Flange Types
Ring Type Joint Flanges
High-integrity flanges using metal ring gaskets for severe service.
Ring type joint (RTJ) flanges use a solid metal ring gasket that seats in a precision-machined groove on the flange face. As the bolts are tightened, the softer ring gasket deforms slightly into the groove surfaces, creating a metal-to-metal seal capable of withstanding extreme pressures and temperatures. RTJ flanges are specified for the most demanding applications in refinery, offshore, and power generation piping.
Three ring gasket styles are commonly used: R-type (standard oval or octagonal cross-section for ASME B16.5 applications), RX-type (pressure-energized design where internal pressure helps seat the gasket), and BX-type (used with API 6A flanges at 5,000 psi and above). Each style requires specific groove dimensions, and the groove pitch diameter tolerance is extremely tight (typically +0.000/-0.010").
RTJ ring gaskets are single-use items that must be replaced every time the joint is broken. The flange grooves must be inspected for damage before reassembly, as nicks, scratches, or corrosion can compromise the seal. Flanges.IO supplies RTJ flanges and matching ring gaskets in all standard sizes and pressure classes. Contact us for groove dimension specifications and ring gasket quotations.
