ASTM A182 F53 Super Duplex Forgings (UNS S32750 / EN 1.4410)
Technical data checked against ASTM A182/A182M. Page updated 29 September 2026. Published by Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China.
ASTM A182 Grade F53 is a 25Cr-7Ni-4Mo nitrogen alloyed super duplex stainless steel forging grade, designated UNS S32750 and equivalent to EN 1.4410. The balanced ferrite and austenite structure, with a PREN of about 42, gives a minimum tensile strength of 800 MPa and roughly twice the yield strength of 316L, plus high resistance to pitting, crevice corrosion and chloride stress corrosion cracking in seawater and sour service. Jiangyin Jiangnan Metal Co., Ltd. forges A182-F53 to customer drawings as seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets, valve parts and nozzles.
- UNS
- S32750
- EN number
- 1.4410
- Tensile min
- 800 MPa
- Yield min
- 550 MPa
- Hardness max
- 310 HBW
- PREN approx.
- 42
Designations and equivalent grades
This grade reaches us under several names. It is written as UNS S32750 in North American practice, as 1.4410 or X2CrNiMoN25-7-4 under EN, as Z3CND25-07Az under AFNOR, and as SAF 2507 as a common commercial name. The same chemistry also appears as F53 in ASTM A276 and ASTM A479 for bar, so one melt can cover both forged and bar requirements provided the order states which standard governs.
Chemical composition
| Element | C | Mn | P | S | Si | Cr | Ni | Mo | N | Cu | Fe |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Minimum | — | — | — | — | — | 24.00 | 6.00 | 3.00 | 0.24 | — | Balance |
| Maximum | 0.030 | 1.20 | 0.035 | 0.020 | 0.80 | 26.00 | 8.00 | 5.00 | 0.32 | 0.50 | Balance |
Tungsten: F53 has no tungsten requirement. Tungsten belongs to the related super duplex grade A182-F55 (UNS S32760). Data sheets that list a W range for F53 are incorrect, and the two grades must not be substituted without written customer approval.
Mechanical properties
Required strength drops as ruling section increases, so ASTM A182 sets two property bands for F53. Which band applies is decided by the governing section thickness at the time of heat treatment, not by the finished machined dimension.
| Property | Section up to 50 mm [2 in.] | Section over 50 mm [2 in.] |
|---|---|---|
| Tensile strength, min | 116 ksi / 800 MPa | 106 ksi / 730 MPa |
| Yield strength, 0.2 % offset, min | 80 ksi / 550 MPa | 75 ksi / 515 MPa |
| Elongation in 50 mm or 4D, min | 15 % | 15 % |
| Brinell hardness, max | 310 HBW | 310 HBW |
Sour service orders to NACE MR0175 / ISO 15156 often add a tighter hardness cap and impact toughness requirements. State these on the enquiry so the test coupons and heat treatment charge are planned correctly from the start.
Forging and heat treatment
Hot working is carried out in the approximate range 1200 to 1025 C, and forgings are cooled below about 540 C before heat treatment. ASTM A182 then requires F53 to be solution treated and quenched from a minimum of 1880 F [1025 C] in a liquid medium, cooling below 500 F [260 C]. For the duplex grades liquid quenching is mandatory, not an option left to the manufacturer.
The reason is metallurgical. Slow cooling through the intermediate temperature range precipitates sigma, chi, nitrides and alpha prime at the ferrite and austenite boundaries. These third phases draw chromium and molybdenum out of the surrounding matrix and cut both impact toughness and corrosion resistance. Toughness starts falling before the particles are large enough to resolve under an optical microscope, which is why quench rate control on the shop floor and independent testing on the finished forging both matter. After heat treatment, surfaces are pickled and rinsed to remove heat tint and any chromium depleted layer.
Inspection and certification
Microstructural quality of super duplex forgings is judged against ASTM A923 or the more demanding ISO 17781. ASTM A923 sets out three methods: Method A, metallographic examination of an etched section; Method B, Charpy impact testing; and Method C, a ferric chloride immersion test derived from ASTM G48. ISO 17781 tightens the sampling rules, specifies an etching practice that also reveals nitrides, and sets an acceptable ferrite range for parent metal.
Method A on its own is a screening test and depends on the operator, and a low Charpy acceptance level can pass material that is already predisposed to further precipitation during welding. Where the forging will be welded downstream, it is better to specify microstructure, impact and corrosion testing together rather than rely on one test alone.
Volumetric inspection is by ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 as agreed. Material certification is issued to EN 10204 3.1, or EN 10204 3.2 with third party witness such as TUV, BV, DNV, LR or ABS.
Machining notes
F53 work hardens quickly and cuts harder than the austenitic grades. Against a machinability improved 316/316L, cutting speed is usually reduced by 50 to 55 percent when turning with coated cemented carbide tooling. Feed should be reduced only slightly. Backing the feed off too far makes the insert rub instead of cut, which drives further work hardening in the cut zone. Rigid setups, sharp positive geometry inserts and heavy coolant flow all pay off on this grade.
Where A182-F53 forgings are used
Offshore oil and gas
Subsea and deepwater production hardware, downhole parts, forged flanges, rings and pipe for platform process, service water and firewater systems.
Seawater and desalination
High pressure reverse osmosis plant, seawater piping, forged manifolds, wheels and rolls where chloride pitting decides the material.
Chemical and petrochemical
Heat exchanger and separator parts, forged tube sheets, tubes, vessel components and piping for injection and ballast water systems.
Valves and flow control
Forged valve stems, seat rings, blocks and bodies for ball, gate, globe, plug and check valves and strainers.
Power and rotating equipment
Seamless rolled rings, shafts, spindles, gears and bars for turbines, gas compressors, gearboxes and FGD systems.
Pulp, paper and minerals
Digester and liquor tank parts, paper machine components, sleeves, bushings, discs and nozzles in abrasive chloride bearing service.
Product forms we forge in A182-F53
We supply this grade as open-die forgings and seamless rolled rings made to drawing: forged and rolled rings, flanges, round bars, discs and disks, shafts and eccentric shafts, sleeves, bushings, tube sheets, forged tubes and pipe, nozzles, blocks, gears, spindles, crankshafts, rolls and wheels. Send the drawing or the rough dimensions, the governing standard, the test package and the quantity, and we will confirm feasibility, forging weight and price.
Related grades we forge: A182-F51 (S31803, duplex 2205), A182-F55 (S32760, super duplex), A182-F44 (S31254, 6Mo austenitic), A182-F61, 904L and Sanicro 28.
Common questions
What is ASTM A182 F53?
A 25Cr-7Ni-4Mo nitrogen alloyed super duplex stainless steel forging grade, designated UNS S32750 and equivalent to EN 1.4410. Its roughly equal ferrite and austenite structure and PREN near 42 give minimum 800 MPa tensile strength with strong resistance to pitting, crevice corrosion and chloride stress corrosion cracking.
Is F53 the same as 2507?
For chemistry, yes. F53 is the ASTM A182 forging grade identifier, S32750 is the UNS number, 1.4410 is the EN number, and 2507 is the common commercial name for the same alloy. The forging standard still governs heat treatment, testing and certification, so orders should cite ASTM A182 F53 rather than the commercial name alone.
Why must F53 be liquid quenched?
ASTM A182 calls for solution treatment from 1025 C minimum followed by liquid quenching and cooling below 260 C. Slow cooling precipitates sigma phase and nitrides that degrade toughness and corrosion resistance, and the loss begins before anything is visible under an optical microscope.
F53 or F55, which should be specified?
Both are 25 percent chromium super duplex grades in a similar strength class. F55 (S32760) adds tungsten and copper and has its own specified solution annealing conditions, while F53 (S32750) has no tungsten requirement. Project specifications and the qualified welding procedures usually decide, and the two should not be swapped without written approval.
What documents come with an order?
Chemical and mechanical test results, heat treatment records, ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, and A923 or ISO 17781 microstructure, impact and corrosion results where specified. Issued on an EN 10204 3.1 certificate, or 3.2 with third party witness.
What is the largest size you can forge?
Size and weight limits depend on the geometry of the part. Send the drawing to sales@steelforgepieces.com and we will confirm it against our press and ring mill capacity.
Request a quotation
Send a drawing or the rough dimensions together with the governing standard, the test package and the quantity. We reply with feasibility, forging weight and price.
Jiangyin Jiangnan Metal Co., Ltd. — Open-Die Forging Factory
Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel: 0086-189-2135-9659
Email: sales@steelforgepieces.com
Standards referenced
Composition, mechanical and heat treatment values on this page follow ASTM A182/A182M, Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service. Microstructure testing references ASTM A923 and ISO 17781, corrosion testing references ASTM G48, ultrasonic testing references EN 10228-3, SEP 1921 and ASTM A388, and certification references EN 10204. Verify against the current edition of the standard that governs your project.