The use of metallic gaskets starts where soft gaskets no longer work reliably enough at the operating pressure or temperature to be sealed, or where there is a risk of gasket failure. Metallic seals are made of various materials such as steel, nickel, stainless steels, titanium, Inconel. They are used when higher chemical stress and extreme operating conditions are present. They are present in a variety of geometric shapes and materials in the industry. Metallic gaskets require high bolt forces and stable flanges. In practice, slightly curved contact surfaces are often used to reduce the forces or to achieve a high surface pressure.