Semi-metallic gaskets are used for applications that require an increase in temperature and pressure, and high loads on the flanges. The most often used semi-metallic gasket for high-pressure joints is the spiral wound gasket. Spiral wound gaskets are manufactured by winding an alternating combination of a metal strip and soft filler material. The material is to be selected in order to fit the application – Teflon or graphite, dependent on running parameters.
Depending on the flange type and application, a wide variety of configurations of the spiral wound gasket can be used.
Available thickness: 2.5 mm; 3.2 mm; 4.5 mm; 6.4 mm; 7.2 mm.
Maximum diameter of the gasket: 4700 mm.
Main standards for spiral wound gaskets:
- ASME B16.20
- EN 1514-2
- EN 12560-2
Any other configuration can be made according to the clients’ specifications.
Shapes of spiral wound gaskets: round, oval, oblong, diamond, square, rectangular.
Types of spiral wound gasket:
GCI – spiral wound gasket with both inner and outer ring, used for Raised Face – RF or Flat Face – FF flanges.
GC – spiral wound gasket only with outer ring, used for Raised Face – RF or Flat Face – FF flanges.
Standard materials for gaskets:
- Inner ring: SS 304; SS 316L; SS 321; SS 304L; Carbon steel, Monel metal; Inconel; Alloy 20
- Filling: Flexible graphite; PTFE; Mica; Ceramics
- Outer ring: Carbon steel; SS 304; SS316L; SS 321; SS 304L; Monel metal; Inconel; Alloy
They are strictly connected to the materials that are to be used in the manufacturing of the spiral wound gasket.
- Temperature: -200°C… 800°C
- Pressure: max 350 bar
- pH: 0…14