Nickel alloy · UNS N08031 · W.Nr. 1.4562 · Alloy 31
X1NiCrMoCu32-28-7 Forgings
Seamless rolled rings, forged flanges, round bars, discs, shafts, sleeves, bushings and tube sheets in X1NiCrMoCu32-28-7, melted and forged in one works, supplied solution annealed with EN 10204 3.1 or 3.2 certification.
X1NiCrMoCu32-28-7 is the EN designation for the super-austenitic stainless steel also known as Alloy 31, UNS N08031 and W.Nr. 1.4562. It contains 30–32% nickel, 26–28% chromium, 6–7% molybdenum, 1.0–1.4% copper and 0.15–0.25% nitrogen, with carbon under 0.015% and iron as the balance. Guaranteed PREN is 48, and the grade is normally selected for concentrated sulfuric acid, wet-process phosphoric acid, flue gas desulfurisation and seawater duty.
Jiangyin Jiangnan Metal Co., Ltd. forges this grade to drawing at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The works has melted its own steel since 1997, so an X1NiCrMoCu32-28-7 forging is traceable to its melt number rather than to a purchased billet. Heats run through the electric arc furnace, the ladle furnace and vacuum oxygen decarburisation, with protective-atmosphere electroslag remelting available for tighter nitrogen control. Parts are then forged, solution annealed, ultrasonically tested and certified to EN 10204 3.1 or 3.2. Send a drawing to sales@steelforgepieces.com or call +86 189 2135 9659 and we will price it.
Published by Jiangyin Jiangnan Metal Co., Ltd., melting works and open-die forge, Jiangyin, Jiangsu, China · Data checked against ASTM B564, B581, B625, B649 and published UNS N08031 producer literature · First published 18 May 2016 · Revised 1 September 2026
X1NiCrMoCu32-28-7 at a glance
- EN / DIN designation
- X1NiCrMoCu32-28-7
- Werkstoff number
- 1.4562
- UNS number
- N08031
- Common trade names
- Alloy 31, Nicrofer® 3127 hMo
- Alloy family
- Super-austenitic stainless steel, iron-nickel-chromium-molybdenum with nitrogen and copper
- Hardening mechanism
- Solid solution only, not precipitation hardenable
- PREN (16 × N convention)
- 48 minimum, typically 51 to 55
- Delivery condition
- Solution annealed 1150 to 1180 °C, rapid quenched
- Density
- 8.05 g/cm³ (0.29 lb/in³)
- Melting range
- 1330 to 1370 °C (2426 to 2498 °F)
- Magnetic response
- Non-magnetic, relative permeability about 1.001 at 20 °C
- Forging standards
- ASTM B564 / SB-564, ASTM B581 / SB-581, ASTM B649 / SB-649
- Sour service
- Listed in NACE MR0175 / ISO 15156
- Certification
- EN 10204 3.1 standard, 3.2 third-party witnessed on request
- Class approvals held
- CCS, BV, DNV, LR and NK
- Forged by
- Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu Province, China
Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from ASTM and EN specifications for UNS N08031 / 1.4562 and from published producer data sheets. Nicrofer is a registered trademark of VDM Metals. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with the trademark holder and the name appears here only to identify an equivalent specification.
What X1NiCrMoCu32-28-7 is, and when to specify it
X1NiCrMoCu32-28-7 sits between the stainless steels and the nickel alloys. Iron is still the largest single element by weight, so the grade is classified and priced as a high-alloy stainless. At 30 to 32% nickel it behaves far more like Alloy 825 than like 316L. Buyers pick it for that reason: most of the corrosion performance of a nickel alloy, at a lower price per kilogram.
Four elements do the work.
Chromium at 26 to 28% builds the passive film. That is what copes with oxidising acids such as nitric, and with the oxidising contaminants normally found in industrial sulfuric acid.
Molybdenum at 6 to 7% carries the pitting and crevice resistance in chloride service, and adds resistance to reducing acids.
Copper at 1.0 to 1.4% is there for sulfuric and phosphoric acid. It holds the corrosion potential in the passive range under reducing conditions, where copper-lean 6Mo grades lose their film.
Nitrogen at 0.15 to 0.25% raises yield strength, keeps the austenite stable against sigma phase during hot work, and counts directly towards PREN.
Carbon is kept under 0.015%, so sensitisation is not a practical problem in welded or hot-worked sections. There is no precipitation hardening in this alloy. All the strength comes from the solid solution and from nitrogen, and the only heat treatment is a solution anneal.
When to specify it
Specify this grade when a 6Mo super-austenitic such as UNS S31254 or N08367, or a 904L, is being attacked in service, and a nickel-base alloy like Hastelloy® C-276 cannot be justified on price. The triggers we see most often on enquiries are sulfuric acid above roughly 70% or at raised temperature, phosphoric acid carrying fluorides and chlorides, FGD condensate, and chloride-bearing streams where 316L or duplex has already cracked.
If the service is straight reducing hydrochloric acid, or wet chlorine, this is the wrong material and a nickel-base alloy is the right answer. X1NiCrMoCu32-28-7 is the economic choice for mixed oxidising and reducing acid duty, not for the extremes at either end.
Chemical composition of X1NiCrMoCu32-28-7 (UNS N08031)
Composition limits for UNS N08031 / W.Nr. 1.4562, in weight percent. The four highlighted rows are the additions that separate this grade from an ordinary 6Mo super-austenitic.
| Element | Minimum % | Maximum % | What it does |
|---|---|---|---|
| Nickel (Ni) | 30.0 | 32.0 | Stabilises the austenite. Resists chloride stress-corrosion cracking and reducing acids |
| Chromium (Cr) | 26.0 | 28.0 | Forms the passive oxide film. Handles oxidising acids and sulfuric acid |
| Molybdenum (Mo) | 6.0 | 7.0 | Pitting and crevice resistance in chlorides, plus resistance to reducing media |
| Copper (Cu) | 1.0 | 1.4 | The addition that makes the grade work in sulfuric and phosphoric acid |
| Nitrogen (N) | 0.15 | 0.25 | Raises yield strength and PREN, suppresses sigma phase |
| Iron (Fe) | Balance | Base element. Keeps the grade below nickel-base pricing | |
| Carbon (C) | — | 0.015 | Held very low to prevent carbide sensitisation at grain boundaries |
| Silicon (Si) | — | 0.30 | Deoxidiser, restricted to protect hot workability |
| Manganese (Mn) | — | 2.00 | Deoxidiser, increases nitrogen solubility |
| Phosphorus (P) | — | 0.020 | Residual limit |
| Sulfur (S) | — | 0.010 | Kept low for hot workability and toughness |
Source: Jiangyin Jiangnan Metal Co., Ltd. Composition limits for UNS N08031 / EN 1.4562. Because the steel is melted here, chemistry is verified at the furnace by optical emission spectrometry rather than taken from a supplier certificate. Every heat carries a ladle analysis on the mill certificate, and product analysis on the finished forging can be added if you ask for it on the order.
PREN of X1NiCrMoCu32-28-7
PREN = %Cr + 3.3 × %Mo + 16 × %N
Minimum composition: 26.0 + 3.3(6.0) + 16(0.15) = 48.2
Mid composition: 27.0 + 3.3(6.5) + 16(0.20) = 51.7
Maximum composition: 28.0 + 3.3(7.0) + 16(0.25) = 55.1
For context, 316L comes out near 24, 904L near 34, and the 6Mo grades near 43 to 45. The guaranteed 48 minimum is usually the number that decides the specification. One caution when you compare datasheets: some producers use a 30 × N coefficient rather than 16, which flatters a nitrogen-alloyed grade like this one. Check which convention the other document used before you compare figures.
Mechanical properties of X1NiCrMoCu32-28-7 forgings
Specified minimums, solution annealed
These are the room-temperature values a mill certificate has to meet for solution-annealed N08031. They are minima. Acceptance is against whichever specification the purchase order names.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength Rm, min | 650 MPa | 94 ksi |
| Yield strength Rp0.2, min | 276 MPa | 40 ksi |
| Elongation A, min | 40 % | 40 % |
| Impact, Charpy-V at −196 °C | 140 J min | 103 ft·lb min |
| Hardness, max | 100 HRB (about 220 HB) | 100 HRB |
Source: Jiangyin Jiangnan Metal Co., Ltd. Published minima for solution-annealed UNS N08031. Forgings ordered to ASTM B564, B581 or B649 are tested to the requirements of the specification cited on the order. Our in-house impact rig runs to −60 °C; testing at −196 °C is placed with an accredited third-party laboratory and the report is issued with the mill certificate.
Typical as-delivered values
Annealed forgings normally test above the specified minimums. The figures below come from our own production records and move around with section thickness, reduction ratio and quench rate.
| Property | Typical range (metric) | Typical range (imperial) |
|---|---|---|
| Tensile strength | 680 to 780 MPa | 99 to 113 ksi |
| Yield strength 0.2 % | 320 to 400 MPa | 46 to 58 ksi |
| Elongation | 45 to 60 % | 45 to 60 % |
| Reduction of area | 55 to 75 % | 55 to 75 % |
| Hardness | 170 to 210 HB | 170 to 210 HB |
Source: Jiangyin Jiangnan Metal Co., Ltd. production records. Typical values are for design screening. The mill test certificate issued with each forging governs acceptance.
On heavy sections. Nitrogen-alloyed super-austenitics lose yield strength as the section gets heavier, because the quench rate at the core drops off. On anything above roughly 200 mm ruling section, tell us on the enquiry where you want the test piece taken from and in which orientation. Agreeing the sampling plan before the material is cut saves an argument later.
Physical properties of X1NiCrMoCu32-28-7
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.05 g/cm³ | 0.29 lb/in³ |
| Melting range | 1330 to 1370 °C | 2426 to 2498 °F |
| Modulus of elasticity, 20 °C | about 195 GPa | about 28.3 × 10⁶ psi |
| Specific heat, 20 °C | about 450 J/kg·K | about 0.11 Btu/lb·°F |
| Thermal conductivity, 20 °C | about 11 W/m·K | about 76 Btu·in/ft²·h·°F |
| Mean thermal expansion, 20 to 100 °C | about 14.5 µm/m·K | about 8.1 × 10⁻⁶ in/in·°F |
| Electrical resistivity, 20 °C | about 1.00 µΩ·m | about 602 Ω·circ mil/ft |
| Relative magnetic permeability, 20 °C | about 1.001 | essentially non-magnetic |
Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from published producer data for UNS N08031 / 1.4562. Values given as approximate are nominal and are not certified acceptance criteria.
Corrosion performance: what the grade is bought for
Sulfuric acid
This is the duty the grade was developed for. The 26 to 28% chromium and 1.0 to 1.4% copper together give workable rates across the whole concentration range at moderate temperature, including the 70 to 96% band that defeats most stainless grades. Oxidising contaminants such as ferric or cupric ions, which make life worse for copper-free grades, generally help here by keeping the film passive.
Phosphoric acid
Wet-process phosphoric acid carries fluorides, chlorides and abrasive solids, and parts usually fail by erosion-corrosion rather than by uniform loss. This alloy stands up to both, so it turns up in evaporator hardware, filters and agitators in fertiliser plants.
Chlorides, pitting and crevice attack
With PREN of 48 or better, the critical pitting temperature in ferric chloride testing sits comfortably above that of the 6Mo grades. In service terms it handles seawater, brackish cooling water and chloride-contaminated process streams at temperatures where 254 SMO® or AL-6XN® are at their limit.
Chloride stress-corrosion cracking
At 30 to 32% nickel the alloy is effectively immune to the chloride stress-corrosion cracking that finishes off 304 and 316 in hot chloride service. On some jobs that is the only reason for the selection, quite apart from any acid resistance.
Other media
The grade also gets used in chlorine dioxide bleaching in pulp and paper, in nitric acid and mixed nitric-hydrofluoric pickling, in flue gas desulfurisation condensate and in hydrometallurgical leaching circuits. It is listed in NACE MR0175 / ISO 15156 for sour service, subject to the environmental limits set out in that standard.
Corrosion data is not a guarantee. Published rates come from controlled laboratory media. Real plant streams have contaminants, velocity gradients, crevices and thermal cycling that a laboratory coupon never sees. Testing in the actual service medium stays with the design authority. We supply material to specification and do not warrant service life.
X1NiCrMoCu32-28-7 compared with the alternatives
These five grades get weighed against each other on most acid and chloride jobs. The table sets out where they differ.
| Criterion | 904L | Alloy 28 | 6Mo (254 SMO / AL-6XN) | X1NiCrMoCu32-28-7 | Hastelloy C-276 |
|---|---|---|---|---|---|
| UNS number | N08904 | N08028 | S31254 / N08367 | N08031 | N10276 |
| Nickel, % | 23 to 28 | 30 to 32 | 17.5 to 25 | 30 to 32 | balance, about 57 |
| Chromium, % | 19 to 23 | 26 to 28 | 19.5 to 22 | 26 to 28 | 14.5 to 16.5 |
| Molybdenum, % | 4 to 5 | 3 to 4 | 6 to 7 | 6 to 7 | 15 to 17 |
| Copper, % | 1 to 2 | 0.6 to 1.4 | 0.5 to 0.75 | 1.0 to 1.4 | — |
| PREN, approx. | 34 | 38 | 43 to 45 | 48 to 55 | about 70 |
| Sulfuric acid | Good at moderate concentration | Very good, wide range | Moderate, copper-lean | Very good across the range | Excellent in reducing conditions |
| Chloride pitting | Moderate | Moderate | Good | Very good | Excellent |
| Chloride SCC | Good | Very good | Very good | Very good | Excellent |
| Relative material cost | Low | Moderate | Moderate | Moderate to high | High |
| Specify it when | Mild acid duty, cost driven | Sulfuric duty, lower chlorides | Chloride duty without strong acid | Acid and chloride together, 6Mo marginal | Reducing HCl or wet chlorine |
Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from published composition limits for each UNS grade. The qualitative corrosion rankings are for screening and do not replace testing in the service medium. 254 SMO is a registered trademark of Outokumpu, AL-6XN of ATI, Hastelloy of Haynes International. These marks appear here only to identify equivalent specifications.
As a rule of thumb, X1NiCrMoCu32-28-7 earns its price where the process combines an aggressive acid with real chloride content and a 6Mo grade has already proved marginal in service.
We forge all five of these grades, so the comparison is not written to push you towards one of them. If you are undecided, send the process conditions with the enquiry and we will say which we would quote.
X1NiCrMoCu32-28-7 equivalent designations
| System | Designation |
|---|---|
| EN / DIN name | X1NiCrMoCu32-28-7, also written X1NiCrMoCu 32-28-7 |
| Werkstoff Nr. (Germany) | 1.4562 |
| UNS (USA) | N08031 |
| Common short name | Alloy 31 |
| Producer trade name | Nicrofer® 3127 hMo (VDM Metals) |
| Sour service listing | NACE MR0175 / ISO 15156 |
| Pressure-vessel approval | VdTÜV Werkstoffblatt 509, SEW 400 |
| Line pipe | API 5LD, for clad and lined pipe |
Source: Jiangyin Jiangnan Metal Co., Ltd. Where a code case or design registration is involved, order to the UNS number and the product specification, and confirm the equivalence against the mill certificate.
Do not confuse 1.4562 with 1.4563. W.Nr. 1.4563 is X1NiCrMoCu31-27-4, that is Alloy 28 / UNS N08028, and it carries only 3 to 4% molybdenum. One digit apart in the Werkstoff number, but a different alloy with roughly ten points less PREN. We see the two mixed up on enquiries and in published datasheets often enough to be worth the warning. Check the UNS number.
Applicable standards by product form
| Product form | ASTM | ASME |
|---|---|---|
| Forgings, our core product | B564, B649, B581 | SB-564, SB-649, SB-581 |
| Rod, bar and wire | B581, B649 | SB-581, SB-649 |
| Plate, sheet and strip | B625 | SB-625 |
| Seamless pipe and tube | B622 | SB-622 |
| Welded pipe and tube | B619, B626 | SB-619, SB-626 |
| Fittings | B366 | SB-366 |
| European approvals | VdTÜV 509, SEW 400, EN 10088 and EN 10028-7 as applicable | |
Source: Jiangyin Jiangnan Metal Co., Ltd. Whether a given ASTM specification applies to a particular forging depends on size, form and the purchase order. Confirm the governing specification with us before placing the order.
For pressure-retaining design the alloy is approved for wall temperatures from −196 °C to 550 °C. Outside that range the design authority should confirm allowable stresses against the governing code.
X1NiCrMoCu32-28-7 forgings we produce
Everything below is forged to your drawing or dimensional sketch. Open-die work needs no dies, so single pieces and prototypes are economic. Minimum order is 10 kg with no minimum piece count, and there is no tooling charge.
Size and weight capability
| Product form | Dimensional range | Unit weight |
|---|---|---|
| Seamless rolled rings | OD 200 to 3,000 mm on the 3 m radial-axial mill | 20 to 8,000 kg |
| Round bars and billets | Ø80 to 800 mm, length to 6,000 mm | 20 to 6,000 kg |
| Discs and tube sheets | Ø200 to 2,500 mm, thickness to 600 mm | 30 to 10,000 kg |
| Shafts, sleeves and blocks | to 6,000 mm long | to 10,000 kg |
| Plant envelope, all grades | Ring OD to 6,000 mm on the 6 m mill; turned length to 14,000 mm; machined diameter to 5,000 mm; bored to Ø1,600 × 10,000 mm | to 30,000 kg single piece |
Source: Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu Province, China. The last row is the plant maximum across all grades, set by a 60 t melt, a 6,300 t press and a 6 m ring mill. For X1NiCrMoCu32-28-7 the practical ceiling is lower than that, because quench rate through the section governs corrosion performance rather than press capacity. Ask before designing to the plant maximum in this grade. Machining allowance is normally 6 to 20 mm per surface depending on section size, unless your drawing says otherwise.
How we melt and forge X1NiCrMoCu32-28-7
- Melting and refiningHeats run through the 25 t electric arc furnace and a ladle furnace, then vacuum oxygen decarburisation, which is the route that gets carbon under 0.015% while holding nitrogen in the 0.15 to 0.25% window. Protective-atmosphere electroslag remelting on the 3 t and 6 t furnaces is available where the order calls for lower segregation or tighter nitrogen control.
- Heat verificationLadle chemistry is checked by optical emission spectrometry against the UNS N08031 limits before any material is cast, with particular attention to the Mo, Cu and N windows that define the grade.
- Open-die forgingForged between 1200 and 1050 °C on hydraulic presses of 2,000 to 6,300 t, with a controlled reduction ratio to close porosity and develop grain flow that follows the part contour. Rings are ring-rolled seamless on radial-axial mills. We avoid finishing below 1050 °C because of the intermetallic precipitation risk in a 7% Mo alloy.
- Solution annealingHeld at 1150 to 1180 °C in a high-temperature car-bottom furnace, then quenched faster than 150 °C per minute down through 500 °C. This dissolves any sigma and chi phase formed during forging and restores full corrosion resistance. There is no ageing step. Long shafts are quenched vertically in the 15 m well furnaces so they do not distort.
- Descaling and picklingScale is removed and the surface pickled so the passive film reforms cleanly on delivered material.
- Rough or finish machiningTurned, bored, drilled and faced to your drawing, with the agreed machining allowance or to final dimensions.
- Non-destructive testingUltrasonic examination to EN 10228-3, SEP 1921, ASTM A388 or your nominated class. Magnetic particle, liquid penetrant and dimensional inspection as required.
- Certification and despatchEN 10204 3.1 mill certificate as standard, 3.2 witnessed by BV, DNV, LR, SGS, TÜV or your own inspector on request. Traceability runs from the melt number, not from a purchased billet. Hard stamped, preserved and packed for sea or air freight.
Why the quench rate matters here. At 6 to 7% molybdenum this alloy will throw sigma and chi phase if it cools slowly through the 1000 to 600 °C range. Those phases pull chromium and molybdenum out of the surrounding matrix and drop the local pitting resistance sharply. A heavy forging that has been annealed but cooled too slowly can pass every mechanical test on the certificate and still pit in service. Quench rate is the controlling variable on thick sections, which is the reason we ask for section thickness at the enquiry stage.
Where X1NiCrMoCu32-28-7 forgings are used
| Industry | Components forged in X1NiCrMoCu32-28-7 |
|---|---|
| Sulfuric acid plants | Acid cooler and heat exchanger tube sheets, distributor and pump components, forged valve bodies, nozzles, flanges, blind covers |
| Phosphoric acid and fertiliser | Evaporator hardware, agitator and pump shafts, filter components, forged rings and discs for reaction vessels |
| Flue gas desulfurisation | Absorber spray header and nozzle forgings, damper shafts, pump casings, wear rings |
| Seawater and desalination | Seawater exchanger tube sheets and shell flanges, pump shafts and sleeves, valve components |
| Oil and gas | Wellhead and Christmas tree components, subsea hardware, valve bodies and stems for sour service under NACE MR0175 |
| Pulp and paper | Chlorine dioxide bleach plant hardware, digester components, forged shafts and bushings |
| Hydrometallurgy and mining | Autoclave internals, leach circuit agitator shafts, forged rings and discs for ore processing |
| Pressure vessels and exchangers | Forged tube sheets, girth rings, shell flanges and blind ends for exchangers, columns and towers |
| Pickling and metal finishing | Pickling line rolls, tank hardware, forged rolls and bushings exposed to mixed acid |
Source: Jiangyin Jiangnan Metal Co., Ltd., drawn from customer orders and from published industry use of UNS N08031. Suitability for any specific service has to be confirmed by the design authority.
Testing, inspection and certification
The works holds CCS, BV, DNV, LR and NK classification society approvals and runs its own laboratory. Because the steel is melted here, chemistry is verified at the furnace rather than taken from a supplier certificate.
In house
- Chemical analysis. Optical emission spectrometry on every heat to ASTM E415, infrared carbon and sulphur analysis to ASTM E1019, and handheld PMI on the finished part.
- Tensile testing. 600 kN and 300 kN universal testing machines to ASTM A370 and ISO 6892.
- Impact testing. Charpy V-notch with a low-temperature bath down to −60 °C, to ASTM A370.
- Hardness. Portable Leeb testing to ASTM A956, converted per ASTM E140.
- Ultrasonic testing. Digital flaw detectors to ASTM A388 and EN 10228-3, to SEP 1921 class C, D or E or your nominated acceptance class.
- Magnetic particle. To ASTM E709, with an industrial endoscope for bore inspection.
- Metallography. Grain size to ASTM E112, plus an intermetallic phase check on heavy sections where sigma is a concern.
Placed with an accredited third-party laboratory
Some order-specific tests are not run here. The report is issued alongside the mill certificate. State the requirement on the enquiry so it is scheduled before shipment rather than added afterwards.
- Intergranular corrosion. ASTM A262 practice as agreed, or ASTM G28 method A for this alloy class.
- Pitting and crevice testing. ASTM G48 method A or C, including critical pitting temperature determination.
- Impact below −60 °C. Including the −196 °C Charpy value quoted in Table 2.
- Bench hardness. Brinell or Rockwell where the specification requires a bench machine rather than a portable instrument.
Certification
EN 10204 3.1 mill test certificate as standard, showing heat number, chemical analysis, mechanical results, heat treatment record and NDT results. EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TÜV or your own inspector is available on request at order stage. Heat-treatment charts, NDT reports, dimensional reports and PMI records are supplied as supporting documents.
Calculators for X1NiCrMoCu32-28-7
Two calculators, free to use. Both run in your browser, and nothing is sent anywhere.
PREN calculator
Pitting resistance equivalent number. The defaults are the mid-range composition of X1NiCrMoCu32-28-7.
PREN = %Cr + 3.3 × %Mo + coefficient × %N. Use 16 when comparing against published values unless the source says otherwise.
Forging weight calculator
Rough weight of an X1NiCrMoCu32-28-7 forging at 8.05 g/cm³, so you can sense-check a budget enquiry before sending a drawing.
Gross forged weight, before machining allowance. Add your machining stock to each dimension first. Indicative only.
Frequently asked questions about X1NiCrMoCu32-28-7
What is X1NiCrMoCu32-28-7?
X1NiCrMoCu32-28-7 is the EN designation for a super-austenitic stainless steel with 30 to 32% nickel, 26 to 28% chromium, 6 to 7% molybdenum, 1.0 to 1.4% copper and 0.15 to 0.25% nitrogen, carbon under 0.015%, iron as the balance. It carries Werkstoff number 1.4562 and UNS number N08031, and most people call it Alloy 31. The name encodes the composition: X marks a high-alloy steel, 1 is the nominal 0.01% carbon, and 32-28-7 gives the approximate nickel, chromium and molybdenum contents in that order.
Is it a stainless steel or a nickel alloy?
Strictly it is a super-austenitic stainless steel, since iron is still the largest single element by weight. In practice it gets catalogued alongside nickel alloys, because 30 to 32% nickel and its corrosion behaviour put it closer to Alloy 825 or Alloy 28 than to any 300-series stainless. Both classifications appear in the literature. For ordering, use UNS N08031 or W.Nr. 1.4562 and the classification stops mattering.
What is the PREN of X1NiCrMoCu32-28-7?
Using PREN = %Cr + 3.3 × %Mo + 16 × %N, the minimum composition gives 48.2, the mid composition about 51.7 and the maximum composition about 55.1. A guaranteed PREN of 48 is the figure normally quoted. Some producers publish PREN with a 30 × N coefficient, which returns a much higher number for a nitrogen-alloyed grade, so check the convention before you compare datasheets.
What is the difference between 1.4562 and 1.4563?
They are different alloys. W.Nr. 1.4562 is X1NiCrMoCu32-28-7 / UNS N08031 / Alloy 31, with 6 to 7% molybdenum. W.Nr. 1.4563 is X1NiCrMoCu31-27-4 / UNS N08028 / Alloy 28, with 3 to 4% molybdenum. The extra molybdenum in 1.4562 buys markedly better pitting and crevice resistance and roughly ten more points of PREN. Check the UNS number, not the Werkstoff number, if there is any doubt.
What heat treatment is correct for these forgings?
Solution annealing at 1150 to 1180 °C, then rapid cooling, faster than about 150 °C per minute down through 500 °C. The alloy is a solid-solution grade and is not precipitation hardened, so there is no ageing step. The anneal dissolves the sigma and chi phases formed during hot working, and the fast quench stops them re-forming. On heavy sections the achievable quench rate at the core is the limiting factor, and it is worth discussing at the enquiry stage.
Can X1NiCrMoCu32-28-7 be welded?
Yes. Weldability is good by GTAW, GMAW and SMAW. Matching UNS N08031 filler is available, and over-alloyed nickel-base filler of the ERNiCrMo-13 type (Alloy 59) is often specified instead, so that the weld metal is not the weakest link in corrosion terms. Keep heat input and interpass temperature low.
One thing to avoid: do not apply a post-weld heat treatment below the solution annealing temperature. An intermediate-temperature stress relief will precipitate intermetallic phase and leave the joint with worse corrosion resistance than it started with.
What is the maximum service temperature?
For pressure-retaining parts the approved wall temperature range is −196 to 550 °C. The upper limit comes from intermetallic phase precipitation rather than oxidation. Sustained exposure between roughly 600 and 900 °C will embrittle the alloy and cost it corrosion resistance. For genuinely high-temperature service, Alloy 800HT or Inconel 617 is the correct selection. This grade is bought for corrosion resistance, not heat resistance.
How does it compare with 6Mo grades such as 254 SMO or AL-6XN?
Molybdenum content is similar at 6 to 7%, but X1NiCrMoCu32-28-7 carries a good deal more chromium (26 to 28% against roughly 20%), more nickel (30 to 32% against 18 to 25%) and about twice the copper. That gives PREN around 48 to 55 against 43 to 45, better sulfuric and phosphoric acid resistance, and more margin against chloride stress-corrosion cracking. It costs more. The usual decision point is a 6Mo installation that has pitted or suffered acid attack and needs an upgrade without moving to a nickel-base alloy.
What sizes can you supply?
Seamless rolled rings from 200 to 3,000 mm outside diameter on the 3 m mill. Round bars from 80 to 800 mm diameter, up to 6,000 mm long. Discs and tube sheets to 2,500 mm diameter and 600 mm thick. Shafts, sleeves and blocks to 6,000 mm long and 10,000 kg.
The plant itself goes further, to 6,000 mm ring outside diameter and 30,000 kg single piece, but in this grade the limit is usually the quench rate through the section rather than the press. Ask before designing a heavy section in X1NiCrMoCu32-28-7. Minimum order is 10 kg, with no minimum piece count.
Do you supply a material certificate?
Every forging ships with an EN 10204 3.1 mill test certificate as standard, showing heat number, chemical analysis, mechanical results, heat treatment record and NDT results. EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TÜV or your own inspector is available if you ask for it at order stage. Corrosion test reports to ASTM G28 or G48 come from an accredited third-party laboratory and are issued with the certificate.
How long does an X1NiCrMoCu32-28-7 forging take?
Lead time across the plant runs 20 to 60 days from order confirmation. This grade sits in the upper half of that range, because the vacuum decarburisation step, the slower forging schedule and the high-temperature solution treatment all add days. An electroslag remelting requirement, heavy machining or third-party witnessed inspection push it further. Send the drawing and we will confirm a firm date with the quotation.
Do you melt your own steel, or buy billet?
We melt it. The works has run its own furnaces since 1997: a 25 t electric arc furnace, 25 t and 50 t ladle furnaces, 30 t and 60 t vacuum oxygen decarburisation units, medium-frequency induction furnaces, and vacuum induction, vacuum arc and protective-atmosphere electroslag remelting for clean and superalloy grades. Maximum heat size is 60 tonnes.
For a grade like X1NiCrMoCu32-28-7 that matters twice over. The chemistry can be aimed at the forging it will become instead of accepted as delivered, and the certificate traces the part back to its melt number rather than stopping at a purchased billet.
Who supplies open-die forged X1NiCrMoCu32-28-7 parts in China?
Jiangyin Jiangnan Metal Co., Ltd. is an integrated melting works and open-die forge at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997. We forge X1NiCrMoCu32-28-7 (Alloy 31 / UNS N08031) along with other nickel alloys, stainless steels, tool steels, alloy steels and carbon steels into seamless rolled rings, flanges, bars, discs, shafts, sleeves, bushings and tube sheets, and we export to North America, Europe, the Middle East and Asia-Pacific. Enquiries to sales@steelforgepieces.com or +86 189 2135 9659.
Sources and revision
Technical content on this page is maintained by the metallurgical engineering staff at Jiangyin Jiangnan Metal Co., Ltd., an integrated melting works and open-die forge in Jiangyin, Jiangsu Province, China. Composition, mechanical and physical data are checked against ASTM B564, B581, B625 and B649, VdTÜV Werkstoffblatt 509, NACE MR0175 / ISO 15156 and published producer literature for UNS N08031 / 1.4562. First published 18 May 2016. Last revised 1 September 2026.
To reference this page: Jiangyin Jiangnan Metal Co., Ltd. (2026). X1NiCrMoCu32-28-7 (Alloy 31 / UNS N08031) Forgings: Chemistry, Properties and Manufacturing. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/X1NiCrMoCu32-28-7.html
Request a quotation for X1NiCrMoCu32-28-7 forgings
Send a drawing, a sketch, or just the dimensions and quantity. Quotations normally come back within two working days. Minimum order is 10 kg, there is no minimum piece count and no tooling charge for open-die work.
Useful details if you have them: grade and standard (X1NiCrMoCu32-28-7 / UNS N08031 / ASTM B564), product form, dimensions with machining allowance, quantity, delivery condition, section thickness, NDT class, certificate type (EN 10204 3.1 or 3.2), any corrosion testing required, and the destination port.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Integrated melting works, open-die forge and ring rolling mill, established 1997
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone / WhatsApp
- +86 189 2135 9659 (0086-189-2135-9659)
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Business hours
- Monday to Saturday, 08:00 to 17:30 China Standard Time (UTC+8)