ThePipingMart Blog other Learn About Different Types Of Ring Type Joint (RTJ) Gaskets

Learn About Different Types Of Ring Type Joint (RTJ) Gaskets

Applications requiring high pressure and high temperature can benefit from ring joint gaskets. The RTJ Gaskets come in oval/octagonal profiles, R, RX, and BX styles. Solid portions of the R type (oval and octagonal) to fit trapezoidal-grooved standard ring joint flanges. For wellhead pressures above 700 bar, types RX and BX with intricate beveled edge portions are available.

Material of Construction 

Stainless steels 304, 304L, 316, 316L, 321, and 347 are low carbon steels, alloy steels F5 and 410, and soft iron. A UKL Ring Joint Gasket (RTJ) creates a solid and long-lasting metal-to-metal seal between two mated RTJ flanges. The softer ring joint gasket is “squeezed” into the grooves of the harder-made flanges when bolted together, creating an extremely tight seal. At high pressure and temperatures, UKL Ring joint gaskets (RTJ) guarantee a durable and reliable seal for flanges, valves, pipe spools, and vessels (typical conditions for many petrochemical processes). UKL-RTJ gaskets come in a variety of designs (referred to as “styles”) and sizes, as shown in the image below (BX, R, and BX).


  • R Type Ring Joint Gasket (Oval and Octagonal)

The most typical RTJ gasket type is “Style R.” R-type ring joint gaskets are made following API 6A and ASME B16.20 and are available with an oval or octagonal cross-section to fit API 6B and ASME/ANSI B16.5 flanges.

To enable proper installation with common ASME B16.5 and API 6B ring joint facing flanges, this type of RTJ gasket is machined to close manufacturing tolerances. According to ASME B16.20 and API, 6A pressure ratings, “R type” oval and octagonal RTJ gaskets may seal pressures up to 6250 psi and 5000 psi, respectively. Valve covers typically employ Type R-RTJ gaskets.

  • Style RX-RTJ Gasket

To fit API 6B and ASME/ANSI B16.5 flanges, the RX-type RTJ gasket is made following API 6A and ASME B16.20. The RX is an R-type flat-bottomed groove-compatible pressure-energized variation of the R octagonal gasket. The RX is taller and uses the pressure within the internal system to energize and enhance the seal when internal pressure rises. Some RX sizes incorporate a pressure release hole to equalize pressure on both sides of the sealing faces.

  • Style BX -RTJ Gasket

The high-pressure API 6BX flanges can employ the BX-type RTJ gaskets produced following API 6A. When assembled, the gaskets create a metal-to-metal seal, and efficiency grows as internal pressure rises. A pressure relief hole is present in every BX size to balance pressure across sealing faces.


To prevent the flange from plastically deforming within the groove of the flange while the two mating flanges are bolted together, the material of RTJ gaskets must match the material of the flanges while having a lower hardness. When the flanges are tightened, the groove would be harmed if a stricter material for the ring-type joint was employed.

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