01What grade 314 is
AISI 314 (UNS S31400) is a fully austenitic heat resisting steel with 23 to 26 % chromium, 19 to 22 % nickel and a deliberate silicon addition of 1.5 to 3 %. The silicon is what separates it from the 310 family: AZoM states that the silicon content improves oxidation and carburisation resistance, and the European data for the same material gives scaling resistance in air of about 1150 °C. The same silicon brings a penalty, and it is the single most important thing to know about the grade: AZoM warns that 314 can become very brittle after prolonged exposure at 649 to 816 °C. Design the duty cycle so the part runs above that band, not inside it.
The grade is not hardenable by heat treatment. AZoM states it can be hardened only by cold working, so forgings are supplied solution annealed and the strength you get is the annealed strength. Typical duty is furnace and heat treatment hardware: radiant tubes, furnace equipment, heat treatment components, and annealing and carburising boxes.
Jiangyin Jiangnan Metal Co., Ltd. melts this grade on site by EAF plus LF plus VOD, with protective atmosphere ESR available, then forges, solution anneals, machines and tests it without the material leaving the works. Seamless rolled rings to 6000 mm outside diameter, single pieces to 30 t. Plant at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China. Enquiries to sales@steelforgepieces.com or +86-189-2135-9659.
Same material, two designations
AISI 314 and the European grade 1.4841 / X15CrNiSi25-21 are the same steel reached from two standards systems. This page is written around the American designations and the ASTM product standards. The EN 10095 view of the grade, with the full creep table and the EN mechanical minima, is on our 1.4841 / X15CrNiSi25-21 page. Note that 314 is not 310H: 310H is UNS S31009 with the EN number 1.4845.
02Designations and equivalents
Any designation below is accepted on an enquiry as the same material. Quote the governing product standard on the order, because the silicon window differs between the American and European listings.
| System | Designation |
|---|---|
| AISI / SAE | 314, SAE 314, SAE 30314, SAE J405 (30314) |
| UNS | S31400 |
| German | DIN 1.4841, X15CrNiSi25-21 |
| AFNOR | Z 12 CNS 25.20 per AZoM, Z15CNS25-20 per the European data sheet |
| Italian UNI | X 16 CrNiSi 25 20, X 22 CrNi 25 20 |
| British | 310 S 24 per AZoM, 314S25 per the European data sheet |
| Japanese | SUS Y 310 per AZoM, SUH 310 per the European data sheet |
| Other national | CSN 17255, PN H25N20S2, RVS 314, INOX 314 |
| Aerospace | AMS 5522, AMS 5652 |
| Product standards | ASTM A276 and A314 for bar and billets, ASTM A473 for stainless steel forgings, ASTM A580 for wire |
The British and Japanese cross references differ between sources. AZoM lists B.S. 310 S 24 and JIS SUS Y 310; the European data sheet for the same material lists BS 314S25 and JIS SUH 310. Both are reproduced rather than reconciled, because the right one depends on which standard your drawing invokes.
03Chemical composition
| Element | AISI 314 per AZoM | 1.4841 per EN 10088-3 data |
|---|---|---|
| Carbon | 0.25 max | 0.20 max |
| Silicon | 1.5 to 3 | 1.50 to 2.00 |
| Manganese | 2 max | 2.00 max |
| Phosphorus | 0.045 max | 0.045 max |
| Sulphur | 0.03 max | 0.015 max |
| Nitrogen | not listed | 0.11 max |
| Chromium | 23 to 26 | 24.0 to 26.0 |
| Nickel | 19 to 22 | 19.0 to 22.0 |
The two columns are not interchangeable. The European limits are tighter on carbon, sulphur and the top end of silicon, and they cap nitrogen. If the drawing calls for 1.4841 to EN 10095 while the enquiry says AISI 314, say so on the order and we set the furnace aim to the tighter of the two. Molybdenum, titanium, niobium, aluminium, vanadium and copper are residuals in this grade, not alloyed additions.
04Mechanical and physical properties
Room temperature values in the annealed condition. Grade 314 does not respond to hardening heat treatment, so these are the properties you design with.
| Property | AISI 314 per AZoM | 1.4841 per EN 10095 practice |
|---|---|---|
| Tensile strength | 689 MPa, 99 900 psi | 550 to 750 MPa |
| Yield strength | 345 MPa, 50 000 psi | Rp0.2 230 MPa min, Rp1.0 270 MPa min |
| Elongation at break | 40 % in 50 mm | 30 % min, longitudinal |
| Modulus of elasticity | 200 GPa, 29 000 ksi | not listed |
| Hardness | 85 HRB | 223 HB max |
The AZoM figures are single typical values; the European figures are specification ranges and minima for diameters to 160 mm in the solution annealed condition. Neither set is a guarantee for a particular forging. Acceptance values are those written into the purchase specification and reported on the mill certificate.
| Property | Value |
|---|---|
| Density | 7.9 kg/dm3 at 20 °C |
| Thermal conductivity | approximately 15 W/m·K at 20 °C |
| Electrical resistivity | 0.9 Ω·mm2/m at room temperature |
| PREN | 24.0 to 29.3 |
| Magnetic response | Not magnetisable as supplied. Slightly magnetisable after cold forming, and the effect increases with the degree of cold work |
05Temperature map
Grade 314 is bought for one reason, which is temperature. Read this block before fixing a service temperature or a hold time.
Cyclic duty derates the grade
Every published scaling limit assumes continuous exposure. The protective oxide on a silicon bearing chromium nickel steel is adherent but not infinitely tough, and thermal cycling cracks and spalls it, exposing fresh metal each time. For fixtures, baskets, trays and hooks that see the full cycle several times a day, derate the continuous figure and expect a finite life. Tell us the cycle when you enquire, because it changes the section we recommend.
06Forging and annealing practice
| Operation | Practice |
|---|---|
| Heating for forging | AZoM specifies a two stage heat: heat the material slowly to 871 °C (1600 °F), soak it thoroughly, then heat quickly to 1093 to 1232 °C (2000 to 2250 °F) to forge, flange or work it. The slow first stage matters, because a 25Cr-20Ni austenitic steel has roughly a third of the thermal conductivity of plain carbon steel and a heavy section pushed straight to top heat will crack from the thermal gradient. |
| Forging window | 1093 to 1232 °C per AZoM. The European practice for the same steel gives 1175 down to 1000 °C, with rapid cooling in air or water after forging, and open-die and drop forging are both described as feasible. |
| Hot forming | 1150 down to 800 °C, air cooled. |
| Annealing | 1038 to 1149 °C, then quench in water or cool rapidly in air, per AZoM. The European solution anneal is 1050 to 1150 °C with air or water cooling. The purpose of the rapid cool is to get through the embrittlement band quickly rather than to harden anything. |
| Hardening | Not possible by heat treatment. AZoM states grade 314 can be hardened only through cold working, so there is no quench and temper route and no age hardening response. |
| Cooling after forging | Cool rapidly through 600 to 900 °C. A heavy forging left to cool slowly in still air spends hours inside the sigma phase window and arrives brittle. |
Our own practice on this grade follows the published two stage heat, because the risk on a 25Cr-20Ni silicon steel is not the forging itself but the heating and the cooling. Heavy rings and tube sheets are equalised at the intermediate temperature before they go to top heat, the last pass is finished well above 1000 °C, and the piece goes to the annealing furnace and out through a forced cool rather than being allowed to drift down through 900 to 600 °C on the shop floor.
07Welding and machining
Welding, workable with care
Suited to TIG, MAG with solid wire, submerged arc, manual arc and laser beam welding. Preheat is normally not required and post-weld heat treatment is normally not applied. Points that matter:
- Keep interpass temperature below 150 °C.
- Limit heat input; this steel is prone to hot cracking, and a weld metal with a low delta ferrite content, up to about 10 %, reduces the tendency.
- Filler 1.4842, which is X12CrNi25-20, is the usual choice.
- Use stringer beads and aim for fast cooling, which lowers both the hot crack and the embrittlement risk.
- Expect distortion: low thermal conductivity combined with a high expansion coefficient means more movement than on carbon steel. Prefer a double-V preparation above 12 mm thickness.
- The grade is susceptible to intergranular corrosion in the as welded condition, and corrosion resistance is reduced by welding.
Machining, medium at best
Machinability is medium. Carbides form during cutting and wear the tooling, and the combination of low thermal conductivity and a strong work hardening tendency makes the grade unforgiving of light, rubbing cuts.
- AZoM recommends coolant and high speed turning tools.
- Keep depth of cut and cutting speed modest and keep the feed positive, so the tool cuts rather than burnishes.
- Provide sufficient coolant flow; heat stays in the cutting zone on this grade.
- Allow more machining stock than you would on a 304 or 316 forging, and expect to replace inserts more often.
Because machining is the awkward part of this grade, we normally supply 314 proof machined or finish machined from our own shop rather than as black forgings, so the difficult cutting is done here against our own stock allowance.
08Forged forms and typical parts
- Rolled ringsSeamless and contoured rolled rings from about 50 mm to 6000 mm outside diameter on the 6 m radial-axial mill. Retaining rings, gear rings, furnace door rings and seat rings.
- FlangesWeld neck, blind, slip-on, socket weld, lap joint, orifice, anchor, girth, swivel and long weld neck, forged to drawing rather than cut from plate.
- Bars and blocksRound, square, flat and hexagon bars, and forged blocks, to ASTM A276 or A314 chemistry with ASTM A473 forging acceptance.
- Discs and tube sheetsSolid and bored discs, tube sheets, covers and hubs, machined to 5000 mm diameter.
- Sleeves and cylindersSleeves, bushings, couplings, hollow cylinders and heavy wall pipe bored from solid to 1600 mm diameter by 10 000 mm.
- ShaftsShafts, spindles, fan hubs and rolls, turned to 14 000 mm between centres.
- Furnace hardwareRadiant tube components, annealing and carburising box parts, retort and muffle sections, burner grids and shields, walking beams, recuperator parts, conveyor components and hooks.
- Valve partsBodies, bonnets, stems, seat rings, spools and nozzles for hot service.
Each item is forged to drawing from a single piece of steel melted on site, with no welding and no casting. Supplied as forged with machining allowance, proof machined for ultrasonic inspection, or finish machined. Delivery standards include ASTM A473 for stainless steel forgings, ASTM A276 and A314 for bar, and EN 10250-4 for open-die stainless forgings.
When another grade suits the duty better
If the part must be welded and then run in a corrosive condensate, the lower carbon AISI 310S / 1.4845 is usually the better answer. If load as well as temperature governs above roughly 700 °C, the step up is Alloy 330, Incoloy 800H or 800HT. If the environment is sulphurous above about 650 °C, no grade in this family is right and the enquiry should move to a nickel alloy. The European view of grade 314 itself, including the full creep table, is on our 1.4841 page.
09Works, testing and commercial terms
| Department | Detail |
|---|---|
| Melting | EAF plus LF plus VOD, with protective atmosphere ESR on request. Maximum heat 60 t. VIM and VAR available for the remelted grades |
| Forging | Hydraulic open-die presses of 6300 t, 4000 t and 2000 t; hammers of 5 t, 3 t, 2 t, 1 t and 750 kg. Maximum single piece 30 000 kg |
| Ring rolling | Radial-axial mills of 6 m, 3 m and 1 m |
| Heat treatment | 14 furnaces, car-bottom chambers to 8000 by 2000 by 2000 mm, two 15 m well-type furnaces for vertical quenching |
| Machining | Vertical lathes to 5000 mm swing, horizontal lathes to 14 m between centres, CNC deep-hole drilling to 1600 mm by 10 000 mm |
| Non-destructive testing | Ultrasonic to ASTM A388, EN 10228-3 or SEP 1921 at the agreed class. Liquid penetrant for surface examination, since the grade is austenitic and magnetic particle inspection is generally not applicable |
| Laboratory | Optical emission spectrometry to ASTM E415, carbon and sulphur to ASTM E1019, PMI, tensile to ASTM A370 and ISO 6892, impact to minus 60 °C, hardness to ASTM A956 converted per ASTM E140, grain size to ASTM E112. ASTM A262, G28 and G48 are placed with an accredited third-party laboratory |
| Approvals and certification | CCS, BV, DNV, LR and NK approved. EN 10204 3.1 as standard; 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's own inspector on request. Traceability from melt number to shipment |
| Commercial terms | Minimum order 10 kg with no minimum piece count. Lead time 20 to 60 days. Quotation normally within two working days |
Operating since 1997 with 460 staff, including 9 senior engineers, 32 intermediate engineers and 140 technicians. Exports to North America, Europe, the Middle East and Asia Pacific.
10Questions
What is AISI 314 stainless steel?
A fully austenitic heat resisting steel with 23 to 26 % chromium, 19 to 22 % nickel and 1.5 to 3 % silicon, UNS number S31400. The silicon addition improves oxidation and carburisation resistance and gives scaling resistance in air of about 1150 °C. It cannot be hardened by heat treatment, only by cold working.
What is the difference between 314 and 310 or 310S?
Silicon. Grade 314 carries a deliberate 1.5 to 3 % silicon addition for oxidation and carburisation resistance, while the 310 family keeps silicon low. The trade is that 314 becomes brittle after prolonged exposure at 649 to 816 °C and is harder to machine. Where the part is welded and run in condensing or corrosive conditions, the lower carbon 310S is usually preferred.
Is AISI 314 the same as 1.4841?
Yes, they are the same steel reached from two standards systems: 314 and UNS S31400 on the American side, 1.4841 and X15CrNiSi25-21 on the European side. The composition limits differ slightly, with the European standard tighter on carbon, sulphur and the top of the silicon range. It is not 310H, which is UNS S31009 and EN 1.4845.
What is the forging temperature of grade 314?
AZoM specifies a two stage heat: slowly to 871 °C, soak thoroughly, then quickly to 1093 to 1232 °C for forging, flanging or working. The European practice for the same steel gives a forging range of 1175 down to 1000 °C with rapid cooling in air or water afterwards. The slow first stage avoids cracking a heavy section on a steel with low thermal conductivity.
Why must 649 to 816 °C be avoided?
Prolonged exposure in that band makes the material very brittle. The European data for the same steel describes the mechanism as sigma phase embrittlement and widens the window to be avoided to 600 to 900 °C. This governs both the service temperature and the cooling rate after forging and annealing, which is why rapid cooling is specified.
Can AISI 314 be hardened by heat treatment?
No. AZoM states that grade 314 can be hardened only through cold working. Forgings are supplied annealed at 1038 to 1149 °C with a water quench or rapid air cool, and the annealed properties are the design properties.
Can Jiangyin Jiangnan Metal supply 314 forgings to ASTM A473 with a 3.1 certificate?
Yes. We are an integrated melting works and open-die forging factory in Jiangyin, Jiangsu, China, supplying grade 314 as seamless rolled rings, forged rings, flanges, bars, blocks, discs, tube sheets, sleeves, shafts and valve parts against ASTM A473, ASTM A276 and A314, and EN 10250-4, with EN 10204 3.1 certificates as standard and 3.2 third-party witnessed certificates on request. Rings to 6000 mm outside diameter, single pieces to 30 t, minimum order 10 kg. Contact sales@steelforgepieces.com or +86-189-2135-9659.
11Request a quotation
Send the grade and standard, the drawing or dimensions, the quantity, the delivery condition, the service temperature and cycle, the testing and certification requirements, and the destination port. For heat resisting work the service cycle matters as much as the drawing, so include it. Quotations are normally returned within two working days. Jiangyin lies between Shanghai and Nanjing on the south bank of the Yangtze, 30 km from Wuxi Shuofang International Airport and 160 km from the Shanghai airports. Customer audits and third-party inspections are welcome.
Jiangyin Jiangnan Metal Co., Ltd.No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Phone, WhatsApp and WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com
12Sources and notes
Where the published sources differ, for example on the silicon and carbon limits, the forging window or the British and Japanese cross references, both figures are reproduced rather than averaged. The data on this page is engineering guidance, not a warranty of properties for a particular application. Acceptance values for a specific order are those written into the purchase specification and reported on the mill certificate.
- AZoM, Stainless Steel Grade 314 (UNS S31400). Composition, mechanical properties, equivalents, annealing, forging heat cycle, machining note, applications, and the 649 to 816 °C embrittlement warning.
- AGST, AISI 314 / 1.4841 / X15CrNiSi25-21 data sheet to DIN EN 10095. EN composition limits, mechanical minima, density, thermal conductivity, resistivity, PREN, scaling and gas atmosphere limits, forging and solution annealing ranges, sigma phase window, weldability and machinability.
- thyssenkrupp Materials UK, Stainless Steel 314 / 1.4841 data sheet. Welding processes, interpass limit, delta ferrite and hot cracking, distortion and joint preparation, laser welding and cutting, and the magnetisability note.
Datasheet MAT-DS/314 · Revision 1 · Published 1 October 2026 · Technical sales department, Jiangyin Jiangnan Metal Co., Ltd.
Cite this page: Jiangyin Jiangnan Metal Co., Ltd. (2026). AISI 314 Forgings (UNS S31400): composition, properties, temperature limits and forging practice. steelforgepieces.com/Stainless-Steel/AISI-314.html