ASTM A182 F347 Weld Neck Flange / EN 1.4550 Stainless Steel Flange WNRTJ Flange
ASTM A182 F347 / 1.4450 Stainless Steel Flange UNS S34700 Forged WN RTJ Flange
ASTM A182 F347 / 1.4550 Stainless Steel Weld Neck RTJ Flange is a high-strength, forged steel pipe connector designed for permanent attachment to piping systems via a full-penetration butt weld. It features a specialized metal-sealing grooved face and is manufactured from a niobium-stabilized austenitic stainless steel, making it specifically engineered for severe high-temperature, high-pressure, and corrosive service environments.
How it works?
When this flange is welded to a pipe (WN) and bolted to an opposing RTJ flange with a metal ring gasket placed in the grooves, the tightening of the stud bolts forces the two flanges together. The gasket is plastically deformed into the groove walls, creating a leak-proof seal that relies solely on the compressive strength of the metal, rather than on soft gasket fillers.
This makes the definition of its primary purpose: a permanent, fatigue-resistant pipeline joint that maintains a positive, blowout-proof metal seal under extreme fluctuating temperatures and pressures, while resisting weld-decay corrosion due to its niobium-stabilized chemistry.
GB | JIS | ASTM | GOST | EN |
06Cr18Ni11Nb | SUS 347 | F347 / S34700 | 08Х18Н12Б | 1.4550 X6CrNiNb18-10 |
Chemical Composition of ASTM A182 F347 / EN 1.4550 Stainless Steel Weld Neck Flange Forged WNRTJ Flange
| Cr | Ni | C | Mn | P | S | Si | Cb&Ta | Fe |
| 347 | 17.00 min.-19.00 max. | 9.00 min.-13.00 max. | 0.08 | 2.00 | 0.04 | 0.03 | 0.75 | 10 x (C + N) min.-1.00 max. | Balance |
Mechanical properties of ASTM A182 F347 / EN 1.4550 Stainless Steel Weld Neck Flange Forged WNRTJ Flange
| Yield Strength 0.2% Offset | Ultimate Tensile Strength | Elongation in 2 in. | Hardness | ||
|---|---|---|---|---|---|
| psi (min.) | (MPa) | psi (min.) | (MPa) | % (min.) | (max.) |
| 30,000 | 205 | 75,000 | 515 | 40 | 201 Brinell |
Typical Applications (Industries)
Due to its high-temperature stability and RTJ sealing reliability, this flange is widely used in:
Oil & Gas Upstream/Downstream: Wellheads, Christmas trees, flow lines, and refinery hydrotreaters.
Petrochemical: High-pressure process piping, cracking units, and reformers.
Power Generation: Superheater and reheater connections in thermal power plants.
Heat Exchangers & Pressure Vessels: Nozzle connections subject to cyclic thermal loading.
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