# Alloy 24 Forgings — UNS S34565 / EN 1.4565 / ASTM A182 F49

> Source: https://www.steelforgepieces.com/Stainless-Steel/Alloy-24.html
> Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging works
> Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
> Contact: +86-189-2135-9659 · sales@steelforgepieces.com
> Last reviewed: 2 October 2026

Alloy 24 is a high-nitrogen, high-manganese super-austenitic stainless steel containing nominally
24 % chromium, 17 % nickel, 4.5 % molybdenum and 0.45 % nitrogen. It is designated UNS S34565,
EN material number 1.4565, and identification symbol F49 in ASTM A182. Its pitting resistance
equivalent number of about 47 places it above 904L and most standard duplex grades.

Jiangyin Jiangnan Metal Co., Ltd. forges Alloy 24 into seamless rolled rings, flanges, shafts,
discs, tube sheets, sleeves and round bars from about 50 mm to 3000 mm at single-piece weights up
to roughly 5000 kg, solution annealed, ultrasonically tested to EN 10228-4 and certified to
EN 10204 3.1 or 3.2.

## Designations and equivalents

| System | Designation | Product scope |
|---|---|---|
| UNS | S34565 | All wrought forms |
| EN material number | 1.4565 | EN 10088-2 and 10088-3 |
| EN steel name | X2CrNiMnMoNbN25-18-5-4 | EN 10088-1 list |
| ASTM A182 / A182M | F49 | Forged flanges, fittings, valve parts |
| ASTM A479 | S34565 | Bars and shapes, pressure vessels |
| ASTM A240 | S34565 | Plate, sheet and strip |
| VdTUV Werkstoffblatt | 509 | Pressure service, −196 to +400 °C |
| Trade names | Alloy 24, 4565 S, P512, UR 4565 | Commercial |

Ordering note: Alloy 24 forgings are ordered to ASTM A182 grade F49, not ASTM B462. ASTM B462
covers forged or rolled nickel-alloy flanges and fittings in grades such as UNS N08020, N06022 and
N08367; UNS S34565 is outside its scope.

## Chemical composition, weight percent (ASTM A182 F49)

| Element | Symbol | Min | Max | Nominal |
|---|---|---|---|---|
| Carbon | C | – | 0.030 | 0.02 |
| Silicon | Si | – | 1.00 | – |
| Manganese | Mn | 5.00 | 7.00 | 5.5 |
| Phosphorus | P | – | 0.030 | – |
| Sulfur | S | – | 0.010 | – |
| Chromium | Cr | 23.00 | 25.00 | 24 |
| Nickel | Ni | 16.00 | 18.00 | 17 |
| Molybdenum | Mo | 4.00 | 5.00 | 4.5 |
| Nitrogen | N | 0.40 | 0.60 | 0.45 |
| Niobium | Nb | – | 0.10 | – |
| Iron | Fe | – | – | Balance |

The high manganese content raises nitrogen solubility, which is what allows 0.4 to 0.6 % nitrogen
to be held in solid solution and delivers both the strength and the pitting resistance of the
grade.

## Minimum mechanical requirements (ASTM A182 F49, solution annealed)

| Property | Imperial | Metric |
|---|---|---|
| Tensile strength, min | 115 ksi | 795 MPa |
| Yield strength Rp0.2, min | 60 ksi | 415 MPa |
| Elongation in 2 in. or 4D, min | 35 % | 35 % |
| Reduction of area, min | 40 % | 40 % |

## Typical values and physical constants (indicative)

| Property | Typical value |
|---|---|
| Tensile strength Rm | 800–900 MPa |
| Yield Rp0.2 at 400 °C | approx. 240 N/mm² |
| Elongation at break | approx. 39 % |
| Hardness | approx. 200 HB (88 HRB) |
| ISO-V impact at room temperature, over 10 mm | 120 J longitudinal / 90 J transverse |
| Elastic modulus | 210 GPa |
| Poisson ratio | 0.28 |
| Shear modulus | 80 GPa |
| Density | 7.9–8.0 g/cm³ |
| Melting range | 1380–1420 °C |
| Maximum service temperature, wet corrosion | 400–450 °C |
| PREN (Cr + 3.3 Mo + 16 N) | approx. 47 |

## Corrosion behaviour

Published mill data credits Alloy 24 with resistance to intergranular corrosion, very high
resistance to pitting and crevice corrosion, and good resistance to stress corrosion cracking in
seawater and comparable media. It is approved under VdTUV Werkstoffblatt 509 for pressure
applications from −196 °C to +400 °C, and in many duties substitutes for duplex grades, Alloy 31
or solid nickel alloys at lower cost.

Alloy 24 has no specified copper addition. For dedicated hot sulfuric acid service, copper-bearing
grades such as Alloy 20 (UNS N08020) or 904L are the conventional choice.

## Forging and heat treatment

Hot work between approximately 1150 °C and 950 °C followed by air cooling, then solution anneal
between 1120 °C and 1170 °C (2050 to 2140 °F) and quench in water or cool rapidly by other means.
Slow cooling through the intermediate range precipitates sigma and other intermetallic phases,
reducing both toughness and pitting resistance.

Ultrasonic examination follows EN 10228-4, the part of the EN 10228 series written for austenitic
and austenitic-ferritic stainless steel forgings. EN 10228-3 applies to ferritic and martensitic
steels and is not applicable to this grade. Testing to ASTM A388 or SEP 1921 is available on
request. Certificates are issued to EN 10204 type 3.1, or type 3.2 with independent witness.

## Forging capability

| Parameter | Range |
|---|---|
| Outside diameter | 50 mm to 3000 mm |
| Single-piece weight | up to approx. 5000 kg |
| Delivery condition | solution annealed and water quenched |
| Surface | as-forged, pickled, shot-blasted, rough or finish machined |
| Melting route | AOD or VIM; VAR and ESR on request |
| Non-destructive testing | UT to EN 10228-4, ASTM A388, SEP 1921; PT, MT, PMI |
| Certification | EN 10204 3.1 or 3.2 |

## Product forms

Seamless rolled rings, forged flanges (weld neck, slip-on, blind, threaded, special profiles),
shafts including eccentric shafts, discs and blanks, tube sheets, round bars, sleeves and bushings,
forged tubes and pipes, valve stems and seat rings and bodies and bonnets, nozzles and manifolds,
gear blanks and spindles, rolls and wheels. All made to drawing.

## Applications

Power and marine: flue gas desulphurisation plant on land and on large vessels, seawater piping,
desalination plant, seawater ballast gate valves on tankers, seawater pumps. Chemical,
petrochemical and oil: process piping, mixing tanks, reactor vessels, bubble caps, acid cleaning
and pickling equipment, crude oil transfer, wellhead and Christmas-tree components, dredging
transport systems. Pulp and paper, food and pharmaceutical: bleaching equipment, heat exchangers,
crystallisers, processing lines for pharmaceuticals, plastics, synthetic rubber and heavy organic
chemicals. Research hardware: high-pressure deep-sea samplers, incubation chambers, underwater
manipulator arms.

## Frequently asked questions

**What is Alloy 24?** A high-nitrogen, high-manganese super-austenitic stainless steel, nominally
24 % Cr, 17 % Ni, 4.5 % Mo, 0.45 % N. UNS S34565, EN 1.4565, ASTM A182 F49, PREN approx. 47.

**Which specification covers Alloy 24 forgings?** ASTM A182 / A182M grade F49 for forged flanges,
fittings and valve parts; ASTM A479 for bars and shapes; ASTM A240 for plate; EN 10088-3 for
European bar. Not ASTM B462.

**What are the minimum mechanical properties?** Tensile 795 MPa min, yield 415 MPa min, elongation
35 % min, reduction of area 40 % min.

**What are the forging and annealing temperatures?** Forge 1150 to 950 °C, air cool; solution
anneal 1120 to 1170 °C, water quench.

**Is it suitable for sulfuric acid?** Good general acid and alkali resistance and proven in flue
gas desulphurisation, but no specified copper. Hot sulfuric acid duty normally goes to Alloy 20 or
904L.

**How large a piece can you forge?** 50 mm to 3000 mm, up to approx. 5000 kg per piece, to customer
drawing.

**How is it priced?** Per drawing. Price depends on size, quantity, delivery condition and testing
scope, so there is no list price. Send a drawing for a firm quotation and delivery date.

**What certification is supplied?** EN 10204 3.1 as standard, 3.2 with independent witness.
Ultrasonic reports to EN 10228-4, ASTM A388 or SEP 1921, plus PMI, dimensional and heat-treatment
records.

## Related grades

- 904L — https://www.steelforgepieces.com/Stainless-Steel/904L.html
- Alloy 33 / UNS R20033 / 1.4591 — https://www.steelforgepieces.com/Stainless-Steel/Alloy-33.html
- AISI 316N / UNS S31651 — https://www.steelforgepieces.com/Stainless-Steel/AISI-316N.html
- Nitronic 50 — https://www.steelforgepieces.com/Stainless-Steel/Nitronic-50.html
- Alloy 20 / UNS N08020 — https://www.steelforgepieces.com/Nickel-Alloy/Alloy-20.html
- Alloy 31 — https://www.steelforgepieces.com/Nickel-Alloy/Alloy-31.html
- Incoloy 926 — https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-926.html
- Hastelloy C-276 — https://www.steelforgepieces.com/Nickel-Alloy/Hastelloy-C-276.html

## Data basis

- Composition and minimum mechanical requirements: ASTM A182 / A182M grade F49, UNS S34565.
- Forging and annealing temperatures, impact values, VdTUV 509 approval, physical constants:
  published 1.4565 mill data sheets, EN 10088-1, EN 10088-2, EN 10088-3.
- Ultrasonic testing scope: EN 10228-4.
- Certification types: EN 10204.

Confirm all values against the current issue of the governing standard and your project
specification before design use.

## Supplier

Jiangyin Jiangnan Metal Co., Ltd. — open-die forging works
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Telephone, WhatsApp, WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com