Two-phase ferritic-austenitic microstructure with approximately 22% chromium and 3% molybdenum for superior corrosion resistance.
Yield strength approximately twice that of standard austenitic stainless steels such as 304 and 316.
Outstanding resistance to chloride-induced stress corrosion cracking, pitting, and crevice corrosion.
Excellent weldability and fabricability with good fatigue strength for demanding applications
Duplex 2205/ S31803/1.4462/F51
Product Overview
Duplex 2205 is a nitrogen-enhanced, two-phase ferritic-austenitic stainless steel that combines the best properties of both microstructures. With approximately 22% chromium, 5-6% nickel, and 3% molybdenum, this alloy offers approximately twice the yield strength of standard austenitic stainless steels such as 304 and 316, while delivering exceptional resistance to stress corrosion cracking, pitting, and general corrosion in aggressive environments . It is the most widely used duplex stainless steel grade across industries worldwide .
Product Details
This nitrogen-strengthened alloy exhibits exceptional resistance to corrosion in environments containing chlorides and hydrogen sulfide, making it ideal for offshore platforms, chemical processing, and desalination plants . The balanced microstructure provides good ductility and toughness across a wide temperature range from cryogenic conditions up to 300°C (572°F) . Typical applications include heat exchangers, pressure vessels, piping systems, pump shafts, and marine hardware. The alloy meets stringent NACE MR0175 requirements for sour gas service and is available with full material traceability and mill test certificates upon request .
Specifications & Designations
| Standard | Designation |
|---|---|
| UNS | S31803, S32205 |
| W.n.r(Germany) | 1.4462 |
| EN/DIN | X2CrNiMoN22.5.3 |
| ASTM | A276, A182 (F51 / F60) |
| BS (British) | 318S13 |
| AFNOR | Z2CND22.05Az |
| Other Designations | SAF 2205, Sandvik 2205, Cronifer 2205 LCN |
Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.03 max |
| Silicon (Si) | 1.00 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.03 max |
| Sulfur (S) | 0.02 max |
| Chromium (Cr) | 21.0 – 23.0 |
| Nickel (Ni) | 4.5 – 6.5 |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Nitrogen (N) | 0.10 – 0.22 |
| Iron (Fe) | Balance |
Mechanical Properties (Annealed)
| Property | Typical Value | |
|---|---|---|
| Tensile Strength | 620 – 750 MPa (90 – 109 ksi) | |
| Yield Strength (0.2% Offset) | 450 – 510 MPa (65 – 74 ksi) | |
| Elongation | 25 – 35% | |
| Hardness | < 270 HB / < 28 HRC | |
| Impact Strength (Room Temp) | 80 J (average) | |
| Impact Strength (-46°C) | 45 – 80 J |
Frequently Asked Questions
Q: What is the difference between Duplex 2205 and standard 316 stainless steel?
A: Duplex 2205 offers approximately twice the yield strength of 316 stainless steel and significantly better resistance to chloride stress corrosion cracking and pitting corrosion .
Q: What is the difference between UNS S31803 and UNS S32205?
A: Both are Duplex 2205 grades, but S32205 has tighter composition limits (higher nitrogen and molybdenum ranges) for enhanced corrosion resistance and is considered the premium version .
Q: What is the maximum operating temperature for Duplex 2205?
A: The recommended service temperature range is -200°C to +300°C (-330°F to +570°F). Above 300°C, embrittling phases such as sigma phase can form, reducing toughness and corrosion resistance .
Q: Is Duplex 2205 magnetic?
A: Yes, Duplex 2205 is ferromagnetic due to its ferrite phase content (approximately 40-55% ferrite) .
Q: Can Duplex 2205 be welded without post-weld heat treatment?
A: Yes, Duplex 2205 can be used in the as-welded condition provided proper welding procedures are followed to maintain the ferrite-austenite balance. No post-weld heat treatment is typically required
