1. The designation: what X15CrNi25-20 means
Read this before ordering
X15CrNi25-20 is not a current EN designation. EN 10095 lists the 25Cr-20Ni austenitic heat-resisting grades as X15CrNiSi25-21 (1.4841) and X8CrNi25-21 (1.4845). Older DIN-era datasheets give the name of 1.4841 as X15CrNiSi25-20, and 1.4842 is named X12CrNi25-20.
Written without the silicon symbol, X15CrNi25-20 points at 1.4841 in the large majority of enquiries. A minority of buyers use it for 1.4842 / AISI 310. The difference is not cosmetic. 1.4841 carries 1.50 to 2.50 % silicon, and that silicon buys the top 50 to 100 °C of scaling resistance. Jiangyin Jiangnan Metal confirms the intended material number in writing before any heat is melted.
Three grades sit within a few percent of each other in chromium and nickel, carry similar names, and behave differently in service. Settle which one applies on paper, not at the goods-in bay.
| Material number | Designation | Carbon | Silicon | Usually called |
|---|---|---|---|---|
| 1.4841 | X15CrNiSi25-21 (old DIN: X15CrNiSi25-20) | ≤ 0.20 % | 1.50 to 2.50 % | AISI 314, S31400 |
| 1.4842 | X12CrNi25-20 | ≤ 0.15 % | Lower, no Si minimum | AISI 310 |
| 1.4845 | X8CrNi25-21 | ≤ 0.10 % | ≤ 1.50 % | AISI 310S, S31008 |
The 1.4841 and 1.4845 limits are from the EN 10095 composition tables. 1.4842 is a DIN-era designation cross-referenced by mills and stockholders to AISI 310 and is not listed in EN 10095. Where a project specification names only X15CrNi25-20, state the material number or the service temperature on the enquiry and the correct grade will be proposed.
2. What the grade is
1.4841 is a fully austenitic chromium-nickel-silicon steel for continuous service in hot gas. Chromium at 24 to 26 % forms the protective oxide. Nickel at 19 to 22 % holds the structure austenitic at temperature, which is what stops the thermal fatigue and spalling that shortens the life of ferritic grades under cyclic heating. Silicon at 1.50 to 2.50 % densifies the oxide layer and lifts the scaling limit to roughly 1150 °C in air.
Carbon is permitted up to 0.20 %, which is high for a stainless grade and deliberate, since it raises hot strength and creep resistance. The cost is that the steel sensitises in the as-welded condition and is not intended for wet chloride or acid duty. This is a heat-resisting steel rather than a corrosion-resisting one, despite a PREN in the region of 24 to 29.
For a forged component the decision is usually simple. Use 1.4841 where the part lives in a furnace, a burner, a radiant tube or a carburising box and stays hot. Use 1.4845 / 310S where the part is welded into a pressure boundary, where intergranular attack after welding matters, or where the duty is wet rather than dry.
3. Standards and equivalent designations
| System | Designation |
|---|---|
| Material number | 1.4841 |
| EN 10095 name | X15CrNiSi25-21 |
| Older DIN rendering | X15CrNiSi25-20, commonly shortened to X15CrNi25-20 |
| AISI / SAE | 314 |
| UNS | S31400 |
| BS | 314S25 |
| AFNOR | Z15CNS25-20 |
| JIS | SUH 310 |
| PN | H25N20S2 |
| Other trade names | INOX 314, RVS 314 |
| Scope | Specification |
|---|---|
| Heat-resisting steels, semi-finished, bar, plate, strip | EN 10095 |
| Stainless bar and semi-finished composition limits | EN 10088-3 |
| Forgings and forged fittings, 25Cr-20Ni (F310) | ASTM A182 / A182M, ASME SA-182 |
| Plate, sheet and strip, type 310 / 310S | ASTM A240 / A240M |
| Ultrasonic testing of forgings | ASTM A388, EN 10228-3, SEP 1921 |
| Liquid penetrant testing | ASTM E165, EN 10228-2 |
| Inspection documents | EN 10204 3.1 standard, 3.2 on request |
The EN and ASTM routes are not fully interchangeable on this grade. ASTM A182 F310 caps silicon at 1.00 % maximum, while EN 1.4841 sets a silicon minimum of 1.50 %. One heat cannot satisfy both. Where a drawing quotes X15CrNi25-20 and ASTM A182 F310 in the same box, raise it at enquiry stage so the governing specification is fixed before melting.
4. Chemical composition
Limits in weight percent. Every heat is analysed by optical emission spectrometry and the result is printed on the mill certificate. Finished pieces are re-checked by XRF positive material identification before packing.
| Element | Min | Max | Function in this grade |
|---|---|---|---|
| C, carbon | – | 0.20 | High for a stainless grade. Raises hot strength and creep resistance, and is the reason the steel sensitises when welded |
| Si, silicon | 1.50 | 2.50 | The defining addition. Densifies the oxide layer and carries scaling resistance to about 1150 °C |
| Mn, manganese | – | 2.00 | Deoxidiser, austenite stabiliser |
| P, phosphorus | – | 0.045 | Impurity |
| S, sulphur | – | 0.015 | Impurity. Affects hot workability |
| Cr, chromium | 24.00 | 26.00 | Forms the protective oxide. Oxidation and scaling resistance |
| Ni, nickel | 19.00 | 22.00 | Holds the austenitic structure hot. Thermal cycling and carburisation resistance |
| N, nitrogen | – | 0.11 | Residual limit |
| Fe, iron | Balance | Matrix | |
EN 10095 gives silicon as 1.50 to 2.50 %. Datasheets issued against EN 10088-3 commonly show the narrower band 1.50 to 2.00 % with a sulphur limit of 0.015 %. Where a project needs the narrower silicon window, state it on the enquiry and it is written into the purchase specification for the heat.
Composition of the neighbouring grades
| Element | 1.4841 X15CrNiSi25-21 | 1.4845 X8CrNi25-21 | ASTM A182 F310 UNS S31000 |
|---|---|---|---|
| C | ≤ 0.20 | ≤ 0.10 | ≤ 0.25 |
| Si | 1.50 – 2.50 | ≤ 1.50 | ≤ 1.00 |
| Mn | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
| P | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 |
| S | ≤ 0.015 | ≤ 0.015 | ≤ 0.030 |
| Cr | 24.0 – 26.0 | 24.0 – 26.0 | 24.0 – 26.0 |
| Ni | 19.0 – 22.0 | 19.0 – 22.0 | 19.0 – 22.0 |
| N | ≤ 0.11 | ≤ 0.11 | Not specified |
Chromium and nickel are identical across all three. Carbon and silicon decide the selection.
5. Mechanical properties
Room-temperature values in the solution annealed condition. Tested results for the delivered heat appear on the EN 10204 certificate and normally sit above these minima.
| Property | Value |
|---|---|
| Tensile strength, Rm | 550 to 750 MPa |
| Proof strength, Rp0.2 | ≥ 230 MPa |
| Proof strength, Rp1.0 | ≥ 270 MPa |
| Elongation A5, longitudinal | ≥ 30 % |
| Hardness | ≤ 223 HB |
| Impact energy | Not called for by EN 10095. Testing available on request |
| Property | A182 F310 forgings | A240 type 310S plate |
|---|---|---|
| Tensile strength, min | 515 MPa (75 ksi) | 515 MPa |
| Yield strength 0.2 %, min | 205 MPa (30 ksi) | 205 MPa |
| Elongation in 50 mm, min | 30 % | 40 % |
| Reduction of area, min | 50 % | Not specified |
| Hardness, max | Per specification | 95 HRB |
The EN and ASTM figures describe different acceptance routes, not different material quality. EN 10095 sets a proof strength floor of 230 MPa and a tensile band. ASTM A182 sets a tensile floor of 515 MPa and a reduction-of-area requirement. State which standard governs acceptance so the test plan is written correctly at order entry.
6. Physical and thermal data
| Property | Value | Note |
|---|---|---|
| Density | 7.9 g/cm³ | At 20 °C |
| Modulus of elasticity | about 200 GPa | At 20 °C |
| Thermal conductivity | about 14 to 15 W/m·K | At 20 °C. Roughly 30 % of unalloyed steel |
| Specific heat capacity | about 500 J/kg·K | At 20 °C |
| Electrical resistivity | about 0.9 to 1.0 µΩ·m | At 20 °C |
| Magnetisability | Non-magnetic | Can become slightly magnetic after cold forming |
| PREN | about 24 to 29 | Indicative. This is a heat-resisting, not a wet-corrosion, grade |
| Solution annealing | 1050 to 1150 °C | Rapid cooling in air or water |
| Hot forming range | 1150 down to 800 °C | Air cooling after forming |
| Forging range | 1175 down to 1000 °C | Rapid cooling in air or water after forging |
Thermal conductivity around 30 % of that of unalloyed steel has two practical effects. Heating and cooling through section are slow, so soak times on thick forgings are set by measured thickness rather than by habit, and machining needs flood coolant to pull heat out of the cut.
7. High-temperature behaviour and its limits
These four limits decide whether the grade suits the duty.
Scaling resistance in air
Up to about 1150 °C. Continuous service is usually held to around 1100 °C, which leaves margin for local hot spots and furnace excursions.
Creep resistance
Generally quoted up to about 690 °C. Above that the grade is being used for oxidation resistance rather than load-bearing capacity, and stresses must be kept low.
Sulphurous gases
Resistant to oxidising and reducing sulphur-bearing gases only to roughly 650 °C. The high nickel content is a liability here, and sulphur attack above that point needs separate assessment.
Carburising and low-oxygen gases
Moderate resistance to nitrogenous, carburising and low-oxygen atmospheres up to about 900 °C. Suitable for carburising boxes and jigs, with service life set by the atmosphere.
Sigma phase embrittlement
Do not process or hold the material in the 600 to 900 °C band. Sigma phase forms there and embrittles the steel. Parts that must cycle through that range need the exposure assessed at design stage.
Thermal cycling
The fully austenitic structure handles cyclic heating better than ferritic heat-resisting grades. Where cycling is severe and welding is involved, the lower-carbon 310S type 1.4845 is often the safer pick.
8. X15CrNi25-20 forged products
Jiangyin Jiangnan Metal is a forging factory, not a stockholder. Every X15CrNi25-20 item is forged against a drawing or a dimensional data sheet, solution annealed, machined to the agreed allowance and tested before shipment. Single pieces and prototype quantities are quoted.
Seamless rolled rings
Radial-axial rolled from an upset and pierced blank, so grain flow follows the circumference.
- Furnace retaining rings, tower and shell flanges
- Rectangular, contoured and stepped sections
Forged flanges
Weld neck, slip-on, blind, lap joint, orifice and custom bore, to ASME B16.5 or B16.47 dimensions or to drawing.
- Class 150 through Class 2500
- RF, RTJ and FF faces
Round bars and shafts
Forged and peeled or rough turned bar for machined furnace parts, roller shafts, stems and fasteners.
- Straightness class and UT class to agreement
- Centreless ground finish on request
Discs, blanks and tube sheets
Upset forged discs for closures, blind flanges, burner plates and heat exchanger tube sheets, drilled or undrilled.
- Solid and bored discs
- Radial and through-thickness ultrasonic testing
Sleeves, bushings and hollows
Bored and trepanned hollows for radiant tubes, liners, nozzles and roller sleeves, which cuts machining loss.
- Trepanned cores returned or credited
- Long hollows supplied in sections
Valve and furnace components
Bodies, bonnets, stems, seat rings, gate and plug blanks, plus grate bars, hanger pins and basket components.
- Matched sets from one heat on request
- Finish or rough machined
Dimensions to state on the enquiry
| Form | Dimensions to give |
|---|---|
| Seamless rolled ring | Outside diameter, inside diameter, height, section profile if not rectangular |
| Flange | Type, nominal size, class, facing, bore, or the drawing |
| Round bar or shaft | Diameter, length, straightness class, surface condition |
| Disc, blank or tube sheet | Diameter, thickness, bore if any, hole pattern if drilled |
| Sleeve or hollow | Outside diameter, inside diameter, length, bored or trepanned |
| All forms | Quantity, material number, delivery condition, NDT class, certification level, service temperature, applicable project specification |
9. Forging route
Melting and billet supply
Electric arc furnace melting with VOD refining, followed by electroslag remelting where the specification or the section size calls for tighter control of segregation and inclusion content. Each heat is analysed before release, and the heat number follows the material through every later operation.
Open-die forging and ring rolling
Billets are heated into the 1175 to 1000 °C window and worked to a controlled reduction schedule, then cooled rapidly in air or water. Finishing below the lower limit risks cracking in a fully austenitic steel that work hardens quickly. Forging reduction is agreed at order stage, with 3:1 taken as the normal minimum and higher ratios applied where the specification demands. Rings are upset, punched and radial-axial rolled so that grain flow follows the circumference, which is why a rolled ring outperforms a ring flame-cut from plate in any part carrying hoop stress at temperature.
Solution annealing
Forgings are solution annealed between 1050 and 1150 °C and cooled rapidly in water or air, with soak time set by section thickness. This returns carbides to solution and restores ductility. Furnace charts are kept with the job file. The grade is not precipitation hardening, so solution annealing is the whole heat treatment. Any request for a solution-plus-age cycle on this material is queried before it reaches the shop floor.
Machining and finishing
Rough or finish machining to the stated allowance, then pickling or bead blasting where a clean surface is specified. Leave 3 to 6 mm of allowance on forgings that will be finish machined after final heat treatment.
10. Testing and certification
Chemical analysis
Optical emission spectrometry on every heat, plus XRF positive material identification on finished pieces before packing.
Mechanical testing
Tensile and hardness to ASTM A370 / ASTM E8 or to the EN route. Elevated-temperature tensile on request.
Ultrasonic testing
To ASTM A388, EN 10228-3 or SEP 1921. Acceptance class agreed at order stage and stated on the certificate.
Surface NDT
Liquid penetrant to ASTM E165 or EN 10228-2. Magnetic particle does not apply, since the grade is non-magnetic.
Intergranular corrosion
ASTM A262 practice testing where a project calls for it, worth specifying on welded assemblies given the 0.20 % carbon ceiling.
Certification
EN 10204 3.1 as standard. 3.2 endorsed by BV, SGS, TUV, Lloyd’s or DNV on request.
Third-party inspection at the works is welcome and can be arranged before production starts. Where a project needs PED 2014/68/EU or AD 2000-W0 material, state it on the enquiry so the correct route is used from the melt onward.
11. Where X15CrNi25-20 forgings are used
Furnace and heat treatment equipment
Furnace linings and rollers, combustion chamber covers, retort components, heat treatment baskets and jigs, carburising boxes, grate bars and hanger pins.
Burners and radiant tubes
Oil and gas burner parts, burner nozzles, radiant tube sections, flame holders and recuperator components.
Petrochemical and refining
Pyrolysis and reformer furnace internals, hanger systems, tube sheets and support rings in hot gas service.
Power generation and boilers
Steam boiler components, superheater supports, flue and exhaust system parts, thermocouple sheaths and pockets.
Cement, glass and ceramics
Kiln and furnace hardware, conveyor and transport components inside the hot zone, where thermal cycling is continuous.
Waste and thermal treatment
Incinerator and thermal oxidiser internals, grate and support components in high-temperature flue gas.
Service life at temperature depends on atmosphere, cycling, stress and contaminants. The data on this page is a selection guide, not a warranty of service performance. Material selection remains with the purchaser or the process licensor. Jiangyin Jiangnan Metal supplies material to the agreed specification.
12. Choosing between 1.4841, 1.4845 and 1.4833
These grades are routinely cross-shopped. The decision usually comes down to two questions: how hot, and is it welded.
| Point of comparison | 1.4841 X15CrNiSi25-21 | 1.4845 X8CrNi25-21 | 1.4833 X12CrNi23-13 |
|---|---|---|---|
| Common name | AISI 314 | AISI 310S | AISI 309S type |
| Cr / Ni, % | 24–26 / 19–22 | 24–26 / 19–22 | 22–24 / 12–14 |
| Silicon, % | 1.50 – 2.50 | ≤ 1.50 | ≤ 1.00 |
| Carbon, % | ≤ 0.20 | ≤ 0.10 | ≤ 0.15 |
| Scaling resistance in air | Highest of the three, to about 1150 °C | High | Moderate |
| Weldability | Weldable, with sensitisation risk from 0.20 % C | Better, lower carbon | Good |
| Usual reason to choose | Maximum dry-gas temperature, unwelded or lightly welded furnace hardware | Welded assemblies and pressure parts at high temperature | Lower nickel cost where the duty is less severe |
The 1.4833 composition is from the EN 10095 table. All three are forged at Jiangyin, so one enquiry can be priced across the alternatives wherever the specification permits substitution.
Related grades forged at the same works
13. Welding and machining
Welding
1.4841 is suitable for all common processes: TIG, MAG, submerged arc, laser beam and manual arc. Preheat is not normally required and post-weld heat treatment is not generally necessary. Hot cracking is the principal risk, so maximum welding energy should be limited and weaving avoided. A commonly used filler is a 1.4842 / X12CrNi25-20 type consumable.
Two cautions follow from the 0.20 % carbon ceiling. Corrosion resistance is reduced by welding, and the material is susceptible to intergranular corrosion in the as-welded condition. Where the weldment will see wet or condensing service rather than dry hot gas, either re-solution-anneal the assembly or move to 1.4845.
Machining
Machinability is medium. Carbides can form during machining and increase tool wear, and the austenitic matrix work hardens. Use rigid setups, sharp positive-rake carbide tooling, modest cutting speeds and depths, steady feed and flood coolant. Do not let the tool dwell in the cut, since a stalled pass work hardens the surface and the following pass rubs rather than cuts.
14. Request a quotation for X15CrNi25-20 forgings
Send a drawing or the raw dimensions and Jiangyin Jiangnan Metal Co., Ltd. will come back with price, forging weight and delivery date.
Include in the enquiry: grade and material number (X15CrNi25-20 / 1.4841, or the ASTM grade if the American route governs), product form, finished or rough dimensions, quantity, delivery condition, service temperature and atmosphere, NDT and acceptance class, certification level (EN 10204 3.1 or 3.2), and any project or end-user specification that applies.
15. Frequently asked questions
What is X15CrNi25-20?
X15CrNi25-20 is a trade designation for the heat-resisting 25 % chromium, 20 % nickel austenitic steel standardised today as X15CrNiSi25-21, material number 1.4841, in EN 10095. Older DIN-era datasheets print the name as X15CrNiSi25-20, and the silicon symbol is often dropped in enquiries, which is where X15CrNi25-20 comes from. The American counterparts are AISI 314 and UNS S31400.
Is X15CrNi25-20 the same as 1.4841?
In most enquiries, yes. A minority of buyers use the name for 1.4842 / X12CrNi25-20, the lower-silicon AISI 310 type. The two are not interchangeable, because 1.4841 carries 1.50 to 2.50 % silicon for scaling resistance. Jiangyin Jiangnan Metal confirms the intended material number in writing before melting.
What is the ASTM equivalent of X15CrNi25-20?
AISI 314 / UNS S31400 is the closest American grade to 1.4841. For forgings ordered against ASTM, the usual specifications are ASTM A182 grade F310 (UNS S31000, 25 chromium 20 nickel) or ASTM A240 type 310 and 310S. ASTM A182 F310 limits silicon to 1.00 % maximum while EN 1.4841 requires a silicon minimum of 1.50 %, so one heat cannot satisfy both specifications.
What is the maximum service temperature of X15CrNi25-20?
Scaling resistant in air to about 1150 °C, with continuous service in practice usually limited to around 1100 °C. Creep resistance is generally quoted up to about 690 °C. Resistance to sulphurous gases, oxidising or reducing, falls away above roughly 650 °C, and resistance in nitrogenous, carburising and low-oxygen gases is only moderate above about 900 °C.
Why does the silicon content matter?
Silicon of 1.50 to 2.50 % is the defining addition in 1.4841. It densifies the protective oxide and lifts scaling resistance to about 1150 °C in air. Any datasheet showing silicon as a maximum of 1.00 or 1.50 % under a DIN or EN heading is in fact describing an AISI 310 or 310S composition, not 1.4841.
What heat treatment do X15CrNi25-20 forgings receive?
Solution annealing between 1050 and 1150 °C followed by rapid cooling in water or air, with soak time set by section thickness. Hot forming runs from about 1150 down to 800 °C and forging from 1175 down to 1000 °C. The grade should not be held or worked in the 600 to 900 °C band, where sigma phase forms and embrittles the steel.
Can X15CrNi25-20 be welded?
Yes, by TIG, MAG, submerged arc, laser and manual arc, normally without preheat and without post-weld heat treatment. Hot cracking is the main risk, so welding energy is limited. A 1.4842 / X12CrNi25-20 type filler is commonly used. Because carbon runs up to 0.20 %, the material is susceptible to intergranular corrosion in the as-welded condition, so wet or condensing service after welding needs review.
Is X15CrNi25-20 magnetic?
No. The grade is austenitic and not magnetisable in the solution annealed condition, though it can become slightly magnetic after cold forming. Magnetic particle inspection therefore does not apply, and surface NDT is carried out by liquid penetrant testing to ASTM E165 or EN 10228-2.
What certificates are supplied?
EN 10204 3.1 mill certificates as standard, listing heat number, chemical analysis, mechanical results, heat treatment record and NDT results. EN 10204 3.2 certificates endorsed by BV, SGS, TUV, Lloyd’s or DNV are available on request, along with PMI reports and ultrasonic test reports to ASTM A388, EN 10228-3 or SEP 1921.
What sizes can be made?
Sizes are quoted against the drawing rather than from a stock list, because every piece is open-die forged or ring rolled to order. Give outside diameter, inside diameter, height or length, wall or thickness and quantity, and Jiangyin Jiangnan Metal will confirm feasibility, weight and price. Single pieces and prototype quantities are quoted.
Who supplies X15CrNi25-20 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges X15CrNi25-20 / 1.4841 seamless rolled rings, flanges, bars, discs, shafts, sleeves, bushings and tube sheets to drawing. Enquiries go to sales@steelforgepieces.com or +86 189 2135 9659.
16. About Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The works sits inside the Yangtze delta forging cluster, within road distance of the container ports at Shanghai and Ningbo.
Production covers carbon steel, alloy steel, tool steel, stainless steel and nickel alloys. Heat-resisting austenitic grades such as 1.4841, 1.4845 and 1.4833, together with the nickel-based heat-resisting families, are a standing product line rather than occasional work. Every order is made to drawing, so dimensions, testing scope and certification are set by the purchaser instead of by what happens to be on a shelf.
How orders run
- Made to drawing, single pieces quoted
- Drawings held in confidence, NDA on request
- EN 10204 3.1 certification as standard
- Third-party inspection welcome at the works
- Export packing in fumigated cases or on steel pallets
Contact
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- +86 189 2135 9659
- sales@steelforgepieces.com
- Contact page
17. Data sources and notes
Composition limits for 1.4841, 1.4845 and 1.4833 are taken from the EN 10095 heat-resisting steel composition tables. Mechanical, physical, heat treatment, welding, machining and scaling-temperature data for 1.4841 is compiled from mill and stockholder datasheets issued against EN 10095 and EN 10088-3. ASTM figures are from ASTM A182 / A182M grade F310 (UNS S31000) and ASTM A240 / A240M type 310S.
Where published sources differ, both figures are shown rather than averaged: silicon 1.50 to 2.50 % per EN 10095 against 1.50 to 2.00 % on EN 10088-3 datasheets, thermal conductivity about 14 to 15 W/m·K, electrical resistivity about 0.9 to 1.0 µΩ·m. Manufacturing, testing and certification statements describe Jiangyin Jiangnan Metal Co., Ltd. Property data is a guide for material selection and is not a warranty of service performance.
Page published 9 October 2026. Last reviewed 9 October 2026 by technical sales, Jiangyin Jiangnan Metal Co., Ltd.