1.4940 (X7CrNiTi18-10) forgings
1.4940 / X7CrNiTi18-10 is a titanium-stabilised 18-10 austenitic creep resisting stainless steel. Its closest commercial counterpart is 321H, UNS S32109. We melt, forge, heat treat, machine and certify it in one works: rolled rings, flanges, bars, discs, tube sheets and shafts, single pieces up to 30 tonnes, EN 10204 3.1 certification as standard and 3.2 witnessed on request.
Designation and classification
| EN material number | 1.4940 |
|---|---|
| EN designation | X7CrNiTi18-10 |
| Classification | Austenitic creep resisting steel |
| Density | 7.9 g/cm³ |
| Standards carrying 1.4940 | EN 10216-5:2014, seamless steel tubes for pressure purposes; EN 10088-1:2005, list of stainless steels |
| Nearest ASTM and UNS | ASTM A182 F321H, ASTM A213 Type 321H, UNS S32109, AISI 321H, SUS 321H. Near equivalents, ranges differ |
| EN forging counterpart | X6CrNiTiB18-10 (1.4941), the titanium-stabilised 18-10 grade listed in EN 10222-5 for pressure purpose forgings |
| Strengthening | Solution treatment and quench. The grade cannot be age hardened, and hardens only by cold work |
Two points are worth correcting, because both circulate widely in trade datasheets. 1.4940 is classified as a creep resisting steel, not as a general purpose austenitic grade. And it cannot be given a solution plus ageing treatment: the 321 and 321H family cannot be hardened by thermal treatment at all.
Which standard governs a 1.4940 forging
This question decides what can be written on the certificate. The number 1.4940 is carried by the seamless tube standard EN 10216-5 and by the stainless steel list EN 10088-1. It is not one of the grades in EN 10222-5, the European standard for steel forgings for pressure purposes. The titanium-stabilised 18-10 grade in that standard is the boron bearing X6CrNiTiB18-10 (1.4941), listed together with X7CrNiNb18-10 (1.4912) and X6CrNi18-10 (1.4948).
An enquiry for 1.4940 forged flanges therefore resolves to one of three deliverable routes. We forge all three.
| Route | Grade | Governing standard | Typical use |
|---|---|---|---|
| ASTM and ASME | F321H, UNS S32109 | ASTM A182/A182M for pieces up to 4540 kg; A965/A965M above that weight, as A182 itself directs for austenitic grades | Piping components, flanges, valve parts, code work |
| EN pressure forgings | 1.4941, X6CrNiTiB18-10 | EN 10222-5. The grade also appears in EN 10028-7, EN 10302:2008, EN 10269 and EN 10216-5 | European pressure vessel and boiler scopes where creep design data is required |
| To 1.4940 chemistry | 1.4940, X7CrNiTi18-10 | EN 10216-5 chemistry applied to a forging by agreement, stated as such on the certificate | Matching an existing tube grade specification or a legacy drawing |
We do not issue documents that imply EN 10222-5 approval for a grade that standard does not list. The certificate states the chemistry actually met and the standard actually applied.
Chemical composition
Three columns, because the differences decide whether a heat passes. Note the nickel ceiling, 13 percent in EN 10216-5 against 12.00 percent in A182 F321H, and the carbon ceiling, 0.08 against 0.10 percent.
| Element | 1.4940, X7CrNiTi18-10 EN 10216-5:2014 |
A182 F321H, S32109 ASTM A182/A182M |
1.4941, X6CrNiTiB18-10 EN 10222-5 grade |
|---|---|---|---|
| Carbon | 0.04 to 0.08 | 0.04 to 0.10 | 0.040 to 0.080 |
| Silicon | 1.00 max | 1.00 max | 1.0 max |
| Manganese | 2.00 max | 2.00 max | 2.0 max |
| Phosphorus | 0.040 max | 0.045 max | 0.035 max |
| Sulfur | 0.015 max | 0.030 max | 0.015 max |
| Chromium | 17.0 to 19.0 | 17.0 to 19.0 | 17 to 19 |
| Nickel | 9.0 to 13.0 | 9.0 to 12.0 | 9.0 to 12 |
| Titanium | 0.20 to 0.80, with 5×(C+N) < Ti < 0.8 | Titanium stabilised. Not less than 4×C, 0.70 max; some editions state 4×(C+N), 0.70 max | 0.40 to 0.80 |
| Nitrogen | 0.10 max | no requirement | no requirement |
| Boron | no requirement | no requirement | 0.0015 to 0.0050 |
| Iron | balance | balance | balance |
Boron is the defining difference in 1.4941. It is a deliberate micro addition in that creep resisting grade and is absent from both 1.4940 and F321H. A heat melted to 1.4941 will not automatically satisfy a drawing calling for 1.4940, and the reverse is also true. Datasheets that show 1.4940 with titanium 0.35 and a tensile strength of 480 MPa have been taken from a generic 321H table rather than from EN 10216-5.
Mechanical properties, solution annealed
| Property | 1.4940, EN 10216-5 (+AT) | A182 F321H, minima | 1.4941, typical values |
|---|---|---|---|
| Tensile strength Rm | 510 to 710 MPa | 515 MPa min, 75 ksi | 590 MPa |
| 0.2 percent proof strength Rp0.2 | 190 MPa min | 205 MPa min, 30 ksi | 210 MPa |
| Elongation A | 35 percent min longitudinal, 30 percent min transverse | 30 percent min | 39 percent |
| Reduction of area | no requirement | 50 percent min | not stated |
| Impact energy KV at +20 °C | 100 J longitudinal, 60 J transverse | no requirement | 98 J |
| Hardness, Brinell | no requirement | no requirement in Table 2 | 180 |
| Modulus of elasticity | not stated | not stated | 200 GPa |
The 1.4940 and F321H columns are specification limits. The 1.4941 column holds typical published values for the solution annealed condition and should not be used as acceptance criteria. Tensile testing is carried out to ASTM A370 or ISO 6892 and Charpy V notch testing to the temperature stated on the order.
Forging and heat treatment
For a titanium-stabilised 18-10 forging the sequence is set by the standard. ASTM A182 clause 7.1 requires forgings to be cooled below 538 °C after hot working before heat treatment begins. F321H is then solution treated from 1095 °C minimum, liquid quenched, and cooled below 260 °C. F321 and F321H are among the grades excluded from the in line rapid quench alternative in clause 7.3.1, so a dedicated furnace cycle is required rather than optional.
| Operation | Parameters | Source of the requirement |
|---|---|---|
| Cooling after hot working | below 538 °C before heat treating | ASTM A182 clause 7.1 |
| Solution treat and quench, F321H | 1095 °C minimum, liquid quench, cool below 260 °C | ASTM A182 Table 1 |
| Solution treat and quench, F321 | 1040 °C minimum, liquid quench, cool below 260 °C | ASTM A182 Table 1 |
| Solution anneal, 321 and 321H generally | 950 to 1120 °C, cool rapidly | Published grade 321 and 347 data |
| Stabilising anneal | 870 to 900 °C, 1 h per 25 mm of thickness, air cool. Used for service above 425 °C and after annealing at the top of the range | Published grade 321 and 347 data |
| Stress relief | 700 °C, 1 to 2 h, air cool | Published grade 321 data |
| Ageing or precipitation hardening | Not applicable. The grade cannot be hardened by thermal treatment | Published grade 321 and 347 data |
One requirement should be settled before the order is placed. A182 carries a warning that solution annealing above 1065 °C may impair resistance to intergranular corrosion after later sensitising exposure in F321, F321H, F347, F347H, F348 and F348H, while the same table sets the F321H solution temperature at 1095 °C minimum. The two pull in opposite directions. Where the service case involves sensitising exposure, A182 provides for a lower temperature stabilisation or a re-solution anneal after the initial cycle under supplementary requirement S10. Stating which of the two matters puts the route into the works order instead of leaving it to the shop floor.
All heat treatment is carried out in our own furnaces, fourteen in total, including car bottom furnaces for solution treatment of rings, discs and tube sheets and well type furnaces for vertical quenching of long shafts. Nothing is subcontracted, so the furnace charts belong to the same traceable record as the melt.
Corrosion and temperature behaviour
Titanium stabilisation is the purpose of this grade. Titanium ties up carbon as titanium carbide so that chromium carbide does not precipitate at the grain boundaries during exposure in the carbide precipitation range, published as 425 to 850 °C for 321 and 347 and 427 to 816 °C for 321H. That is why 321 is chosen ahead of 304L where the operating temperature runs above roughly 500 °C, since 304L has lower hot strength. Oxidation resistance is good to 900 °C intermittent and 925 °C continuous. With its higher carbon, 321H carries higher hot strength than 321 and is the choice for high temperature structural work.
The limits matter as much as the strengths. The 321 family is subject to pitting and crevice corrosion in warm chloride environments and to stress corrosion cracking above about 60 °C. Above roughly 1100 °C the grade is out of its range and 310 or S30815 is the sensible substitution.
On intergranular corrosion the published record is not consistent. The steelnumber entry for 1.4940 under EN 10216-5 states no resistance to intergranular corrosion, while the same database records 1.4941 as resistant both as delivered and in the sensitised condition under EN 10028-7. Where the service case depends on it, order ASTM A262 practice testing. We place that with an accredited third party laboratory and issue the report with the mill certificate.
Two claims that appeared on the earlier version of this page have been removed because we could not support them: excellent resistance in hydrofluoric acid and fluorine, and good resistance to hot strong alkali. Neither is consistent with the sources listed at the foot of this page. For hydrofluoric service, ask about the nickel alloys instead.
On fabrication, titanium does not transfer well across a high temperature arc, so 321 is not used as a welding consumable. Grade 347 is the standard filler for welding 321, the niobium performing the same stabilising function. Post weld annealing is not required for this family. Our forgings are single piece, with no welding and no purchased billet of unknown origin.
Products in 1.4940 and 321H
Each item below is forged from one piece of steel melted in our own furnaces.
| Product | Notes on size and standard |
|---|---|
| Seamless rolled rings, contoured rings, bearing races, slewing and yaw rings | Rolled on a 6 m radial axial ring mill. Upset and punch route used below ring mill range |
| Forged rings, gear rings, retaining rings, valve seat rings | Sections outside the ring mill envelope forged on the 6300 t press |
| Forged flanges, weld neck, blind, slip on, socket weld, lap joint, orifice, long weld neck | To ASME B16.5, B16.47 and API 6A dimensions. A182 limits single pieces to 4540 kg |
| Forged shafts, spindles, rolls, rotors, tie rods | Vertical quenching available in well type furnaces to control distortion |
| Tube sheets, discs, covers, hubs | Supplied as forged or proof machined for ultrasonic testing |
| Forged bars and blocks, round, flat and square | Sizes to drawing |
| Forged cylinders, sleeves, bushings, heavy wall pipe sections | Bored on CNC deep hole drilling equipment |
| Valve and wellhead parts, bodies, bonnets, stems, seat rings, spools, nozzles, manifolds | API 6A and NACE MR0175 / ISO 15156 where specified on the order |
| Single piece weight, any product | Up to 30 tonnes, from heats up to 60 tonnes |
The weight limit has a commercial consequence for this grade. ASTM A182 restricts products made to it to 10 000 lb, 4540 kg, and directs larger austenitic forgings to A965/A965M. Our press and ring mill reach 30 tonnes, so heavy 321H rings and tube sheets are inside our range but outside the scope of A182. Send the weight and the code you are working to, and we will confirm which specification the certificate should be written against before the order is placed.
Melted here, not bought in
Most forging suppliers in China buy billet. This works starts at the furnace, which for a stabilised grade is where the part is decided. The titanium to carbon plus nitrogen ratio that EN 10216-5 writes as 5×(C+N) < Ti < 0.8 is set in the melt shop, and a purchased billet certificate either happens to satisfy it or does not.
Carbon, alloy, stainless and duplex grades run through the electric arc furnace, the ladle furnace and vacuum oxygen decarburisation, which is the route used where low carbon and controlled nitrogen are needed, as they are for 1.4940 with its 0.08 percent carbon and 0.10 percent nitrogen ceilings. Maximum heat size is 60 tonnes. Clean and superalloy grades take the vacuum induction, vacuum arc and protective atmosphere electroslag remelting routes, so double melt specifications need no subcontracting. Traceability runs from the melt number through forging, heat treatment and machining to shipment.
Testing, approvals and certification
| Class approvals held | CCS, BV, DNV, LR, NK |
|---|---|
| Standard certificate | EN 10204 3.1 mill test certificate |
| Witnessed certificate | EN 10204 3.2, witnessed by BV, DNV, LR, SGS, TÜV or the customer's own inspector, on request |
| Chemistry | Optical emission spectrometry to ASTM E415, infrared carbon and sulfur analysis to ASTM E1019, positive material identification |
| Mechanical | Tensile to ASTM A370 and ISO 6892, Charpy V notch, grain size to ASTM E112 |
| Non destructive testing | Ultrasonic to ASTM A388 and EN 10228-3, magnetic particle to ASTM E709 where applicable |
| Placed with accredited laboratories | ASTM A262 and ASTM G28 intergranular attack, ASTM G48 pitting, low temperature impact testing, bench hardness |
| Supporting records | Heat treatment charts, NDT reports, dimensional reports, material identification records |
Request a quotation
Open die work has no list price. Cost follows finished weight, input weight after machining allowance, the number of heating and forging operations, the heat treatment cycle and the testing scope. Six items are enough for a firm price.
| Item | Example for this grade |
|---|---|
| Grade and governing standard | ASTM A182 F321H, UNS S32109; or EN 10222-5 grade 1.4941; or 1.4940 chemistry to EN 10216-5 |
| Dimensions or drawing in PDF, DWG, DXF or STEP | Rolled ring, OD 1200 × ID 900 × H 260 mm |
| Quantity and expected repeat volume | 12 pieces, about four times per year |
| Delivery condition | As forged, proof machined for ultrasonic testing, or finish machined |
| Heat treatment and testing | Solution treated and water quenched, stabilising anneal 870 to 900 °C, UT to ASTM A388, ASTM A262 Practice E |
| Certification and destination port | EN 10204 3.2 witnessed by DNV, Rotterdam |
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. Customer audits and third party witness testing are welcome. Please book by email so that an English speaking engineer is available.
Frequently asked questions
Is 1.4940 the same as 321H?
Near equivalents, not identical grades. Published equivalence tables map 1.4940 / X7CrNiTi18-10 to UNS S32109, AISI 321H and SUS 321H. EN 10216-5 gives 1.4940 carbon 0.04 to 0.08 percent and nickel 9 to 13 percent, while A182 F321H allows carbon 0.04 to 0.10 percent and nickel 9.00 to 12.00 percent. Equivalence tables for S32109 also list X8CrNiTi18-10 (1.4878) as a European equivalent. One heat can meet one specification and fail another, so name the governing standard on the order.
Can 1.4940 be supplied as a forging under a European standard?
Not under its own number. 1.4940 sits in EN 10216-5 for seamless tube and in EN 10088-1. The titanium-stabilised 18-10 grade in EN 10222-5 for pressure purpose forgings is X6CrNiTiB18-10 (1.4941), listed with 1.4912 and 1.4948. For forged rings, flanges and discs the clean routes are EN 10222-5 grade 1.4941 or ASTM A182 F321H. Both are forged here.
How is 1.4940 or 321H heat treated after forging?
Cool below 538 °C after hot working, then solution treat from 1095 °C minimum for F321H and liquid quench below 260 °C. F321 uses 1040 °C minimum. Both are excluded from the in line rapid quench alternative in A182 clause 7.3.1, so a separate furnace cycle is required. A182 also warns that annealing above 1065 °C can impair intergranular corrosion resistance after later sensitising exposure, in which case a lower temperature stabilisation or re-solution anneal applies. No ageing: the grade hardens only by cold work.
What is the largest 1.4940 forging available?
Single pieces up to 30 tonnes, from heats up to 60 tonnes, on a 6300 t press with a 6 m ring mill. A182 limits products made to it to 4540 kg and directs heavier austenitic forgings to A965/A965M, so for parts above that weight the certifying standard needs to be settled before the order.
Does 1.4940 resist intergranular corrosion?
Test it rather than assume it. Titanium stabilisation is what keeps 321 and 321H free from sensitisation in the 425 to 850 °C carbide precipitation range, yet the steelnumber entry for 1.4940 under EN 10216-5 states no resistance to intergranular corrosion, while 1.4941 is recorded as resistant both as delivered and sensitised under EN 10028-7. Where it matters, order ASTM A262 practice testing. We place it with an accredited third party laboratory and issue it with the mill certificate.
What does a 1.4940 forging cost?
There is no list price for open die work. Cost is driven by finished weight, input weight after machining allowance, the number of heating and forging operations, the heat treatment cycle and the testing scope. Send the six items listed above and we will price the part.
Sources for the data on this page
Every figure above traces to one of the following. Where two sources disagree, the disagreement is stated rather than resolved silently.
- EN 10216-5:2014, Seamless steel tubes for pressure purposes, stainless steel tubes. Chemistry and solution annealed mechanical values for X7CrNiTi18-10 (1.4940).
- EN 10088-1:2005, Stainless steels, list of stainless steels.
- EN 10222-5, Steel forgings for pressure purposes, martensitic, austenitic and austenitic-ferritic stainless steels. Grade list including X6CrNiTiB18-10 (1.4941).
- EN 10302:2008, Creep resisting steels, nickel and cobalt alloys.
- EN 10028-7, Flat products made of steels for pressure purposes, stainless steels.
- ASTM A182/A182M, Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service. F321H chemistry and footnote, Table 2 mechanical minima, Table 1 heat treatment, clauses 1.2, 7.1 and 7.3.1, supplementary requirement S10.
- Published grade datasheets for stainless steel 321 (UNS S32100) and 321H (UNS S32109), for heat treatment ranges, oxidation and corrosion limits and welding practice.
- Applus Laboratories materials portal, datasheet X7CrNiTi18-10 / 1.4940, for standard status and international cross references.
- steelnumber.com, European steel and alloy grades database, entries for 1.4940 and 1.4941 and the equivalence table for S32109.
- MakeItFrom material property record for EN 1.4941 (X6CrNiTiB18-10), for typical solution annealed values and the boron range.
Reviewed 27 September 2026 by the technical department, Jiangyin Jiangnan Metal Co., Ltd. The data is indicative and does not replace the governing standard or an agreed order specification.