2507 vs 2205 Stainless Steel
Side-by-side comparison · Composition · Properties · Selection guide
2507 is the super-duplex upgrade of 2205: chromium rises from 22 to 25%, molybdenum from about 3 to 4%, and nitrogen increases, pushing typical PREN above 40. Its specified yield strength is also higher, while fabrication controls are tighter; current price and availability must be compared for the actual product form and order.
Full datasheets:2507 Stainless Steel·2205 Stainless Steel
At a Glance
| 2507 | 2205 | |
|---|---|---|
| Type | Super-duplex (austenitic-ferritic) | Duplex (austenitic-ferritic) |
| UNS | S32750 | S32205 |
| Standard | ASTM A240/A240M, A789/A790 | ASTM A240/A240M, A276 |
| Density | 7.8 g/cm³ | 7.8 g/cm³ |
Corrosion Resistance and Service Limits
2507
- The mixed austenitic-ferritic structure provides high strength and improved resistance to chloride pitting and stress-corrosion cracking relative to 304/316-type grades.
- PREN is only a screening index. Temperature, crevices, weld phase balance, heat tint, deposits and actual solution chemistry still govern suitability.
2205
- The mixed austenitic-ferritic structure provides high strength and improved resistance to chloride pitting and stress-corrosion cracking relative to 304/316-type grades.
- PREN is only a screening index. Temperature, crevices, weld phase balance, heat tint, deposits and actual solution chemistry still govern suitability.
Fabrication and Heat Treatment
| Operation | 2507 | 2205 |
|---|---|---|
| Welding | Use a qualified duplex procedure with controlled heat input, interpass temperature and filler to maintain phase balance, toughness and corrosion resistance. | Use a qualified duplex procedure with controlled heat input, interpass temperature and filler to maintain phase balance, toughness and corrosion resistance. |
| Forming | Higher yield strength increases forming load and springback. Severe cold work may require solution annealing under a qualified route. | Higher yield strength increases forming load and springback. Severe cold work may require solution annealing under a qualified route. |
| Machining | Use rigid equipment, positive feeds and lower cutting speed than common austenitic grades because high strength and work hardening raise cutting load. | Use rigid equipment, positive feeds and lower cutting speed than common austenitic grades because high strength and work hardening raise cutting load. |
| Heat treatment | Solution anneal and rapid cooling are used to restore the specified duplex structure. Local stress relief can form harmful intermetallic phases and is not a generic remedy. | Solution anneal and rapid cooling are used to restore the specified duplex structure. Local stress relief can form harmful intermetallic phases and is not a generic remedy. |
Chemical Composition (wt%)
| Element | 2507 | 2205 |
|---|---|---|
| C | ≤0.030 | ≤0.030 |
| Mn | ≤1.20 | ≤2.00 |
| Si | ≤0.80 | ≤1.00 |
| Cr | 24.0–26.0 | 22.0–23.0 |
| Ni | 6.0–8.0 | 4.5–6.5 |
| Mo | 3.0–5.0 | 3.0–3.5 |
| N | 0.24–0.32 | 0.14–0.20 |
| P | ≤0.035 | ≤0.030 |
| S | ≤0.020 | ≤0.020 |
Mechanical Properties
| Property | 2507 | 2205 |
|---|---|---|
| Tensile strength | ≥795 MPa (116 ksi) | ≥655 MPa (95 ksi) |
| Yield strength (0.2%) | ≥550 MPa (80 ksi) | ≥450 MPa (65 ksi) |
| Elongation (50 mm) | ≥15% | ≥25% |
| Hardness | ≤310 HBW | — |
| PREN | ≥40 | ≥34 |
Which One Should You Choose?
Choose 2507 for:
- Hot seawater and firewater systems offshore
- High-pressure desalination (SWRO) piping
- Sour oil & gas flowlines and manifolds
- Crevice-prone joints in warm chlorides
Choose 2205 for:
- General brines, brackish water and cargo tanks
- Structural duplex duty — bridges, blast walls, tanks
- Fabrication-heavy projects with ordinary shop skills
- Budget-bound chloride upgrades from 316L
Our verdict
Match PREN to chloride temperature: 2205 handles most brines to ~60–80 °C; above that, or in crevice-heavy seawater service, super-duplex 2507 earns its premium. Do not over-specify — 2507's narrow welding window punishes casual fabricators, and 2205 already outperforms austenitics by a wide margin.
Cost and Availability
Compare the current stock position, mill route, minimum production quantity, processing yield, testing and delivered cost for 2507 and 2205 at quotation time. A fixed price ratio would be misleading because product form, size, condition and market timing can change the commercial result.
Do Not Substitute Without Review
Do not replace 2507 with 2205, or the reverse, from the grade name alone. Recheck chemistry, mechanical-property condition, product standard, dimensions, corrosion environment, welding procedure and project approval before substitution.
2507 & 2205 Products We Export
Frequently Asked Questions
What does PREN over 40 actually buy?
Classification as a seawater-resistant alloy: resistance to pitting and crevice corrosion in warm, stagnant, chlorinated seawater — conditions that pit 2205. If your water is cooler, flowing or diluted, 2205's ~35 usually suffices.
Are 2507 and 2205 welded the same way?
Same philosophy (matched over-alloyed filler, controlled heat input), narrower margins for 2507: its higher alloy content precipitates sigma phase faster if cooled slowly. Procedure qualification with corrosion testing (ASTM G48) is standard for super-duplex work.
Can 2507 replace 2205 in the same piping class?
Material strength and corrosion resistance may improve, but welding, impact testing, heat treatment, fittings, bolting and project approvals must be reviewed before changing the piping class.
RFQ
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Technical content updated: 2026-07-29
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.