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Z3CND25.07Az Super Duplex Forgings (UNS S32750 / EN 1.4410 / ASTM A182 F53)
Open-die forged rings, seamless rolled rings, flanges, shafts, discs, sleeves and bars made to drawing in Jiangyin, China.
Z3CND25.07Az is the AFNOR designation for a 25% chromium, 7% nickel, 4% molybdenum, nitrogen-alloyed super duplex stainless steel. The same material is listed as UNS S32750, EN 1.4410 (X2CrNiMoN25-7-4), ASTM A182 F53 and the commercial grade 2507. Its roughly 50/50 ferrite and austenite structure gives about twice the yield strength of 316L, together with high resistance to chloride pitting, crevice corrosion and chloride stress corrosion cracking.
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges this grade to customer drawing. Parts are supplied solution annealed and quenched, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, with EN 10204 3.1 or 3.2 certificates. Enquiries: 0086-189-2135-9659, sales@steelforgepieces.com.
- UNS
- S32750
- EN number
- 1.4410X2CrNiMoN25-7-4
- ASTM forging
- A182 F53
- Yield, min
- 550 MPa80 ksi
- Tensile, min
- 795 MPa116 ksi
- PREN
- 38 to 46super duplex class
Equivalent grades and designations
The same steel reaches us under six or seven different names, depending on which standard the drawing quotes. All of the designations below refer to one grade.
| Standard or system | Designation | Usual product scope |
|---|---|---|
| AFNOR, France | Z3CND25.07Az | Bar, forgings |
| UNS, USA | S32750 | All product forms |
| EN material number | 1.4410, X2CrNiMoN25-7-4 | EN 10088, EN 10216-5, EN 10222-5 |
| ASTM forgings | A182 Grade F53 | Flanges, fittings, valve parts |
| ASTM bar | A276 and A479, S32750 | Bar and shapes |
| SIS, Sweden | 2328 | Bar, plate |
| Trade names | 2507, UR 47N+ | General |
One point on the name: Z3CND25.07Az comes from the AFNOR system, not from DIN. The European reference for the same steel is the material number 1.4410. It should not be mixed up with Z3CN25.06Az, which carries no molybdenum in its designation.
Chemical composition
The figures below follow the ASTM A182 F53 and UNS S32750 limits normally applied to forgings. Where EN 1.4410 sets a different limit, it is shown in the last column.
| Element | Symbol | UNS S32750 / A182 F53 | EN 1.4410 where different |
|---|---|---|---|
| Chromium | Cr | 24.0 to 26.0 | 24.0 to 26.0 |
| Nickel | Ni | 6.0 to 8.0 | 6.0 to 8.0 |
| Molybdenum | Mo | 3.0 to 5.0 | 3.0 to 4.5 |
| Nitrogen | N | 0.24 to 0.32 | 0.24 to 0.35 |
| Carbon | C | 0.030 max | 0.030 max |
| Manganese | Mn | 1.20 max | – |
| Silicon | Si | 0.80 max | – |
| Copper | Cu | 0.50 max | – |
| Phosphorus | P | 0.035 max | – |
| Sulphur | S | 0.020 max | – |
| Iron | Fe | Balance | Balance |
Melting route in our works: EAF plus VOD as standard, with ESR remelting available on request where cleanliness or segregation control is critical.
Mechanical properties
Values apply at room temperature in the solution annealed and quenched condition, and match the acceptance minimums of ASTM A182 F53.
| Property | Metric | Imperial |
|---|---|---|
| 0.2% proof stress | 550 N/mm² min | 80 ksi min |
| Tensile strength | 795 N/mm² min | 116 ksi min, typically 110 to 135 ksi |
| Elongation | 15% min | 15% min in 2 in |
| Hardness | 310 HB max | 28 HRC max |
| Charpy V notch, room temperature | To order, full size specimens, lateral expansion and sub-zero testing such as minus 46 C on request | |
The 28 HRC ceiling is also the hardness limit set by NACE MR0175 and ISO 15156 for sour service, which is one reason this grade turns up so often on downhole and wellhead hardware. Tell us the revision you work to and we will test against it.
Corrosion resistance and PREN
The combination of chromium, molybdenum and nitrogen puts EN 1.4410 and Z3CND25.07Az in the 38 to 46 PREN band, above the PREN 40 threshold used to define super duplex. What that buys in service:
- Pitting and crevice corrosion resistance in warm chloride and seawater well beyond 316L or 904L.
- High resistance to chloride stress corrosion cracking, the usual failure mode for austenitic grades in hot chloride duty.
- Good behaviour under erosion corrosion and corrosion fatigue, useful on pumps, impeller hardware and high velocity piping.
- Higher thermal conductivity and lower thermal expansion than austenitic stainless, which keeps distortion down in heat exchanger work.
- Resistance to dilute hydrochloric acid and to many organic and inorganic acids, within limits set by temperature and concentration.
Service limit: like every duplex grade, Z3CND25.07Az should not run continuously above about 300 C because of 475 C embrittlement and sigma phase, and low temperature use needs qualification testing.
Forging, heat treatment and machining
Forging temperature
SEM and EBSD work on industrial UNS S32750 puts the optimal forging temperature range at 1050 to 1300 C, since the ferrite and austenite stay workable and free of damaging intermetallics inside that window. Material suppliers commonly quote a narrower practical band of 1100 to 1250 C. Super duplex has a tighter hot working window and higher flow stress than austenitic stainless, so soak uniformity, press capacity and finishing temperature matter far more than they do on 304 or 316.
Solution annealing
Solution annealing has to follow any hot or cold forming. Typical practice is 1040 to 1120 C, not below 1050 C, then an immediate quench in rapid air or water. Slow cooling through the 600 to 1000 C range throws out sigma and chi phases that take away both toughness and pitting resistance. Heat treated surfaces should be pickled and rinsed where maximum corrosion performance is wanted.
Machining
Tooling data has to be adjusted. Against 316 and 316L, cutting speed comes down by roughly 50 to 55 percent when turning with coated cemented carbide, and other operations follow much the same rule. Feed should be reduced only slightly and with care, because a feed that is too light work hardens the surface. Rigid fixturing, sharp edges and plenty of coolant are needed.
Welding
The low carbon content makes the grade weldable. Use over-alloyed super duplex filler, control heat input and interpass temperature to hold the phase balance, and do not preheat. Where the specification calls for it, ferrite content is checked after welding.
Forged products we make in this grade
Everything below is produced to customer drawing or specification.
| Forged product | Typical end use | Usual standard |
|---|---|---|
| Seamless rolled rings | Pump and compressor casings, flange blanks, bearing housings | ASTM A182 F53 |
| Forged flanges | Offshore piping, heat exchangers, seawater systems | ASTM A182 F53, EN 1092-1 |
| Forged round bars and billets | Machined components, fasteners, stems | ASTM A276, A479 S32750 |
| Forged discs and blanks | Blind flanges, valve discs, closure plates | ASTM A182 F53 |
| Forged shafts and spindles | Pump shafts, eccentric shafts, drive shafts | Per drawing |
| Forged sleeves and bushings | Subsea connectors, wear sleeves, housings | Per drawing |
| Forged tubes and hollow bars | Heat exchanger and separator internals | Per drawing |
| Forged tube sheets | Shell and tube heat exchangers, condensers | ASME Section VIII, TEMA |
| Valve components | Bodies, bonnets, stems, seat rings, blocks | ASTM A182 F53, NACE MR0175 |
| Open-die forgings to drawing | Nozzles, crankshafts, manifolds, rolls, structural parts | Per drawing |
Industries and applications
Desalination and seawater
High pressure reverse osmosis plant, seawater piping, ballast and injection water systems, energy recovery devices.
Chemical and petrochemical
Pressure vessels, heat exchangers, separators, reactor internals, acid and chloride process piping.
Power generation
Flue gas desulphurisation plant, condenser and feedwater hardware, turbine and gas compressor components.
Pulp and paper
Digesters, liquor tanks, bleach plant and paper machine parts working in chlorides and organic acids.
Marine and mechanical
Propulsion and deck hardware, industrial air compressors, nitrogen generators, gearboxes, power transmission parts.
Testing, inspection and certification
- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, to the acceptance class stated on the order.
- Material certificates to EN 10204 3.1, or 3.2 witnessed by a third party such as BV, DNV, LR, ABS, TUV or SGS.
- Chemical analysis by spectrometer including nitrogen determination, with PREN calculation on request.
- Mechanical testing: tensile, Charpy V notch including sub-zero, hardness survey and bend tests.
- Phase balance checks: ferrite content by point count or ferritescope, intermetallic phase testing to ASTM A923 Method A, B or C.
- Corrosion testing: ASTM G48 Method A pitting test at the specified temperature, ASTM A262 where applicable.
- Dimensional inspection, PMI and liquid penetrant testing, with traceability from heat number through to the finished part.
What to send with your enquiry
The first four items are enough for a budget price. A drawing is better.
- Grade and standard as written on your specification. Z3CND25.07Az, S32750, 1.4410 or A182 F53 are all fine.
- Shape and dimensions. OD by ID by height for rings, diameter by length for bars and shafts.
- Quantity and the date you need the parts.
- Delivery condition: as forged, rough machined or finish machined.
- Testing, NDT class, NACE or NORSOK requirements, and certificate level 3.1 or 3.2.
Request a price for Z3CND25.07Az forgings
Send a drawing or a size list and we will quote.
Common questions about Z3CND25.07Az
What is Z3CND25.07Az?
It is the AFNOR designation for a 25Cr-7Ni-4Mo-N super duplex stainless steel, the same material as UNS S32750, EN 1.4410 (X2CrNiMoN25-7-4), ASTM A182 F53 and the commercial grade 2507. Jiangyin Jiangnan Metal Co., Ltd. open-die forges it into rings, flanges, shafts and discs.
Is Z3CND25.07Az the same as 2507 or F53?
Yes, one alloy under several standards. The only practical difference is in the limits: EN 1.4410 holds molybdenum to 3.0 to 4.5 percent and allows nitrogen to 0.35 percent, while ASTM A182 F53 permits 3.0 to 5.0 percent molybdenum and 0.24 to 0.32 percent nitrogen. A heat whose chemistry sits inside every window can be certified to all of them.
What are the mechanical properties?
Solution annealed and quenched: 0.2% proof stress 550 N/mm² (80 ksi) minimum, tensile strength 795 N/mm² (116 ksi) minimum with typical values of 110 to 135 ksi, elongation 15 percent minimum, hardness 310 HB (28 HRC) maximum.
At what temperature is it forged and heat treated?
Published work on industrial S32750 gives 1050 to 1300 C as the optimal forging range, and suppliers commonly work 1100 to 1250 C. Solution anneal afterwards at 1040 to 1120 C, not below 1050 C, then quench at once in rapid air or water. Slow cooling precipitates sigma phase and ruins both toughness and corrosion resistance.
What is the PREN?
38 to 46 for EN 1.4410, above the PREN 40 mark that defines super duplex, which is why the grade holds up in seawater and chloride service.
Can it be used in sour service?
It is widely specified for sour duty and its 28 HRC maximum hardness lines up with the NACE MR0175 and ISO 15156 limit. Acceptance still depends on the partial pressures, chloride level, temperature and pH of your service envelope, so state the environment and we will confirm what testing is needed.
Who supplies these forgings?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Rings, seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings and tube sheets to drawing, with EN 10204 3.1 or 3.2 certificates and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388. Telephone 0086-189-2135-9659, email sales@steelforgepieces.com.
Standards referenced on this page: ASTM A182/A182M for forged fittings and flanges, ASTM A276 and A479 for bar, ASTM A923 for intermetallic phase detection in duplex steels, ASTM G48 for pitting tests, ASTM A262, EN 10088 and EN 10222-5, EN 10204 for inspection documents, EN 10228-3, SEP 1921 and ASTM A388 for ultrasonic testing, EN 1092-1 for flange dimensions, NACE MR0175 and ISO 15156 for sour service.
Related grades we forge
If this grade is not the right fit, the following run on the same equipment: A182 F53 with identical chemistry under ASTM naming, A182 F55 (UNS S32760) super duplex with tungsten and copper, A182 F51 (S31803 and S32205) standard 22Cr duplex, A182 F44 (S31254) 6Mo super austenitic, 904L, Sanicro 28, Inconel 625 and Hastelloy C-276.
Maintained by the engineering team at Jiangyin Jiangnan Metal Co., Ltd. Last reviewed . Figures are given for guidance; the purchase specification always governs.