2205 Duplex Stainless Steel Sheet

What is 2205 duplex stainless steel sheet?

Duplex stainless steels are balanced so that the solidified metal is roughly half ferrite and half austenite: 2205 does it with about 22 % chromium, 5.5 % nickel, 3 % molybdenum and 0.17 % nitrogen, the nitrogen being the trick that stabilises the austenite without the nickel that makes 316L expensive and gives the alloy its pitting resistance. Two consequences follow. The ferrite makes the steel strong — 450–500 MPa yield, 650–880 MPa tensile, against 220–300 MPa for 316L — and immune to chloride stress-corrosion cracking, the failure that austenitic steels suffer above about 50 °C in brine, so that a duplex tank wall can be designed at roughly twice the allowable stress and a duplex heat-exchanger shell does not crack where a 316L one would. The austenite keeps it tough and weldable, with 100 J or more at −40 °C. PREN (Cr + 3.3 Mo + 16 N) is about 35, comfortably above the 30 that seawater at ambient temperature requires and far above 316L's 24 — which is why 2205 is the standard material of reverse-osmosis desalination pipework and high-pressure vessels, brine and produced-water separators, chemical tankers' cargo tanks, pulp and paper digesters, flue-gas scrubbers, biogas and wastewater equipment, and bridges and offshore blast walls where strength and corrosion resistance are both needed. Its limits are temperature — do not use it continuously above 250–300 °C or below −50 °C, because the ferrite embrittles — and the need to weld it correctly: heat input and interpass temperature must keep the ferrite-austenite balance in the weld. Two UNS numbers exist: the older S31803 with a wider chemistry and the tighter, nitrogen-enhanced S32205 that all modern mills produce and dual-certify; EN calls both 1.4462. Super duplex 2507 (1.4410, PREN ≥ 40) is the step above for hot seawater and is supplied on request.

Chemical composition

Mechanical properties

Equivalent grades

Duplex 2205 vs 316L vs super duplex

Desalination and brine service

Reverse-osmosis plants are the largest single use of 2205 in the Gulf: high-pressure feed and brine pipework at 60–80 bar, energy-recovery manifolds, cartridge-filter housings, brine tanks and the pressure vessels around the membranes all run at PREN 35 minimum, with super duplex specified where the brine is warm or concentrated. The same logic applies to produced-water and oil-field brine separators, cooling-water systems on sea water, chlor-alkali and de-icing-salt plants, and to tanks storing seawater-derived salt solutions. In these services 316L fails by pitting and crevice attack at flanges and welds within a few years; 2205 with correctly executed welds and a pickled, passivated surface lasts the design life. We supply sheet and plate with 3.2 certification and, for NACE MR0175 sour service, with hardness below 28 HRC on the certificate.

Thickness range and stock sizes

Weight per m² and per sheet

Forming, welding and finishing

Forms at 1.5–2.5 × t but springs back about twice as much as 316L and needs 50 % more press force — plan tooling for the strength; deep drawing is limited. Welding is the critical process: use 2209 (22-9-3 N) consumables with 2–3 % more nickel than the base metal, keep heat input between 0.5 and 2.5 kJ/mm and interpass below 150 °C so the weld retains 30–70 % ferrite, and shield the root with nitrogen-bearing argon — too cold a weld leaves brittle ferrite, too hot precipitates sigma phase. No preheat, no PWHT (solution annealing only at 1 020–1 100 °C with water quench if required). Plasma cut with nitrogen, laser or waterjet; pickle and passivate all welds; do not use carbon-steel tools. Machining is harder than 316L — rigid set-ups, sharp carbide, positive rake.

Where it is used

• Reverse-osmosis desalination pipework, manifolds and pressure vessels
• Brine, produced-water and seawater cooling systems
• Chemical and product tankers' cargo tanks; storage tanks for chlorides
• Pulp digesters, flue-gas scrubbers, biogas and wastewater equipment
• Pressure vessels and heat exchangers in chloride service (EN 10028-7)
• Bridges, blast walls and structural parts needing strength plus corrosion resistance

2205 vs 316L vs 904L

316L remains the choice for food, pharma and general chemical work and for anything formed deeply or used above 300 °C; 2205 takes over in brine and sea water and wherever the doubled strength cuts weight. 904L, the high-nickel austenitic, competes with 2205 in sulphuric-acid service but costs more and is weaker. For warm sea water and oil-and-gas sour service the next step is super duplex 2507, supplied to order. All grades on the stainless sheet hub.

Price

Duplex 2205 is priced per ton on the stainless list at about 15–30 % above 316L (less nickel, more molybdenum and chromium, and the mill's nitrogen practice) — but per unit of strength it is the cheaper material. The bands below are the month's indicative FOB Istanbul ranges for 2B sheet and 1D plate; UT, 3.2 and NACE hardness certification are added per ton.

Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.

Export and packing

Packing of 2205 duplex stainless steel sheet: coils on cradles (eye-to-sky, VCI wrap, four straps, 5–25 t) or sheet packs on skids up to 3 t with interleaving paper and corner protectors; 20' ≈ one coil (≤ 20 t), 40' HC ≈ two coils or 24 t of sheet. Tariff 7210 / 7209 / 7208.

Certificates and testing

Every lot of 2205 duplex stainless steel sheet carries an EN 10204 3.1 inspection certificate listing heat, chemistry, mechanical and impact results. On request we add 3.2 witnessing by a classification society or inspector, EN 10160 ultrasonic testing and supplementary impact tests at the customer's design temperature.

How to order

Specify 1.4462 / S32205, thickness × width × length or the cutting file, finish (2B / 1D), certificate level (3.1 / 3.2, NACE if sour service), UT for plate, quantity and port; state the service (desalination, vessel, structural) so the right mill test scope is offered.

Standards

• EN 10088-2 — 1.4462 (X2CrNiMoN22-5-3)
• ASTM A240 / A240M — UNS S32205 / S31803
• EN 10028-7 (pressure) — 1.4462
• NACE MR0175 / ISO 15156 — sour service limits
• EN 10204 3.1 / 3.2

Grades

Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: 1.4462 · 1.4404 · 1.4410