Full definition
Solid metal gasket with octagonal or oval cross-section that seals in machined grooves on RTJ (Ring Type Joint) flanges. Rated for pressures up to 20,000 psi and temperatures to 650 °C in refinery, petrochemical and wellhead service. Materials: soft iron, 316 SS, Inconel 625. Governed by ASME B16.20; ring hardness must be lower than flange hardness to ensure proper seating.