Jiangyin Jiangnan Metal Co., Ltd. Integrated melting works and open-die forging factory, Jiangyin, Jiangsu, China +86 189 2135 9659 sales@steelforgepieces.com
SteelForgePieces

GOST 5632 · 03Х23Н6 · ЗИ68 · Austenitic-ferritic

03KH23N6 Forged Steel Components

Seamless rolled rings, forged rings, flanges, discs, tube sheets, bars and valve parts in GOST grade 03Х23Н6. Melted, forged, solution annealed and machined in one works in Jiangyin, Jiangsu, and shipped worldwide with EN 10204 3.1 certificates.

GOST designation
03Х23Н6 (works code ЗИ68)
Structural class
Austenitic-ferritic (duplex)
Chromium / nickel
22.00 to 24.00 % / 5.30 to 6.30 %
Molybdenum, nitrogen
Neither is an alloying element
Solution anneal
1000 to 1050 °C, water quench
Max service temperature
about 300 °C

Summary

03KH23N6 is the transliteration of 03Х23Н6, a Russian GOST 5632 corrosion-resistant steel of the austenitic-ferritic (duplex) class, also carried under the works code ЗИ68 / ZI68. It contains 22.00 to 24.00 % chromium and 5.30 to 6.30 % nickel, with carbon held to 0.030 % maximum.

03Х23Н6 contains no molybdenum and no nitrogen as alloying elements. GOST 5632 normalises neither for this grade, and the grade name itself carries no letter for nitrogen. This is the main difference between 03ХУ23Н6 and the modern duplex grades, and several published datasheets for 03KH23N6 state it incorrectly, including the earlier version of this page.

In the solution annealed condition to GOST 7350-77, minimum yield strength is 345 MPa, minimum tensile strength 590 MPa and minimum elongation 25 %. It is specified for strength and for resistance to knife-line attack in welds. It is not a seawater or sour-service grade: calculated on guaranteed chromium, its PREN is about 22 to 24.

Jiangyin Jiangnan Metal Co., Ltd. forges 03Х23Н6 into seamless rolled rings, forged rings, flanges, discs, tube sheets, bars, sleeves and valve components at its integrated melting and open-die forging works at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The steel is melted on site, so the chemistry is set for the part rather than accepted from a billet supplier. Call +86 189 2135 9659 or email sales@steelforgepieces.com.

What is 03KH23N6 steel?

03KH23N6 is the Latin transliteration of the Russian grade 03Х23Н6, listed in GOST 5632 among the steels of the austenitic-ferritic class. The mill code ЗИ68 appears on older certificates and on material supplied against TU 14-1-1541-75.

The name states the chemistry. Under the GOST naming rules the leading figures give carbon in hundredths of a percent, so 03 means 0.030 % maximum. Х is chromium and the 23 after it is the nominal chromium content. Н is nickel and the 6 after it is the nominal nickel content. There are no further letters, and under GOST 5632 a letter in the middle of a grade name declares an element such as nitrogen. The absence of one here is not an omission in the published tables, it is what the standard specifies.

The structure is roughly half ferrite and half austenite, and that two-phase structure gives the grade its strength: minimum yield strength is 345 MPa against 205 MPa for an austenitic grade such as 08Х18Н10Т. GOST itself recommends 03Х23Н6 as a higher-strength substitute for 08Х18Н10Т and 03Х18Н11 in chemical process equipment.

The grade was developed for welded vessels and apparatus in nitric acid, ammonium nitrate and adipic acid plants, where the combination of very low carbon and a duplex structure gives good resistance to intergranular attack and to knife-line attack in the weld fusion boundary. It also appears in equipment operating in radioactive environments that is not itself in contact with the aggressive medium, and as a welding consumable composition.

Designations, transliterations and aliases

Cyrillic Х and Н look like Latin X and H, so this grade reaches suppliers under at least five different spellings. They are all the same steel, and an enquiry sent under any of them is understood.

Ways 03Х23Н6 is written in enquiries, drawings and certificates.
FormWritten asWhere it comes from
GOST, Cyrillic03Х23Н6The official grade designation
Latin lookalike03X23H6Cyrillic characters typed on a Latin keyboard
Transliteration03KH23N6Х rendered as KH, Н as N. The most common export spelling
Alternative transliteration03H23N6Х rendered as H
Works codeЗИ68 / ZI68Zlatoust works designation, used in TU documents
By chemical elements03Cr23Ni6Used in some cross-reference tables
Do not confuse 03Х23Н6 with 03Х22Н6М2 (ЗИ67). The two grades were developed together and sit next to each other in GOST 5632 as grades 5-2 and 5-3. 03Х22Н6М2 carries 1.80 to 2.50 % molybdenum; 03Х23Н6 carries none. If a drawing calls for molybdenum in a GOST duplex, the grade wanted is almost certainly 03Х22Н6М2.

A correction to the data published for this grade, including ours

An earlier version of this page described 03KH23N6 as a 22 % chromium, 3 % molybdenum, nitrogen-alloyed duplex and printed a composition table with molybdenum 2.30 to 3.50 % and nitrogen 0.10 to 0.22 %. Those figures belong to duplex 2205 (1.4462 / UNS S31803 and S32205), not to 03Х23Н6. The mechanical figures on that page, 0.2 % proof stress of 450 MPa and tensile strength of 620 MPa, were also the 2205 bar values.

The table further down this page is taken from GOST 5632-2014 table 1, grade 5-2, and from GOST 7350-77 and TU 14-1-1541-75 for the plate limits. The change is stated here rather than made silently, because a buyer who ordered against the old figures needs to know which numbers moved.

What this means commercially. A certificate showing 2 to 3 % molybdenum does not satisfy a 03Х23Н6 drawing, and a certificate showing no molybdenum does not satisfy a 2205 drawing. If the enquiry says 03KH23N6 and the application is chloride-bearing or sour service, the drawing grade may not suit the duty. Send the service conditions with the enquiry so they can be checked before any steel is melted.

Chemical composition of 03KH23N6

Chemical composition of 03Х23Н6 in weight percent. Iron balance. GOST 5632-2014 gives the grade limits; GOST 7350-77 and TU 14-1-1541-75 narrow nickel for plate.
StandardCSiMn CrNiSP MoTiCuN
GOST 5632-2014 (5-2) max 0.030max 0.401.00–2.00 22.00–24.005.30–6.30max 0.020max 0.035 res. max 0.30res. max 0.20res. max 0.30not specified
GOST 7350-77 (plate) max 0.03max 0.41–2 22–245.6–6.3max 0.02max 0.035 max 0.3max 0.05max 0.3not specified
TU 14-1-1541-75 (ЗИ68) max 0.03max 0.41–2 22–245.6–6.3max 0.02max 0.035 —max 0.05—not specified
Residual element rules that come with the grade. Under GOST 5632-2014 clause 6.3, titanium in steels not alloyed with titanium is limited to 0.20 %, and by agreement between maker and buyer 03Х23Н6 is supplied with titanium at 0.05 % maximum. Under clause 6.7, residual molybdenum is limited to 0.30 % and, on the buyer's order, to 0.10 % maximum for this grade specifically. GOST 7350-77 permits the finished product to deviate by plus 0.40 % on silicon, plus 0.005 % on sulphur, plus or minus 0.20 % on nickel and plus 0.50 % on chromium. State on the enquiry if your drawing needs the tighter molybdenum limit, because it is a melt-shop decision that cannot be made after the heat is cast.

Is 03KH23N6 the same as duplex 2205, 2304 or 329?

No, and the published cross-references disagree with each other. Some Russian equivalence tables map 03Х23Н6 to 1.4362 / X2CrNiN23-4 / UNS S32304 on the strength of the chromium and nickel figures. Others map it to 1.4460 / AISI 329 / UNS S32900, on the grounds that it belongs to the older generation of duplex grades that predate nitrogen alloying. Neither is an exact match, and no standard declares them interchangeable.

03Х23Н6 against the three duplex grades it is most often cross-referenced to. Weight percent, iron balance. PREN calculated as Cr + 3.3Mo + 16N on the specified limits.
Element 03Х23Н6
GOST 5632
1.4362 / S32304
2304
1.4462 / S32205
2205
1.4460 / S32900
329
C max0.0300.0300.0300.05
Si max0.401.001.001.00
Mn1.00–2.00max 2.00max 2.00max 2.00
Cr22.00–24.0022.0–24.521.0–23.025.0–28.0
Ni5.30–6.303.5–5.54.5–6.54.5–6.5
Moresidual only0.10–0.602.50–3.501.30–2.00
Nnot specified0.05–0.200.10–0.220.05–0.20
Curesidual only0.10–0.60——
PREN, approx.22–2423–2932–3330–36

Why the nickel is higher and the nitrogen is missing

One figure in the table above runs against expectation. 03Х23Н6 carries more nickel than 2304 does, yet it is the more ferritic of the two. Nitrogen accounts for that. In the standard austenite-balance formulae nitrogen counts roughly thirty times as strongly as nickel, so 2304 with 0.05 to 0.20 % nitrogen has a higher austenite potential than 03Х23Н6 with nothing but its extra nickel. The nickel in 03Х23Н6 partly compensates for the absent nitrogen, but does not fully replace it.

The consequence shows up in a weld. Nitrogen diffuses quickly at high temperature and re-forms austenite in the heat-affected zone as the joint cools, while nickel diffuses too slowly to do the same work in the seconds available. A nitrogen-free duplex therefore leaves a ferrite-rich heat-affected zone unless heat input and interpass temperature are controlled, which is why GOST practice for this family prescribes a solution anneal after welding on fabrications where corrosion performance in the weld region governs.

Mechanical properties of 03KH23N6

Room-temperature mechanical properties of 03Х23Н6 in the solution annealed and water quenched condition, as specified for plate. Forgings are agreed against these values or against the customer specification.
Product and condition Rp0.2 min Rm min A5 min
Plate 4.0–50.0 mm hot rolled and 4.0–5.0 mm cold rolled to GOST 7350-77, water quenched from 1030–1050 °C 345 MPa
(50 ksi)
590 MPa
(86 ksi)
25 %
Hot-rolled plate 4–11 mm to TU 14-1-1541-75, water quenched from 1000–1025 °C 343 MPa
(50 ksi)
588 MPa
(85 ksi)
25 %
Reference: austenitic 08Х18Н10Т, solution annealed 205 MPa510 MPa40 %

The third row shows why the grade is specified. At the same chromium level a duplex structure delivers roughly seventy percent more yield strength than an austenitic grade, which for a pressure vessel means a thinner wall, less weld metal and a lighter fabrication. Elongation falls from 40 % to 25 %, which is ample for a pressure part and tight enough to matter if the part is to be cold formed after machining.

GOST does not specify impact energy for 03Х23Н6, and no hardness range is laid down for the grade. Where a drawing calls for Charpy values or a hardness band on a forging, they are agreed at order stage and tested on a representative test piece. Impact testing down to minus 60 °C runs in our own laboratory; below that it is placed with an accredited third party. Impact energy falls off in any duplex grade as the ferrite phase becomes the controlling phase at low temperature, so a cryogenic requirement should be raised before the grade is fixed.

Physical properties

GOST publishes no separate physical property table for 03Х23Н6. The figures below are those of 08Х22Н6Т, the closest published austenitic-ferritic grade at the same chromium and nickel level, and are given for preliminary work only. Do not use them in a design calculation without confirming them against the governing code.

Indicative physical properties for a 22 to 24 percent chromium austenitic-ferritic steel, from published GOST data for 08Х22Н6Т.
Property20 °C200 °C300 °CConfidence
Density7,700 kg/m³——Indicative
Modulus of elasticity203 GPa193 GPa181 GPaIndicative
Thermal conductivity—16 W/(m·K)18 W/(m·K)Indicative
Electrical resistivity740 nΩ·m——Indicative
Magnetic responseFerromagnetic. The ferrite phase makes any duplex steel attracted to a magnet.Certain
The magnetic response is stated here because it surprises buyers who expect a stainless grade to be non-magnetic. It also has a practical consequence on inspection: magnetic particle examination works on this grade, where it cannot be used on a fully austenitic steel.

Forging and heat treatment of 03KH23N6

Forging and solution annealing route for 03KH23N6 Temperature plotted against time. The billet is heated to 1150 degrees Celsius and soaked, forged down to a finishing temperature of 850 degrees, air cooled, then reheated to 1000 to 1050 degrees for solution annealing and water quenched to room temperature. A shaded band between 600 and 950 degrees marks the range in which sigma phase and chromium carbides form. A second shaded band between 280 and 500 degrees marks the range in which 475 degree embrittlement affects the ferrite phase. 1150 °C 950 °C 600 °C 280 °C soak 1150 °C forge to 850 °C 1000–1050 °C solution anneal water quench sigma phase and chromium carbides 475 °C embrittlement Time
Processing route for 03Х23Н6 open-die forgings. The two shaded bands are the ranges the part must pass through quickly rather than dwell in: sigma phase forms between roughly 600 and 950 °C, and 475 °C embrittlement affects the ferrite phase between roughly 280 and 500 °C.
Forging and heat treatment parameters for 03Х23Н6. Forging temperatures follow published practice for the closely related austenitic-ferritic grade 08Х22Н6Т.
OperationTemperatureCooling
Start of forging1150 °C
(2100 °F)
—
Finish of forgingnot below 850 °C
(1560 °F)
Air
Solution anneal, GOST 7350-771030–1050 °C
(1885–1920 °F)
Water
Solution anneal, TU 14-1-1541-751000–1025 °C
(1830–1875 °F)
Water
Anneal to restore resistance to intergranular attack1050 ± 25 °CWater or air
Range to avoid on cooling and in service600–950 °C and 280–500 °CPass through, do not hold

Why the absence of molybdenum makes this grade easier to forge heavy

Molybdenum and tungsten strongly accelerate sigma phase formation in duplex steels. Sigma is a hard, brittle chromium-rich intermetallic that precipitates between roughly 600 and 950 °C, and a few percent of it will halve the impact toughness of a forging. In 2205, with 2.5 to 3.5 % molybdenum, sigma can appear in minutes at the nose of the curve, so heavy 2205 sections have to be forged and quenched quickly.

03Х23Н6 carries molybdenum only as a residual, capped at 0.30 % and at 0.10 % if the order asks for it. Sigma formation is correspondingly sluggish. In a heavy ring or a thick disc, where the core cools more slowly than the surface, the grade tolerates section thicknesses that give a molybdenum-bearing duplex trouble. This offsets the lower PREN and is one reason the grade is still specified for large welded vessel components rather than replaced outright by 2205.

The forging must be quenched, not air cooled. GOST specifies water quenching from the solution anneal for this grade. Slow cooling through 600 to 950 °C precipitates chromium carbides at the ferrite-austenite boundaries and undoes the low-carbon chemistry the grade was designed around. On heavy sections we confirm the quench route at order stage against the part geometry.

Welding 03KH23N6

Published GOST practice for 03Х23Н6 names manual argon-arc welding with a non-consumable electrode, with or without filler, and automatic submerged-arc welding. The grade is also used as a welding consumable composition in its own right.

  • No preheat required
  • Control heat input and interpass temperature
  • Argon-arc, with or without filler
  • Automatic submerged-arc welding
  • Solution anneal after welding where weld corrosion performance governs
  • Ferrite count on the weld and heat-affected zone where specified

The issue described in the comparison section applies here. With no nitrogen in the base metal, austenite reformation in the heat-affected zone depends on nickel diffusion, which is slow. High heat input and a long time in the ferritic range leave a coarse, ferrite-rich heat-affected zone with reduced toughness and reduced corrosion resistance. The remedy is a controlled, moderate heat input and, where the weld must match the base metal in service, a post-weld solution anneal at 1050 ± 25 °C followed by a quench.

Where a fabricator cannot solution anneal a completed assembly, and the joint is in the corrosive path, the grade choice should be reviewed before the joint is accepted. A nitrogen-bearing duplex such as 2205 or 2304 recovers its weld-zone austenite without a post-weld heat treatment, which is what nitrogen alloying was introduced to achieve.

Corrosion behaviour and service limits

03Х23Н6 resists intergranular corrosion well. Carbon at 0.030 % maximum leaves too little to form chromium carbides in quantity, and the duplex structure interrupts the continuous austenite grain boundary network that carries intergranular attack in a single-phase steel. Published Russian practice specifically credits the grade with improved resistance to knife-line attack in welded joints, which is the failure mode that takes stabilised austenitic grades such as Х18Н9Т and Х18Н10Т out of service in nitric acid plants.

The grade is not suited to chloride service. Pitting and crevice resistance track the PREN number, and on the chromium guaranteed by GOST, with no molybdenum and no nitrogen to contribute, 03Х23Н6 sits at about 22 to 24. Duplex grades are normally expected to carry a PREN above 32 before seawater is considered, and above 40 for warm seawater.

A second correction to the earlier version of this page. That page listed seawater desalination plants, subsea and deepwater offshore production systems, and downhole service in sour gas wells among the applications. None of those is appropriate for a PREN 22 to 24 steel with no molybdenum. 03Х23Н6 is also not a listed material in NACE MR0175 / ISO 15156 for sour service. For chloride or sour duty the grades to look at are SAF 2205, SAF 2507 or A182 F55, and we quote all three.

Temperature limits

The ferrite phase in any duplex steel decomposes on long holding between roughly 280 and 500 °C, with the worst of it near 475 °C. The steel becomes harder and markedly less tough, and the change is not reversible in service. Published GOST application notes cap the closely related duplex grades 08Х22Н6Т and 03Х22Н6М2 at 300 °C for this reason, and the same limit should be applied to 03Х23Н6.

At the cold end, duplex grades lose impact toughness well before austenitic grades do, because the ferrite phase has a ductile-to-brittle transition. Where a low-temperature requirement exists, state it with the enquiry so the test temperature can be agreed and tested rather than assumed.

Testing and certification

Because the steel is melted here, chemistry is verified at the furnace rather than taken from a purchased billet certificate, and the melt number traces through forging, heat treatment and machining to shipment.

Test methods applied to 03Х23Н6 forgings and the standards they are run to.
TestStandardWhere it is run
Chemical analysisASTM E415, GOST 12344 to 12365In-house optical emission spectrometer and carbon-sulphur analyser
Positive material identificationHandheld alloy analyserIn-house
TensileASTM A370, ISO 6892In-house, 600 kN and 300 kN machines
Impact, to −60 °CASTM A370In-house, pendulum machine with low-temperature bath
Ultrasonic examinationEN 10228-4, ASTM A745In-house, full-digital flaw detectors
Magnetic particleASTM E709In-house. Applicable because duplex is ferromagnetic
Intergranular corrosionGOST 6032, ASTM A262Accredited third-party laboratory
Ferrite phase balanceASTM A923, ASTM E562Accredited third-party laboratory
Grain size and microstructureASTM E112In-house metallography
Use the right ultrasonic standard. The earlier version of this page cited EN 10228-3 and ASTM A388. Both are written for ferritic and martensitic forgings. An austenitic-ferritic forging has a coarse, acoustically anisotropic structure that scatters and attenuates the beam, and results obtained under a ferritic procedure are not reliable. The correct standards are EN 10228-4, which covers austenitic and austenitic-ferritic stainless steel forgings, and ASTM A745. State the acceptance class on the enquiry so the probe frequency and calibration block are set before the part is machined for inspection.

EN 10204 3.1 material certificates are supplied as standard, covering melt analysis, mechanical results and heat-treatment records. EN 10204 3.2 certificates witnessed by a classification society or by a third-party inspection body are available on request. The works holds CCS, BV, DNV, LR and NK classification society approvals.

Forged shapes supplied in 03KH23N6

Seamless rolled rings

Radial-axial rolled, rectangular or contoured section, outside diameter to 6,000 mm

Forged rings

Upset and punched, for sections outside the ring-mill envelope

Flanges

Weld neck, blind, slip-on, lap joint and orifice flanges to drawing

Discs and tube sheets

Solid forged discs, tube sheets and vessel covers, proof-machined for inspection

Bars and blocks

Round, flat and square forged bar, die blocks and machining stock

Sleeves and hollow bars

Bushings, shells and heavy-wall cylinders bored from solid

Valve components

Bodies, bonnets, seat rings, stems and blocks for chemical service

Custom forgings

Any profile forged to a 2D drawing or 3D model

Minimum order is 10 kg with no minimum piece count, so both a single small part and a one-off large ring can be quoted. Small parts are grouped into a batch to share furnace and setup time, so quantity still affects the unit price.

Forging capability for this grade

Jiangyin Jiangnan Metal Co., Ltd. has operated as an integrated melting works and open-die forge in Zhouzhuang Town, Jiangyin, since 1997. Unlike a forging shop that buys billet, the plant melts its own steel, so for a grade with tight residual limits such as 03Х23Н6 the chemistry is set at the furnace rather than accepted as delivered.

Melting
Electric arc furnace, ladle furnace and vacuum oxygen decarburisation for stainless and duplex grades. Maximum heat size 60 tonnes
Forging
Hydraulic open-die presses of 6,300 t, 4,000 t and 2,000 t; hammers from 750 kg to 5 t
Ring rolling
Radial-axial mills of 6 m, 3 m and 1 m. Rings from outside diameter 50 mm to 6,000 mm
Heaviest piece
30 tonnes single-piece weight
Heat treatment
14 furnaces on site, including car-bottom furnaces with a working chamber to 8,000 × 2,000 × 2,000 mm and two 15 m well-type furnaces for vertical quenching of long parts
Machining
Vertical lathes to Ø5,000 mm swing, horizontal lathes to 14,000 mm, CNC deep-hole drilling to Ø1,600 × 10,000 mm
Delivery condition
As-forged with allowance, proof-machined for volumetric inspection, or finish-machined to drawing
Certification
EN 10204 3.1 as standard, 3.2 witnessed on request. CCS, BV, DNV, LR and NK approvals
Minimum order
10 kg, no minimum piece count
Lead time
20 to 60 days from order confirmation, depending on section and testing scope
Quotation
Returned within two working days
Plant address
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Contact
+86 189 2135 9659 · sales@steelforgepieces.com

Applications of 03KH23N6 forgings

The list below follows the published purpose of the grade rather than a generic duplex application list. Chloride and sour-service applications are deliberately absent, for the reason given in the corrosion section.

  • Welded apparatus for chemical process plant
  • Vessel shells, heads and flanges in nitric acid service
  • Ammonium nitrate production equipment
  • Adipic acid plant components
  • Heat exchanger tube sheets and covers
  • Valve bodies and internals for chemical duty
  • Higher-strength replacement for 08Х18Н10Т and 03Х18Н11 parts
  • Equipment connections in radioactive environments not contacting the medium
  • Welding consumable and electrode stock

How to order 03KH23N6 forgings

  1. Send the drawing or dimensions Email a drawing in PDF, DWG, DXF or STEP, or the plain dimensions, to sales@steelforgepieces.com. For a ring, outside diameter, inside diameter and height are enough to start.
  2. State the grade standard you are buying to Confirm whether the order is against GOST 5632 grade 03Х23Н6 or against an equivalent such as 1.4362 or UNS S32304. They are not interchangeable and the certificate has to name the standard the drawing calls for.
  3. Confirm heat treatment, testing and certification Specify the delivery condition, the EN 10204 certificate level, and any intergranular corrosion testing to GOST 6032 or ASTM A262, ultrasonic examination to EN 10228-4 or ASTM A745, ferrite counting, or third-party witness inspection.
  4. Receive the quotation You get forging weight, unit price, lead time and Incoterms within two working days. Minimum order is 10 kg and normal lead time runs 20 to 60 days.

Frequently asked questions about 03KH23N6

What is 03KH23N6 steel?

03KH23N6 is the transliteration of the Russian GOST grade 03Х23Н6, a corrosion-resistant steel of the austenitic-ferritic or duplex class, also known by the works code ЗИ68 or ZI68. It contains 22.00 to 24.00 % chromium and 5.30 to 6.30 % nickel with carbon limited to 0.030 % maximum. It is used for welded chemical process equipment, particularly in nitric acid, ammonium nitrate and adipic acid production, and is recommended by GOST as a higher-strength substitute for the austenitic grades 08Х18Н10Т and 03Х18Н11.

Does 03KH23N6 contain molybdenum?

No. Molybdenum is not an alloying element in 03Х23Н6. GOST 5632-2014 permits it only as a residual at 0.30 % maximum, and clause 6.7 allows the buyer to order the grade with residual molybdenum at 0.10 % maximum. Any datasheet showing 2 to 3 % molybdenum for this grade has copied the composition of duplex 2205. The GOST grade that does carry molybdenum in this family is 03Х22Н6М2, at 1.80 to 2.50 %.

Is 03KH23N6 nitrogen alloyed?

No. GOST 5632 does not specify nitrogen for 03Х23Н6, and under the GOST naming rules a letter in the middle of a grade name declares an element such as nitrogen. 03Х23Н6 has no such letter. By comparison, the neighbouring GOST duplex grade 03Х22Н5АМ3 carries the letter А and is specified with 0.08 to 0.20 % nitrogen. The absence of nitrogen is the main practical difference between 03Х23Н6 and every modern duplex grade, and it affects how the heat-affected zone of a weld behaves.

What is the equivalent of 03KH23N6 in EN or UNS?

There is no exact equivalent, and published cross-reference tables disagree. Some map 03Х23Н6 to 1.4362 / X2CrNiN23-4 / UNS S32304 on the chromium and nickel figures, others to 1.4460 / AISI 329 / UNS S32900 as an older nitrogen-free duplex. Neither match is exact: 2304 is nitrogen and copper alloyed and carries less nickel, while 329 carries far more chromium and 1.3 to 2.0 % molybdenum. If the drawing calls for GOST 03Х23Н6, order against GOST 5632 and have the certificate name that standard.

What are the mechanical properties of 03KH23N6?

In the solution annealed and water quenched condition to GOST 7350-77, minimum yield strength is 345 MPa, minimum tensile strength 590 MPa and minimum elongation 25 %. Under TU 14-1-1541-75 for hot-rolled plate of 4 to 11 mm the corresponding values are 343 MPa, 588 MPa and 25 %. GOST specifies no impact energy and no hardness range for this grade, so where a drawing calls for them they are agreed at order stage and tested on a representative test piece.

What heat treatment is applied to 03KH23N6 forgings?

Forging starts at 1150 °C and finishes no lower than 850 °C. The part is then solution annealed and water quenched, at 1030 to 1050 °C under GOST 7350-77 or 1000 to 1025 °C under TU 14-1-1541-75. Where resistance to intergranular corrosion has to be restored, the anneal is run at 1050 plus or minus 25 °C. Slow cooling is not acceptable: the part must pass quickly through 600 to 950 °C, where chromium carbides and sigma phase form.

Can 03KH23N6 be used in seawater or sour service?

No. Calculated on the chromium guaranteed by GOST, with no molybdenum and no nitrogen contributing, the PREN of 03Х23Н6 is only about 22 to 24. Duplex grades are normally expected to exceed PREN 32 before seawater is considered. The grade is also not a listed material in NACE MR0175 / ISO 15156 for sour service. For chloride-bearing or sour duty, use SAF 2205, SAF 2507 or A182 F55 instead.

What is the maximum service temperature of 03KH23N6?

About 300 °C. The ferrite phase in any duplex steel decomposes on prolonged holding between roughly 280 and 500 °C, with the effect strongest near 475 °C, and the resulting loss of toughness is not reversible in service. Published GOST application notes cap the closely related duplex grades 08Х22Н6Т and 03Х22Н6М2 at 300 °C, and the same limit applies here.

Is 03KH23N6 magnetic?

Yes. The ferrite phase makes 03Х23Н6 ferromagnetic, as it does every duplex stainless steel. This surprises buyers who expect a stainless grade to be non-magnetic, but it has a useful consequence for inspection: magnetic particle examination can be used on this grade, where it cannot be used on a fully austenitic steel such as 08Х18Н10Т.

Which ultrasonic standard applies to 03KH23N6 forgings?

EN 10228-4 or ASTM A745. Both are written for austenitic and austenitic-ferritic stainless steel forgings. EN 10228-3 and ASTM A388 are written for ferritic and martensitic forgings and are not appropriate, because the coarse, acoustically anisotropic structure of a duplex forging scatters and attenuates the beam and gives unreliable results under a ferritic procedure.

How is 03KH23N6 welded?

Published GOST practice names manual argon-arc welding with a non-consumable electrode, with or without filler, and automatic submerged-arc welding. No preheat is required. Because the grade contains no nitrogen, austenite reformation in the heat-affected zone depends on slow nickel diffusion, so heat input and interpass temperature have to be controlled to avoid a ferrite-rich heat-affected zone. Where weld corrosion performance governs, the fabrication is solution annealed at 1050 plus or minus 25 °C and quenched after welding.

Why is 03KH23N6 easier to forge in heavy sections than 2205?

Molybdenum strongly accelerates sigma phase formation, the brittle chromium-rich intermetallic that precipitates between roughly 600 and 950 °C. Duplex 2205 carries 2.50 to 3.50 % molybdenum and forms sigma quickly, which makes heavy sections difficult because the core of a thick part cools slowly through that range. 03Х23Н6 carries molybdenum only as a residual, so sigma formation is far more sluggish and the grade tolerates section thicknesses that give a molybdenum-bearing duplex trouble.

What forged shapes are available in 03KH23N6?

Seamless rolled rings to 6,000 mm outside diameter, forged rings, weld neck and blind flanges, discs, tube sheets and vessel covers, round, flat and square bars, blocks, sleeves, bushings, hollow bars, and valve bodies, bonnets, seat rings and stems. Custom profiles are forged to a 2D drawing or 3D model. Minimum order is 10 kg with no minimum piece count.

Who supplies 03KH23N6 forgings?

Jiangyin Jiangnan Metal Co., Ltd. is 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. It melts its own steel and forges 03Х23Н6 to drawing for export worldwide, with EN 10204 3.1 certificates as standard. Contact +86 189 2135 9659 or sales@steelforgepieces.com. Quotations are returned within two working days and minimum order is 10 kg.

What certificates are supplied with 03KH23N6 forgings?

EN 10204 3.1 material certificates are supplied as standard, covering melt analysis, mechanical test results and heat-treatment records. EN 10204 3.2 certificates witnessed by a classification society or a third-party inspection body such as SGS or TUV are available on request, as are ultrasonic examination reports to EN 10228-4 or ASTM A745, intergranular corrosion test reports to GOST 6032 or ASTM A262, ferrite counts and positive material identification records. The works holds CCS, BV, DNV, LR and NK classification society approvals.

Citing this page

The technical data on this page may be quoted with attribution. Suggested reference:

Jiangyin Jiangnan Metal Co., Ltd. “03KH23N6 (03Х23Н6 / ЗИ68) Forged Steel Components.” steelforgepieces.com, reviewed 21 September 2026. https://www.steelforgepieces.com/Stainless-Steel/03KH23N6.html

Standards referenced on this page

  • GOST 5632-2014, Stainless steels and corrosion resisting, heat-resisting and creep resisting alloys. Grades. Table 1, austenitic-ferritic class, grade 5-2
  • GOST 5632-72, the superseded edition, still cited on older drawings and certificates
  • GOST 7350-77, Thick sheets of corrosion-resistant, heat-resistant and high-temperature steel
  • GOST 6032, Corrosion-resistant steels and alloys. Methods of testing for resistance to intergranular corrosion
  • TU 14-1-1541-75, hot-rolled sheet in grade 03Х23Н6 (ЗИ68)
  • TU 14-1-1905-76, TU 14-1-1554-75 and TU 14-11-245-88, further product forms
  • OST 3-1686-90, ingots, billets and slabs
  • OST 95 10441-2002, welding and cutting of metals
  • EN 10204, Metallic products. Types of inspection documents
  • EN 10228-4, Non-destructive testing of steel forgings. Ultrasonic testing of austenitic and austenitic-ferritic stainless steel forgings
  • ASTM A745/A745M, Ultrasonic Examination of Austenitic Steel Forgings
  • ASTM A262, Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
  • ASTM A923, Detecting Detrimental Intermetallic Phase in Duplex Austenitic/Ferritic Stainless Steels
  • EN 10088-3, referenced for the comparison grades 1.4362, 1.4462 and 1.4460

Page last reviewed 21 September 2026 by Jiangyin Jiangnan Metal Co., Ltd.

Values on this page are indicative and drawn from the standards listed above. They do not replace the current edition of the applicable standard or design code. Physical properties are taken from a closely related grade and are labelled accordingly. Confirm all design values against the governing code for your project before use.

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