A gasket is a ring made of a material capable of plastic deformation and possessing a certain strength. Most gaskets are cut from non-metallic sheets or manufactured to specified dimensions by specialized factories, using materials such as asbestos rubber sheets, asbestos sheets, PTFE sheets, and polyethylene sheets. There are also metal-clad gaskets made by wrapping asbestos and other non-metallic materials with thin metal sheets (galvanized iron, stainless steel). Another type is the spiral wound gasket, made by winding thin steel strips and asbestos strips together. The most common type is the spiral wound gasket made of stainless steel strips and graphite. Depending on the application environment, asbestos can also be used for the winding strip.
Ordinary rubber gaskets are suitable for temperatures below 120℃; asbestos rubber gaskets are suitable for water vapor temperatures below 450℃, oil temperatures below 350℃, and pressures below 5MPa. For general corrosive media, acid-resistant asbestos sheets are most commonly used. In high-pressure equipment and pipelines, lens-shaped or other shaped metal gaskets made of copper, aluminum, No. 10 steel, or stainless steel are used. The contact width between the high-pressure gasket and the sealing surface is very narrow (line contact), and the surface finish of the sealing surface and the gasket is relatively high.
