Duplex Stainless Steel
Duplex 2205 (UNS S31803 / S32205), 2304 and S31500 in sheet, plate, coil, round bar, pipe, tube, flange, fitting and forged-ring form — ASTM A240 / A790 / A182 with 3.1 / 3.2 MTC.
What is duplex steel?
Duplex stainless steel has a roughly 50:50 austenitic-ferritic microstructure that gives about twice the yield strength of 304 or 316 (450 MPa minimum for 2205) together with far better resistance to chloride stress-corrosion cracking. The workhorse grade is Duplex 2205 (UNS S31803 / S32205, PREN 34–35), with lean duplex 2304 used where strength matters more than chloride resistance.
Steelco Metal & Alloys stocks duplex steel in Mumbai in plate, sheet, coil, round bar, seamless and welded pipe, tube, ASTM A182 F51 flanges, buttweld fittings and rolled rings, in solution-annealed and pickled condition with ferrite content reports on request. Every dispatch leaves our Mumbai warehouse with an EN 10204 3.1 mill test certificate (3.2 with TUV, SGS, BV, Lloyd's, IRS or IBR witness on request), PMI verification and full heat-number traceability.
Duplex grades we stock.
Open a grade for full chemistry, mechanical properties, PREN, international equivalents and the size range we hold.
Duplex Steel we hold in ready stock.
Plate & sheet
1.5 – 100 mm thick to ASTM A240 UNS S31803 / S32205, hot- and cold-rolled.
Round bar
Ø 6 – 400 mm to ASTM A276 / A479, forged, peeled and ground.
Seamless & welded pipe
1/2" – 24" NB to ASTM A790 / A928, Sch 10S to Sch 160.
Tube
Ø 6 – 219 mm heat-exchanger and instrumentation tube to ASTM A789.
Flanges
ASTM A182 F51 / F60 flanges 1/2" – 36", Class 150 – 2500.
Fittings & rings
ASME B16.9 buttweld fittings, forged fittings and rolled rings to Ø 3000 mm.
Use our free metal weight calculator — bars, sheets, plates, pipes and sections.
Our duplex steel range
Ready stock across every mainstream form — dispatched with mill test certificates and full traceability from our Mumbai warehouse.
Duplex Sheet & Plate
1.5 – 100 mm, ASTM A240 S31803 / S32205.
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Duplex Round Bar
Ø 6 – 400 mm, ASTM A276 / A479.
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Pipe & Fittings
Seamless and welded 1/2" – 24" NB.
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Tube
Heat-exchanger and instrumentation tube.
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Flanges
ASTM A182 F51, Class 150 – 2500.
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Rolled rings to Ø 3000 mm.
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Fasteners
F51 studs, bolts and nuts to NACE.
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Welding Consumables
ER2209 wire and E2209 electrodes.
ExploreDuplex Steel specifications.
Standards, sizes, thickness and condition we routinely supply across every product form.
| Product | Size Range | Thickness / Wall | Finish / Condition | Standards |
|---|---|---|---|---|
Plate | 1000 – 3000 mm wide | 3 – 100 mm | Hot-rolled, annealed & pickled (1D) | ASTM A240 / ASME SA240 |
Sheet | 1000 – 2000 mm wide | 1.5 – 6 mm | 2B, cold-rolled | ASTM A240 / EN 10088-2 |
Round Bar | Ø 6 – 400 mm | — | Black, peeled, ground | ASTM A276 / A479 / A484 |
Seamless Pipe | 1/2" – 12" NB | Sch 10S – Sch 160 | Annealed & pickled | ASTM A790 / A789 |
Welded Pipe | 1/2" – 24" NB | Sch 5S – Sch 40S | Annealed & pickled | ASTM A928 / A790 |
Flanges | 1/2" – 36" | Class 150 – 2500 | Forged, RF / RTJ | ASTM A182 F51 / ASME B16.5 |
Note: Other sizes, thicknesses and custom dimensions available on request.
Where duplex steel is used.
Oil & Gas
Flowlines, manifolds, separator internals and subsea hardware to NACE MR0175.
Desalination
High-pressure piping, RO vessels and brine handling in 2205.
Chemical & Fertiliser
Urea plant piping, storage tanks and process vessels.
Pulp & Paper
Digesters, bleach washers and chloride-bearing white liquor service.
Bridges & Structures
Rebar, cladding, tie rods and coastal structural steelwork.
Marine
Ballast tanks, chemical tanker cargo tanks and seawater systems.
Frequently asked questions.
Answers to the questions our Mumbai desk is asked most often.
What is the difference between duplex and super duplex steel?
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Duplex 2205 has a PREN of 34–35 with about 22% chromium and 3% molybdenum. Super duplex such as 2507 raises chromium to 25% and molybdenum to 4% with added nitrogen, giving a PREN above 40, higher yield strength (550 MPa minimum) and a critical pitting temperature about 15–20 °C higher, at a higher price.
Is duplex 2205 stronger than 316L?
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Yes. Duplex 2205 has a minimum yield of 450 MPa against 170–205 MPa for 316L, so wall thicknesses and section weights can typically be reduced by 25–40% in a pressure-containing design, often offsetting the higher price per kilogram.
What is UNS S31803 and how does it differ from S32205?
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Both are Duplex 2205. S32205 is the tighter modern specification with higher minimum chromium, molybdenum and nitrogen, giving more consistent corrosion performance and weldability. Most mills now supply dual-certified S31803 / S32205 material, which is what we stock.
What welding consumables are used for duplex 2205?
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ER2209 filler wire for GTAW and GMAW, and E2209 electrodes for SMAW. Heat input should be controlled between roughly 0.5 and 2.5 kJ/mm and interpass temperature kept below 150 °C to maintain the ferrite-austenite balance.
Every dispatch is traceable, tested and certified.
Material is supplied with EN 10204 3.1 (3.2 on request) mill test certificates, PMI and spectro verification, and is open to third-party inspection by TUV, SGS, BV, Lloyd’s and IRS from our Mumbai warehouse.
EN 10204 3.1 / 3.2
Mill test certificate with every consignment.
PMI & Spectro
Positive material identification before dispatch.
Third-party Inspection
TUV · SGS · BV · Lloyd's · IRS welcome.
Export Documentation
Full set prepared for 40+ countries.
Other grades you may also need
Ready to price your requirement?
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