1.4652 Forgings (UNS S32654 / 654 SMO): Rings, Flanges, Bars and Discs
Summary
EN 1.4652 (chemical name X1CrNiMoCuN24-22-8, UNS S32654, trade name 654 SMO) is a super-austenitic stainless steel alloyed with about 24 % chromium, 22 % nickel, 7 to 8 % molybdenum and 0.45 to 0.55 % nitrogen. Its pitting resistance equivalent number (PREN = Cr + 3.3Mo + 16N) is about 54 to 60, the highest of any commercial austenitic stainless steel. That puts its resistance to chloride pitting and crevice corrosion close to nickel-based alloys, at a lower alloy cost.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge 1.4652 / UNS S32654 into seamless rolled rings, flanges, round bars, discs, sleeves, bushings, shafts, tube sheets and valve components, all to customer drawing. Parts are supplied solution annealed and water quenched, with EN 10204 3.1 or 3.2 certification and ultrasonic testing to EN 10228-3, ASTM A388 or SEP 1921. Contact sales@steelforgepieces.com or +86-189-2135-9659.
- EN number
- 1.4652
- UNS
- S32654
- PREN
- 54 to 60
- Rm min.
- 750 MPa
- Rp0.2 min.
- 430 MPa
- Certificate
- EN 10204 3.1 / 3.2
1.4652 forged product forms we manufacture
Every item below is made to order from the customer's drawing, size list or specification. There is no fixed catalogue. Open-die forging and ring rolling suit single prototypes and repeat production batches equally well.
| Forged form | Size range | Typical application |
|---|---|---|
| Seamless rolled rings | OD 200 to 4000 mm, wall 20 to 600 mm, height up to 1200 mm | Pump casings, compressor cases, flange blanks, bearing races |
| Forged flanges | DN 15 to DN 2000, weld neck, slip-on, blind, lap joint, orifice, special | Seawater, firewater and subsea pipework, risers, manifolds |
| Forged round bars | Dia. 60 to 1200 mm, length up to 8000 mm | Valve stems, shafts, fastener stock, machining blanks |
| Forged discs and blanks | Dia. up to 2500 mm, thickness 30 to 500 mm | Tube sheets, blind flanges, closure plates, cover plates |
| Forged sleeves and bushings | ID from 60 mm, OD up to 2000 mm | Wear sleeves, liners, spacers, separator internals |
| Forged shafts and spindles | Dia. 80 to 1000 mm, length up to 8000 mm | Pump and agitator shafts, eccentric shafts, crankshafts |
| Forged tube sheets | Dia. up to 2500 mm, drilled or blank | Heat exchangers, brine heaters, condensers |
| Valve components | Bodies, bonnets, stems, seat rings, balls, blocks | Ball, gate, globe, check, plug and choke valves |
| Near-net shapes | Nozzles, hubs, rolls, wheels, gear blanks, manifolds | Reduced machining allowance on high-cost alloy |
Single-piece forged weight range: about 5 kg to 20 000 kg. Minimum order quantity: 1 piece.
Chemical composition of 1.4652 / UNS S32654
1.4652 is conventionally melted. It is not a powder-metallurgy grade. Forging stock is produced by electric arc furnace melting followed by AOD or VOD refining, with electroslag remelting where a heavy section needs low segregation and high cleanliness.
| Element | EN 1.4652 (EN 10088-1) | UNS S32654 (ASTM A240) | Role in the alloy |
|---|---|---|---|
| Carbon (C) | 0.020 max. | 0.020 max. | Kept very low to avoid chromium carbide sensitisation |
| Silicon (Si) | 0.50 max. | 0.50 max. | Deoxidiser |
| Manganese (Mn) | 2.00 to 4.00 | 2.00 to 4.00 | Held high to raise nitrogen solubility |
| Phosphorus (P) | 0.030 max. | 0.030 max. | Residual |
| Sulphur (S) | 0.005 max. | 0.005 max. | Very low, for hot workability and pitting resistance |
| Chromium (Cr) | 23.0 to 25.0 | 24.0 to 25.0 | Passive film former, main PREN contributor |
| Molybdenum (Mo) | 7.0 to 8.0 | 7.0 to 8.0 | Pitting and crevice corrosion resistance |
| Nickel (Ni) | 21.0 to 23.0 | 21.0 to 23.0 | Austenite stabiliser, stress-corrosion resistance |
| Nitrogen (N) | 0.45 to 0.55 | 0.45 to 0.55 | Strength and pitting resistance, about twice that of 254 SMO |
| Copper (Cu) | 0.30 to 0.60 | 0.30 to 0.60 | Resistance to reducing acids, sulphuric in particular |
| Iron (Fe) | Balance | ||
Sources: EN 10088-1:2023 (X1CrNiMoCuN24-22-8, material number 1.4652) and ASTM A240/A240M (UNS S32654). The two systems differ slightly on chromium. We forge to the overlapping 24.0 to 25.0 % Cr window so that a single heat satisfies both EN and ASTM limits.
Pitting resistance equivalent number (PREN)
PREN is calculated as PREN = %Cr + 3.3 × %Mo + 16 × %N. Worked through for 1.4652:
- Leanest EN composition, 23.0 Cr / 7.0 Mo / 0.45 N: 23.0 + 23.1 + 7.2 = 53.3
- Leanest ASTM composition, 24.0 Cr / 7.0 Mo / 0.45 N: 24.0 + 23.1 + 7.2 = 54.3
- Typical heat, 24.5 Cr / 7.5 Mo / 0.50 N: 24.5 + 24.75 + 8.0 = 57.3
- Richest composition, 25.0 Cr / 8.0 Mo / 0.55 N: 25.0 + 26.4 + 8.8 = 60.2
A PREN above 40 is the usual threshold for warm seawater service. Because we work to the overlapping chromium window, delivered 1.4652 sits in the 54 to 60 band.
Mechanical properties of 1.4652 forgings
Values apply to the solution-annealed and water-quenched condition at room temperature and follow ASTM A240 for UNS S32654. Nitrogen in solid solution raises the proof strength to about double that of 316L, and elongation still holds at 40 % minimum.
| Property | Symbol | Metric | Imperial |
|---|---|---|---|
| Tensile strength, min. | Rm | 750 MPa | 109 ksi |
| 0.2 % proof strength, min. | Rp0.2 | 430 MPa | 62 ksi |
| 1.0 % proof strength, typical | Rp1.0 | 470 MPa | 68 ksi |
| Elongation, min. | A | 40 % | 40 % |
| Hardness, max. | 250 HBW | about 24 HRC | |
| Impact energy at −46 °C, typical | KV | 100 J min. | 74 ft·lb min. |
Source: ASTM A240/A240M for UNS S32654, giving tensile 750 MPa, yield 430 MPa, elongation 40 % and 250 HBW maximum. The Rp1.0 and impact figures are typical test results rather than specification minima, so confirm test requirements at enquiry. Heavy sections are tested per EN 10250-4 sampling rules.
Physical properties
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ (0.289 lb/in³) |
| Modulus of elasticity | 195 GPa |
| Thermal conductivity | about 8.5 W/(m·K) |
| Specific heat capacity | about 510 J/(kg·K) |
| Electrical resistivity | about 0.78 µΩ·m |
| Mean thermal expansion, 20 to 100 °C | about 15.0 × 10⁻⁶ /K |
| Magnetic permeability | < 1.01, non-magnetic when annealed |
Typical values for guidance. Note that 1.4652 has lower thermal conductivity and higher thermal expansion than carbon steel, which has to be allowed for in heat-exchanger and flange design. For design calculations refer to EN 10088-1 or the relevant pressure-vessel code.
Corrosion resistance and grade comparison
1.4652 resists chloride pitting and crevice corrosion in warm and chlorinated seawater. It also resists sulphuric, phosphoric and organic acids, and mixed acids containing chlorides. Its critical pitting temperature usually exceeds 90 °C in the ASTM G48 Method A ferric chloride test, and the high nickel content gives better chloride stress-corrosion-cracking resistance than 304 or 316 grades.
| Grade | EN / UNS | Mo % | N % | PREN approx. | Rp0.2 min. | Relative alloy cost |
|---|---|---|---|---|---|---|
| 316L | 1.4404 / S31603 | 2.0 to 2.5 | 24 | 200 MPa | Baseline | |
| 904L | 1.4539 / N08904 | 4.0 to 5.0 | 34 | 220 MPa | 2 to 3 times | |
| 254 SMO (A182 F44) | 1.4547 / S31254 | 6.0 to 7.0 | 0.18 to 0.25 | 43 | 300 MPa | 3 to 4 times |
| Super duplex (A182 F53) | 1.4410 / S32750 | 3.0 to 5.0 | 0.24 to 0.32 | 42 | 550 MPa | 2 to 3 times |
| 1.4652 (654 SMO) | 1.4652 / S32654 | 7.0 to 8.0 | 0.45 to 0.55 | 54 to 60 | 430 MPa | 6 to 8 times |
| Alloy 625 | 2.4856 / N06625 | 8.0 to 10.0 | 50+ | 415 MPa | 8 to 12 times |
PREN calculated as Cr + 3.3Mo + 16N from mid-range specified compositions. Cost multipliers are indicative market ratios, not quotations. Super-duplex grades are limited to roughly 300 °C service by 475 °C embrittlement, whereas 1.4652 stays fully austenitic. That temperature limit, rather than PREN alone, is often what decides the selection.
When to specify 1.4652 instead of a nickel alloy
Four situations account for most 1.4652 enquiries we see. The first is service beyond the limit of 6 % Mo grades, where UNS S31254 or super-duplex pits in warm chlorinated seawater but 1.4652 still passes. The second is weight or wall thickness: at 430 MPa minimum proof strength, sections can be thinner than in 904L or Alloy 625. The third is budget, since 1.4652 gets close to Alloy 625 pitting performance for a lower alloy cost. The fourth is any application that has to stay non-magnetic, which rules out the duplex grades.
How we forge and heat treat 1.4652
1.4652 has a narrow hot-working window. Its high molybdenum and nitrogen content makes it prone to sigma and chi phase precipitation if forging finishes too cold, and those intermetallics reduce both toughness and corrosion resistance. Forging and heat treatment are controlled around that limit.
1. Melting
EAF with AOD or VOD refining, and ESR remelting for heavy sections and critical service. Full heat traceability from ingot to part.
2. Heating
Soak at about 1180 to 1220 °C with controlled ramp rate, in thermocouple-monitored furnaces with calibrated charts.
3. Open-die forging
Upsetting, drawing and punching on hydraulic presses, plus ring rolling for seamless rings. Forging finishes above about 1050 °C, with reheating between passes.
4. Solution annealing
1150 to 1200 °C followed by a rapid water quench, to redissolve intermetallics and restore a fully austenitic structure.
5. Machining
Rough or finish machining to drawing. Low thermal conductivity and a high work hardening rate call for rigid setups, positive geometry and generous coolant.
6. Testing and release
Chemistry, mechanicals, UT, corrosion testing, dimensional report, marking and EN 10204 3.1 or 3.2 certification.
Testing and certification available
- Ultrasonic examination to EN 10228-3, ASTM A388/A388M or SEP 1921, acceptance class to order.
- Spectrometric ladle and product analysis, with PMI on request.
- Tensile and hardness testing, and Charpy V-notch down to −196 °C on request.
- Intergranular corrosion testing to ASTM A262 Practice E (Strauss) or EN ISO 3651-2.
- Pitting corrosion testing to ASTM G48 Method A, test temperature agreed at order.
- Grain size to ASTM E112, with an intermetallic phase check to ASTM A923-type practice.
- Liquid penetrant testing to ASTM E165 or EN ISO 3452.
- EN 10204 3.1 certification as standard. EN 10204 3.2 witnessed by BV, SGS, TUV, DNV, Lloyd's Register or the customer's own inspector.
Ordering standards in common use for this grade: EN 10250-4 for open-die stainless forgings, EN 10088-3 for technical delivery conditions, ASTM A240/A240M, ASTM A479/A479M, ASTM A484/A484M and ASTM A965/A965M. NORSOK M-650 manufacturing summary reports can be prepared on request.
Applications for 1.4652 forgings by industry
| Industry | Environment | Forged components |
|---|---|---|
| Offshore oil and gas | Chlorinated seawater, produced water, subsea and deepwater systems | Flanges, rolled rings, manifold blocks, valve bodies and stems, riser components |
| Seawater desalination | High-salinity brine at elevated temperature, MSF and MED plants, high-pressure RO | Tube sheets, brine heater components, pump casings, high-pressure flanges |
| Chemical processing | Sulphuric, phosphoric, organic and mixed acids containing chloride ions | Reactor rings, agitator shafts, sleeves, discs, nozzles, valve seat rings |
| Pulp and paper | Chlorine dioxide bleaching, black and white liquor | Bleach plant washers, rolls, shafts, bushings, flanges |
| Power and FGD | Flue-gas desulphurisation scrubbers, chloride-rich condensate | Absorber internals, pump shafts, spray header flanges, wear sleeves |
| Chlor-alkali | Chlorine and chlorine dioxide generation, oxidising chloride service | Heat exchanger tube sheets, piping components, valve blocks |
| Marine and shipbuilding | Ballast and firewater systems, seawater cooling | Flanges, pipe fittings, pump and strainer bodies, shafts |
| Waste water and environment | Demineralised water, down-hole and polycarbonate production duty | Nozzles, crankshafts, eccentric shafts, gear blanks, rings |
1.4652 equivalent grades and designations
| System | Designation |
|---|---|
| EN material number | 1.4652 |
| EN chemical name | X1CrNiMoCuN24-22-8 |
| UNS (USA) | S32654 |
| Common trade name | 654 SMO |
| ASME and ASTM plate | ASTM A240 / ASME SA-240 UNS S32654 |
| Closely related grade | S32652, also listed against 1.4652 in EN 10088-1 |
| Commonly compared with | 1.4547 / S31254 (254 SMO), 1.4529 / N08926, 1.4659 / S31266, N08031 (Alloy 31) |
654 SMO is a registered trademark of Outokumpu. Jiangyin Jiangnan Metal Co., Ltd. is an independent forging manufacturer and is not affiliated with, sponsored by or endorsed by Outokumpu. The trade name is used here only to identify the equivalent grade.
Frequently asked questions about 1.4652 forgings
What is 1.4652 stainless steel?
EN 1.4652 (X1CrNiMoCuN24-22-8, UNS S32654, trade name 654 SMO) is a super-austenitic stainless steel containing about 24 % chromium, 22 % nickel, 7 to 8 % molybdenum, 0.45 to 0.55 % nitrogen and 0.30 to 0.60 % copper. Its PREN of about 54 to 60 gives localised corrosion resistance close to nickel-based alloys. It is produced by conventional melting, normally EAF plus AOD or VOD refining, with ESR for critical forging stock. It is not a powder-metallurgy steel.
What is the difference between 1.4652 and UNS S32654?
There is no metallurgical difference. 1.4652 is the European material number under EN 10088 and S32654 is the North American UNS designation for the same alloy. The only nuance is chromium: EN 10088-1 allows 23.0 to 25.0 % while ASTM A240 specifies 24.0 to 25.0 %. We forge to the overlapping window so one heat satisfies both.
Who supplies 1.4652 forged rings and flanges?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, manufactures 1.4652 / UNS S32654 seamless rolled rings, forged flanges, round bars, discs, sleeves, bushings, shafts and tube sheets to customer drawing. Enquiries go to sales@steelforgepieces.com or +86-189-2135-9659.
What is the PREN of 1.4652?
Using PREN = %Cr + 3.3 × %Mo + 16 × %N: about 54.3 at the leanest ASTM composition, 53.3 at the leanest EN composition, about 60.2 at the rich end, and about 57 for a typical heat. By comparison 316L is about 24, 904L about 34, and UNS S31254 (254 SMO) about 43.
What are the minimum mechanical properties of 1.4652 forgings?
Solution annealed: tensile strength Rm 750 MPa (109 ksi) minimum, proof strength Rp0.2 430 MPa (62 ksi) minimum, elongation 40 % minimum, hardness 250 HBW maximum. These are the values given in ASTM A240 for UNS S32654. High nitrogen is what lifts the proof strength to about double that of 316L.
How is 1.4652 forged and heat treated?
Soak at about 1180 to 1220 °C, forge or ring-roll with a finishing temperature above roughly 1050 °C, reheating between passes as needed, then solution anneal at 1150 to 1200 °C and water quench. Finishing too cold risks sigma and chi phase precipitation, which reduces both impact toughness and corrosion resistance. This is the process control that matters most for the grade.
Is 1.4652 suitable for seawater and chlorinated seawater service?
Yes. With PREN above 54 and a critical pitting temperature usually above 90 °C in the ASTM G48 Method A test, 1.4652 is specified where 6 % Mo grades and super-duplex steels reach their limit: desalination brine heaters, firewater and subsea pipework, risers and manifolds, and offshore produced-water systems.
What certification is supplied with 1.4652 forgings?
EN 10204 3.1 mill certificates as standard, and EN 10204 3.2 certificates witnessed by BV, SGS, TUV, DNV, Lloyd's Register or your own inspector on request. Accompanying tests normally include ultrasonic examination to EN 10228-3, ASTM A388 or SEP 1921, intergranular corrosion to ASTM A262 Practice E, pitting to ASTM G48 Method A, PMI, and grain size to ASTM E112.
What size range of 1.4652 forgings can be produced?
Seamless rolled rings from about 200 mm to 4000 mm outside diameter, round bars from about 60 mm to 1200 mm diameter, discs up to about 2500 mm, and single-piece forged weights from a few kilograms up to about 20 tonnes. All parts are made to the customer's drawing rather than from a catalogue.
What is the lead time and how do I get a quotation?
Typical lead time is 30 to 50 days from order confirmation, depending on billet availability, forged weight and third-party inspection scope. Send a drawing or a size list to sales@steelforgepieces.com and a technical and commercial quotation normally follows within 24 hours.
Can you supply other grades alongside 1.4652 on the same order?
Yes. The same press and ring mill run carbon steel, alloy steel, tool steel, stainless steel, duplex and super-duplex, super-austenitic grades and nickel alloys, so mixed-grade packages for one project can be consolidated into a single shipment. See our stainless steel forging grades and nickel alloy forging grades.
Request a quotation for 1.4652 forgings
Send a drawing, quotation within 24 hours
To quote accurately we need as much of the following as you have:
- Drawing, sketch or rough size list (OD x ID x height, or dia. x length)
- Quantity and required delivery date
- Grade confirmation: 1.4652, UNS S32654 or an equivalent you have to match
- Ordering specification, for example EN 10250-4, ASTM A240 or a client MDS
- Supply condition: as-forged, rough machined or finish machined
- Testing and certification scope: UT class, corrosion tests, EN 10204 3.1 or 3.2
Jiangyin Jiangnan Metal Co., Ltd.
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Phone, WeChat and WhatsApp: +86-189-2135-9659
Email: sales@steelforgepieces.com
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin City, Jiangsu Province, in the Yangtze River Delta about two hours from the Port of Shanghai. The plant produces open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel, duplex and super-duplex stainless steel, super-austenitic grades such as 1.4652, and nickel-based alloys. We supply the oil and gas, desalination, chemical processing, power generation, pulp and paper, marine and general engineering sectors.
Work is made to customer drawing with full heat traceability, in-house heat treatment, and inspection documentation to EN 10204 3.1 or 3.2. Contact the sales engineering team to discuss a specific part.
Related forging grades
A182 F44 (1.4547 / S31254)
6 % Mo super-austenitic, the step below 1.4652 for seawater service.
904L (1.4539 / N08904)
High-nickel austenitic for sulphuric acid and reducing media.
A182 F53 (1.4410 / S32750)
Super-duplex, higher strength but a lower maximum service temperature.
Sanicro 28 (N08028)
High-alloy austenitic for phosphoric and sulphuric acid duty.
Alloy 31 (N08031)
6.5 % Mo nickel-iron-chromium alloy for aggressive acid service.
Inconel 625 (N06625)
Nickel-base alternative where 1.4652 is still not sufficient.