What is the chemical composition of A182 F55?

Per ASTM A182: carbon 0.030 percent max, manganese 1.00 percent max, silicon 1.00 percent max, phosphorus 0.030 percent max, sulfur 0.010 percent max, chromium 24.00 to 26.00 percent, nickel 6.00 to 8.00 percent, molybdenum 3.00 to 4.00 percent, copper 0.50 to 1.00 percent, tungsten 0.50 to 1.00 percent, nitrogen 0.20 to 0.30 percent, balance iron.

What are the mechanical properties of A182 F55 forgings?

Tensile strength 750 to 895 MPa (109 to 130 ksi), minimum 0.2 percent yield strength 550 MPa (80 ksi), minimum elongation 25 percent in 50 mm or 4D, and minimum reduction of area 45 percent.

What is the difference between A182 F53 and A182 F55?

Both are super duplex grades with a pitting resistance equivalent number of 40 or above. F53 is UNS S32750, a 25 Cr, 7 Ni, 4 Mo grade. 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.

Who supplies ASTM A182 F55 open-die forgings?

Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, produces A182 F55 forged rings, flanges, shafts, discs, sleeves and bars to customer drawings. Contact +86-189-2135-9659 or sales@steelforgepieces.com.

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

Q: What is ASTM A182 F55?

ASTM A182 F55 is the forging grade designation for super duplex stainless steel UNS S32760, also known as EN 1.4501 or X2CrNiMoCuWN25-7-4 and by the trade name Zeron 100. It is a 25 Cr, 7 Ni, 3.5 Mo duplex grade additionally alloyed with copper, tungsten and nitrogen, giving a pitting resistance equivalent number of at least 40.

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.

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, so pressure parts can be built with thinner walls.

ASTM grade: A182 F55
UNS: S32760
EN / Werkstoff: 1.4501
Tensile strength: 750-895 MPa
Yield, min: 550 MPa (80 ksi)
Elongation, min: 25 %
PREN: 40 minimum
Melting route: EAF + VOD + ESR

Designations and equivalents

This alloy reaches us under several names. 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 of ASTM A182 F55

Table 1. ASTM A182 grade F55 (UNS S32760) chemical requirements, weight percent
Element	C	Si	Mn	P	S	Cr	Ni	Mo	Cu	W	N	Fe
Min %	-	-	-	-	-	24.00	6.00	3.00	0.50	0.50	0.20	Balance
Max %	0.030	1.00	1.00	0.030	0.010	26.00	8.00	4.00	1.00	1.00	0.30	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.

Pitting resistance equivalent number

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

Mechanical properties

Table 2. ASTM A182 F55 room temperature mechanical requirements
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, so please state your acceptance limits at enquiry stage and we will heat treat and test to them.

Melting, forging and heat treatment

We melt F55 in an electric arc furnace with vacuum oxygen decarburisation, followed by electroslag remelting (EAF + VOD + ESR) to control sulfur, gas content and segregation before the ingot reaches the press. Open-die forging is carried out with controlled reductions so the austenite and ferrite structure is worked uniformly through the section instead of only near the surface.

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. The rapid quench is not optional with super duplex. Slow cooling through the 700 to 950 C range precipitates sigma and other intermetallic phases that reduce both impact toughness and corrosion resistance. For the same reason we do not locally heat treat or stress relieve F55 parts. If any hot work is needed after annealing, the whole forging is re-solutioned.

Testing and certification

Ultrasonic examination is performed to ASTM A388, EN 10228-3 or SEP 1921 class as required. Depending on the order we also supply positive material identification, ferrite count to ASTM E562, sub-zero impact testing, microstructural examination for intermetallic phases, and ASTM G48 Method A pitting corrosion tests at the temperature stated in your specification. Documentation is issued as EN 10204 3.1 mill certification, or 3.2 with third party witness by a nominated inspection body.

Machining guidance

F55 is harder to machine than austenitic 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, because too light a feed rubs rather than cuts and glazes the surface. Use rigid setups, short tool overhangs, sharp positive rake coated carbide inserts, generous flood coolant and a consistent depth of cut so the tool stays below the work hardened layer left by the previous pass.

Forged F55 products and applications

Product forms we forge

We supply F55 as 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. All parts are made to customer drawing or size list, as single pieces or production batches.

Where F55 forgings are used

Typical service is anywhere chloride attack and pressure occur together: seawater, firewater and produced water systems, subsea and deepwater production equipment, risers and manifolds, separators, heat exchangers and pressure vessels. Valve and pump components make up a large share of the demand, including bodies, bonnets, stems, seat rings, balls, chokes and connectors for ball, gate, globe, check and plug valves. Other established uses include flue gas desulphurisation plant, pulp and paper digesters and liquor tanks, desalination and high pressure reverse osmosis plant, and chemical, pharmaceutical, mining and metallurgical process equipment.

A182 F55 compared with other duplex forging grades

Table 3. Duplex and super duplex forging grades we produce
ASTM A182 grade	UNS	Type	Key distinction
F51	S31803	Duplex 22 Cr	Standard duplex grade, lower alloy content than the super duplex grades
F53	S32750	Super duplex 25 Cr	PREN 40 minimum, no mandatory tungsten or copper addition
F55	S32760	Super duplex 25 Cr	PREN 40 minimum with mandatory Cu 0.50-1.00 % and W 0.50-1.00 %

F53 and F55 are both super duplex grades at the same guaranteed PREN level. The choice between them is normally made by the project specification or by client precedent rather than by a clear performance gap. We forge both, and we quote the same parts against the designations UNS S32760, 1.4501 and Zeron 100.

Frequently asked questions

What is ASTM A182 F55?

It is 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. The 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. A182 F55, UNS S32760, EN 1.4501, X2CrNiMoCuWN25-7-4, Zeron 100 and Seacol 760 all 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. Rapid quenching is essential to avoid sigma phase precipitation, and local or partial heat treatment is not acceptable.

Can F55 forgings be supplied with third party certification?

Yes. We issue EN 10204 3.1 certification as standard and EN 10204 3.2 with third party witness on request, together with ultrasonic reports to ASTM A388, EN 10228-3 or SEP 1921 and any specified ferrite, impact and G48 corrosion test results.

What sizes can you forge?

Send the drawing or the rough dimensions, meaning outside diameter, inside diameter, thickness or length and weight, plus the quantity and the applicable specification. We will confirm feasibility, price and lead time for your part.

Request a quotation for A182 F55 forgings

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China.

Send your drawing or size list to sales@steelforgepieces.com or call +86-189-2135-9659. We also forge Zeron 100, UNS S32760 and 1.4501 to the same specifications, and we quote single prototypes as well as production batches.

Related grades

Technical data compiled from ASTM A182/A182M, EN 10088-2 and NORSOK M-630 requirements for UNS S32760. Published by Jiangyin Jiangnan Metal Co., Ltd. Last reviewed 30 September 2026. Plain text version: A182-F55.md. Values are for guidance. The governing figures are those on the purchase specification and on the mill certificate of the heat supplied.