Duplex Steel Flanges are robust and corrosion-resistant flanges made from duplex stainless steel, combining austenitic and ferritic properties. These flanges provide high strength, excellent resistance to stress corrosion cracking, pitting, and crevice corrosion, making them suitable for demanding environments such as oil and gas, chemical processing, petrochemical, and marine industries. Duplex steel flanges come in various types including weld neck, slip-on, blind, threaded, and lap joint to accommodate different piping requirements. They comply with international standards like ASTM A182, ASME B16.5, and EN 1092-1, ensuring compatibility and reliable sealing performance in high-pressure and high-temperature applications. Their durability and strength make them ideal for critical pipelines where both mechanical performance and corrosion resistance are essential.
| Parameter | Description / Options |
|---|---|
| Material Grades | UNS S31803, UNS S32205, UNS S32750 (Super Duplex), ASTM A182 F51, F53, F55 |
| Standards | ASTM A182, ASME B16.5, ASME B16.47, EN 1092-1, MSS-SP-44 |
| Types | Weld Neck, Slip-On, Blind, Threaded, Lap Joint, Socket Weld |
| Sizes | 1/2″ to 72″ (DN 15 to DN 1800) |
| Pressure Ratings | Class 150, 300, 600, 900, 1500, 2500 |
| Facing Types | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Surface Finish | Mill Finish, Shot Blasted, Polished |
| Heat Treatment | Solution Annealed (typically 1050–1150 °C) |
| Testing | Hydrostatic Test, PMI, NDT (Ultrasonic, Radiographic), Visual Inspection |
| Applications | Oil & Gas, Chemical Processing, Petrochemical, Marine, Desalination Plants |
| Flange Type | Description | Applications |
|---|---|---|
| Weld Neck Flange | Features a long tapered neck welded directly to the pipe. | High-pressure systems, reactors, petrochemical plants. |
| Slip-On Flange | Flange slides over the pipe and welded on both sides. | Used in low-pressure and non-critical applications. |
| Socket Weld Flange | Flange with a socket for the pipe to be inserted and welded. | Common in high-pressure, small-bore systems. |
| Blind Flange | Seals the end of a pipe or vessel. | Used to seal pipe ends or to close vessels. |
| Threaded Flange | Flange with internal threads that screw directly onto the pipe. | Low-pressure systems, where welding is difficult or not allowed. |
| Lap Joint Flange | Designed for easy disassembly, fits over a stub end of the pipe. | Ideal for low-pressure piping systems, particularly for inspection or maintenance. |
| Orifice Flange | Flange with built-in orifice for flow measurement. | Used in flow metering systems in pipes or gas lines. |
| Ring-Type Joint Flange | Flange with a groove for sealing with a metal ring gasket. | Suitable for high-pressure applications in the oil and gas industry. |
| Expander Flange | Connects pipes of different diameters. | Used where pipe size changes within the same system. |
| Reducing Flange | Connects pipes of different diameters, reducing pipe size. | Useful for systems requiring diameter transition. |
| Long Weld Neck Flange | A variation of Weld Neck with a longer neck. | Used in applications involving high pressures and high temperatures. |
