Frequently Asked Question FAQ

Metal seals are used in the extreme environment of temperature, pressure, radiation and so on. Almost all the applications where elastomeric seals fail.

Yes they can be used in Aluminum flanges. Low seating load seals are used for these applications.

Plating is only done when high leak tightness is required e.g. 1 x 10^-9 mbar.lit/sec.

Grooves are not essential one can have retainer rings or spacer rings. But there has to be some method to avoid compression of ring beyond the specified limit.

One should not use soft solid wires especially in the applications involving high pressure and temperature. Due to high pressure the flange lifts off and due to high temperature thermal expansion of flanges takes place. This movement can only be compensated me resilient metal seals.

Flexoresist seal can withstand 3000 bar pressure provided the setup is up to mark. Though theoretically it is said that metal seals can withstand pressures up to 10000 bars. We at Kwality Products we have not tried pressures up to 10000 bars.

Yes they can be used for cryogenic application, most of the times they are PTFE coated.

Metal seals after compression gets a footprint on its surface due to waviness/roughness of flanges. These footprints do not match the mating surfaces once removed and can lead to leakage. So reuse of metal seals is never advised.

The shelf life of metal seals is unlimited.

The surface finish of flanges is required between 0.4 to 1.6 um for good leak tightness. The most important parameter is the flanges should be turned in circular manner with a uniform feed rate. The flanges should not have any vibration/chatter marks in the sealing area.

No they are available in various shapes; shaped seals are designed as per the requirements. One has to take in to consideration the turn radius of the seal as drastic turn in seal is not possible.

No, the max torque has to be applied only once, but it is essential to select the right seal. A seal with maximum cross section should be selected, so that it can have maximum resilience and compensate the flange lift off due to high pressure or bolt relaxation.

It depends on pressure difference between the internal and external pressure along with the application. If the pressure difference is negligible one can use it but in few applications like vacuum only certain seals can be used.