve even compression of the seal.
  • When installing MCA type seals, ensure excellent guidance of the components to be sealed to each other (see chapter Design Recommendations) to avoid damage, e.g. due to tilting. Assembly tools are available on request.
  • Work with the utmost care during assembly.

GFD recommends not to reuse resilient metal seals after disassembly. Background: The rings are not only elastically but also plastically deformed during assembly. In addition, there is a risk of damage and contamination. In case of repeated use, this usually leads to a (significant) decrease in sealing performance and thus to the original specification not being met.

General information Materials Overview Metal O-Rings Metal C-Rings Metal U-Rings Customized designs




made with ♡ by andres.media