Steel oval and octagonal gaskets are used as a sealing product for flange connections of fittings with flanges having a sealing surface of version 7 according to GOST 12815 and version J according to GOST 33259-2015, for nominal pressure PN from 6.3 to 16.0 MPa and temperature from minus 70 to 600 ° С. Armco rings maintain the tightness of the network when working with high and overpressure and its sharp drops. Flange seals are used in cases where parts of other types are not suitable for their strength or technical characteristics.
The ring billet plant produces steel gaskets in accordance with OST 26.260.461-99, from low-alloy, carbon and corrosion-resistant steel grades, such as 08KP, 10895, 20, 09G2S and 08X18H10T in accordance with GOST R 53561-2009, GOST 28759.8-90.
Types of flange gaskets:
- oval - gaskets that have a double sealing area, and due to the rounded surface, stress concentration arises at the contact between the gasket and the groove wall, which ensures tightness even on worn flanges;
- octagonal - spacers that are placed in special trapezoidal grooves. These products have a double sealing area, which guarantees tightness even in harsh working conditions
For the most tight fit of the metal gaskets to the grooves of the sealing surfaces of the flanges, it is necessary to tighten the studs or bolts that are responsible for fixing the flange connection as tightly as possible. As a result, a very high pressure will be exerted on the insignificant contact surface of the metal gasket with the grooves of the sealing surfaces of the flange products, which will provide the most effective sealing.
The material of the flange joint gasket should be comparatively softer than the flange material, even when using a metal gasket. Steel gaskets are made of carbon and stainless steel. When the flanges are compressed by fasteners (pins, nuts, bolts), a high pressure is exerted on the relatively small contact surface of the metal gasket with the grooves of the sealing surface of the flange product. As a result, the deformation of the gasket element, made of a material softer than the base material of the flanges, occurs, due to which the sealing is especially effective.
The manufacture of metal gaskets is a complex high-tech process, which makes their cost quite high. However, it is impossible to do without them when operating pipeline systems with high temperatures or chemical aggressiveness of the transported substance.