RTJ blind flanges (ring type joint blind flanges) for high-pressure, high-temperature service – class 150 to 2500, NPS 1/2″ – 24″ per ASME B16.5, larger per B16.47. Octagonal and oval ring grooves machined in-house.
What Is an RTJ Blind Flange?
An RTJ blind flange is a blind flange whose sealing face carries a machined V-groove that holds a solid metal ring gasket (octagonal or oval cross-section, per ASME B16.20). When the bolts are torqued, the ring deforms slightly and seals metal-to-metal – no soft gasket material involved. This makes RTJ blinds the default choice for high-pressure and high-temperature line terminations: steam headers, hydrocarbon service, wellhead and manifold pipework, class 900 and above.
Specifications
| Item | Range |
|---|---|
| Size | NPS 1/2″ – 24″ (B16.5); 26″ – 80″ (B16.47 / custom) |
| Pressure class | Class 150 – 2500 (RTJ standard from class 900 up; available all classes) |
| Ring groove | Octagonal or oval, per ASME B16.20 (R through RX/BX series) |
| Materials | A105, A350 LF2, A182 F304/F304L/F316/F316L, F11/F22 alloy |
| Ring gasket material | Soft iron, low-carbon steel, 410 SS, 304/316 SS – matched to flange |
| Certificates | EN 10204 3.1 standard, 3.2 on request |
RTJ vs Raised Face (RF) Blind Flanges
An RF blind seals through a compressed soft gasket and suits most process lines up to class 600-900. An RTJ blind seals metal-to-metal through a ring trapped in the groove: it withstands higher pressure and temperature, resists blowout, and survives thermal cycling that would destroy a soft gasket. The trade-off is higher machining precision and cost, and the flange pair must both be RTJ – you cannot mix facings in one joint. If you are unsure which your line uses, check the mating flange face or the line class specification.
Machining Quality Matters
RTJ sealing depends on groove geometry: the 23° and 23°-side angles, surface finish (typically 63 µin Ra or better in the groove) and gasket contact width must be right or the joint weeps. We machine ring grooves on CNC equipment and inspect groove dimensions and finish before shipping. Matching ring gaskets can be supplied with the blind on request.
FAQs
Which ring gasket number fits my RTJ blind?
The ring number (e.g. R45, RX82) follows from flange size and pressure class in ASME B16.20 tables. Tell us size and class and we will quote the blind with the correct ring included if needed.
Can a blind flange be RTJ in class 150?
Yes – RTJ facings exist in all classes (class 150 uses oval rings), but above class 600 they become the practical standard. We machine RTJ grooves in any class on request.
Request an RTJ blind flange quote – size, class, material and ring number if known.
Related Blind Flange Products
Standard Blind Flanges (blank flanges) · Spectacle Blinds · Spade / Paddle Blinds · RTJ Blinds · Tapped Blinds · All Flange Types