2507 Super Duplex Stainless Steel
2507 is selected when standard stainless grades are not enough. It combines very high strength with strong resistance to chloride corrosion.
The structure is duplex, which means a balanced mix of ferrite and austenite. This helps reduce cracking risk in salt-rich service, while keeping strength high.
Strength level
Very high
Common minimum yield is around 550 MPa for many supply specs.
Chloride service
Strong resistance
Designed for pitting, crevice attack, and chloride cracking control.
Typical use
Offshore & desalination
Used for seawater, marine, and chemical processing equipment.
Magnetism
Slightly magnetic
Duplex grades are often lightly magnetic after processing.
2507 is used where corrosion risk and downtime cost are high. It is often chosen for chloride-rich and marine environments.
- Offshore and marine: topside piping, riser parts, seawater lines, structural members
- Desalination: brine systems, high-chloride piping, pumps and valves
- Chemical and process: heat exchangers, reactors, scrubbers, pressure parts
- Energy and heavy industry: high-load frames that also face corrosion exposure
2507 may be written differently across standards. Equivalents help alignment, but ordering must follow the required specification.
| System | Designation | Note |
|---|---|---|
| AISI / ASTM | 2507 (F53 in some product specs) | Common commercial grade name |
| UNS | S32750 | Used in many ASTM material standards |
| EN | 1.4410 | European grade number |
| DIN | X2CrNiMoN25-7-4 | European naming format |
| JIS | SUS329J4L | Common reference in Asia |
| GOST | 02Х25Н7М3 / 07Х25Н7М2 | Often seen in regional documents |
| GB | 00Cr25Ni7Mo4N | China standard naming format |
- High strength: supports thinner wall options in some designs and reduces weight.
- Chloride corrosion control: strong resistance to pitting and crevice attack.
- Cracking resistance: designed to reduce chloride stress cracking risk in many cases.
- Good fatigue performance: helps in cyclic load service.
- Service planning: best results come from correct welding and surface cleaning.
Limits can vary by product form and standard. Always confirm by Mill Test Certificate. The nitrogen level is a key part of 2507 performance.
| Grade | Standard | C | Cr | Ni | Mo | N | Mn | Si | P | S | Cu | Fe |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2507 / S32750 | ASTM A240 (typical) | ≤ 0.03 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | ≤ 1.2 | ≤ 0.8 | ≤ 0.035 | ≤ 0.02 | ≤ 0.5 | Balance |
| 1.4410 | EN 10088-2 (typical) | ≤ 0.03 | 24.0–26.0 | 6.0–8.0 | 3.0–4.5 | 0.24–0.35 | ≤ 2.0 | ≤ 1.0 | ≤ 0.035 | ≤ 0.015 | ≤ 0.5 | Balance |
Strength values depend on thickness and condition. Use the governing specification for acceptance. Duplex grades are ordered for both strength and corrosion control.
| Property | Typical requirement | Notes |
|---|---|---|
| Tensile strength | ≥ 800 MPa | Common minimum for plate and sheet routes |
| Yield strength (0.2%) | ≥ 550 MPa | Often about 2–3x 316L yield level |
| Elongation | ≥ 15% | Lower ductility than 316L, plan forming accordingly |
| Hardness | ≤ 310 HBW | Confirm by standard and heat treatment |
2507 is built for chloride-rich service. It is widely used where seawater, brine, or salt deposits are present.
Duplex grades are typically used at moderate temperatures. For many projects, long-term service is planned below about 250°C.
2507 can be supplied in standard stainless product forms. Availability depends on tolerance, inspection scope, and delivery time.
| Form | Typical size range | Notes |
|---|---|---|
| Sheet / plate | Common widths 1000–2000 mm, various thicknesses | For fabrication, pressure parts, and structural use |
| Cold-rolled coil | Width 1000–2000 mm, thickness often up to 6.0 mm | Slitting and cut-to-length available |
| Hot-rolled coil | Width 1000–2000 mm, thickness often 3–14 mm | Used for heavier coil supply routes |
| Strip | Width 7–600 mm, thickness often 0.3–10 mm | For formed parts and welded components |
| Pipe / tube | Seamless or welded, project-based | Define NDT, impact test, and corrosion requirements |
| Bar | Round and flat bar, project-based | Used for machining, fittings, and valves |
- Machining: more demanding than 304/316 due to high strength. Use stable tooling and coolant.
- Forming: higher press force is needed. Plan larger bend radius and tighter process control.
- Cutting: plasma and waterjet are common for plate. Keep edges clean before welding.
- Cleaning: proper cleaning supports corrosion performance in chloride service.
2507 can be welded well when procedures are controlled. Heat input and interpass temperature should be managed to protect the duplex structure.
- Common processes: TIG, MIG, SMAW, and SAW are widely used.
- Filler guidance: ER2594 or equivalent is a common choice for many joints.
- Heat control: control heat input to reduce brittle phase risk.
- Post-weld care: pickling and passivation help restore full corrosion performance.
These three grades are often reviewed together. 316L is the baseline for general corrosion, while duplex grades target chloride service and higher strength.
| Property | 316L | 2205 | 2507 |
|---|---|---|---|
| Yield strength | Lower | High | Very high |
| Chloride resistance | Good | Excellent | Outstanding |
| Elongation | Higher | Medium | Lower |
| Magnetism | Non-magnetic | Slight | Slight |
| Typical cost level | Lower | Medium | Higher |
Use these internal tools to confirm equivalents, check corrosion indicators, and prepare a clear RFQ.
Is 2507 stronger than 2205?
In many standards, yes. 2507 is commonly specified with a higher minimum yield strength. It is often chosen for high-load structures and pressure parts in chloride service.
Is 2507 stainless steel magnetic?
It is often slightly magnetic. Duplex grades contain ferrite, which can show magnetism after processing.
Can 2507 be welded?
Yes, with correct procedures. Heat input control and post-weld cleaning help protect corrosion performance. For critical jobs, use qualified welding procedures.
When should I choose 2507 instead of 316L?
Choose 2507 when chloride risk is high and strength is also important. Typical cases include seawater, brine, and offshore exposure.
What information helps you quote 2507 faster?
Please share standard, form, size, finish, quantity, test scope, packing, and destination port. If the project has a code requirement, include it in the RFQ.