As a material, flexible graphite offers some unique advantages that make it a preferred choice for gaskets in certain applications.
Flexible graphite is generally known as a material that performs well in high-temperature applications. However, these applications can also present a potential failure mode for flexible graphite gaskets should the material oxidize and lose density. This can happen in applications where strongly oxidizing media are present.
When flexible graphite gaskets oxidize, the gasket material undergoes weight loss. This reduces the density of the installed material, with a consequent loss in sealing ability due to the gasket’s inability to support a full compressive load. To address this failure mode, some material manufacturers may add oxidization inhibitors to their flexible graphite products. The Teadit GR1700 sheet described below is an example of a best-in-class oxidation-resistant flexible graphite sheet.
The addition of oxidization inhibitors is a much larger determinant of the oxidation rate in flexible graphite gaskets than either graphite purity or material thickness. Selection of the appropriate material is therefore a key to preventing premature failure due to oxidization.
Oxidation-resistant flexible graphite gaskets: Teadit GR1700 sheet
In applications where strongly oxidizing media are present, CRGI generally recommends flexible graphite gaskets manufactured from Teadit GR 1700 sheet.
Teadit GR1700 – SIGRAFLEX APX2 Hochdruck is a multilayer, high-strength gasket sealing sheet designed for high-temperature applications. This sheet is comprised of 0.020” thick layers of highly oxidation-resistant SIGRAFLEX APX2 flexible graphite and 0.002” thick inserts of 316L stainless steel foil, manufactured with SIGRAFLEX Hochdruck technology.
Teadit GR1700 material was created for end users in the process industry to cover a broad range of demanding gasket requirements with a reliable and safe product. It is specifically designed for high temperature flat gasket applications. GR1700 sheet combines the outstanding characteristics of both SIGRAFLEX APX2 flexible graphite and reinforced sheets manufactured with SIGRAFLEX Hochdruck technology.
Oxidation-resistant flexible graphite gaskets: applications
Gaskets made from GR1700 sheet perform particularly well in critical applications due to their high mechanical strength, resistance to oxidation and blow-out, working pressure resistance up to 3600 psi (250 bar), excellent chemical resistance, and very low cold or hot relaxation. GR 1700 sheet services a temperature range from -418°F (-250°C) to approximately 1202°F (650°C). Besides its high resistance to oxidation, gaskets made from GR 1700 sheet feature excellent conformance to sealing surfaces, excellent torque retention and high sealing function.
Oxidation-resistant flexible graphite gaskets that CRGI fabricates from GR1700 sheet are well-suited for applications in the chemical, petrochemical, refining, power generation, pulp and paper, steel industries, as well as other critical processes. These gaskets are ideal for use in pumps and valves, pipe flanges, equipment and pressure vessels, non-typical geometry flanges tongue/groove and heat exchanger flanges.
To find out more about oxidation-resistant flexible graphite gaskets that CRGI can fabricate from Teadit GR1700 sheet, please contact our sales department at crg@canadarubbergroup.com.