Grade 2205 duplex
Duplex stainless · 1.4462, duplex, UNS S31803
High-strength duplex for chloride service. Listed pending DUPLEX_GRADES.
Data sheet
| Designations | Alloy 2205 / ASTM A240 · UNS S32205 · EN 1.4462 (X2CrNiMoN22-5-3) |
|---|---|
| Standards | EN 10088-2, ASTM A240 |
| Used for | chemical tanks, marine shafts |
Metallurgy
Reference data for Duplex 2205 Stainless Steel (UNS S32205 / S31803), against ASTM A240, ASTM A276, EN 10088-2, NACE MR0175.
Elemental composition
X2CrNiMoN22-5-3 to 1.4462
- Chromium 22,50%22,00–23,00%
- Nickel 5,50%4,50–6,50%
- Molybdenum 3,25%3,00–3,50%
- Nitrogen 0,17%0,14–0,20%
- Carbon 0,020%max 0,030%
- Other additions 1,73%Mn, Si, P, S
- Iron 66,83%Balance
Proportions use the normalised midpoint of each specified range. The midpoint is a derived figure, not something the standard states: read the table for what is actually specified.
Performance profile
Comparative scores out of ten, for weighing one grade against another
These are relative ratings, not measured properties, and they carry no units. Use them to narrow a shortlist, then work from the specified values.
Composition as specified
| Element | Specified | Nominal |
|---|---|---|
| Iron Fe | Balance | 66,83% |
| Carbon C | max 0,030%cap | 0,020% |
| Chromium Cr | 22,00–23,00% | 22,50% |
| Nickel Ni | 4,50–6,50% | 5,50% |
| Molybdenum Mo | 3,00–3,50% | 3,25% |
| Nitrogen N | 0,14–0,20% | 0,17% |
| Manganese Mn | max 2,00%cap | 1,20% |
| Silicon Si | max 1,00%cap | 0,50% |
| Phosphorus P | max 0,030%cap | 0,020% |
| Sulphur S | max 0,020%cap | 0,010% |
A cap is a ceiling, not a quantity: a heat may contain far less. The nominal column is the midpoint of each range, used for the chart's proportions only.
Mechanical and physical properties
| Property | Value |
|---|---|
| Tensile strength, ultimate | 655 MPa95 ksi |
| Yield strength, 0,2% offset | 450 MPa65,3 ksi |
| Elongation at break | 25% |
| Hardness | 260 HBW / 100 HRB |
| Modulus of elasticity | 200 GPa29 Mpsi |
| Density | 7,8 g/cm³0,28 lb/in³ |
| Thermal conductivity | 19 W/(m·K)131,7 BTU·in/(hr·ft²·°F) |
| Thermal expansion | 13 µm/(m·K)7,2 µin/(in·°F) |
Test condition not yet confirmed. These figures are typical values for the grade; the condition a bar was supplied in changes them materially, so ask us for the mill certificate before designing to a number.
Pitting resistance
PREN 35,95
Cr + 3,3 Mo + 16 N, across the full specified composition
- Freshwater0–20
- Brackish20–32
- Seawater32–40
- Extreme offshoreover 40
A standard states its elements as ranges, so a grade has a window rather than a single score. The bar is that window; the tick is the midpoint.
Corrosion and fabrication
Chloride and marine service
Superb resistance to chloride stress corrosion cracking (SCC) and localized pitting in marine and brackish waters.
Acidic and chemical media
High resistance to wet sulfuric, phosphoric, and organic acids, and hydrogen sulfide (H2S sour service).
Sensitisation and thermal behaviour
Excellent; duplex microstructural balance (50% ferrite / 50% austenite) retards intergranular corrosion; vulnerable to 475°C embrittlement and sigma phase precipitation between 600°C–900°C.
Welding
Very Good; requires controlled heat input and over-alloyed filler metal (e.g., 2209) to preserve 50:50 phase ratio and nitrogen retention.
Machining and cold forming
Machinability index 40% relative to AISI 1212. Moderate; higher yield strength requires double the forming power of 304 and displays higher springback.
Where it is used
- Offshore oil and gas flowlines, subsea manifolds, and risers
- Chemical cargo tanks and maritime chemical tankers
- Desalination high-pressure reverse osmosis (RO) piping and pumps
- Pulp and paper digesters and bleaching scrubbers
Offshore Oil & Gas · Desalination · Marine Cargo · Pulp & Paper · Chemical Processing
Performance scores in full
The same six scores the profile plots, as numbers.
| Property | 2205 |
|---|---|
| Corrosion resistance | 9.5 / 10 |
| Weldability | 8.5 / 10 |
| High-temperature resistance | 6 / 10 |
| Tensile strength | 8 / 10 |
| Cold formability | 7 / 10 |
| Machinability | 4.5 / 10 |
This page is guidance for selecting a grade, not a specification. Design to the governing standard and the mill certificate for the heat you are supplied.
The specifications and data on this site are provided for general information only. Verify any real-world project with a qualified metallurgist before relying on these figures. We take no responsibility for the use and application of this information.