CHEMICAL COMPOSITION (%)

Chromium (Cr)22.0 - 23.0

Nickel (Ni)4.5 - 6.5

Molybdenum (Mo)3.0 - 3.5

Nitrogen (N)0.14 - 0.20

Manganese (Mn)2.0 max

Silicon (Si)1.0 max

Carbon (C)0.030 max

Phosphorus (P)0.030 max

Sulfur (S)0.020 max

PREN32-34

MECHANICAL PROPERTIES

Tensile Strength655 MPa min

Yield Strength (0.2%)450 MPa min

Elongation25% min

HardnessHRc 31 max

Impact (KV)45J min at -40C

Ferrite Content25-65%

DIMENSIONS AVAILABLE

Thickness3mm - 80mm

Width1000mm - 2000mm

Length2000mm - 12000mm

FinishNo.1 / 2B / Polished

TypeHot Rolled Plate

SUPPLY CONDITIONS

Mill Test CertEN 10204 3.1

PMI TestingIncluded

Ferrite CheckASTM E562

UT TestPer ASTM A240

Lead TimeStock: 7-10 days

What is Duplex 2205 Stainless Steel?

Duplex 2205 (UNS S32205) is a nitrogen-alloyed duplex stainless steel with a two-phase microstructure of approximately 50% austenite and 50% ferrite. This unique structure gives 2205 approximately twice the strength of standard austenitic stainless steels (like 304L and 316L) while maintaining excellent corrosion resistance.

The PRE (Pitting Resistance Equivalent) of 2205 is 32-34, significantly higher than 316L (PREN 24-28), making it suitable for chloride-rich environments where 316L would fail. The higher chromium content provides excellent chloride stress corrosion cracking (SCC) resistance.

Duplex 2205 vs 316L: Key Differences

Property	Duplex 2205	316L Austenitic	Advantage
Yield Strength	450 MPa min	200 MPa	2205: 2.25x stronger
Tensile Strength	655 MPa min	485 MPa	2205: 35% stronger
PREN	32-34	24-28	2205: better pitting resistance
Chloride SCC	Excellent	Poor	2205: far superior
Price	Higher	Lower	316L: cost advantage
Formability	Moderate	Excellent	316L: easier to form
Weldability	Good	Excellent	316L: more forgiving

Bottom line: Duplex 2205 costs more upfront but allows thinner sections (due to higher strength), longer equipment life in chloride environments, and lower lifecycle costs. Use 2205 when 316L would require thickness above 15mm or when chloride SCC is a concern.

Applications

Desalination Plants: Brine heaters, heat recovery exchangers, MSF stills, product water tanks

Oil & Gas: Flowlines, subsea equipment, wellhead components, process vessels for offshore platforms

Chemical Processing: Storage tanks, heat exchangers, pressure vessels handling chlorides

Marine: Seawater cooling systems, ship hull structures, desalination piping

Pulp & Paper: Black liquor heaters, bleach plant washers, storage tanks

Frequently Asked Questions

What is the ferrite content requirement for Duplex 2205?

ASTM A240 requires ferrite content of 25-65% (typical target: 50%). Ferrite content below 25% reduces corrosion resistance; above 65% risks embrittlement. We verify ferrite content using ASTM E562 point count method on every heat.

Can Duplex 2205 be welded to 316L?

Yes, but the weld filler must match the service conditions. For matching strength and corrosion: use ER2209 filler wire (AWS A5.9). For dissimilar joints, preheat to 100-150C is recommended. Post-weld heat treatment is generally NOT required for 2205.

What is the difference between UNS S32205 and UNS S31803?

S32205 is a tighter composition of S31803 with enhanced nitrogen (0.14-0.20% vs 0.08-0.20%), tighter chromium (22-23% vs 21-23%), and tighter molybdenum (3.0-3.5% vs 2.5-3.5%). S32205 has better corrosion resistance and is the preferred specification for new projects. Most mills now produce to S32205 chemistry.

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Duplex 2205 Stainless Steel Plate