Grade 2507
Duplex stainless · Alloy 2507 / ASTM A240, UNS S32750, EN 1.4410
Super Duplex 2507 Stainless Steel (UNS S32750), duplex stainless steel.
Data sheet
| Designations | Alloy 2507 / ASTM A240 · UNS S32750 · EN 1.4410 (X2CrNiMoN25-7-4) |
|---|---|
| Standards | ASTM A240, ASTM A276, EN 10088-2, NACE MR0175 |
Metallurgy
Reference data for Super Duplex 2507 Stainless Steel (UNS S32750), against ASTM A240, ASTM A276, EN 10088-2, NACE MR0175.
Elemental composition
X2CrNiMoN25-7-4 to 1.4410
- Chromium 25,00%24,00–26,00%
- Nickel 7,00%6,00–8,00%
- Molybdenum 4,00%3,50–5,00%
- Nitrogen 0,28%0,24–0,32%
- Carbon 0,020%max 0,030%
- Other additions 1,48%Mn, Si, Cu, P, S
- Iron 62,22%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 | 62,22% |
| Carbon C | max 0,030%cap | 0,020% |
| Chromium Cr | 24,00–26,00% | 25,00% |
| Nickel Ni | 6,00–8,00% | 7,00% |
| Molybdenum Mo | 3,50–5,00% | 4,00% |
| Nitrogen N | 0,24–0,32% | 0,28% |
| Manganese Mn | max 1,20%cap | 0,80% |
| Silicon Si | max 0,80%cap | 0,40% |
| Copper Cu | max 0,50%cap | 0,25% |
| Phosphorus P | max 0,035%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 | 800 MPa116 ksi |
| Yield strength, 0,2% offset | 550 MPa79,8 ksi |
| Elongation at break | 15% |
| Hardness | 290 HBW / 105 HRB |
| Modulus of elasticity | 200 GPa29 Mpsi |
| Density | 7,8 g/cm³0,28 lb/in³ |
| Thermal conductivity | 15 W/(m·K)104 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 42,68
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
Benchmark PREN >= 42; immune to chloride-induced stress corrosion cracking in boiling seawater and high-halide brines.
Acidic and chemical media
Extreme resistance to organic acids (formic, acetic) and strong non-oxidizing inorganic acids with chlorides.
Sensitisation and thermal behaviour
Highly resistant to intergranular attack, but highly prone to rapid intermetallic precipitation (sigma phase σ, chi phase χ) between 600°C–1000°C.
Welding
Good; requires strict interpass temperature controls (<150°C) and 2509 filler metal with shielding gas containing 2% N2.
Machining and cold forming
Machinability index 35% relative to AISI 1212. Moderate; extremely high yield strength causes substantial springback and requires heavy forming machinery.
Where it is used
- Seawater reverse osmosis (SWRO) desalination high-pressure headers and pumps
- Subsea petroleum Christmas trees, manifolds, and umbilical lines
- Marine scrubbers for heavy fuel oil exhaust cleansing
- Chemical injection quills and heat exchangers handling sour gas
Desalination · Offshore Oil & Gas · Marine Engineering · Chemical Processing
Performance scores in full
The same six scores the profile plots, as numbers.
| Property | 2507 |
|---|---|
| Corrosion resistance | 10 / 10 |
| Weldability | 8 / 10 |
| High-temperature resistance | 5.5 / 10 |
| Tensile strength | 8.8 / 10 |
| Cold formability | 6 / 10 |
| Machinability | 3.8 / 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.