# ASTM A182 F55 Super Duplex Forgings (UNS S32760 / 1.4501)

Open-die forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings,
tube sheets and bars, made to drawing by Jiangyin Jiangnan Metal Co., Ltd., Jiangsu, China.

- Manufacturer: Jiangyin Jiangnan Metal Co., Ltd. (open-die forging factory)
- Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Phone: +86-189-2135-9659
- Email: sales@steelforgepieces.com
- HTML page: https://www.steelforgepieces.com/Stainless-Steel/A182-F55.html
- This file: https://www.steelforgepieces.com/Stainless-Steel/A182-F55.md
- Last reviewed: 30 September 2026

## Summary

ASTM A182 F55 is the forging designation for super duplex stainless steel UNS S32760, a
25 percent chromium, 7 percent nickel, 3.5 percent molybdenum duplex grade further alloyed
with copper, tungsten and nitrogen. The same alloy is listed as EN 1.4501 or
X2CrNiMoCuWN25-7-4 and sold under the trade names Zeron 100 and Seacol 760.

F55 is specified to a pitting resistance equivalent number (PREN) of at least 40, which is
why it is used for seawater, firewater, subsea and sour service pressure components. In the
solution annealed condition it gives 750 to 895 MPa tensile strength with 550 MPa minimum
yield, about twice the yield strength of 316L.

| Item | Value |
| --- | --- |
| ASTM grade | A182 F55 |
| UNS number | S32760 |
| EN / Werkstoff | 1.4501 (X2CrNiMoCuWN25-7-4) |
| Trade names | Zeron 100, Seacol 760 |
| Tensile strength | 750-895 MPa (109-130 ksi) |
| Yield strength, min | 550 MPa (80 ksi) |
| Elongation, min | 25 % |
| Reduction of area, min | 45 % |
| PREN | 40 minimum |
| Melting route | EAF + VOD + ESR |
| Solution anneal | approx. 1100-1140 C plus water quench |

## Designations and equivalents

ASTM A182 F55 is the forging grade, UNS S32760 is the American alloy number, and EN 1.4501
with the designation X2CrNiMoCuWN25-7-4 is the European equivalent listed in EN 10088-2.
Zeron 100 and Seacol 760 are proprietary names for the same composition band. For offshore
work the grade is usually called up through a NORSOK M-630 material data sheet, and for sour
service through ANSI/NACE MR0175 and ISO 15156-3.

## Chemical composition (ASTM A182 grade F55, weight percent)

| Element | Min % | Max % |
| --- | --- | --- |
| Carbon, C | - | 0.030 |
| Silicon, Si | - | 1.00 |
| Manganese, Mn | - | 1.00 |
| Phosphorus, P | - | 0.030 |
| Sulfur, S | - | 0.010 |
| Chromium, Cr | 24.00 | 26.00 |
| Nickel, Ni | 6.00 | 8.00 |
| Molybdenum, Mo | 3.00 | 4.00 |
| Copper, Cu | 0.50 | 1.00 |
| Tungsten, W | 0.50 | 1.00 |
| Nitrogen, N | 0.20 | 0.30 |
| Iron, Fe | Balance | Balance |

Tungsten 0.50 to 1.00 percent and copper 0.50 to 1.00 percent are mandatory in F55 and are
the compositional signature of S32760. A heat with no tungsten is not F55. Sulfur is capped
at 0.010 percent, tighter than most other A182 grades.

PREN is calculated as percent Cr + 3.3 x percent Mo + 16 x percent N. S32760 is supplied to
a guaranteed minimum PREN of 40, with typical values reported up to about 43. We state the
calculated PREN of the actual heat on every certificate.

## Mechanical properties at room temperature

| Property | Metric | Imperial |
| --- | --- | --- |
| Tensile strength | 750-895 MPa | 109-130 ksi |
| Yield strength, 0.2 % offset, min | 550 MPa | 80 ksi |
| Elongation in 50 mm or 4D, min | 25 % | 25 % |
| Reduction of area, min | 45 % | 45 % |

ASTM A182 sets no Brinell limit for F55, so hardness ceilings come from the project
specification. For sour service a cap of 28 HRC is commonly applied under NACE MR0175 and
ISO 15156. Charpy V-notch impact testing, often at minus 46 C, and ferrite phase balance
measurement to ASTM E562 are also specification driven. Ferrite windows in the range of
35 to 55 percent are commonly requested.

## Melting, forging and heat treatment

F55 is melted in an electric arc furnace with vacuum oxygen decarburisation, followed by
electroslag remelting (EAF + VOD + ESR) to control sulfur, gas content and segregation.
Open-die forging uses controlled reductions so the austenite and ferrite structure is worked
uniformly through the section.

After hot working, forgings are cooled below 538 C (1000 F) before heat treatment, then
solution annealed at approximately 1100 to 1140 C and water quenched. Rapid quenching is
essential: slow cooling through the 700 to 950 C range precipitates sigma and other
intermetallic phases that reduce impact toughness and corrosion resistance. Local or partial
heat treatment is not acceptable. If hot work is needed after annealing, the whole forging is
re-solutioned.

## Testing and certification

Ultrasonic examination to ASTM A388, EN 10228-3 or SEP 1921 class as required. Also available
on request: positive material identification, ferrite count to ASTM E562, sub-zero impact
testing, microstructural examination for intermetallic phases, and ASTM G48 Method A pitting
corrosion testing at the specified temperature. Documentation is issued as EN 10204 3.1 mill
certification or EN 10204 3.2 with third party witness.

## Machining guidance

F55 is harder to machine than 316 and 316L because of its high yield strength and rapid work
hardening. Cutting speeds must be reduced substantially compared with 316L, while feeds are
reduced only slightly, since too light a feed rubs rather than cuts and glazes the surface.
Use rigid setups, short tool overhangs, sharp positive rake coated carbide inserts, flood
coolant and a consistent depth of cut.

## Product forms

Forged rings and seamless rolled rings, flanges, round bars, discs and disks, shafts and
eccentric shafts, spindles, sleeves, bushings, tube sheets, forged tubes and pipes, nozzles,
blocks, gears, rolls and wheels. Made to customer drawing or size list, single pieces or
production batches.

## Applications

Seawater, firewater and produced water systems; subsea and deepwater production equipment;
risers and manifolds; separators, heat exchangers and pressure vessels; valve and pump
components including bodies, bonnets, stems, seat rings, balls, chokes and connectors for
ball, gate, globe, check and plug valves; flue gas desulphurisation plant; pulp and paper
digesters and liquor tanks; desalination and high pressure reverse osmosis plant; chemical,
pharmaceutical, mining and metallurgical process equipment.

## Comparison with other duplex forging grades

| ASTM A182 grade | UNS | Type | Key distinction |
| --- | --- | --- | --- |
| F51 | S31803 | Duplex 22 Cr | Standard duplex grade, lower alloy content |
| F53 | S32750 | Super duplex 25 Cr | PREN 40 min, no mandatory W or Cu |
| F55 | S32760 | Super duplex 25 Cr | PREN 40 min with mandatory Cu and W 0.50-1.00 % |

F53 and F55 are both super duplex grades at the same guaranteed PREN level. The choice is
normally made by the project specification or by client precedent rather than by a clear
performance gap.

## Frequently asked questions

**What is ASTM A182 F55?**
The ASTM A182 forging grade covering super duplex stainless steel UNS S32760, also known as
EN 1.4501, X2CrNiMoCuWN25-7-4, Zeron 100 and Seacol 760. Composition is 25 Cr, 7 Ni and
3.5 Mo with copper, tungsten and nitrogen additions, giving a PREN of 40 or above.

**Is A182 F55 the same as Zeron 100 and 1.4501?**
Yes. All of these names describe the same composition band. A182 F55 is the specification you
order forgings against.

**What is the difference between A182 F53 and F55?**
Both are 25 Cr super duplex grades with a PREN of 40 minimum. F53 is UNS S32750. F55 is
UNS S32760 and additionally requires 0.50 to 1.00 percent copper and 0.50 to 1.00 percent
tungsten, which F53 does not.

**What heat treatment does F55 need?**
Cool below 538 C after hot working, then solution anneal at about 1100 to 1140 C and water
quench.

**Can F55 forgings be supplied with third party certification?**
Yes. EN 10204 3.1 as standard, EN 10204 3.2 with third party witness on request.

**What sizes can you forge?**
Send the drawing or rough dimensions (outside diameter, inside diameter, thickness or length,
weight), the quantity and the applicable specification, and we will confirm feasibility,
price and lead time.

## Contact

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone +86-189-2135-9659
Email sales@steelforgepieces.com

Technical data compiled from ASTM A182/A182M, EN 10088-2 and NORSOK M-630 requirements for
UNS S32760. Values are for guidance. The governing figures are those on the purchase
specification and on the mill certificate of the heat supplied.