X7CrNiTi18-10 (1.4940) Forgings
Titanium-stabilised austenitic stainless steel. Forged rings, seamless rolled rings, flanges, shafts, discs, tube sheets and hollow cylinders, made from steel melted in our own furnaces.
Material number 1.4940 · UNS S32109 · 321H · ISO 4955 old code H11 · Page reviewed 11 October 2026 by the metallurgical department, Jiangyin Jiangnan Metal Co., Ltd.
X7CrNiTi18-10 is the EN and ISO name for material number 1.4940, a titanium-stabilised austenitic stainless steel with 17 to 19 % chromium, 9 to 13 % nickel and a carbon range of 0.04 to 0.08 % under EN 10216-5:2014. The titanium addition, limited by the rule 5 × (C+N) < Ti < 0.80 %, binds free carbon as titanium carbide so chromium stays in solution after welding and after long periods in the 427 to 816 °C carbide precipitation range. SteelNumber classifies 1.4940 as an austenitic creep resisting steel. It is the elevated-temperature counterpart of 1.4541 (X6CrNiTi18-10, AISI 321).
Jiangyin Jiangnan Metal Co., Ltd. forges X7CrNiTi18-10 from steel melted on its own site at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu, China. Rings roll to 6,000 mm outside diameter on a 6 m radial-axial mill, single pieces reach 30 tonnes under a 6,300 t press, minimum order is 10 kg, and certificates are issued to EN 10204 3.1 or witnessed 3.2 with traceability back to the melt number rather than to a purchased billet.
What the grade is
X7CrNiTi18-10 sits in the 18/10 chromium-nickel austenitic family and carries a deliberate titanium addition. The Applus materials portal records the DIN EN 10088-1 entry for 1.4940 with the remark that this high-temperature material is used for seamless pressurised tubes, which is where the grade originates. The carbon minimum of 0.04 % is there on purpose: carbon in solution is what gives this steel calculable creep and stress rupture strength above about 540 °C, and the titanium is what stops that carbon from attacking the grain boundaries on the way.
Three statements that appear on older listings for this grade should be ignored. The steel is not a hydrofluoric acid or fluorine material; published data for 321 and 321H puts it in chloride-free and fluoride-free caustic at moderate temperature, and warns against chloride solutions and sulfuric acid. It is not a hot strong caustic material either. And it cannot be solution treated and aged, because austenitic stainless steel cannot be hardened by heat treatment at all, only by cold work.
Standards that list X7CrNiTi18-10
| Standard | Designation | Scope |
|---|---|---|
| EN 10216-5:2014 | X7CrNiTi18-10 (1.4940) | Seamless steel tubes for pressure purposes, stainless steel tubes. Source of the chemistry and mechanical limits below. |
| EN 10088-1:2005 | X7CrNiTi18-10 (1.4940) | Stainless steels, list of stainless steels. That edition has since been superseded by EN 10088-1:2014. |
| ISO 4955 (1994 and later editions) | X7CrNiTi18-10, old code H11 | Heat-resisting steels and alloys. |
| ISO 9327-5 | X7CrNiTi18-10, grade F54 | Steel forgings and rolled or forged bars for pressure purposes, stainless steels. The forging-specific listing. |
| ISO 15510 / ISO/TS 15510 | X7CrNiTi18-10 | Stainless steels, chemical composition. |
| ISO/DIS 9328-7 | X7CrNiTi18-10 | Steel flat products for pressure purposes, stainless steels. |
| ASTM A182 / ASME SA-182 | F321H, UNS S32109 | The usual ASTM route for forged flanges, fittings, valves and parts in this grade. |
State on the enquiry which framework governs. The limits are close but not identical, as the next two tables show, and we build the melt and the test plan around whichever one is named on the order.
Equivalent grades
| Region or body | Designation | Region or body | Designation |
|---|---|---|---|
| EN number | 1.4940 | Japan, JIS | SUS 321H, SUS 321HTP |
| ISO 4955 | X7CrNiTi18-10, old code H11 | Korea, KS | STS 321H |
| USA, ASTM | 321H, A182 F321H | Germany, DIN | X8CrNiTi18-10 (1.4878) |
| USA, UNS | S32109 | France, NF | Z6CNT 18-10 |
| China, GB | 07Cr19Ni11Ti (S32169) | Russia, GOST | 12Kh18N10T |
| UK, BS | 321S51, 321S20 | Closest general-purpose grade | 1.4541 / X6CrNiTi18-10 / AISI 321 / A182 F321 |
1.4940 against 1.4541. X6CrNiTi18-10 (1.4541, AISI 321, A182 F321) has a carbon maximum of 0.08 % and no minimum, and is the general-purpose stabilised grade. X7CrNiTi18-10 (1.4940, 321H) holds carbon between 0.04 and 0.08 % so that high-temperature strength is predictable. A 1.4541 heat analysing at 0.02 % carbon will not satisfy a 1.4940 order. Where the carbon of a single heat falls inside both windows, dual certification is often possible, and we will say so at quotation stage rather than after the steel is poured.
Chemical composition
| Element | EN 10216-5:2014 1.4940 | ISO 4955:1994 X7CrNiTi18-10, H11 | ASTM A182 F321H / S32109 |
|---|---|---|---|
| Carbon C | 0.04 – 0.08 | 0.04 – 0.10 | 0.04 – 0.10 |
| Silicon Si | max 1.00 | max 1.00 | max 1.00 |
| Manganese Mn | max 2.00 | max 2.00 | max 2.00 |
| Phosphorus P | max 0.040 | max 0.045 | max 0.045 |
| Sulphur S | max 0.015 | max 0.030 | max 0.030 |
| Chromium Cr | 17.0 – 19.0 | 17.0 – 19.0 | 17.00 – 19.00 |
| Nickel Ni | 9.0 – 13.0 | 9.0 – 12.0 | 9.00 – 12.00 |
| Nitrogen N | max 0.10 | not specified | max 0.10 where Ti is set on C+N |
| Titanium Ti | 0.20 – 0.80 with 5 × (C+N) < Ti < 0.80 | 5 × C, max 0.80 | 4 × (C+N) min 0.70 max |
The titanium to carbon ratio is the controlling figure for this grade, and the three frameworks express it differently: EN 10216-5 sets the floor at 5 × (C+N), ASTM at 4 × (C+N). Our laboratory checks the ratio on every heat by optical emission spectrometry to ASTM E415, with carbon confirmed on an infrared carbon and sulphur analyser to ASTM E1019, and the as-melted figures are printed on the certificate.
Mechanical properties
| Property | Longitudinal | Transverse |
|---|---|---|
| Proof strength Rp0.2, min | 190 MPa | 190 MPa |
| Tensile strength Rm | 510 – 710 MPa | 510 – 710 MPa |
| Elongation at fracture A, min | 35 % | 30 % |
| Impact energy KV at +20 °C, min | 100 J | 60 J |
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, min (A182 F321H) | 515 MPa | 75 ksi |
| Yield strength, min (A182 F321H) | 205 MPa | 30 ksi |
| Elongation in 50 mm or 4D, min (A182 F321H) | 30 % | 30 % |
| Reduction of area, min (A182 F321H) | 50 % | 50 % |
| Elongation, min (A240 321H plate) | 40 % | 40 % |
| Hardness, max (A240 321H plate) | 217 HBW | 217 Brinell |
The two frameworks do not agree, and the ASTM strength minima are the higher of the two. Testing here runs on a 600 kN WE-600B hydraulic machine and a WDW-300 electronic machine to ASTM A370 and ISO 6892, with Charpy V-notch on a JBN-300 pendulum and a low-temperature bath to minus 60 °C.
Physical properties
| Property | Value |
|---|---|
| Density | 7.9 g/cm³ (EN 1.4940); 7.92 g/cm³ quoted for 321/321H |
| Modulus of elasticity at 20 °C | 193 GPa |
| Thermal conductivity at 100 °C | 16.0 W/m·K |
| Specific heat, 0 to 100 °C | 444 J/kg·K |
| Mean coefficient of thermal expansion | 16.0 × 10-6/K (20–100 °C) 18.9 × 10-6/K (20–600 °C) 20.5 × 10-6/K (20–1000 °C) |
| Melting range | 1,398 – 1,446 °C |
| Magnetic response | Non-magnetic as annealed; slightly magnetic after heavy cold work |
Corrosion behaviour
The titanium is there for stabilisation. Free carbon is tied up as titanium carbide, so it is no longer available to form chromium carbides at grain boundaries when the steel sits in the sensitisation range of roughly 427 to 816 °C. That is what lets a stabilised grade be welded in heavy section, cycled thermally and run hot without the chromium depletion that attacks unstabilised 304 and 304H in the same duty. Published data for 321 also credits the grade with resistance to polythionic acid stress corrosion cracking in hydrocarbon service, which is why refineries specify it for hot piping and exchanger parts.
General corrosion resistance is comparable to 304: usable in dilute organic acids at moderate temperature, in pure phosphoric acid at lower temperature, and in chloride-free and fluoride-free caustic solutions at moderate temperature. It is not suitable for chloride solutions even at low concentration, and not for sulfuric acid. There is no molybdenum in the composition, so pitting resistance is low. For seawater, chloride-bearing process streams or sour service the right families are duplex and super-duplex (A182 F51, F53, F55), the 6 % molybdenum grades (A182 F44, 904L) or nickel alloys (Incoloy 825, Hastelloy C-276). We forge all of them, and we will say so if the service conditions point away from 1.4940.
One point worth putting on the order. The EN 10216-5 property listing for 1.4940 records resistance to intergranular corrosion as not guaranteed. Stabilisation is a mechanism, not a certified property, and the standard does not undertake to demonstrate it. Where intergranular corrosion resistance matters, name a test on the order: ASTM A262, with Practice E the usual choice for stabilised grades, or EN ISO 3651-2. We place that work with an accredited third-party laboratory and issue the report with the mill certificate. It needs scheduling before shipment, so raise it at enquiry stage.
Forging and heat treatment
Supply condition is +AT, solution annealed and rapidly cooled. Published practice for 321 and 321H puts hot working at 1,149 to 1,260 °C for forging and upsetting, with no working below 927 °C, and requires a water quench or a full anneal after hot work to bring corrosion resistance back. We work to that schedule unless the customer specification says otherwise, and record the cycle on a chart that ships with the certificate.
Heat treatment is in-house across fourteen furnaces. Car-bottom furnaces take work up to 8,000 × 2,000 × 2,000 mm, three high-temperature car-bottom furnaces cover the upper end of the solution-annealing range, and two 15 m well-type furnaces let long shafts be quenched vertically so they come out straight.
On machining, this steel work-hardens as it is cut, in the same way as 304, so it wants sharp tooling, a positive rake, rigid setups, flood coolant and a feed that stays engaged rather than dwelling. Published turning data for the grade runs around 12 to 28 m/min with high speed steel and 67 to 108 m/min with carbide, depending on depth of cut. Our vertical lathes go to 5,000 mm swing, horizontal lathes to 14,000 mm between centres, and a CNC deep-hole drilling machine bores 1,600 × 10,000 mm. For welding, the grade takes standard processes and post-weld heat treatment is not normally needed; ER347 or ER321 filler is the conventional match, with ER347 often preferred because niobium carries across the arc more reliably than titanium.
Forged products in X7CrNiTi18-10
| Product | Size limit | Set by |
|---|---|---|
| Seamless rolled rings | OD 50 mm to 6,000 mm | 6 m, 3 m and 1 m radial-axial ring mills |
| Forged shafts | up to 14,000 mm turned length | C61160 horizontal lathe; 15 m well furnace for vertical quench |
| Discs, tube sheets, blocks | up to 5,000 mm machined diameter | 5,000 mm swing vertical turning lathe |
| Bored cylinders and hollow shafts | up to 1,600 × 10,000 mm | CNC deep-hole drilling machine |
| Single-piece weight | up to 30,000 kg | 60 t maximum heat size; 6,300 t, 4,000 t and 2,000 t presses |
| Minimum order | 10 kg, no minimum piece count | Limit is by weight, so one-off parts are quotable |
Where the grade is used
X7CrNiTi18-10 earns its place wherever a stabilised austenitic has to stay hot for a long time and still be weldable. Forged applications include superheater and reheater headers, steam piping components and boiler parts in power generation; cracking furnace and reformer components, hot transfer-line flanges and pyrolysis header forgings in petrochemical plant; exchanger tube sheets, covers, shells and nozzle forgings in refineries, where resistance to polythionic acid cracking matters; furnace rollers, radiant tube components, muffle and annealing box hardware in thermal processing; and manifold and hot ducting components in aerospace and heavy engine work. ATI quotes a maximum use temperature of 816 °C for 321, 347 and 348 in code applications. Pressure-boundary forgings are normally ordered against ISO 9327-5 F54 or ASTM A182 F321H, with ultrasonic examination to EN 10228-3 or ASTM A388.
For cold service rather than hot, the general-purpose stabilised grades are usually the better buy. See A182 F321 (1.4541), or the niobium-stabilised A182 F347 and 347H.
Testing, inspection and certification
Because the steel is melted here rather than bought in, chemistry is verified at the furnace and the certificate traces a part back to its melt number. Release runs through melt analysis, mechanical testing on a representative test piece, non-destructive examination, dimensional inspection, then certification.
| Discipline | Method or equipment | Standard |
|---|---|---|
| Chemical analysis | Optical emission spectrometer, SPECTROTEST TXC25 | ASTM E415 |
| Carbon and sulphur | Infrared analyser HIR-9440D, used to hold the 0.04 % carbon floor | ASTM E1019 |
| Alloy verification | Handheld PMI analyser X-Mwt3000TX, titanium confirmed | Positive material identification |
| Tensile | WE-600B 600 kN; WDW-300 electronic | ASTM A370, ISO 6892 |
| Impact | JBN-300 pendulum with DWC-60 bath, to minus 60 °C | ASTM A370 |
| Ultrasonic | PXUT-3300, USM35XS, CTS-22 | ASTM A388, EN 10228-3, SEP 1921 |
| Magnetic particle and visual | CYE-3A; industrial endoscope for bores | ASTM E709 |
| Grain size and metallography | XJP-6A microscope, mounting press, polisher | ASTM E112 |
| Intergranular corrosion | Placed with an accredited third-party laboratory | ASTM A262, ASTM G28, EN ISO 3651-2 |
Certification is EN 10204 3.1 as standard, or EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or your own inspector on request. The works holds CCS, BV, DNV, LR and NK class approvals. Heat-treatment charts, NDT reports, dimensional reports and PMI records go out with the certificate.
How to order
Quotations are prepared from a drawing or a written specification. Sending the six items below in the first email removes a round trip and usually gets a price back within two working days. Normal lead time for this grade is 20 to 60 days from order confirmation; standard stainless grades sit at the lower end because no remelting step is involved.
| # | Item | Example for this grade |
|---|---|---|
| 1 | Grade and governing specification | X7CrNiTi18-10 / 1.4940 to EN 10216-5, or 321H to ASTM A182 F321H |
| 2 | Dimensions, or a drawing (PDF, DWG, DXF, STEP) | Ring OD 1,450 × ID 1,100 × H 300 mm |
| 3 | Quantity and expected repeat volume | 8 pieces, about 3 per year |
| 4 | Delivery condition | Solution annealed +AT, proof-machined |
| 5 | Heat treatment and testing requirements | UT to EN 10228-3 class 3, ASTM A262 Practice E |
| 6 | Certification and destination port | EN 10204 3.2 witnessed by DNV, Rotterdam |
Email the enquiry Call +86 189 2135 9659
Frequently asked questions
Is X7CrNiTi18-10 the same as 1.4541 or AISI 321?
No. X7CrNiTi18-10 is material number 1.4940, with carbon held between 0.04 and 0.08 % under EN 10216-5 so that strength at temperature is predictable. X6CrNiTi18-10 is 1.4541, also sold as AISI 321 and A182 F321, with carbon capped at 0.08 % and no minimum. Both are titanium-stabilised 18/10 austenitic grades and both resist sensitisation by the same mechanism, but they are separate grades with separate certificates, and a low-carbon 1.4541 heat cannot be certified as 1.4940.
Can resistance to intergranular corrosion be guaranteed for X7CrNiTi18-10?
Not by reference to EN 10216-5 on its own, because that standard lists resistance to intergranular corrosion for 1.4940 as not guaranteed. The titanium stabilisation is designed to prevent sensitisation, but where the resistance has to be demonstrated rather than assumed, name ASTM A262, usually Practice E for stabilised grades, or EN ISO 3651-2 on the order. We place that testing with an accredited third-party laboratory and issue the report with the mill certificate.
Does Jiangyin Jiangnan Metal melt its own steel?
Yes. A 25 t electric arc furnace with 25 t and 50 t ladle furnaces and 30 t and 60 t vacuum oxygen decarburisation units covers carbon, alloy, stainless and duplex grades, alongside 2 t, 8 t and 25 t medium-frequency induction furnaces. Maximum heat size is 60 tonnes. For a grade whose identity rests on a 0.04 to 0.08 % carbon window and a titanium level keyed to carbon plus nitrogen, the vacuum oxygen decarburisation step is where that control happens, so the certificate traces back to a melt number rather than to a purchased billet certificate.
What are the maximum size and the minimum order for X7CrNiTi18-10 forgings?
Seamless rings roll to 6,000 mm outside diameter, the heaviest single forging is 30 tonnes, and shafts machine to 14,000 mm between centres. The minimum order is 10 kg with no minimum piece count, so a single small ring or one prototype disc can be quoted. Very small parts are grouped into a batch to share furnace and setup time, which is why quantity still affects the unit price.
Does X7CrNiTi18-10 need post-weld heat treatment?
Generally no. Published data for 321 and 321H states that post-weld heat treatment is not necessary, which is one reason stabilised grades are specified. Stress relief may still be called for on heavily restrained fabrications for dimensional stability, or because the construction code demands it. ER347 or ER321 filler is the conventional match.
Can X7CrNiTi18-10 be solution treated and aged for higher strength?
No. The grade is austenitic and cannot be hardened by heat treatment, only by cold work. The delivery condition is solution annealed and rapidly cooled, designated +AT. For a high-strength stainless forging the precipitation-hardening family is the right place to look, such as 17-4PH, 15-5PH or PH13-8Mo.
What certification is supplied with X7CrNiTi18-10 forgings?
EN 10204 3.1 mill test certificates are standard, and EN 10204 3.2 certificates witnessed by BV, DNV, LR, SGS, TUV or the buyer's own inspector are available on request. The works holds CCS, BV, DNV, LR and NK approvals. Heat-treatment charts, non-destructive testing reports, dimensional reports and positive material identification records go out with the certificate.
Factory visits
Audits and third-party inspections are welcome. The plant is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, between Shanghai and Nanjing on the south bank of the Yangtze, 30 km from Wuxi Shuofang International Airport and about 160 km from the Shanghai airports. Email sales@steelforgepieces.com or call +86 189 2135 9659 to arrange a visit.
Related grades we forge
A182 F321 (1.4541) · A182 F347 · AISI 347H · AISI 330 · A286 · 904L · A182 F44 · A182 F51 · A182 F53 · A182 F55 · Nitronic 50 · Nitronic 60 · Incoloy 800H · Inconel 625
Data sources: composition, mechanical limits and the intergranular corrosion note for 1.4940 are from EN 10216-5:2014 and EN 10088-1 as listed in the European Steel and Alloy Grades database; the DIN EN 10088-1 entry and its seamless-tube remark are from the Applus materials portal; ISO 4955 composition and the international cross-references are from published grade comparison tables; F321H forging limits are from ASTM A182 / A182M; 321 and 321H plate properties, hot forming, machining and corrosion data are from published mill datasheets for that grade; the 816 °C code temperature limit is quoted from an ATI datasheet for 321, 347 and 348. Capability, equipment, approvals and commercial terms are our own. Standard values are given for guidance, and the edition of the specification named on your order takes precedence.