EN 10088-2 X1NiCrMoCuN25-20-7 1.4529 Stainless Steel Plate

EN 10088-2 X1NiCrMoCuN25-20-7 1.4529 stainless steel plate is a high-alloy austenitic flat product supplied to EN 10088-2, the European standard for stainless steel sheet, plate and strip for general purposes. X1NiCrMoCuN25-20-7 contains up to 0.020 % carbon, 19.0 – 21.0 % chromium, 24.0 – 26.0 % nickel, 6.0 – 7.0 % molybdenum, 0.15 – 0.25 % nitrogen and 0.50 – 1.50 % copper. It is in effect a higher-molybdenum, nitrogen-alloyed development of 1.4539, and is often called a 6 % molybdenum or super-austenitic steel. EN 10088-2 places 1.4529 among its special grades, defined as grades for special use and/or with limited availability, and Table 7 lists it as hot rolled plate (P) up to 75 mm only, solution annealed. Table 7 rates it resistant to intergranular corrosion both as delivered and after sensitization.

SHH STEEL works as a steel sourcing partner with long-term relationships with Chinese stainless mills that roll high-alloy austenitic hot rolled plate. For large tonnages, the buyer can contract directly with a suitable mill, with SHH STEEL assisting for a modest service fee and handling follow-up and documents. For small orders we consolidate demand, so that 1 – 5 t lots are placed against genuine mill production instead of stock of unknown origin. Each shipment can be released after third-party inspection by TUV, ABS, BV, DNV, CCS or an agency the buyer nominates, and payment by TT or LC is accepted. The rest of this page covers the technical side of EN 10088-2 1.4529 and the steps we take so that the sheet that arrives is the sheet that was ordered.

The table below lists the concerns buyers raise most often when sourcing EN 10088-2 X1NiCrMoCuN25-20-7 sheet and plate from China, and how SHH STEEL deals with each of them.

1.4529 corresponds to UNS N08926 in ASTM A240. Trade names are also used for this composition: VDM Metals markets it as VDM Alloy 926 (Cronifer 1925 hMo), and these names belong to their owner. SHH STEEL orders and certifies by EN steel number and UNS number; a specific producer’s branded product has to be named and agreed in the order. For pressure equipment the grade is ordered to EN 10028-7; see EN 10028-7 1.4529 pressure vessel plate.

The ranges are the same except manganese, where EN 10088-2 is tighter (1.00 % against 2.00 %), so a 1.4529 heat normally also meets N08926. ASTM A240-22 lists N08926 with a minimum proof strength of 295 MPa, a tensile strength of 650 MPa and 35 % elongation, against 300 MPa, 650 – 850 MPa and 40 % in EN 10088-2. SHH STEEL checks both sets of values when a buyer needs dual certification.

1.4529 is also listed in EN 10028-7:2016 for pressure purposes, as is 1.4539 (EN 10028-7 1.4539 pressure vessel plate). That standard may set its own test and property requirements, which we have not reproduced here.

Edition note: the values on this page are taken from EN 10088-2:2014. A revised edition (EN 10088-2:2024) has since been published. If your contract names the newer edition, SHH STEEL checks the order against that text before production, and any difference is raised at the quotation stage rather than after rolling.

The 1.4529 chemical composition below is the cast (heat) analysis from EN 10088-2:2014 Table 1. Values are percentages by mass; a single figure is a maximum.

The 1.4529 molybdenum of 6.0 – 7.0 % and nitrogen of 0.15 – 0.25 % are what separate it from 1.4539. Phosphorus (0.030 %) and sulphur (0.010 %) limits are tighter than for the 300-series grades. SHH STEEL checks molybdenum, nitrogen, nickel and copper on every certificate as part of the 1.4529 chemical composition review.

Product analysis tolerances (EN 10088-2 Table 5)

A product analysis is a check made on the delivered sheet. It is not mandatory under EN 10088-2; it is carried out when agreed at the time of enquiry and order, and SHH STEEL can arrange it through a partner laboratory. The permissible tolerances on the cast limits are:

Where several product analyses are made on one cast, individual results may exceed the maximum or fall below the minimum, but not both for the same element. Chromium uses ± 0.20 % at the 19.0 % minimum and ± 0.25 % at the 21.0 % maximum; copper uses + 0.04 % (plus only) at the 0.50 % minimum and ± 0.10 % at the 1.50 % maximum, because Table 5 changes band at 20.0 % Cr and 1.00 % Cu. If a product analysis is required, it should be stated in the order.

The 1.4529 mechanical properties below are the room-temperature values from EN 10088-2:2014 Table 7 for austenitic steels in the solution annealed condition. Test pieces are transverse; the A80 elongation applies below 3 mm and the proportional elongation A from 3 mm.

Rp1.0 values are for guidance only. For bigger sizes than those listed, mechanical values are to be agreed at the time of enquiry and order.

EN 10088-2 lists 1.4529 as hot rolled plate only. Table 7 rates its resistance to intergranular corrosion (EN ISO 3651-2) as “yes” in both the delivery condition and the sensitized condition.

Cold worked condition (process route 2H)

EN 10088-2 Tables 19 and 20 list no cold worked (2H) strength levels for 1.4529, so the grade is ordered in the solution annealed condition (+AT). Its nitrogen content already gives a higher annealed proof strength than 1.4539.

Minimum proof strength at elevated temperature (EN 10088-2 Table 12, +AT)

EN 10088-2 Table 12 gives values for 1.4529 from 100 °C to 400 °C only, for the solution annealed condition (+AT); no values are given above 400 °C. They are minimum values for design and are not tested unless agreed.

EN 10088-2 Table A.1 gives the following guideline temperatures for 1.4529:

The footnotes to Table A.1 state that with a continuous furnace the upper part of the range is usually preferred or even exceeded, and that the lower end of the range should be aimed at when the heat treatment is part of further processing, because otherwise the mechanical properties may be affected. Solution annealing may be omitted if hot working and cooling achieve the required mechanical properties and resistance to intergranular corrosion.

The Euro Inox tables give the same 1 120 – 1 180 °C range with cooling in air or water. This is clearly higher than the 1 030 – 1 110 °C used for the 316L grades, so mixed furnace loads should be avoided. Plate is delivered as +AT.

The values below are approximate reference figures for X1NiCrMoCuN25-20-7 at room temperature, from the worldstainless “Tables of Technical Properties”, which follow EN 10088-1. They are suitable for design estimates and weight calculation; where a figure is critical, use EN 10088-1 itself.

The EN 10088-1 extract by Häuselmann and the worldstainless table both give 1.4529 a density of 8.1 g/cm³, a modulus of 195 GPa, a thermal conductivity of 12 W/(m·K) and an electrical resistivity of 1.00 Ω·mm²/m. Häuselmann lists it as not magnetisable, with the note that small amounts of ferrite and/or martensite from cold working increase magnetisability.

The Euro Inox fabrication tables list 1.4529 for marine technology, heat exchangers at up to 400 °C, and fasteners in tunnel and indoor swimming pool environments. They describe high resistance to sulphuric and phosphoric acid, also with chloride impurities, and good resistance to pitting, crevice corrosion and stress corrosion cracking. EN 10088-2 Table 7 rates its resistance to intergranular corrosion, tested to EN ISO 3651-2, as “yes” in the delivery condition and “yes” in the sensitized condition.

The lower-molybdenum, copper-richer EN 10088-2 1.4539 plate is the related standard grade; the other 6 % molybdenum grade in EN 10088-2 is EN 10088-2 1.4547 plate, with less nickel.

As EN 10088-2 notes, corrosion resistance depends strongly on the environment and cannot always be judged from laboratory tests, so experience with the grade in similar service should be used.

1.4529 is weldable by the common arc and resistance processes; as a highly alloyed, fully austenitic grade, filler choice and heat input need attention.

• The Euro Inox fabrication tables rate TIG/MIG, manual metal arc, resistance and autogenous welding as suitable for 1.4529.
• Filler materials listed include the nickel alloys 2.4621 and 2.4831 and the stainless fillers 1.4529 and 1.4539.
• EN 10088-2 Table 7 rates 1.4529 “yes” for intergranular corrosion after sensitization.
• EN 10088-2 does not specify welding procedures; these are published guidelines and general practice.

These points reflect industry practice for high-alloy austenitic stainless steels rather than requirements of EN 10088-2, which does not specify welding procedures. In the SHH STEEL workshop, plate blanks are cut with clean, burr-free edges, ready for the fabricator’s own joint preparation.

Annealed 1.4529 plate forms with standard austenitic practice, but its higher proof strength (300 MPa) means more forming force and springback than for 1.4539 of the same thickness.

Plate is cut by plasma or waterjet, or sawn. Machining needs sharp tools, rigid set-ups and positive feeds to avoid work hardening at the cut.

We run our own workshop next to the warehouse, so 1.4529 hot rolled plate and X1NiCrMoCuN25-20-7 plate blanks can be delivered cut to size or bent. Details are on our steel cutting services and bending and forming services pages.

EN 10088-2 Table 7 lists 1.4529 only as hot rolled plate (P) up to 75 mm.

For bigger sizes than those listed, the mechanical values shall be agreed at the time of enquiry and order. Under section 6.9 of the standard, EN ISO 18286 applies to individually rolled quarto plate.

SHH STEEL can supply 1.4529 super-austenitic hot rolled plate in standard sizes or cut to your drawing, after confirming availability with the mill.

Surface finish is ordered by the process route symbols of EN 10088-2 Table 6; trade names from ASTM and JIS are shown for reference. Not every route is available for every grade, and the mill confirms which ones it can supply.

EN 10088-2 Table 7 lists this grade as hot rolled plate (P) only, so the cold rolled routes 2D, 2B and 2R are not part of the standard offer and would have to be agreed separately. The No.1 cross-reference follows worldstainless and IMOA comparison tables. The Euro Inox tables give no polishability rating for 1.4529.

The usual 1.4529 equivalent is UNS N08926 in ASTM A240.

UNS N08367 is a different 6 % molybdenum alloy with lower nickel and is not a substitute without engineering approval. Because a 1.4529 heat normally meets N08926, dual certification is usually straightforward.

1.4529 vs 1.4539 and 1.4547

Compared with EN 10088-2 1.4539 plate, 1.4529 has 6.0 – 7.0 % molybdenum against 4.0 – 5.0 %, adds 0.15 – 0.25 % nitrogen and has less copper; its plate proof strength is 300 against 220 MPa. Compared with 1.4547, it has more nickel (24.0 – 26.0 % against 17.5 – 18.5 %) and the same plate proof strength in Table 7, and both are special grades.

Typical applications of 1.4529 plate listed in the Euro Inox fabrication tables include:

• Marine technology
• Heat exchangers at up to 400 °C
• Equipment for sulphuric and phosphoric acid, also with chloride impurities
• Fasteners in tunnel environments
• Fasteners in indoor swimming pool environments

For pressure equipment, 1.4529 plate is ordered to EN 10028-7; for other uses, EN 10088-2 applies.

Buyers choose 1.4529 when 1.4539 is not resistant enough to chlorides. SHH STEEL can advise when 1.4547 or a nickel alloy should be compared. For still more nickel and chromium, EN 10088-2 1.4563 plate (26.0 – 28.0 % chromium, 30.0 – 32.0 % nickel, 3.0 – 4.0 % molybdenum) is the related EN 10088-2 grade.

For 1.4529 the main risks are molybdenum or nitrogen below the EN minimums, 1.4539 or N08367 supplied instead, and the plate-only listing in EN 10088-2.

None of these steps is complicated, but they need to be agreed at the start. When you send an enquiry, tell us which of these points matters most to you, and the order will be built around it.

Every 1.4529 order is supported by documents and checks that make the material traceable to the heat:

• Cast analysis with molybdenum, nitrogen, nickel, chromium and copper checked
• Tensile test (transverse) to Table 7
• Impact test for plate over 10 mm when agreed
• Intergranular corrosion test to EN ISO 3651-2 when agreed
• Thickness, flatness and surface inspection
• Additional checks through our third-party testing service: PMI, dimensional, flatness and surface inspection

If the order does not name an inspection document, EN 10088-2 requires only a test report 2.2. Because this is rarely enough for marine, heat exchanger and acid plant equipment or export work, SHH STEEL supplies an EN 10204 3.1 inspection certificate as standard and a 3.2 certificate when an independent inspector (TUV, ABS, BV, DNV, CCS or an agency you nominate) witnesses testing and countersigns the document.

Ordering example and lead time

Following the pattern of the example in EN 10088-2, a typical order line would read: 4 plates, 10 mm × 1 500 mm × 6 000 mm, EN ISO 18286, EN 10088-2, steel X1NiCrMoCuN25-20-7 (1.4529), process route 1D, inspection certificate 3.1 to EN 10204. Mill production lead time is generally 30 – 40 days from order confirmation, depending on the rolling schedule, the size and the tests requested; because 1.4529 is a special grade, the campaign date should be confirmed at enquiry. Consolidated small lots follow the same mill schedule, and we send progress updates at rolling, testing and packing.

• Mill relationships: long-term cooperation with Chinese stainless mills helps us secure competitive pricing and steadier delivery for 1.4529 and related high-alloy austenitic grades.
• Direct mill contracts: for larger tonnages you can contract directly with a suitable mill, for a modest service fee, while we handle follow-up and documents.
• Order consolidation: 1 – 5 t lots are combined so they can be placed against genuine mill production.
• Own workshop: slitting, cut-to-length, laser cutting, bending and protective film before shipment.
• Inspection and certificates: third-party inspection by TUV, ABS, BV, DNV, CCS or your nominated agency, with EN 10204 3.1 or 3.2 certificates.
• Flexible payment: TT, LC or a combination of both.
• Port logistics: coil and sheet are packed seaworthy with heat-number labels and shipped through our worldwide shipping service, together with other grades if needed.

As a 1.4529 plate supplier SHH STEEL also stocks and sources the wider range of stainless steel sheets and plates, so mixed orders of different stainless grades can travel in one container with one set of paperwork.

EN 10088-2 X1NiCrMoCuN25-20-7 1.4529 is the 6 % molybdenum, nitrogen-alloyed high-nickel austenitic special grade, supplied as hot rolled plate up to 75 mm for marine, heat exchanger and acid plant equipment. Choosing it is the easy part. Getting genuine material that matches the certificate, in the gauge and finish your parts need and on a predictable schedule, is where a sourcing partner earns its place, and that is the work SHH STEEL does every day through long-term mill cooperation, consolidation and its own workshop.

The next step is simple. Send SHH STEEL your drawing, or an enquiry with the quantity, thickness, width, finish and delivery destination, and we will judge whether a direct mill contract or consolidation with processing fits your order better, and quote accordingly. Send your sizes and quantities for a quotation.