S32760 forged products
Everything below is produced from steel melted on site, forged or ring-rolled from a single piece, with no welding and no casting. Items are supplied as forged, proof machined or finish machined to your drawing.
Seamless rolled rings
Ring-rolled from a punched preform on the radial-axial mills, rectangular or contoured section. See rolled rings.
Forged rings
Upset and punched rings for sections outside the ring mill envelope, plus valve seat rings and retaining rings.
Flanges
Weld neck, blind, slip-on, socket weld, orifice and long weld neck to ASME B16.5, B16.47 and API 6A.
Bars and blocks
Forged round, flat and square bars, the feedstock route for machined valve bodies.
Shafts and spindles
Stepped, eccentric and pump shafts, valve stems, rotors and tie rods, vertically quenched in the pit furnaces.
Discs and tube sheets
Solid forged discs, tube sheets and covers, proof machined for volumetric inspection.
Cylinders and sleeves
Hollow forged cylinders, sleeves, bushings and heavy-wall sections bored from solid forged blanks.
Valve and wellhead parts
Bodies, bonnets, blocks, chokes, connectors, spools and manifolds to API 6A and NACE MR0175 / ISO 15156.
Designations and product standards
| UNS | S32760 |
|---|---|
| EN material number | 1.4501 |
| EN name | X2CrNiMoCuWN25-7-4 |
| ASTM forgings | A182 / A182M Grade F55, A473 |
| ASTM bar | A479, A276 condition A |
| ASTM plate and sheet | A240 |
| HIP products | A988 |
| EN bar and section | EN 10088-3 |
| AFNOR | Z3CND25.06Az |
| Project data sheets | NORSOK M-630 MDS D57 (bars), qualification to NORSOK M-650 |
| Sour service | NACE MR0175 / ISO 15156-3 |
| Pressure equipment | ASME approved for pressure vessel use, PED 97/23/EC |
| Trade names | Zeron 100, Seacol 760 |
Zeron 100 is a registered trademark of Rolled Alloys. Trade names are listed for cross reference only. Jiangyin Jiangnan Metal supplies material certified to UNS S32760, ASTM A182 F55 and EN 1.4501, not to any trademarked brand unless that owner’s material is purchased specifically.
Chemical composition
| Element | Min | Max | Element | Min | Max |
|---|---|---|---|---|---|
| Carbon | — | 0.030 | Chromium | 24.00 | 26.00 |
| Manganese | — | 1.00 | Nickel | 6.00 | 8.00 |
| Silicon | — | 1.00 | Molybdenum | 3.00 | 4.00 |
| Phosphorus | — | 0.030 | Copper | 0.50 | 1.00 |
| Sulfur | — | 0.010 | Nitrogen | 0.20 | 0.30 |
| Iron | Remainder | Tungsten | 0.50 | 1.00 | |
State on the order which specification governs. The ASTM A182 F55 limits above are 0.030 percent phosphorus and 0.010 percent sulfur; the EN 1.4501 ranges published for 24 to 26 chromium material are otherwise the same for chromium, nickel, molybdenum, nitrogen, copper and tungsten. Where both are called up, the tighter figure is applied and reported.
Pitting resistance equivalent number
PREN is calculated as percent Cr + 3.3 × percent Mo + 16 × percent N, the form written into NORSOK M-630 MDS D57, which sets the acceptance limit at 40.0 minimum. Supplier datasheets for this grade quote PREN at 40 or above. Standard 22 percent chromium duplex sits nearer 35, and a PREN around 32 to 35 is often taken as the practical floor for seawater duty, which is why this grade is specified where 2205 is marginal. For a two-phase steel the limiting value is the lower PREN of the two phases, so ferrite balance after solution annealing matters as much as the bulk analysis. Each certificate we issue states the calculated PREN for the heat.
Mechanical and physical properties
| Property | ASTM A182 F55 | EN 10088-3 (1.4501) | NORSOK MDS D57 |
|---|---|---|---|
| Tensile strength Rm | 750 to 895 MPa | 730 to 930 MPa | 750 MPa min |
| Proof stress Rp0.2 min | 550 MPa (79.8 ksi) | 530 MPa | 550 MPa min |
| Elongation min | 25 percent | 25 percent | 25 percent min |
| Reduction of area min | 45 percent | — | — |
| Hardness | 270 HB max | — | Tested per heat and heat treatment load |
| Impact, ambient | 80 J min | — | — |
| Impact at −46 °C | 45 J average, 35 J single | — | 45 J average, 35 J single, to ASTM A370 |
The three columns differ because they are three different acceptance documents, not because the data conflicts. ASTM A182 F55 governs forgings, EN 10088-3 covers bar and section, and NORSOK M-630 MDS D57 applies to 25Cr duplex bars up to 200 mm thickness and is itself written on the mechanical properties of S32760. Typical yield in production runs higher than the minimum, up to around 600 MPa. Notch ductility stays good down to about −50 °C.
| Property | Value |
|---|---|
| Density | 7.81 g/cm³ |
| Young’s modulus | 199 kN/mm² (199 GPa, 28.9 × 10³ ksi) |
| Magnetic permeability | 33 (the ferrite phase is magnetic) |
| Structure | Ferrite and austenite, approximately 50:50 |
Thermal conductivity, specific heat, thermal expansion and resistivity for the as-supplied condition are issued with the material certificate on request. Ask at enquiry stage if you need them for a design calculation, and state the service temperature.
Forging, heat treatment, machining and welding
Hot working
S32760 is forged in the two-phase range, with supplier guidance for this grade putting the working window at roughly 1100 to 1250 °C. Reheats and finishing temperature are planned so that reduction is enough to break down the cast structure right through the section, while finishing is not taken so low that intermetallic phases start to form. Every S32760 job here is run to a written heat and reduction plan rather than left to the press operator.
Solution annealing and quenching
- After hot working, forgings are cooled below 538 °C before heat treatment begins.
- Solution treat and quench. The ASTM A182 solutioning temperature for F55 is given as 1100 to 1140 °C minimum, followed by water quenching.
- Pieces are spaced in the furnace and in the quench tank so that air and water circulate freely around each one. MDS D57 makes this a requirement, and inadequate spacing is the usual cause of a failed ferrite count or G48 test on heavy sections.
- Target structure is 35 to 55 percent ferrite, free from intermetallic phases and precipitates at 400 times magnification.
- The solution annealing temperature and holding time are recorded on the certificate, as MDS D57 requires.
Machining
Machining this grade presents no particular problem in itself, but it does not behave like 316L. Proof stress is roughly three times higher, so cutting forces, chip control and tool wear all change, and start values should be set for the measured hardness of the actual lot rather than taken from a generic stainless table. Forming needs more force and shows more springback than austenitic grades, and the grade will not take as tight a bend radius. We rough machine, finish machine and deep-hole bore in house, up to 5,000 mm swing on the vertical lathes and 1,600 mm diameter by 10,000 mm on the CNC deep-hole drill.
Welding
Weldability is good and the grade is routinely welded in fabrication. Consumable selection, heat input limits and any production weld test requirements are agreed per project and written into the manufacturing procedure before work starts. One point worth flagging at the enquiry stage: NORSOK M-630 MDS D57 does not accept weld repair. Forgings supplied against that data sheet are not weld repaired here under any circumstances.
Corrosion performance and grade selection
The combination of 25 percent chromium, 3 to 4 percent molybdenum and 0.20 to 0.30 percent nitrogen gives excellent resistance to pitting and crevice corrosion and to stress corrosion cracking in chloride-bearing and sour environments, with high resistance to general corrosion and to erosion corrosion and corrosion fatigue. Strength is above both austenitic grades and 22 percent chromium duplex.
- Against 316L and 2205. This is the standard upgrade path when 316L or 2205 is being lost to pitting or chloride cracking, and it can also be considered in place of more costly materials where a duplex structure is acceptable.
- Against S32750 and 2507. Both are super duplex, both are specified above PREN 40 and both have similar seawater performance. The chemistry difference is the copper and tungsten in S32760. Published literature for this grade records its heaviest use in seawater service, sour gas service and sulfuric acid service. For plain chloride duty either grade will normally do, so the choice usually follows the project specification and product availability rather than a clear technical gap.
- Service temperature. Duplex structures are limited at elevated temperature by intermetallic precipitation, which costs toughness and corrosion resistance. State the design temperature at enquiry so the heat treatment and test plan can be set against it.
- Sour service. The grade is listed in NACE MR0175 for sour service. Where MR0175 / ISO 15156-3 is called up, hardness and microstructure acceptance are tested and reported against it.
Where S32760 forgings are used
Offshore oil and gas
Christmas trees, wellheads, chokes, connectors, manifolds, risers, BOP parts, downhole components and sour service hardware.
Seawater and firewater
Seawater cooling and firewater pump parts, piping components, separator and heat exchanger parts, pressure vessel parts.
Desalination
Seawater reverse osmosis plant, high pressure RO components and seawater piping.
Chemical and process
Chemical processing plant, sulfuric acid duty, pharmaceutical process equipment.
Power and environmental
Flue gas desulfurisation plant and pollution control equipment.
Pulp, paper and mining
Digesters, liquor tanks, paper machine parts, mining and metallurgical equipment.
Inspection, testing and certification
| Item | Standard and acceptance |
|---|---|
| Melting and refining | Electric arc furnace, ladle furnace and vacuum oxygen decarburisation on 30 t or 60 t VOD units. MDS D57 requires AOD refining or equivalent. |
| Chemical analysis | Full product analysis by optical emission spectrometry to ASTM E415, PREN calculated and stated, 40.0 minimum |
| Tensile test | ASTM A370. Rp0.2, Rm, elongation and reduction of area |
| Impact test | Charpy V-notch to ASTM A370 at −46 °C, 45 J average and 35 J single minimum |
| Hardness | One test per heat and heat treatment load |
| Micrographic examination | Minimum 10 × 10 mm area at the test specimen location and near surface. Ferrite 35 to 55 percent to ASTM E562, free from intermetallic phases and precipitates at 400 times |
| Corrosion test | ASTM G48 Method A, 50 °C, 24 hours, specimen pickled before weighing. No pitting at 20 times and weight loss below 4.0 g/m². Placed with an accredited third-party laboratory |
| Extent of testing | One set of impact, tensile, hardness, microstructure and corrosion tests per heat and per heat treatment load |
| Test sampling | Section thickness to 50 mm, specimen at mid thickness with mid length at least 50 mm from any second surface. Above 50 mm, at least one quarter T from the nearest surface |
| Volumetric examination | Ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388. Magnetic particle to ASTM E709 and liquid penetrant on request |
| Surface finish | White pickled. Machined surfaces are not pickled |
| Weld repair | Not accepted on product supplied to MDS D57 |
| Marking | Marked for full traceability to melt and heat treatment lot |
| Certificate | EN 10204 Type 3.1 as standard, stating steel maker, melting and refining practice and the solution annealing temperature and holding time. Type 3.2 witnessed by BV, DNV, LR, SGS, TUV or your own inspector on request |
The works behind the grade
Most forging suppliers in China buy billet. This plant starts at the furnace, which is the reason a S32760 certificate from here carries a melt number rather than a purchased billet reference.
| Melting | EF, LF, VOD, VIM, VAR and ESR. Maximum heat 60 t. Stainless and duplex run EF to LF to VOD |
|---|---|
| Forging | Open-die hydraulic presses at 6,300 t, 4,000 t and 2,000 t, plus hammers from 750 kg to 5 t |
| Ring rolling | Radial-axial mills to 6,000 mm, 3,000 mm and 1,000 mm outside diameter |
| Heat treatment | 14 furnaces, including car-bottom chambers to 8,000 mm long and pit furnaces 15,000 mm deep by 1,500 mm diameter for vertical quenching of shafts |
| Machining | Vertical lathes to 5,000 mm swing, horizontal lathes to 14,000 mm between centres, CNC deep-hole drilling to 1,600 mm by 10,000 mm |
| Size limits | Rings from 50 mm up to 6,000 mm outside diameter. Single piece weight to 30,000 kg |
| Order terms | Minimum order 10 kg, no minimum piece count. Lead time 20 to 60 days |
| Approvals | CCS, BV, DNV, LR and NK. Established 1997, 460 staff including 9 senior and 32 intermediate engineers and 140 technicians |
Questions we are asked about this grade
Is UNS S32760 the same thing as ASTM A182 F55?
Yes. ASTM A182 / A182M assigns the identification symbol F55 to UNS S32760 and describes it as 25 chromium, 7 nickel, 3.5 molybdenum, modified with nitrogen and tungsten. F55 is the designation to use when ordering forged flanges, fittings, valve bodies, rings and bars in this grade.
S32760 or 2507. Which should I specify?
Both are super duplex, both are specified above PREN 40, and both perform similarly in seawater. S32760 differs by containing copper and tungsten. Published literature for the grade records its main service record in seawater, sour gas and sulfuric acid duty. For plain chloride service either grade is usually acceptable, so the decision normally comes down to the governing project specification and to which grade is available in the product form and section you need. Tell us the service and we will quote both if that helps the comparison.
What heat treatment will my forgings get?
Cooled below 538 °C after hot working, then solution treated and water quenched. ASTM A182 gives the solutioning temperature for F55 as 1100 to 1140 °C minimum. Parts are spaced so water and air reach every surface during quenching, and the actual temperature and holding time go on the certificate.
Can you meet NORSOK requirements?
MDS D57 acceptance criteria are built into our standard test package for this grade: PREN 40.0 minimum, Rp0.2 from 550 MPa, Rm from 750 MPa, elongation from 25 percent, Charpy 45 J average and 35 J single at −46 °C, ferrite 35 to 55 percent, G48 Method A at 50 °C for 24 hours with no pitting at 20 times and weight loss below 4.0 g/m², one test set per heat and heat treatment load, white pickled finish, no weld repair and EN 10204 Type 3.1 certification. Note that manufacture to the data sheet also calls for qualification under NORSOK M-650, so raise that at the enquiry stage rather than after the order.
How large and how heavy can you go?
Seamless rolled rings to 6,000 mm outside diameter on the 6 m radial-axial mill, and rings from 50 mm outside diameter by the upset and punch route below that. Shafts to 14,000 mm turned length. Discs and tube sheets to 5,000 mm machined diameter. Single piece weight to 30,000 kg, set by the 60 t heat size and the 6,300 t press.
What do you need from me to quote?
A drawing or a dimension list, the governing specification, quantity, the machining condition you want, any NDT requirement and the certificate type. Email it to sales@steelforgepieces.com or call +86 189 2135 9659. Quotations normally go back within one working day.
Jiangyin Jiangnan Metal Co., Ltd. — open-die forging works
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone +86 189 2135 9659 · Email sales@steelforgepieces.com
Monday to Saturday, 08:00 to 17:30 China Standard Time
Sources and revision
Figures on this page are drawn from ASTM A182 / A182M for Grade F55 chemistry, mechanical requirements and heat treatment, EN 10088-3 and published 1.4501 datasheets, NORSOK M-630 Material Data Sheet MDS D57 Rev. 4 for 25Cr duplex bars, ASTM G48 for the corrosion test, ASTM E562 for ferrite counting and ASTM A370 for mechanical testing. Plant capability figures are our own. Data is given for guidance; the governing purchase specification and the issued mill certificate take precedence. Record maintained by the technical department, Jiangyin Jiangnan Metal Co., Ltd., last reviewed 8 October 2026.