Duplex & Super Duplex Pipes & Tubes

Duplex stainless steel takes its name from its two-phase microstructure roughly a 50/50 mix of austenite and ferrite. This dual structure is what gives duplex its headline advantages over single-phase austenitic grades: higher mechanical strength, markedly better resistance to chloride-induced stress corrosion cracking, and strong pitting and crevice-corrosion performance. Because duplex pipes hold their mechanical and corrosion properties even when bent to tight radii, they suit both onshore and offshore pipelines and demanding process piping where reliability cannot be compromised.

Super duplex is the higher-alloyed step up. By raising chromium, molybdenum and nitrogen (and, in S32760, adding tungsten and copper), super duplex pipes reach a Pitting Resistance Equivalent Number (PREN) of 40 or above, qualifying them for seawater, high chloride concentrations, elevated temperatures and higher operating pressures. In short, if standard 316L would pit and crack, duplex or super duplex is usually the correct specification.

Both product types carry pressure efficiently thanks to their high yield strength, which means thinner walls, lower material weight, reduced pressure loss and better flow performance, a cost-effective package for aggressive service. Jade Alloys supplies this material as seamless, welded, ERW and EFW pipe, plus tight-tolerance heat-exchanger tube.

Jade Alloys stocks and supplies duplex and super duplex pipe in the following grades. Click through for full grade-specific specifications and datasheets:

Understanding the process helps buyers confirm quality assurance at source. Jade Alloys produces duplex pipe through the following routes:

Seamless Duplex Pipe

Seamless duplex pipe is produced by hot extrusion or cold drawing of solid billets, with no weld seam anywhere in the cross-section. The absence of a heat-affected zone makes seamless the preferred choice for high-pressure, high-temperature and severely corrosive duty. After forming, pipes are solution annealed and water quenched to restore the balanced duplex microstructure.

Welded & ERW Duplex Pipe

Welded duplex pipe is formed by rolling a stainless strip into a tubular shape and joining the longitudinal seam using the TIG (Tungsten Inert Gas) process; submerged-arc or plasma welding is used for larger diameters. Pipes are solution annealed after welding to remove any weld-induced phase imbalance. ERW duplex pipe is available for standard-pressure applications where full-penetration weld and NDT compliance are confirmed by eddy-current or ultrasonic testing.

EFW & Large-Diameter Duplex Pipe

Electric Fusion Welded (EFW) pipe is produced for larger diameters, typically above DN 400. The fusion weld is followed by full heat treatment and 100% radiographic testing. Once formed, pipes are cut to length by sawing, lathe or laser, cleaned, straightened, pickled and finally marked with grade, size and heat number.

Common duplex pipe sizes with outer diameter, wall thickness, schedule and approximate weight per metre. Need another grade or wall? Use our Metal Weight Calculator.

Custom sizes, non-standard wall thicknesses and cut-to-length orders available on request for quantities above 2 tons.

• Oil & Gas / Offshore: Extensively used in offshore platforms, subsea flowlines, topside piping and pipeline risers. Resistance to chloride SCC and sour-gas (H₂S) environments makes grade 2205 and super duplex 2507 the standard choice for high-pressure wells.
• Chemical & Petrochemical: Reactor circuits, heat-exchanger shells, acid-handling lines and process vessels handling chlorides, sulphuric acid or organic acids. Corrosion resistance plus pressure capacity at elevated temperature reduces total installed cost.
• Desalination & Water Treatment: Super duplex S32750 and S32760 are specified for seawater intake piping, brine lines and reverse-osmosis pressure vessels, with PREN above 40 ensuring resistance in hot seawater.
• Marine & Shipbuilding: Seawater cooling systems, ballast-water units, deck drainage and cargo-tank piping. Resistance to biofouling and marine corrosion extends service life well beyond carbon steel or standard austenitic grades.
• Pulp & Paper: Digesters, bleach-plant pipelines, chemical-recovery systems and washing equipment exposed to chlorine compounds, caustic soda and black liquor.
• Heat Exchangers & Condensers: Higher thermal conductivity and yield strength allow thinner tube walls, raising heat-transfer efficiency while cutting material cost.
• Pharmaceutical & Food Processing: Fluid-transfer and process lines needing corrosion-resistant, hygienic, smooth-bore surfaces, bright-annealed and electropolished finishes available.

Duplex Seamless Pipe (ASTM A790 / ASME SA790)

Hot-extruded with no weld seam for the highest pressure integrity. OD from 6 mm to 250 mm, schedules to XXS.

Duplex Welded Pipe (ASTM A790 / A928)

TIG or plasma welded and solution annealed after forming; 5 mm to 1219.2 mm OD with full radiographic testing.

Duplex ERW Pipe

Electric-resistance welded for standard-pressure service, with NDT compliance confirmed by eddy-current or ultrasonic testing.

Duplex Heat Exchanger Tubes (ASTM A789)

Bright-annealed or polished tubes for shell-and-tube exchangers, condensers and evaporators, held to strict dimensional tolerances.

Large-Diameter Duplex Pipe

Above DN 400 for offshore, petrochemical and desalination projects — EFW or fabricated, with full documentation.

Material without paperwork is scrap at the gate. Every order of duplex and super duplex pipe from Jade Alloys is supplied with documentation compliant to EN 10204 3.1 or 3.2. Our standard package includes:

• Material Test Certificate (MTC) as per EN 10204 3.1 / 3.2 with heat-number traceability
• 100% Radiography Test Report (where applicable) and Hydrostatic Test Report
• Ultrasonic Test Report and Heat Treatment Charts
• IGC (ASTM A262), ferrite count and pitting resistance (ASTM G48) reports
• PMI / spectro analysis and Laboratory Test Certificate from a government-approved lab
• Third-Party Inspection (Bureau Veritas, TÜV, Lloyd’s, SGS, DNV) on request
• Form A (GSP) and fumigation certificates for wooden packaging

See our Quality Policy and Certificates for full details.

• Direct supply, no layered margin: We are a manufacturer and stockist, not a broker reselling at a markup.
• Genuine grade traceability: Heat-number-linked MTCs; PMI at your gate will match the certificate.
• Ready stock, faster shutdowns: Standard duplex and super duplex sizes dispatch within days of PO confirmation.
• Export-ready documentation: Sea-worthy packing, fumigation and LC-compliant documents for the Gulf, Europe and Southeast Asia.
• One-stop procurement: Pipes and tubes plus matching duplex round bars, sheets & plates, tube plugs and RTJ gaskets from a single vendor.

New to duplex specification? Our technical blog covers grade selection, PREN and welding guidance in more depth.

• Super Duplex S32760 Pipes & Tubes
• Super Duplex S32750 Pipes & Tubes
• Duplex S32205 Pipes & Tubes
• Duplex S31803 Pipes & Tubes
• Duplex Sheets & Plates
• Super Duplex Sheets & Plates
• Duplex Round Bars
• Super Duplex Round Bars
• Duplex Tube Plugs
• Duplex RTJ Gaskets
• Stainless Steel Pipes & Tubes
• SMO 254 Pipes & Tubes

Jade Alloys supplies duplex and super duplex pipe worldwide, with sales representation and stocking support across every major industrial region — the Middle East, Europe, Southeast Asia, Africa and the Americas.