ASTM A182 F55 / 1.4501 / S32760 Super Duplex Steel Flange Super Duplex 2507

Product Specification

ASTM A182 F55 WNRTJ FLANGE, UNS S32760 SUPER DUPLEX STAINLESS STEEL FLANGE

ASTM A182 F55 Super Duplex Steel Weldneck RTJ Flange is a high-performance forged component designed for critical service in extreme environments. This flange features a super duplex microstructure that offers nearly double the yield strength of standard stainless steel while providing exceptional resistance to pitting, crevice corrosion, and chloride stress corrosion cracking. The weldneck design incorporates a long, tapered hub that distributes stress and allows for full-penetration butt welding, ensuring structural integrity under high pressure. The RTJ (Ring Type Joint) facing features a precision-machined groove that compresses a metal gasket to form a leak-proof metal-to-metal seal, making it mandatory for high-pressure and high-temperature applications in oil and gas, offshore, and chemical processing. 

Equivalent Grade of ASTM A182 F55 / S32760 Super Duplex Steel Flange

Chemical Composition % of ASTM A182 F55 / S32760 Super Duplex Steel Flange

Mechanical properties of ASTM A182 F55 Super Duplex Steel WNFF Flange

Here are the specific conditions dictating the use of RTJ Flange Face:

1. High Pressure & High Temperature (Severe Service)
RTJ is standard for ASME pressure classes 600# and above (specifically 900#, 1500#, and 2500#). In these classes, the internal pressure is so high that standard gaskets (used on RF/FF flanges) would extrude out of the joint or blow out. The metal ring gasket used in RTJ faces seals by deforming within the groove, creating a seal that is stronger than the pipe wall itself.

2. Ring Type Joint Gasket
RTJ flanges use a metal gasket (oval or octagonal), whereas RF flanges use a soft/composite spiral wound gasket.

Use RTJ when: You need to contain lethal fluids, gases, or hydrocarbons at high velocity where a standard gasket would fail.

3. Critical Cyclic Conditions
In environments with extreme temperature fluctuations or vibration (common in offshore platforms and wellheads), bolted tension can relax. RTJ grooves are designed to maintain the seal even if bolt stretch occurs, whereas RF connections rely entirely on constant gasket compression.

4. Industry Standards (API)
RTJ is mandatory in the Oil & Gas industry for drilling manifolds, Christmas trees (wellheads), and choke/kill lines per API 6A specifications.

Characteristic of Flange Facing -- Type RTJ (Ring Type Joint)

• Gasket Type: RTJ flanges use a metal ring gasket (oval or octagonal) that sits in a machined groove on the flange face.

• Sealing Mechanism: When the flange bolts are tightened, the metal gasket compresses into the groove, deforming slightly to create a metal-to-metal seal.

• Application: RTJ facings are specifically designed for high-pressure and high-temperature services. They are mandatory in many oil and gas wellhead and manifold applications.

• Standards: The groove dimensions are standardized (typically per API 6A or ASME B16.5) to accept specific ring gasket numbers (e.g., R24, R31, etc.).

Application

• Offshore Oil & Gas: Topside and subsea pipelines, manifold systems, and risers.

• Chemical Processing: Handling chlorides, acids, and aggressive catalysts.

• Desalination Plants: High-pressure reverse osmosis units.

• Marine Environments: Shafts and bulkheads where seawater corrosion is a factor.