# X3CrNiMoNbN23-17 (Material 1.3974) Open-Die Forgings **X3CrNiMoNbN23-17 is a supplier designation for material number 1.3974, standardised as X2CrNiMnMoNNb23-17-6-3 in SEW 390. It is a non-magnetizable austenitic Cr-Ni-Mo-N stainless steel.** The Applus+ materials portal records X3CrNiMoNbN23-17 as a trade name used by Heine + Beisswenger against that material number. Supplied by Jiangyin Jiangnan Metal Co., Ltd., an integrated steel melting works and open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997. Telephone +86 189 2135 9659. Email sales@steelforgepieces.com. Approvals: CCS, BV, DNV, LR, NK. HTML version: https://www.steelforgepieces.com/Stainless-Steel/X3CrNiMoNbN23-17.html ## Grade record | Field | Detail | |---|---| | Material number | 1.3974 | | Standard designation | X2CrNiMnMoNNb23-17-6-3 | | Specification | SEW 390 : 1991-11, WL 1.3974 | | Trade name | X3CrNiMoNbN23-17 | | Nickname | Submarine steel | | Microstructure | Austenitic, nonmagnetizable | | Relative magnetic permeability | below 1.01 | | Density at 20 C | 7.90 kg/dm3 | | Seawater resistance | up to approximately 60 C | | Application temperature | up to 400 C | | VDA 231-106 classification | 1.1.2 | | Delivery condition | Solution annealed | ## Chemical composition, percent by mass | C | Si | Mn | P | S | Cr | Ni | Mo | N | Nb | |---|---|---|---|---|---|---|---|---|---| | max 0.03 | max 1.00 | 4.50-6.50 | max 0.025 | max 0.010 | 21.0-24.5 | 15.5-18.0 | 2.80-3.40 | 0.30-0.50 | 0.10-0.30 | Balance iron. Einsal additionally lists tungsten 0.10 to 0.30 percent; Remystahl narrows the chromium minimum to 21.5 percent. Pitting resistance equivalent calculated from these limits with PRE = Cr + 3.3 Mo + 16 N falls between about 35 and 44. This is arithmetic, not a measured value. Deutsche Edelstahlwerke notes for the sister grade 1.3964 that high manganese can reduce actual pitting resistance below the calculated figure, so warm chloride service should be confirmed by ASTM G48 test. ## Comparison with the grades it is confused with | Grade | C | Mn | Cr | Ni | Mo | N | Nb | |---|---|---|---|---|---|---|---| | 1.3974 X2CrNiMnMoNNb23-17-6-3 | max 0.03 | 4.50-6.50 | 21.0-24.5 | 15.5-18.0 | 2.80-3.40 | 0.30-0.50 | 0.10-0.30 | | 1.3964 X2CrNiMnMoNNb21-16-5-3 | max 0.03 | 4.00-6.00 | 20.0-21.5 | 15.0-17.0 | 3.00-3.50 | 0.20-0.35 | max 0.25 | | XM-19 to ASTM A479 | max 0.06 | 4.0-6.0 | 20.0-23.5 | 11.5-13.5 | 1.5-3.0 | 0.20-0.40 | 0.10-0.30 | 1.3964 and XM-19 data as published by Deutsche Edelstahlwerke and voestalpine Specialty Metals. 1.3974 carries the highest nickel and nitrogen of the three and is not interchangeable with either without the buyer's written agreement. ## Mechanical properties, solution annealed, room temperature Published supplier figures differ by product form and section size. Both bands are given rather than averaged. | Property | Remystahl, 1.3974.9 bar 18-50 mm | Nicromal and Einsal, general | |---|---|---| | Tensile strength Rm | 700-900 N/mm2 | 800-1050 MPa | | 0.2 % proof stress Rp0.2 | min 450 N/mm2 | not published | | Elongation A5 | min 25 % | not published | | Impact energy ISO-V | min 100 J | not published | | Hardness | approx. 280 HB | max 341 HBW | | Magnetizability | none | relative permeability below 1.01 | ## Physical properties | Property | Value | |---|---| | Density at 20 C | 7.90 kg/dm3 | | Thermal conductivity at 20 C | 13.5 W/m K | | Electrical resistivity at 20 C | 0.70 ohm mm2/m | | Mean thermal expansion 20-100 C | 15.5 x 10-6 /K | | Mean thermal expansion 20-400 C | 17.3 x 10-6 /K | Source: Einsal and the Applus+ materials portal datasheets for material 1.3974. ## Corrosion, welding, machining and hot working Applus+ states that 1.3974 resists seawater up to about 60 C, resists stress corrosion cracking and intercrystalline corrosion, keeps intercrystalline resistance in the welded condition, has very good resistance to eroding corrosion, and is weldable. Nicromal and Remystahl also cite pitting resistance. **Welding.** Carbon capped at 0.03 percent with niobium stabilisation suppresses chromium carbide precipitation. Use a nitrogen-bearing filler of matching or higher alloy content and keep heat input controlled. **Machining.** Sources disagree. Applus+ describes cutting properties as good; Nicromal states the high manganese and nitrogen make the material difficult to machine. Deutsche Edelstahlwerke publishes a guideline for the sister grade 1.3964 with coated carbide tooling: 6 mm depth of cut at 0.5 mm/rev and 110 m/min, through to 1 mm at 0.2 mm/rev and 150 m/min. Plan for work hardening. **Hot working.** The Deutsche Edelstahlwerke schedule for 1.3964 is a soak at 950 to 1150 C, forging between 900 and 1100 C, then rapid cooling in air or water to avoid unwanted phases. A comparable window is used for 1.3974 and confirmed against the customer specification. Precipitation behaviour in this steel has been studied since Brandis, Heimann and Schmidtmann reported on the effect of nitrogen in X3CrNiMoNbN23-17 in TEW-Technische Berichte in 1976. Slow cooling through the intermediate range costs both toughness and intercrystalline corrosion resistance. ## Forged products and size envelope | Product | Size limit | Set by | |---|---|---| | Seamless rolled rings | OD 50 mm up to OD 6,000 mm | 6 m, 3 m and 1 m radial-axial ring mills | | Forged rings, retaining rings, valve seat rings | outside the ring-mill envelope | 6,300 t, 4,000 t and 2,000 t presses | | Flanges, weld neck and blind | to drawing, ASME B16.5 and B16.47 profiles | Press and ring mill | | Discs, tube sheets, covers | up to 5,000 mm machined diameter | 5,000 mm vertical turning lathe | | Shafts, spindles, rotors | up to 14,000 mm turned length | C61160 lathe; 15 m well furnace for vertical quenching | | Bored cylinders, sleeves, bushings | up to 1,600 mm dia x 10,000 mm | CNC deep-hole drilling machine | | Round, flat and square bars, blocks | to drawing | Presses and hammers 750 kg to 5 t | | Single piece weight | up to 30,000 kg | 60 t maximum heat, 6,300 t press | Minimum order 10 kg, no minimum piece count. Lead time 20 to 60 days. Holding nitrogen between 0.30 and 0.50 percent is a melting problem before it is a forging problem. This works runs 30 t and 60 t vacuum oxygen decarburisation units for stainless and duplex grades, and 3 t and 6 t protective-atmosphere electroslag furnaces used for clean and nitrogen-alloyed grades. A forge that buys billet inherits whatever nitrogen its supplier achieved. Delivery condition: as-forged with allowance, proof-machined for volumetric inspection, or finish-machined to drawing. Solution annealing and quenching run in 14 on-site furnaces, the largest taking 8,000 x 2,000 x 2,000 mm, with two 15 m well-type furnaces for vertical quenching of long parts. ## Testing and certification | Discipline | Equipment | Standard | |---|---|---| | Chemical analysis | SPECTROTEST TXC25 optical emission spectrometer | ASTM E415 | | Carbon and sulphur | HIR-9440D infrared analyser | ASTM E1019 | | Alloy verification | X-Mwt3000TX handheld analyser | Positive material identification | | Tensile | WE-600B 600 kN, WDW-300 | ASTM A370, ISO 6892 | | Impact | JBN-300 with DWC-60 cold bath to -60 C | ASTM A370 | | Ultrasonic | PXUT-3300, USM35XS, CTS-22 | ASTM A388, EN 10228-3 | | Magnetic particle | CYE-3A | ASTM E709 | | Metallography | XJP-6A microscope and preparation line | ASTM E112 | Placed with an accredited third-party laboratory and reported with the mill certificate: intergranular corrosion to ASTM A262 or ASTM G28, pitting resistance to ASTM G48, impact testing below -60 C. Magnetic permeability verification on the finished part is available on request. Certification to EN 10204 3.1, or EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's inspector. Works approvals: CCS, BV, DNV, LR, NK. Traceability runs from melt number to shipment because melting is on site. ## Applications - Shipbuilding and naval engineering, the dominant use, where low magnetic signature meets seawater exposure. - Seawater and offshore equipment, resistant to about 60 C and against stress corrosion cracking. - Electrical engineering, where permeability below 1.01 keeps eddy currents and field distortion out of the design. - Mechanical and plant engineering, up to the 400 C application limit. - Defence, chemical process, aerospace, medical technology and hydrogen equipment, as listed by Einsal for this material. Not the right grade for nitric acid coolers, polythionic acid refinery service or furnace baskets. Ask instead about Sanicro 28, AISI 347H or Incoloy 800H. ## Frequently asked questions ### Is X3CrNiMoNbN23-17 a DIN grade? Not as such. The material is specified in SEW 390, the Stahl-Eisen-Werkstoffblatt series, under the number 1.3974 and the name X2CrNiMnMoNNb23-17-6-3. X3CrNiMoNbN23-17 is a mill trade name recorded against that same material number by the Applus+ materials portal. Quoting SEW 390 and 1.3974 on the order is what makes the drawing and the mill certificate agree. ### Does 1.3974 stay non-magnetic after cold work? Applus+ classes 1.3974 as a nonmagnetizable steel with a relative magnetic permeability below 1.01. High nickel and high nitrogen stabilise the austenite, which is the difference between this family and an ordinary 304 that turns magnetic once it is worked. Where a numerical permeability limit appears on the drawing, state it on the order and Jiangyin Jiangnan Metal will measure and report it on the finished part. ### What are the mechanical properties of 1.3974 in the solution annealed condition? Published supplier figures differ by product form and section size. Remystahl quotes tensile strength 700 to 900 N/mm2, 0.2 percent proof stress at least 450 N/mm2, elongation A5 at least 25 percent, ISO-V impact energy at least 100 J and hardness around 280 HB for solution annealed bar of 18 to 50 mm diameter. Nicromal and Einsal quote tensile strength 800 to 1050 MPa and hardness max 341 HBW. Acceptance values for a specific forging are written into the order and verified on prolongations or sacrificial test rings. ### How does 1.3974 differ from 1.3964 and XM-19? They are three separate non-magnetic austenitic grades. 1.3974 carries 21.0 to 24.5 percent chromium, 15.5 to 18.0 percent nickel and 0.30 to 0.50 percent nitrogen. 1.3964 carries 20.0 to 21.5 percent chromium, 15.0 to 17.0 percent nickel and 0.20 to 0.35 percent nitrogen. XM-19 to ASTM A479 carries 20.0 to 23.5 percent chromium but only 11.5 to 13.5 percent nickel. 1.3974 has the highest nickel and nitrogen of the three, so substitution needs the buyer's written agreement. ### Can you roll a ring in this grade, or does it have to be upset and punched? Both routes are available on site. Rings roll on 6 m, 3 m and 1 m radial-axial mills, so the practical ceiling is 6,000 mm outside diameter. Below roughly 50 mm outside diameter, or where the section needs heavier reduction than rolling gives, the part is upset and punched on the press instead. voestalpine lists open-die forged parts and seamless rolled rings as separate delivery forms for the sister grade 1.3964, which reflects how this family is normally bought. ### What is the maximum service temperature of 1.3974? The Applus+ datasheet lists an application temperature of 400 C for material 1.3974, and seawater resistance up to about 60 C. Those are two different limits for two different exposures, and the lower one governs any part sitting in warm seawater. ### Do you hold stock of 1.3974? No. Jiangyin Jiangnan Metal is a forging works rather than a stockholder, and parts in 1.3974 are made to order from the company's own melt. Minimum order is 10 kg with no minimum piece count, so a single small ring is quotable and so is a one-off 30 tonne forging. Send the drawing to sales@steelforgepieces.com or call +86 189 2135 9659. ### What is the lead time for 1.3974 forgings? Normal lead time at this works is 20 to 60 days from order confirmation. A nitrogen-alloyed grade sits in the middle to upper part of that band because the melt needs vacuum oxygen decarburisation or protective-atmosphere electroslag remelting to hold nitrogen, and the forging and solution treatment schedules run slower than for carbon steel. Witnessed inspection to EN 10204 3.2 and outside corrosion testing should be declared at enquiry stage so they are built into the quoted date. ## Request a quotation | # | Item | Example | |---|---|---| | 1 | Grade and specification | X3CrNiMoNbN23-17 / 1.3974, SEW 390 | | 2 | Dimensions or drawing (PDF, DWG, DXF, STEP) | OD 980 x ID 720 x H 180 mm | | 3 | Quantity and repeat volume | 6 pcs, twice a year | | 4 | Delivery condition | Proof-machined | | 5 | Heat treatment and testing | Solution annealed, UT to EN 10228-3, ASTM A262 practice E, permeability check | | 6 | Certification and destination | EN 10204 3.2 witnessed by DNV, Hamburg | **Jiangyin Jiangnan Metal Co., Ltd.** No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China Telephone, WhatsApp and WeChat: +86 189 2135 9659 Email: sales@steelforgepieces.com Monday to Saturday, 08:00 to 17:30 China Standard Time (UTC+8) --- Page last reviewed 10 October 2026. Grade data drawn from published datasheets for material 1.3974 issued by the Applus+ materials portal, Einsal, Nicromal and Remystahl, and from Deutsche Edelstahlwerke and voestalpine Specialty Metals datasheets for the related grade 1.3964 where stated. Figures are informative and are not a warranty of properties. Copyright 1997 to 2026 Jiangyin Jiangnan Metal Co., Ltd.