A cost-effective duplex stainless steel, UNS S31803/2205 combines high strength with excellent resistance to pitting, crevice corrosion and chloride stress-corrosion cracking in aggressive environments. Available from NeoNickel in sheet, plate, round bar, pipe and tube.
UNS S31803/2205 (also known as duplex 2205 or 1.4462) is a 22% chromium duplex stainless steel with a balanced ferritic-austenitic microstructure containing roughly 40 to 50% ferrite in the annealed condition. The combination of chromium, molybdenum and nitrogen delivers the high strength of ferritic grades alongside the corrosion resistance of austenitic grades, typically at a lower cost than high-nickel austenitic alternatives.
The grade is widely specified for warm seawater, sour-gas and chloride-rich service in the oil and gas, chemical processing and pulp and paper industries where 316L and 317L stainless steels are no longer adequate.
Key Benefits of Alloy UNS S31803/2205:
We stock UNS S31803/2205 in a range of product forms to suit different applications and fabrication methods, including sheet, plate, round bar, pipe and tube. To view available sizes and submit an enquiry, use the dropdown selector below.
The following elements give UNS S31803/2205 its balance of high strength and resistance to pitting, crevice corrosion and stress-corrosion cracking.
| % | Cr | Fe | Mo | N | Ni | P | S | Si |
|---|---|---|---|---|---|---|---|---|
| Min | 22 | Balance | 3 | 0.14 | 4.50 | - | - | 0.20 |
| Max | 23 | - | 3.50 | 0.20 | 5.50 | 0.030 | 0.020 | 0.70 |
UNS S31803/2205 is built for long service in chloride-bearing, sour-gas and sulphuric acid environments. Key physical and mechanical properties include:
UNS S31803/2205 is a 22% chromium duplex stainless steel developed to combine the strength of ferritic grades with the corrosion resistance of austenitic grades. It is dual-certified to both UNS S31803 and the tighter-chemistry UNS S32205, and meets Werkstoff 1.4462 under EN standards. Most modern material is produced to meet both UNS numbers simultaneously.
The difference between UNS S31803 and UNS S32205 comes down to tightened chemistry ranges in S32205:
The S32205 range guarantees better pitting resistance and as-welded corrosion performance, which is why many modern specifications call for dual S31803/S32205 certification.
Three alloying elements work together to deliver this performance:
UNS S31803/2205 can be welded using standard stainless steel processes including GTAW, GMAW, SMAW and SAW. Recommended filler metals and procedures:
NeoNickel supplies UNS S31803/2205 in sheet, plate, round bar, pipe and tube, all with full mill certification and traceability, supported by technical guidance from our specialist team.
With its high strength and resistance to chloride-induced pitting, crevice corrosion and stress-corrosion cracking, UNS S31803/2205 is specified across industries where austenitic stainless steels fall short. Duplex stainless steel UNS S31803 plate is commonly used for pressure vessels and tank fabrication, while duplex UNS S31803 pipe and tube are widely specified for corrosive fluid handling.
This combination of properties makes UNS S31803/2205 a common choice across industries that demand both strength and corrosion resistance.
A 22% chromium duplex stainless steel with a balanced ferritic-austenitic microstructure. It combines high yield strength (roughly twice that of austenitic grades) with excellent resistance to chloride pitting, crevice corrosion and stress-corrosion cracking.
Both designations describe the same base alloy, but S32205 has a tighter chemistry with higher minimum chromium, molybdenum and nitrogen content. S32205 was introduced to guarantee better as-welded corrosion resistance. Most modern material is dual-certified to both.
Typical applications include seawater systems, offshore oil and gas piping, chemical process vessels, heat exchangers, pulp mill digesters, FGD scrubbers and food processing equipment. It is specified wherever 316L or 317L fall short on chloride resistance or strength.
Yes. It offers excellent resistance to chloride pitting, crevice corrosion and stress-corrosion cracking, with a PREN of 35 or higher. It also performs well in sulphuric acid and sour-gas environments.
Maximum recommended service temperature is around 300°C. Above this range the grade is susceptible to 475°C embrittlement and sigma-phase formation, which reduce toughness.
Yes, using GTAW, GMAW, SMAW and SAW. The standard filler metal is AWS ER2209, which contains additional nickel to produce a balanced phase structure in the weld.
Sheet, plate, round bar, pipe and tube.
NeoNickel supplies UNS S31803/2205 across the UK and Europe, supporting both urgent requirements and long-term project needs. All material is supplied with NACE MR0175 and NORSOK MDS D45 certification where required for sour service, alongside full mill traceability to ASTM and ASME standards. Our technical team can help specify the right form for oil and gas, chemical processing and marine applications.
If you're unsure which grade or form is right for your application, fill out our enquiry form and a member of the team will be in touch.
Can't find the information you need? Please contact us directly.
Proud members of the British Valve & Actuator Association