What is the minimum operating temperature for non-metallic materials in metal wound gaskets?
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In the design of the recontact tower, the design temperature is -98°C, and metal wound gaskets are used for the flange connections. The metal strip material is 0Cr18Ni9, while the non-metallic strip material is flexible graphite strip. The standards only specify the maximum operating temperature; may I ask, experts, what is the minimum operating temperature for flexible graphite? What are the minimum operating temperatures for special asbestos paper, special non-asbestos paper, and polytetrafluoroethylene? What are the main factors to consider when making a choice?
Minimum operating temperature for polytetrafluoroethylene: -196 to +260 pressure
SH3407-96 specifies that at nominal pressures of PN1.0 to 25 MPa, the range for polytetrafluoroethylene is -193 to +200; for special asbestos, it is -50 to +500; and for flexible graphite, it is -193 to 800. It’s not clear which of these values is correct
If you choose the standard gasket for HG pipe flanges, the technical requirements for wound gaskets as specified in SH3407 are suitable. If non-standard gaskets are used, the specific operating temperature can be determined based on the information provided by the gasket manufacturer.