Grade datasheet for austenitic stainless steel. Reviewed September 2026.
1.4429 open-die forgings X2CrNiMoN17-13-3 / AISI 316LN / UNS S31653 / 022Cr17Ni12Mo2N
1.4429 is the nitrogen-alloyed, 2.5 to 3.0 % molybdenum version of 316L. Nitrogen at 0.12 to 0.22 % acts as a solid-solution strengthener, so the EN 10088-3 minimum 0.2 % proof strength is 280 MPa against 200 MPa for 1.4404 / 316L, an increase of 40 %. Carbon stays capped at 0.030 %, which is what keeps the grade resistant to intergranular attack after welding. Designers choose it when a 316L vessel or flange is thickness-limited by yield strength rather than by corrosion.
Jiangyin Jiangnan Metal melts 1.4429 in its own shop on the electric-arc, ladle-furnace and vacuum-oxygen-decarburisation route. VOD is the process that makes the 0.030 % carbon ceiling and the narrow nitrogen window controllable. The part is then forged, solution annealed, machined and tested without leaving the site. Rolled rings run to 6,000 mm outside diameter, single pieces to 30 tonnes, and the minimum order is 10 kg.
Grade record
EN 10088-3:2014 and EN 10222-5:2017- EN steel number
- 1.4429
- EN steel name
- X2CrNiMoN17-13-3
- Structure
- AusteniticNon-magnetic when solution annealed
- Delivery condition
- +AT solution annealed1020 to 1120 °C, water or air
- Rp0,2 minimum
- 280 MPa316L is 200 MPa
- Tensile Rm
- 580 to 800 MPa
- Elongation A, min
- 40 % longitudinal30 % transverse above 160 mm
- Impact KV, min
- 100 J longitudinal60 J transverse above 160 mm
- PREN
- 26.7 to 31.9Typically about 29
- Cross-references
- UNS S31653, 316LNASTM A182 F316LN, JIS SUS316LN
- Forged here to
- 30 t single pieceRings to OD 6,000 mm
- Certification
- EN 10204 3.1 or 3.2CCS, BV, DNV, LR and NK approvals
01
1.4429, 1.4406 and 316LN are not one grade
This is the most expensive misunderstanding on the material, and it usually surfaces after the heat has been melted.
Both 1.4429 (X2CrNiMoN17-13-3) and 1.4406 (X2CrNiMoN17-11-2) are cross-referenced to AISI 316LN and UNS S31653, and neither reference is wrong. The American specification permits molybdenum anywhere from 2.00 to 3.00 %, and both European grades sit inside that band. They are not the same steel.
| Grade | EN name | Mo % | Ni % | N % | PREN |
|---|---|---|---|---|---|
| 1.4429 | X2CrNiMoN17-13-3 | 2.50 to 3.00 | 11.0 to 14.0 | 0.12 to 0.22 | 26.7 to 31.9 |
| 1.4406 | X2CrNiMoN17-11-2 | 2.00 to 2.50 | 10.0 to 12.5 | 0.12 to 0.22 | 25.0 to 30.3 |
| A 1.4406 heat at 2.2 % Mo satisfies ASTM A182 F316LN and fails a 1.4429 certificate. If a drawing calls for 316LN and nothing else, settle which European number is intended before the melt is scheduled rather than at the inspection stage. | |||||
Full designation set
| System | Designation | Note |
|---|---|---|
| EN and DIN | 1.4429, X2CrNiMoN17-13-3 | EN 10088-1, -2, -3, EN 10222-5, EN 10272, EN 10269 |
| ASTM and UNS | 316LN, UNS S31653 | Forgings: ASTM A182 grade F316LN |
| JIS | SUS316LN | Japan |
| GB/T | 022Cr17Ni12Mo2N (S31653) | China. Former designation 00Cr17Ni13Mo2N |
| BS | 316S63 | United Kingdom, superseded by EN |
| AFNOR | Z3CND17-12Az | France, superseded by EN |
| Cross-references are for identification. They are not a statement that a heat meeting one specification automatically meets another. See section 02. | ||
02
Composition, and the dual-certification window
EN 10088-3:2014 and EN 10222-5:2017 specify identical cast-analysis limits for 1.4429, so a forging ordered to either standard is melted to the same aim. ASTM A182 grade F316LN is close but not congruent, and the differences decide whether one heat can carry both certificates.
| Element | EN 1.4429 | ASTM F316LN (S31653) | Dual window |
|---|---|---|---|
| C | max 0.030 | max 0.030 | max 0.030 |
| Si | max 1.00 | max 1.00 | max 1.00 |
| Mn | max 2.00 | max 2.00 | max 2.00 |
| P | max 0.045 | max 0.045 | max 0.045 |
| S | max 0.015 | max 0.030 | max 0.015 (EN governs) |
| Cr | 16.50 to 18.50 | 16.00 to 18.00 | 16.50 to 18.00 |
| Ni | 11.00 to 14.00 | 11.00 to 14.00 | 11.00 to 14.00 |
| Mo | 2.50 to 3.00 | 2.00 to 3.00 | 2.50 to 3.00 (EN governs) |
| N | 0.12 to 0.22 | 0.10 to 0.16 | 0.12 to 0.16 (both govern) |
| Fe | Balance | Balance | Balance |
| Product analysis may deviate from the cast analysis only within the tolerances of EN 10222-5:2017 Table 3. Sulphur may be restricted further by agreement where machinability or transverse toughness is critical. | |||
Nitrogen is what decides it. The dual window is only 0.04 % wide, from 0.12 to 0.16 %. A heat aimed at the middle of the EN range, around 0.17 %, is a sound 1.4429 that cannot be certified to ASTM A182 F316LN. The decision belongs in the melt shop, well before inspection. State on the enquiry whether the forging needs EN only, ASTM only, or both, and the ladle is trimmed accordingly.
03
Mechanical properties and heat treatment
Values below are the acceptance requirements in the solution annealed (+AT) condition. Section thickness does not change the strength requirements. What it changes is which test direction is qualified, and how much ductility and toughness is demanded of it.
| Property | EN, t up to 160 mm | EN, 160 to 250 mm | ASTM F316LN |
|---|---|---|---|
| Rp0,2 minimum | 280 MPa | 280 MPa | 205 MPa |
| Rp1,0 minimum | 315 MPa | 315 MPa | not specified |
| Tensile Rm | 580 to 800 MPa | 580 to 800 MPa | 515 MPa minimum |
| Elongation A minimum | 40 % longitudinal | 30 % transverse | 30 % |
| Impact KV minimum | 100 J longitudinal | 60 J transverse | not required |
| Reduction of area minimum | not specified | not specified | 50 % |
| Hardness maximum | 250 HB | 250 HB | not specified |
| Intergranular corrosion | resistant, as delivered and sensitized | resistant, as delivered and sensitized | by agreement |
| EN hardness values are given for guidance only. Above 250 mm section, EN 10088-3 stops tabulating, and the test-piece position and acceptance values are agreed at the time of order. Every European requirement above is more demanding than its ASTM counterpart, so a forging that passes EN 10088-3 passes ASTM A182 F316LN on mechanicals. | |||
Heat treatment
| Operation | Parameter | Basis |
|---|---|---|
| Heating for forging | Soak to 1150 to 1200 °C | Works practice |
| Finish forging | Not below 950 °C | Works practice. Nitrogen grades are stiff and crack-sensitive if worked cold. |
| Solution anneal (+AT) | 1020 to 1120 °C | EN 10222-5:2017 Table 1 |
| Cooling | Water or water-based medium, or air | EN 10222-5:2017 Table 1 |
| Heavy sections | Water quench | Works practice. Air cooling a thick section is too slow through 850 to 500 °C. |
| Stress relief | Avoid 550 to 850 °C | Works practice. This is the sensitization and sigma range, and austenitic forgings are not tempered. |
| EN 10222-5 permits the solution treatment to be omitted where the hot-working and cooling route demonstrably delivers both the mechanical properties and the resistance to intergranular corrosion of EN ISO 3651-2, and continues to do so after any subsequent solution anneal. In practice this works is asked to prove it, so the anneal is run. | ||
No post-weld heat treatment is normally required once a 1.4429 forging is welded into an assembly. The 0.030 % carbon ceiling exists so that it is not. Where a customer's code demands one, it has to stay clear of 550 to 850 °C, and guidance is set out in EN 10222-5:2017 Annex B.
04
Physical properties, corrosion and magnetism
| Property | Value | Comment |
|---|---|---|
| Density | 8.0 kg/dm³ | Nominal |
| Modulus of elasticity | 200 GPa | Falls to roughly 172 GPa at 400 °C |
| Thermal expansion, 20 to 200 °C | 16 x 10-6 K-1 | About 60 % higher than carbon steel. Allow for it in bolted joints and dissimilar welds. |
| Thermal conductivity | 15 W/(m·K) | Roughly a third of carbon steel, so heat builds locally during machining |
| Specific heat capacity | 500 J/(kg·K) | Nominal |
| Electrical resistivity | 0.75 Ω·mm²/m | Nominal |
| Magnetizable | No | Solution annealed condition. See below. |
Pitting resistance
PREN is calculated as %Cr plus 3.3 times %Mo plus 16 times %N. Across the EN composition limits, 1.4429 works out at 26.7 to 31.9, typically about 29. Set against its neighbours:
| Grade | PREN range | Typical | Where it changes the answer |
|---|---|---|---|
| 1.4404 / 316L | 23.1 to 28.4 | about 25 | General chemical service |
| 1.4429 (this grade) | 26.7 to 31.9 | about 29 | Moderate chloride, where 316L pits |
| 1.4462 / 2205 duplex | 30.9 to 38.1 | about 35 | Seawater, sour service, high chloride |
| 1.4547 / 254 SMO | see specification | about 43 | 6 % Mo, hot seawater and bleach plant |
| 1.4429 gains roughly four PREN points over 316L and does not reach duplex. In seawater, or in chloride service above about 60 °C, specify a duplex or 6 % Mo grade instead, and treat the extra strength as a bonus rather than the reason for the choice. | |||
Magnetic permeability
The nitrogen that raises the strength also stabilises the austenite, which is why 1.4429 rather than 316L turns up in accelerator, MRI, superconducting-magnet and instrument work. Relative permeability is not a property EN 10088-3 specifies. A limit, commonly 1.05 and sometimes 1.02, has to be written on the enquiry to exist at all.
Two things deliver it, and both sit upstream of inspection: delta ferrite controlled in the melt and at the solution anneal, and no cold work left on the finished surface, since cold deformation forms strain-induced martensite and lifts permeability locally. Where a project needs it, ferrite content is measured to ASTM E562 or the ferrite number determined, and permeability checked with a Severn gauge or a calibrated probe.
Behaviour in service
Intergranular corrosion
Resistant both as delivered and after the sensitization treatment of 15 minutes at 700 °C, tested to EN ISO 3651-2 or ASTM A262 Practice E. This follows directly from the 0.030 % carbon ceiling, and it is why 1.4429 is welded without a post-weld anneal.
Cryogenic service
Face-centred cubic, so there is no ductile-to-brittle transition. Toughness is retained to liquid helium temperature, which is why the grade is standard for LNG, liquid nitrogen and magnet structures. Charpy testing runs to minus 60 °C in house, and below that it goes to an accredited laboratory.
Elevated temperature
Useful to around 550 °C for non-creep duty. It is not a creep grade, because low carbon becomes a liability above roughly 525 °C where sustained load matters. For creep service use 1.4948 / 316H or 1.4910, and do not let a 316LN certificate be accepted in their place.
Machining and work hardening
Comparable to 316L and noticeably tougher than a martensitic grade. It work-hardens quickly, so it needs sharp tooling, heavy positive feed and no dwelling. Deep-hole boring and heavy turning are done in house on the CNC lathes and the 1,600 by 10,000 mm drilling machine.
05
What this works forges in 1.4429
Every item below is forged from a single piece of steel melted on site, with no welding, no casting and no purchased billet of unknown origin.
| 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 | Sections outside the ring-mill envelope | Upset-and-punch route on the presses |
| Forged flanges | ASME B16.5, B16.47, API 6A | Weld neck, blind, slip-on, orifice, long weld neck |
| Shafts and spindles | Up to 14,000 mm turned length | C61160 lathe, 15 m well furnace for vertical quench |
| Discs, tube sheets, covers | Up to 5,000 mm diameter machined | 5,000 mm vertical turning lathe |
| Valve bodies, bonnets, stems, seat rings | Per drawing | Machine shop and CNC lathes |
| Hollow cylinders, sleeves, bushings | Up to 1,600 by 10,000 mm bored | CNC deep-hole drilling machine |
| Bars, blocks, billets | Up to 30 t single piece | 60 t heat size, 6,300 t hydraulic press |
Where 1.4429 forgings from this plant are used
- Nuclear and conventional power. Pressure-boundary piping components, nozzles, pressuriser and auxiliary-system parts, where low carbon and verified nitrogen are both code requirements.
- Cryogenic plant. LNG and liquid-nitrogen vessel flanges, transfer-line components and magnet structures.
- Chemical and petrochemical. Heat-exchanger tube sheets, covers, columns, pump and valve parts in chloride-bearing process streams.
- Offshore and subsea. Manifolds, spools and instrument housings where the section is yield-limited.
- Pharmaceutical, pulp and paper, desalination. Digesters, evaporators and process vessels where 316L is marginal on pitting.
06
Melting, testing and what the certificate traces back to
Most forging suppliers in China buy billet. This plant starts one step earlier, at the furnace, and that changes two things on a 1.4429 order specifically.
First, the nitrogen window. A 0.04 % dual-certification band is a melt-shop target, and it cannot be corrected later. Vacuum oxygen decarburisation is the process that takes carbon down to the 0.030 % ceiling while nitrogen is trimmed to aim, and it is on site: 30 t and 60 t VOD units behind a 25 t electric arc furnace and 25 t and 50 t ladle furnaces. Second, traceability. The certificate runs from the melt number through forging, heat treatment and machining to shipment, instead of stopping at a purchased billet certificate.
Non-destructive examination, and the standard that is usually cited in error
Ultrasonic examination of 1.4429 forgings is to EN 10228-4 or ASTM A745/A745M, the austenitic parts of their respective series. EN 10228-3 and the general practice of ASTM A388 are written for ferritic and martensitic forgings. They appear on stainless enquiries constantly, and the acceptance criteria do not transfer, because a coarse austenitic grain structure attenuates and scatters the beam differently.
Magnetic particle inspection cannot be used on this grade at all. The solution annealed structure is non-magnetic, so surface examination is by liquid penetrant to EN 10228-2 or ASTM E165. An enquiry asking for MT on 1.4429 is queried before it is quoted rather than after.
| Test | Standard | Where |
|---|---|---|
| Chemical analysis | ASTM E415 optical emission, ASTM E1019 for C and S | In house, at the furnace |
| Positive material identification | Handheld analyser | In house |
| Tensile | ISO 6892-1, ASTM A370 | In house, 600 kN and 300 kN machines |
| Charpy V-notch impact | ASTM A370, to minus 60 °C | In house. Below minus 60 °C placed outside. |
| Ultrasonic | EN 10228-4, ASTM A745/A745M | In house |
| Liquid penetrant | EN 10228-2, ASTM E165 | In house |
| Grain size, metallography | ASTM E112 | In house |
| Intergranular corrosion | EN ISO 3651-2, ASTM A262 Practice E | Accredited third-party laboratory |
| Pitting resistance | ASTM G48 | Accredited third-party laboratory |
| Ferrite content and permeability | ASTM E562, Severn gauge or calibrated probe | By agreement. State it at enquiry. |
| Class approvals: CCS, BV, DNV, LR and NK. Certification to EN 10204 3.1 as standard, and EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's own inspector on request. Tests placed outside must be stated at enquiry so they are scheduled before shipment rather than added to the delivery date. | ||
07
Ordering 1.4429 forgings
Quotations are prepared from a drawing or a written specification. Sending the seven items below in the first email removes a round trip and usually gets a price back within two working days. Minimum order is 10 kg with no minimum piece count, and lead time runs 20 to 60 days from order confirmation.
| No. | Item | Example |
|---|---|---|
| 1 | Standard and grade | EN 10222-5 1.4429, or ASTM A182 F316LN, or both |
| 2 | Dimensions or drawing | OD 1200 x ID 900 x H 260 mm, as PDF, DWG, DXF or STEP |
| 3 | Quantity and repeat volume | 12 pieces, about 4 times per year |
| 4 | Delivery condition | As-forged, proof-machined or finish-machined |
| 5 | Heat treatment and NDT | Solution annealed +AT, UT to EN 10228-4, PT to EN 10228-2 |
| 6 | Certification and destination | EN 10204 3.2 witnessed by DNV, to Rotterdam |
| 7 | Grade-specific requirements | Dual EN and ASTM certification, permeability limit, impact at minus 196 °C, ASTM A262 Practice E |
| Line 7 is the one that changes how the steel is melted. Nitrogen aim, ferrite control and sub-zero impact testing all have to be decided before the heat is tapped. | ||
Sales and engineering
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).
Visiting the works
The plant is in Zhouzhuang Town, east Jiangyin, on the south bank of the Yangtze between Shanghai and Nanjing. Wuxi Shuofang International Airport is 30 km away and Shanghai's airports are 160 km. Nearest export ports are Zhangjiagang and Shanghai.
Customer audits, pre-shipment inspections and third-party witness testing are welcome. Arrange visits by email in advance so an English-speaking engineer is available.
08
Frequently asked questions
Is 1.4429 the same as 316LN?
Yes, but so is 1.4406, and the two are not interchangeable. Both 1.4429 (X2CrNiMoN17-13-3) and 1.4406 (X2CrNiMoN17-11-2) are cross-referenced to AISI 316LN and UNS S31653, because the American designation covers 2.00 to 3.00 % molybdenum and both European grades fall inside it. 1.4429 carries 2.50 to 3.00 % Mo and 11.0 to 14.0 % Ni, while 1.4406 carries 2.00 to 2.50 % Mo and 10.0 to 12.5 % Ni. If a drawing says only 316LN, settle which European number is intended before the heat is melted, because a 1.4406 heat at 2.2 % Mo will fail a 1.4429 certificate.
What is the difference between 1.4429 and 1.4404 (316L)?
Nitrogen and molybdenum. 1.4429 specifies 0.12 to 0.22 % N against a maximum of 0.10 % for 1.4404, and 2.50 to 3.00 % Mo against 2.00 to 2.50 %. Nitrogen is a solid-solution strengthener, so the EN 10088-3 minimum 0.2 % proof strength rises from 200 MPa to 280 MPa, an increase of 40 %, and the tensile band moves from 500 to 700 MPa up to 580 to 800 MPa. Carbon stays at 0.030 % maximum in both, so resistance to intergranular attack after welding is unchanged. The extra molybdenum and nitrogen together lift PREN from about 25 to about 29.
Can one heat be certified to both EN 1.4429 and ASTM A182 F316LN?
Yes, if the melt is aimed at the overlap from the start. The binding constraint is nitrogen, since EN allows 0.12 to 0.22 % and ASTM allows 0.10 to 0.16 %, which leaves a dual window of 0.12 to 0.16 %. Chromium must be held to 16.50 to 18.00 %, molybdenum to 2.50 to 3.00 % and sulphur to 0.015 % maximum. On mechanical properties the European requirements govern throughout, so meeting EN 10088-3 automatically satisfies the ASTM minima. Both acceptance tables are reported on one EN 10204 3.1 or 3.2 certificate.
What is the solution annealing temperature for 1.4429 forgings?
1020 to 1120 °C, cooled in water or a water-based medium, or in air. This is EN 10222-5:2017 Table 1, delivery condition +AT. The cooling rate through 850 to 500 °C is what protects the grade from chromium carbide precipitation, so heavy sections are water quenched rather than air cooled. EN 10222-5 permits the treatment to be omitted only where the hot-working and cooling route demonstrably produces both the mechanical properties and the resistance to intergranular corrosion required.
Is 1.4429 magnetic?
No. In the solution annealed condition it is fully austenitic and practically non-magnetic, and its nitrogen content stabilises the austenite, which is why it is chosen over 316L for magnet, accelerator and MRI hardware. Relative permeability is not specified by EN 10088-3, so any limit has to be stated on the enquiry. It is achieved by controlling delta ferrite in the melt and avoiding cold work on the finished surface, since cold deformation forms strain-induced martensite and raises permeability locally.
What is the PREN of 1.4429?
Between 26.7 and 31.9, typically about 29, from %Cr plus 3.3 times %Mo plus 16 times %N over the EN 10088-3 limits. For comparison, 1.4404 / 316L runs 23.1 to 28.4 and 1.4462 / 2205 duplex about 31 to 38. So 1.4429 gives roughly four PREN points over 316L but does not reach duplex. In seawater or chloride service above about 60 °C, a duplex or 6 % Mo grade is the safer specification.
Can 1.4429 be used at cryogenic temperatures?
Yes. The face-centred cubic austenitic structure has no ductile-to-brittle transition, so toughness is retained to liquid helium temperature, and the grade is a standard choice for LNG, liquid nitrogen and superconducting magnet structures. Charpy testing to minus 60 °C is run in the works laboratory. Test temperatures below minus 60 °C are placed with an accredited third-party laboratory and must be stated at enquiry so they are scheduled before shipment.
Is 1.4429 suitable for high-temperature or creep service?
Up to roughly 550 °C for non-creep duty, yes. For sustained load above about 525 °C, no. Low carbon is a disadvantage for creep strength, which is what the H grades add carbon to provide. Specify 1.4948 / 316H or 1.4910 instead, and do not let a 316LN certificate be accepted against an H-grade requirement. The claim that 1.4429 was developed for enhanced creep resistance belongs to 316H and has been repeated onto 316LN datasheets across the industry.
What size 1.4429 forgings can you supply, and what is the minimum order?
Seamless rolled rings up to 6,000 mm outside diameter on the 6 m radial-axial mill, single forgings up to 30 tonnes on the 6,300 t press, shafts up to 14,000 mm turned length, discs and tube sheets up to 5,000 mm machined diameter, and bored cylinders up to 1,600 by 10,000 mm. Minimum order is 10 kg with no minimum piece count, so a single small part is quotable. Note that EN 10088-3 tabulates properties only to 250 mm section, and above that the test position and acceptance values are agreed at order.
Which non-destructive tests apply, and what certification is supplied?
Ultrasonic examination is to EN 10228-4 or ASTM A745/A745M, the austenitic parts of their series. EN 10228-3 and the general practice of ASTM A388 are written for ferritic and martensitic forgings and are frequently specified in error for this grade. Surface examination is by liquid penetrant to EN 10228-2 or ASTM E165. Magnetic particle inspection cannot be used on 1.4429 at all, because the structure is non-magnetic. Certification is EN 10204 3.1 as standard, or 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's own inspector. The works holds CCS, BV, DNV, LR and NK approvals.
Sources and revision. Data on this page is taken from EN 10088-3:2014, EN 10222-5:2017, EN 10088-1:2014 Annex E and ASTM A182/A182M. Capability figures are this works' own equipment. Reviewed 22 September 2026.
Jiangyin Jiangnan Metal Co., Ltd. 1.4429 (X2CrNiMoN17-13-3) open-die forgings. steelforgepieces.com, 22 September 2026. https://www.steelforgepieces.com/Stainless-Steel/1.4429.html