The selection of gasket material shall consider medium temperature, pressure, corrosivity, and flange sealing face type simultaneously. The following summary is classified by gasket type.

Rubber gaskets achieve sealing through material elasticity and are suitable for low-pressure, ambient-temperature service. The upper temperature limit depends on the rubber type.

Asbestos rubber sheets have been largely phased out due to asbestos restrictions and are rarely used in current engineering practice. Synthetic fiber rubber gaskets and flexible graphite composite gaskets are currently the most widely applied solutions.

Jacketed gaskets consist of a metallic outer shell enclosing a non-metallic filler, combining the strength of metal with the sealing adaptability of non-metallic materials.

Spiral wound gaskets are formed by alternately winding metallic and non-metallic strips, combining strength and sealing performance. They are a common choice for high-temperature, high-pressure flanged connections.

Camprofile gaskets feature concentric serrations machined on the upper and lower surfaces of a metallic core plate, covered with flexible graphite or PTFE layers. They are suitable for high-temperature, high-pressure, and temperature-fluctuating service.

Packing is used for stem sealing, and its temperature applicability directly affects the reliability of the dynamic stem seal.

Cast iron valves have poor thermal conductivity and are brittle materials. According to ANSI B16.1, the operating temperature range is -29 to 232°C. However, cast iron exhibits pronounced low-temperature brittleness; it is recommended that the service temperature not be lower than 0°C. Currently, cast iron valves are rarely used in the petrochemical industry, and national regulations have explicitly prohibited the use of cast iron for household faucets.

Cast carbon steel (ASTM A216 WCB) and forged carbon steel (ASTM A105) have an operating temperature range of -29 to 425°C. To ensure safety, it is recommended that the operating temperature not exceed 400°C.

Common materials for cryogenic valves include LCB, LCC, LF2, LF3, and austenitic stainless steels such as CF8, CF3, CF8M, CF3M, 304, 304L, 316, and 316L. In actual production, austenitic stainless steel is the mainstream material for cryogenic valves:

Gate valves, globe valves, and ball valves must be provided with an extended bonnet and insulating plate to ensure the packing box temperature remains above 0°C.

Gate valves and ball valves must have a pressure relief hole on the upstream end. Liquefied petroleum gas and other cryogenic liquids can increase in pressure by nearly 100 times and expand in volume by approximately 600 times upon warming. Without pressure relief, the packing and gasket may be blown out, and in severe cases, the valve body or bonnet may rupture.

Due to the pressure relief hole, all cryogenic valves are unidirectional sealing. The valve body must be marked with a medium flow direction arrow.

Corrosion-resistant stainless steels are high-chromium-nickel or high-chromium-nickel-molybdenum austenitic stainless steels used for various corrosive media. They are classified into three types according to corrosion type:

Stainless steels used for corrosion-resistant valves require carbon content as low as possible (≤0.08%) or ultra-low carbon (≤0.03%). Their operating temperature is typically ≤200°C.

Austenitic stainless steels can also be used for high-temperature valves. However, when used as heat-resistant steel, the carbon content is required to be appropriately increased (to obtain higher high-temperature strength), and the material must undergo specialized high-temperature steel melting and heat treatment. Low-carbon grade stainless steels that have not undergone high-temperature steel melting and treatment cannot be used for high-temperature valves. For the same stainless steel material, the requirements for heat treatment condition and carbon content differ fundamentally among cryogenic, corrosion-resistant, and heat-resistant applications. This must be distinguished during material selection.