Duplex Stainless Steel Forged Flanges for Desalination Seawater Service

Duplex forged steel flanges for desalination seawater service combine high mechanical strength with the corrosion resistance that SWRO plants demand from every wetted component. Seawater is one of the most aggressive natural media for piping systems, attacking ordinary stainless steel through pitting and crevice corrosion, so desalination projects specify duplex and super duplex materials with a high pitting resistance equivalent number.

Our duplex forged steel flanges are manufactured in 2205 and super duplex 2507 grades to meet exactly this requirement. Each flange is forged and solution annealed to restore the balanced austenite-ferrite microstructure that gives duplex steel its combination of strength and corrosion resistance.

Because the corrosion performance of duplex steel depends on this phase balance, we verify the ferrite content and perform PMI testing on every heat used for desalination seawater service orders. The flanges are available with RF or RTJ faces, in weld neck, slip-on, blind and socket weld types, and every piece is hydrostatically tested before dispatch.

• Duplex 2205 and super duplex 2507 grades engineered for chloride and seawater corrosion resistance
• Solution annealed microstructure with verified ferrite balance for consistent performance
• High mechanical strength allows thinner, lighter flanges than austenitic stainless equivalents
• PMI and ferrite content verified per heat for desalination seawater service quality control
• Proven in SWRO intake, pretreatment and brine discharge piping systems
• Full EN 10204 3.1 documentation with hydrostatic test reports

Duplex forged steel flanges for desalination seawater service are released only after the full test sequence is completed. PMI analysis confirms the grade, ferrite measurement verifies the phase balance after solution annealing, and dimensional inspection checks the flange against the standard tables.

Each duplex forged steel flange for desalination seawater service ships with EN 10204 3.1 certificates, PMI and ferrite reports, and our workshop can arrange third-party inspection for SWRO projects that require independent verification.

Duplex steel offers a combination of high strength and excellent resistance to chloride pitting and stress corrosion cracking. In desalination seawater service this means longer plant life and lower wall thickness than 316L stainless steel.

Super duplex 2507 contains higher chromium, molybdenum and nitrogen, giving a higher PREN value and better resistance in the most aggressive seawater and brine conditions. 2205 is the economical choice for less severe duty.

Every heat is verified by PMI analysis and the ferrite content is measured after solution annealing. The results are recorded in the material certificate so the phase balance is traceable.

Yes, we can supply duplex forged steel flanges up to 48 inches for large seawater intake and outfall lines, including custom hub dimensions for project piping.