UNS S32205 Duplex Stainless Steel: Twice the Strength of 316L

ASTM A240/A789 · Updated: 2026-05-25

UNS S32205 (2205) is a duplex stainless steel with a balanced ferrite-austenite microstructure (~50/50), combining the best properties of both phases: approximately double the yield strength of 316L (450 vs 170 MPa) with excellent chloride stress corrosion cracking resistance. Its PREN (Pitting Resistance Equivalent Number) of 34-36 exceeds 316L (25-28), making it suitable for seawater-cooled heat exchangers, chemical tankers, desalination plants, and offshore structures. Resistant to temperatures from -50°C to +300°C, though prolonged exposure above 300°C may cause embrittlement from alpha-prime phase formation.

Quick Facts

CategoryStainless Steel
StandardASTM A240/A789
Density7.80 g/cm³
Yield Strength450 MPa (65 ksi)
Tensile Strength655 MPa (95 ksi)

Global Equivalents & Cross-Reference

Alternative Standard / GradeAction
EN 1.4462 Compare
X2CrNiMoN22-5-3 Compare
SUS329J3L Compare
022Cr22Ni5Mo3N Compare
2205 Compare

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Frequently Asked Questions

What are the welding requirements for 2205 duplex?

Use matching or slightly over-alloyed filler (ER2209). Maintain heat input of 0.5-2.5 kJ/mm—too low prevents proper austenite reformation, too high promotes intermetallic phases. Interpass temperature must stay below 150°C. No preheat is needed. Post-weld solution annealing at 1020-1100°C followed by water quenching is recommended for critical corrosion service, though many non-critical applications accept as-welded condition.