Super Duplex 2507 Tube Sheet
The highest-PREN duplex grade in common use — reached for when Duplex 2205's chloride resistance genuinely isn't enough, typically in aggressive offshore seawater or concentrated brine service.
Chemical Composition
| Element | Min % | Max % |
|---|---|---|
| Chromium (Cr) | 24.0 | 26.0 |
| Nickel (Ni) | 6.0 | 8.0 |
| Molybdenum (Mo) | 3.0 | 5.0 |
| Nitrogen (N) | 0.24 | 0.32 |
| Carbon (C) | — | 0.030 |
PREN Calculation
Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 795 MPa min |
| Yield Strength (0.2% offset) | 550 MPa min |
| Elongation | 15% min |
| Max. Practical Service Temp. | ~300°C |
Equivalent Grades
| Standard | Designation |
|---|---|
| ASTM / UNS | S32750 |
| EN / DIN | 1.4410 |
| JIS | SUS329J4L (reference) |
2507 vs. 2205 — Which One
See the full Duplex 2205 datasheet for the standard duplex grade.
Applications
Offshore oil & gas platforms, seawater injection systems, and high-chloride desalination brine concentrate service where 2205's PREN margin is judged insufficient by the project's corrosion engineer.
Advantages & Limitations
Advantages
- Highest practical PREN of the commonly specified duplex grades
- Very high yield strength allows thinner sections
- Excellent resistance to chloride stress-corrosion cracking
Limitations
- Cost premium over Duplex 2205
- Requires tighter welding heat input control than 2205
- Often over-specified where 2205 would be entirely adequate
FAQ
Not always — for the majority of seawater and brackish-water applications, 2205's PREN of ~35 is adequate. 2507 earns its premium specifically in the most aggressive offshore and concentrated-brine services where a corrosion engineer has identified a genuine PREN shortfall with 2205.
Yes — super duplex grades require even more precise heat input control than standard duplex to maintain the correct phase balance, since the higher alloy content narrows the acceptable welding parameter window.
Longer than 2205 given lower stock availability — send your specification and quantity for a confirmed schedule.