# UNS S32750 Forgings: Super Duplex Rings, Flanges, Bars and Discs

ASTM A182 F53 | EN 1.4410 (X2CrNiMoN25-7-4) | Super Duplex 2507 | PREN 41-43

Manufacturer: 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
Page: https://steelforgepieces.com/Stainless-Steel/UNS-S32750.html
Last updated: 8 October 2026

## Summary

UNS S32750 is a 25% chromium super duplex stainless steel with a roughly 50:50
ferrite and austenite microstructure. In forged form it is designated ASTM A182
F53; the European equivalent is EN 1.4410 (X2CrNiMoN25-7-4), and the common
trade name is Super Duplex 2507. A PREN of 40 and above gives it high resistance
to pitting, crevice corrosion and chloride stress corrosion cracking in warm
seawater, at roughly twice the yield strength of 316L. Jiangyin Jiangnan Metal
Co., Ltd. forges UNS S32750 to ASTM A182, supplied solution annealed and
quenched with EN 10204 3.1 or 3.2 certification.

## Equivalent designations

| System | Designation | Scope |
|---|---|---|
| UNS | S32750 | Unified alloy number |
| ASTM / ASME | A182 F53, SA-182 F53 | Forged flanges, fittings, valves, pressure parts |
| EN 10088-3 | 1.4410, X2CrNiMoN25-7-4 | Bar, semi-finished products, sections |
| Trade name | Super Duplex 2507, SAF 2507 | Commercial designation |
| NORSOK | MDS D51 to D55, D57, D58 | Offshore material data sheets |
| Sour service | NACE MR0175 / ISO 15156 | H2S containing environments |
| Cast equivalent | ASTM A995 Grade 5A | Cast valve and pump bodies |
| Other forms | A790 S32750 pipe, A815 S32750 fittings | Seamless pipe, buttweld fittings |

EN 1.4410 and ASTM A182 F53 cover the same alloy but set different minimum
mechanical properties, so the purchase order should name the product form as
well as the grade.

## Chemical composition (weight %)

| Element | ASTM A182 F53 (forgings) | EN 10088-3, 1.4410 |
|---|---|---|
| Carbon | 0.030 max | 0.03 max |
| Chromium | 24.0 - 26.0 | 24.0 - 26.0 |
| Nickel | 6.0 - 8.0 | 6.0 - 8.0 |
| Molybdenum | 3.0 - 5.0 | 3.0 - 4.5 |
| Nitrogen | 0.24 - 0.32 | 0.24 - 0.35 |
| Manganese | 1.20 max | 2.00 max |
| Silicon | per ASTM A182 | 1.00 max |
| Phosphorus | per ASTM A182 | 0.035 max |
| Sulphur | per ASTM A182 | 0.015 max |
| PREN | 41 - 43 typical | 40 minimum |

PREN = %Cr + 3.3 x %Mo + 16 x %N. A value of 40 or above separates super duplex
from standard 22% Cr duplex (S31803, S32205), which falls in the 33 to 36 range.

## Mechanical properties, solution treated

| Property | ASTM A182 F53 forgings | EN 1.4410 bar up to 160 mm |
|---|---|---|
| Tensile strength | 795 MPa (116 ksi) min | 730 - 930 MPa (106 - 135 ksi) |
| 0.2% proof strength | 550 MPa (80 ksi) min | 530 MPa (77 ksi) min |
| Elongation | 15% min | 25% min |
| Hardness | 310 HBW max (32 HRC) | 290 HB max |
| Impact energy | commonly specified at -46 C | 100 J (74 ft.lb) |
| Ferrite content | 40 - 60% | approx. 50:50 phase balance |

Notch ductility stays good down to about minus 50 C.

## Physical properties (1.4410, typical)

| Property | Value | Condition |
|---|---|---|
| Density | 7.8 kg/dm3 | 20 C |
| Modulus of elasticity | 200 GPa | 20 C |
| Thermal conductivity | 15 W/m.K | 20 C |
| Mean coefficient of thermal expansion | 13.0 x 10-6 /K | 20 - 100 C |
| Specific heat capacity | 500 J/kg.K | 20 C |
| Electrical resistivity | 0.80 ohm.mm2/m | 20 C |
| Magnetisable | Yes | ferritic phase present |

## F51 compared with F53

| Property | F51, S31803 / S32205 | F53, S32750 |
|---|---|---|
| PREN | 34 - 36 | 41 - 43 |
| Critical pitting temperature | 35 - 45 C | 55 - 70 C |
| Minimum yield strength | 450 MPa (65 ksi) | 550 MPa (80 ksi) |
| Chloride SCC limit | approx. 100 C | approx. 130 C |
| Seawater service | Ambient temperature only | Up to approx. 50 C |
| Relative material cost | Baseline | +30 to 50% |

Specify F53 when the process fluid carries chlorides above roughly 40 C, when
sour gas conditions under NACE MR0175 call for PREN above 40, or when subsea
valve bodies and wellhead components see warm produced water at high salinity.
Maximum continuous service temperature is about 315 C (600 F). Above that,
sigma phase and 475 C embrittlement cut toughness permanently.

## Heat treatment, forming and machining

Solution anneal between 1025 and 1125 C, with roughly 1050 C (1925 F) as the
usual floor, then quench immediately in water or by rapid forced air. Slow
cooling through the 600 to 1000 C band precipitates sigma phase and destroys
both toughness and pitting resistance. Pickle and rinse heat treated surfaces
before dispatch.

Cutting speed must come down substantially against 316 or 316L with coated
carbide tooling, while feed is reduced only slightly. Rigid setups, positive
geometry and uninterrupted cuts matter more than tool grade. Welding presents no
particular difficulty provided heat input and interpass temperature are
controlled to keep the phase balance.

## Forged products available in UNS S32750

- Seamless rolled rings and forged rings: bearing rings, retaining rings, spacers, large diameter ring blanks
- Forged flanges: weld neck, blind, slip-on, orifice, long weld neck, special drilled, to ASME B16.5 / B16.47 or drawing
- Forged round bars, blocks and billets, rough turned or peeled, ultrasonically tested
- Forged discs and heat exchanger tube sheets, blind discs, cover plates
- Forged shafts, spindles, eccentric shafts, crankshafts
- Forged sleeves, bushings, hollow bars, tubes and pipes, trepanned or bored
- Forged valve components: stems, bodies, seat rings, blocks, bonnets for ball, gate, globe, check and plug valves
- Forged nozzles, manifolds, gears, wheels and rolls to drawing

Produced from EAF and VOD refined billet, with ESR remelted material available
where the specification calls for it. Forged to customer drawing, to rough
machined condition, or to finish machined parts.

## Applications

- Offshore oil and gas: subsea and deepwater production systems, wellhead and manifold flanges, christmas tree components, chokes, connectors, bolting, downhole equipment
- Seawater and ballast systems: injection pumps, firewater and ballast piping, cooling water systems, service water pump shafts and sleeves
- Chemical and petrochemical: heat exchangers, separators, pressure vessels, piping, tube sheets and flanges in hot chloride brine, ferric chloride and concentrated seawater
- Desalination: high pressure reverse osmosis components, energy recovery devices, seawater piping
- Pulp and paper: digesters, liquor tanks, bleaching plant hardware, paper machine parts
- Power and rotating equipment: FGD systems, gas compressors, industrial air and nitrogen generators, gearboxes, turbine and power transmission shafting

## Testing and certification

| Test | Standard or method | Purpose |
|---|---|---|
| Ultrasonic examination | EN 10228-3, SEP 1921, ASTM A388 | Internal soundness |
| Liquid penetrant | ASTM E165 or client specification | Surface discontinuities |
| Corrosion test | ASTM A923 Method C, ferric chloride at 50 C | Detects intermetallic phase |
| Ferrite content | Point count or Feritscope, 40 - 60% | Phase balance |
| Charpy V-notch impact | Commonly at -46 C | Low temperature toughness |
| Hardness | 310 HBW / 32 HRC max | Sour service compliance |
| Material certificate | EN 10204 3.1 or 3.2 | Traceability, third party inspection on request |

## FAQ

**What is UNS S32750 equivalent to?**
ASTM A182 F53 in forged form, EN 1.4410 / X2CrNiMoN25-7-4 under EN 10088-3,
commonly sold as Super Duplex 2507 or SAF 2507. Cast counterpart is ASTM A995
Grade 5A. Listed in NORSOK MDS D51 to D55, D57, D58 and NACE MR0175 / ISO 15156.

**What is the PREN of UNS S32750?**
At least 40, typically 41 to 43, calculated as %Cr + 3.3 x %Mo + 16 x %N.

**What is the difference between A182 F51 and A182 F53?**
F51 is duplex 2205 with PREN 34 to 36, critical pitting temperature 35 to 45 C
and 450 MPa minimum yield. F53 is super duplex 2507 with PREN 41 to 43, critical
pitting temperature 55 to 70 C and 550 MPa minimum yield, at roughly 30 to 50
percent higher material cost.

**What are the mechanical properties of A182 F53 forgings?**
795 MPa (116 ksi) minimum tensile, 550 MPa (80 ksi) minimum 0.2% proof strength,
15 percent minimum elongation, 310 HBW (32 HRC) maximum hardness, ferrite 40 to
60 percent.

**How is UNS S32750 heat treated after forging?**
Solution anneal 1025 to 1125 C, minimum around 1050 C (1925 F), then immediate
water or rapid forced air quench, followed by pickling and rinsing.

**What is the maximum service temperature of super duplex 2507?**
About 315 C (600 F) continuous. Above that, sigma phase and 475 C embrittlement
permanently reduce ductility and corrosion resistance.

**Is UNS S32750 magnetic?**
Yes, because roughly half the microstructure is ferrite. This is normal for
duplex and super duplex grades and does not indicate wrong material.

**Can Jiangyin Jiangnan Metal supply UNS S32750 forgings to drawing?**
Yes. Open-die forgings and seamless rolled rings to customer drawing or standard
dimensions, EAF and VOD refined with ESR available, solution annealed and
quenched, EN 10204 3.1 or 3.2 certification. Contact
sales@steelforgepieces.com or 0086-189-2135-9659.

## Request a quotation

Send the drawing, or the outside diameter, inside diameter, height or length and
the quantity. You will get price, forged weight, lead time and the proposed test
and certification scope.

Email: sales@steelforgepieces.com
Tel: 0086-189-2135-9659
Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China

## Related grades

A182 F51, A182 F53, A182 F55, A182 F61, 904L, Sanicro 28, Alloy 24, 17-4PH,
15-5PH, Nitronic 50, Incoloy 825, Inconel 625.

## References

1. ASTM A182 / A182M, forged or rolled alloy and stainless steel pipe flanges, forged fittings, valves and parts for high temperature service.
2. EN 10088-3, stainless steels, technical delivery conditions for semi-finished products, bars, rods and sections, grade 1.4410 X2CrNiMoN25-7-4.
3. Smiths Metal Centres, UNS S32750 / 1.4410 / F53 technical datasheet, 2023.
4. ProjectMaterials, ASTM A182 Grade F53 technical summary.
5. NORSOK MDS D51 to D55, D57, D58; NACE MR0175 / ISO 15156.

Values are given for guidance. The purchase order specification and the mill
test certificate always take precedence.