UNS S32750 (2507) Super Duplex Stainless Steel Plate/Coil
2507 (UNS S32750) Super Duplex Stainless Steel – Properties, Equivalents & Applications
Comprehensive reference data for 2507 (UNS S32750) super duplex stainless steel including chemical composition, mechanical & thermal properties, global equivalents and application guide.
Hot rolling, Cold rolling, Solution annealing, Pickling
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UNS S32750 Super Duplex Stainless Steel Plate/Coil Introduction
2507 (UNS S32750) is a super duplex stainless steel combining high strength with exceptional resistance to pitting, crevice corrosion and stress corrosion cracking in chloride‑rich environments. Its balanced microstructure of approximately 50 % austenite and 50 % ferrite is achieved through careful control of chromium, molybdenum, nitrogen and nickel. The alloy offers roughly twice the yield strength of conventional austenitic grades and superior thermal conductivity, enabling lightweight design and cost savings. Widely specified for aggressive oil & gas, chemical process and marine applications, 2507 is supplied in plate and coil form in the solution‑annealed condition.
UNS S32750 Super Duplex Stainless Steel Plate/Coil Chemical Composition according to ASTM A240
The nominal chemical balance is designed to obtain a dual‑phase structure with high pitting resistance equivalent (PREN ≥40). Nitrogen strengthens the austenite and improves corrosion resistance. All values are in weight percent.
| Element | Content (%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.030 | Max |
| Silicon (Si) | ≤ 0.80 | Max |
| Manganese (Mn) | ≤ 1.20 | Max |
| Phosphorus (P) | ≤ 0.035 | Max |
| Sulfur (S) | ≤ 0.020 | Max |
| Chromium (Cr) | 24.0 – 26.0 | Min / Max |
| Nickel (Ni) | 6.0 – 8.0 | Min / Max |
| Molybdenum (Mo) | 3.0 – 5.0 | Min / Max |
| Nitrogen (N) | 0.24 – 0.32 | Min / Max |
| Copper (Cu) | ≤ 0.50 | Max |
UNS S32750 Super Duplex Stainless Steel Plate/Coil Physical Properties
Physical constants are typical for the solution‑annealed condition. Thermal conductivity is higher than that of conventional austenitic stainless steels, benefiting heat exchanger applications. Expansion coefficient is moderate, approaching that of carbon steel.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.8 | g/cm³ | 20 °C |
| Elastic Modulus (E) | 200 | GPa | 20 °C, tension |
| Shear Modulus (G) | 78 | GPa | 20 °C, estimated |
| Poisson's Ratio (ν) | 0.30 | — | 20 °C |
| Coefficient of Thermal Expansion (α) 20–100 °C | 13.0 | ×10⁻⁶ K⁻¹ | 20–100 °C |
| Coefficient of Thermal Expansion (α) 20–200 °C | 13.5 | ×10⁻⁶ K⁻¹ | 20–200 °C |
| Coefficient of Thermal Expansion (α) 20–300 °C | 14.0 | ×10⁻⁶ K⁻¹ | 20–300 °C |
| Thermal Conductivity (λ) | 15 | W/(m·K) | 20 °C |
| Thermal Conductivity (λ) | 17 | W/(m·K) | 100 °C |
| Thermal Conductivity (λ) | 19 | W/(m·K) | 200 °C |
| Specific Heat Capacity | 500 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρe) | 0.80 | µΩ·m | 20 °C |
UNS S32750 Super Duplex Stainless Steel Plate/Coil Mechanical Properties
Data comply with ASTM A240/A240M for plate. Minimum values apply to transverse specimens; typical values are given for reference. High strength enables reduced wall thickness in pressure‑containing components.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (Rp0.2) | ≥ 550 | MPa | Transverse, room temperature |
| Tensile Strength (Rm) | 800 – 1000 | MPa | Transverse, room temperature |
| Elongation (A50) | ≥ 25 | % | Longitudinal, 50 mm gauge |
| Elongation (A200) | ≥ 15 | % | Transverse, 200 mm gauge (for plate) |
| Impact Energy (KV₂) | ≥ 100 (typical) | J | Charpy‑V, transverse, 20 °C |
| Hardness | ≤ 300 | HBW | As delivered |
| Bend Test (180 °) | No cracks, radius 3 t | — | As per ASTM A240 |
UNS S32750 Super Duplex Stainless Steel Plate/Coil Fully Equivalent Standards and Replaceable Grades
| Country/Region | Standard | Grade Designation | Remarks |
|---|---|---|---|
| USA | ASTM A240/A240M | UNS S32750 | Super duplex 25Cr‑7Ni‑4Mo‑N |
| Europe | EN 10088-2 | 1.4410 (X2CrNiMoN25‑7‑4) | Identical composition and properties |
| Sweden | SS 14 | SS 2328 | National equivalent, fully interchangeable |
| International | ISO 15510 | X2CrNiMoN25‑7‑4 | Harmonized grade |
| China | GB/T 20878 | 022Cr25Ni7Mo4N (S25073) | Equivalent to UNS S32750 |
| Japan | JIS G4304 | SUS 329J4L (approximate) | Close but verify exact limits |
UNS S32750 Super Duplex Stainless Steel Plate/Coil Application Introduction
2507 super duplex sheet and plate serve in critical components where high strength and corrosion resistance under chlorides are required. Design guides prefer its use in welded structures after proper filler metal selection (e.g., ER2594 or similar). Construction codes such as ASME Section VIII Div. 1 cover its pressure‑retaining applications.
Product Applications: Heat exchangers and plate‑fin cores, Pressure vessels and storage tanks, Flexible flowlines and risers, Structural supports for offshore platforms, Seawater intake and outfall systems, Chemical injection lines and manifolds, Cable trays and gratings
Processed into products: Tube sheets and baffles for shell‑and‑tube exchangers, Welded impellers and diffusers for centrifugal pumps, Forged flanges and fittings (WNRF, lap joint), Expansion bellows and metal hoses, Blade and disc assemblies for butterfly valves, Bolting (studs, nuts) for subsea connectors, Strainer baskets and filter housings, Vessel shell courses and clad / lined plates
Application industries: Oil & Gas (subsea, topside piping, umbilicals), Chemical & Petrochemical (reactors, digestors, acid coolers), Marine & Offshore (seawater pumps, propeller shafts, fasteners), Desalination (flash evaporators, reverse‑osmosis frames), Pulp & Paper (digestor vessels, bleach plant equipment), Pollution Control (flue‑gas desulfurisation scrubbers, dampers), Pharmaceutical & Food Processing (high‑purity vessels)
UNS S32750 Super Duplex Stainless Steel Plate/Coil Similar or Alternative Super Duplex and Duplex Grades
| Country/Region | Standard | Grade Designation | Remarks |
|---|---|---|---|
| USA | ASTM A240 | UNS S32760 (Zeron 100®) | 25Cr‑7Ni‑3.5Mo‑W‑Cu N; similar PREN, slightly different alloy balance |
| Europe | EN 10088-2 | 1.4501 (X2CrNiMoCuWN25‑7‑4) | Equivalent to S32760, contains W and Cu |
| USA | ASTM A240 | UNS S32550 (Ferralium® 255) | 25Cr‑6Ni‑3Mo‑Cu N; earlier super duplex, lower PREN |
| USA | ASTM A240 | UNS S31260 | 25Cr‑6Ni‑3Mo‑N W‑Cu; less common super duplex |
| USA | ASTM A240 | UNS S32808 | 27.5Cr‑7Ni‑1.2Mo‑N; lower molybdenum, high nitrogen |
| Sweden | SS 14 | SS 2324 (SAF 2205) | Classic duplex, lower alloy content; suitable for less aggressive environments |
Notes:
Important clarification: The designation "2507(S31750)" sometimes appears in commercial documents, but UNS S31750 refers to austenitic 317L stainless steel. The correct UNS for 2507 super duplex is S32750 (EN 1.4410). All data in this sheet correspond to UNS S32750 / 1.4410. For critical applications, always specify the full UNS or EN designation to avoid mix‑ups. This material achieves pitting resistance equivalent number PREN ≈ 42–43, making it suitable for chloride levels up to ~ 50 000 ppm at moderate temperatures. Post‑weld heat treatment is not normally required for corrosion resistance if proper welding procedures are followed.
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