ASTM A182 F61 (Alloy 255) — Chemical Composition & Mechanical Properties
ASTM A182 F61 (Alloy 255) is a super duplex stainless steel grade for forged flanges & fittings (UNS S32550, EN / W.Nr 1.4507). It is also known as 255 · Ferralium 255 (trade name). This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group manufactures flanges and fittings in this grade.
ASTM A182 F61 (Alloy 255) at a glance
| Specification | ASTM A182 F61 (Alloy 255) |
|---|---|
| Material family | Super duplex stainless steel |
| Product form | Forged flanges & fittings |
| UNS number | S32550 |
| EN / W.Nr equivalent | 1.4507 |
| Also known as | 255 · Ferralium 255 (trade name) |
| PREN (min values) | 35.2 |
| Document | TG-MG-076 · Rev. 1 · October 2026 |
Typical service
Sulphuric acid, phosphoric acid and seawater service
Heat treatment
Solution annealed 1050–1125 °C, water quench
Chemical composition of ASTM A182 F61 (Alloy 255) (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 750 MPa |
|---|---|
| Yield strength (0.2 % offset), min | 550 MPa |
| Elongation, min | 25 % |
| Hardness | Not specified |
About super duplex stainless steel
Super duplex stainless steels raise chromium to 25 %, molybdenum to 3.5–4 % and nitrogen to about 0.25 %, giving a PREN above 40. That makes them resistant to pitting and crevice corrosion in warm seawater, while keeping a minimum yield of 550 MPa.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A182 F61 (Alloy 255)
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A182 F61 (Alloy 255) · ASME SA-182 F61 (Alloy 255) |
| USA — UNS | S32550 |
| Europe — EN designation | X2CrNiMoCuN25-6-3 |
| Europe — W.Nr | 1.4507 |
| China — GB / NB | S25554 (03Cr25Ni6Mo3Cu2N) |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Standards for ASTM A182 F61 (Alloy 255)
All material standardsFAQ
ASTM A182 F61 (Alloy 255): common questions
What is the minimum yield strength of ASTM A182 F61 (Alloy 255)?
550 MPa, with a minimum tensile strength of 750 MPa.
What is the carbon content of ASTM A182 F61 (Alloy 255)?
0.04 max %.
What is the PREN of ASTM A182 F61 (Alloy 255)?
About 35, calculated as Cr + 3.3Mo + 16N using the specification minimum values. Typical heats are a little higher.
What is the UNS number and EN equivalent of ASTM A182 F61 (Alloy 255)?
UNS S32550; the nearest European designation is W.Nr 1.4507. Equivalents are close but not identical — check the specification if substituting.
How is ASTM A182 F61 (Alloy 255) heat treated?
Solution annealed 1050–1125 °C, water quench.
What is the Chinese (GB) equivalent of ASTM A182 F61 (Alloy 255)?
The nearest Chinese equivalent is S25554 (03Cr25Ni6Mo3Cu2N). Equivalents are close but not identical — compare chemistry and properties before substituting.
Does Teshi Group supply ASTM A182 F61 (Alloy 255)?
Teshi Group manufactures flanges and fittings in this grade. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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