Plate Flange (PL)
Flat-type flange with simple structure, light weight and low cost — ideal for low-pressure pipeline systems.
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Ring Type Joint Flange (RTJ)
HPHT flange with metal ring gasket groove — superior metal-to-metal seal for extreme pressure and temperature.
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RTJSteel Pipe Flanges
Overview
A Ring Type Joint (RTJ) Flange is a heavy-duty, high-performance piping flange specifically engineered for extreme high-pressure and high-temperature (HPHT) service. It is distinguished by its precision-machined annular groove on the sealing face, which holds a solid metal ring gasket to create a superior, leak-proof, pressure-energized metal-to-metal seal. When bolts are tightened, the gasket deforms plastically and flows into the groove to form an impermeable seal that strengthens as internal pressure increases.
Size Range
½" – 48"
Pressure Class
Class 600 – 2500 / PN100 – PN420
Key Features
- Precision-machined annular groove for secure metal gasket seating
- Metal-to-metal seal — gasket deforms into groove for impermeable joint
- Pressure-energized design — process pressure enhances sealing as load increases
- Gasket styles: Style R (octagonal/oval), Style RX and Style BX (ultra-high pressure)
- Gasket materials: soft iron, carbon steel, stainless, nickel alloys
- Primarily Class 600 (PN100) and above; service typically above 427°C (800°F)
- Available in weld neck, blind and socket weld configurations
Benefits
- Superior sealing — most reliable leak-proof connection for demanding HPHT conditions
- Durability — metal gaskets resist heat, pressure and chemical degradation
- Safety-critical — essential where leakage poses catastrophic risk
- Customized per project standards, gasket style and material grade
Specifications
| Standards | ASME B16.5, ASME B16.47, API 6A |
| Pressure Ratings | Class 600 – 2500 / PN100 – PN420 |
| Gasket Styles | Style R (Octagonal/Oval), Style RX (pressure-energized), Style BX (Class 2500) |
| Temperature | Typically above 427°C (800°F); HPHT service |
| Configurations | Weld Neck, Blind, Socket Weld |
| Sealing Principle | Solid metal ring gasket in machined groove — metal-to-metal seal |
Applications
Oil & gas — wellhead equipment, offshore platforms, HP transmission pipelinesPetrochemical and refining — reactors, heat exchangers, steam linesPower generation — boiler circuits, high-temperature steam systemsChemical processing — severe-duty, corrosive or high-pressure process lines
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Standards
- • ASME B16.5
- • ASME B16.47
- • API 6A
Materials
- • Carbon Steel: A105, A350 LF2
- • Stainless Steel: 304, 304L, 316, 316L
- • Alloy Steel: F11, F22, 16Mn, 15CrMo
- • Duplex & Special Alloys: F51, F53, Inconel, Hastelloy (on request)
Related Products
Slip On Flange (SO)
Sleeve-type flange slipped over the pipe and fixed by fillet welding — economical for medium and low pressure systems.
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Lap Joint Flange (LJ)
Loose flange with stub end — convenient disassembly for large-diameter, low and medium pressure systems.
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