Beyond standard duplex, for the most aggressive chloride service — see the grade table below for full datasheets and equivalents within this family.
See All Grades ↓Super duplex steel raises chromium, molybdenum, and nitrogen content beyond standard duplex grades, pushing the pitting resistance equivalent number (PREN) from roughly 35 up to the low-to-mid 40s. It's reserved for services where standard Duplex 2205 has been assessed as insufficient — typically the most aggressive offshore, desalination brine concentrate, or high-chloride process environments.
2507 is the standard super duplex grade, and the cost premium over 2205 is usually only justified when a corrosion engineer has specifically identified a PREN shortfall in the standard duplex grade for the actual service conditions.
| Grade | Designation | Best For |
|---|---|---|
| 2507 | UNS S32750 | Aggressive offshore, brine concentrate, and high-chloride service |
Not always — most seawater and brackish-water applications are adequately served by 2205's PREN of ~35. Super duplex earns its premium in the most aggressive services specifically.
There's no single universal number, but once required PREN is assessed above roughly 40, super duplex 2507 (PREN ~43) becomes the appropriate choice over standard duplex.
Yes — the higher alloy content narrows the acceptable welding heat input window compared to standard duplex, requiring more precise procedure control.
Every enquiry is checked against governing code, material compatibility and manufacturing feasibility before a quote is issued. Use our product, material, grade and standards guides to freeze the RFQ — then confirm with engineering.
Send your fluid composition and temperature — our engineering team will confirm the right grade.
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