# AISI 314 Forgings (UNS S31400)

Silicon bearing 25Cr-20Ni austenitic heat resisting steel. Also designated UNS S31400, SAE 314, SAE 30314, SAE J405 (30314), DIN 1.4841, X15CrNiSi25-21, AFNOR Z15CNS25-20, BS 314S25, JIS SUH 310, CSN 17255, PN H25N20S2, AMS 5522, AMS 5652.

Supplier: Jiangyin Jiangnan Metal Co., Ltd., integrated steel melting works and open-die forging factory, No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China. Established 1997. Phone +86 189 2135 9659. Email sales@steelforgepieces.com. Source page: https://www.steelforgepieces.com/Stainless-Steel/AISI-314.html

## Summary

AISI 314 is a fully austenitic heat resisting steel with 23 to 26 percent chromium, 19 to 22 percent nickel and a deliberate silicon addition of 1.5 to 3 percent. The silicon improves oxidation and carburisation resistance and gives scaling resistance in air of about 1150 C. The same silicon brings the grade's main limitation: it can become very brittle after prolonged exposure at 649 to 816 C. It is not hardenable by heat treatment, only by cold working, so forgings are supplied solution annealed and the annealed properties are the design properties.

AISI 314 and the European grade 1.4841 / X15CrNiSi25-21 to EN 10095 are the same steel reached from two standards systems. It is not 310H, which is UNS S31009 with the EN number 1.4845. The EN view of this grade, including the full creep table, is at https://www.steelforgepieces.com/Stainless-Steel/1.4841.html

| Item | Value |
|---|---|
| Type | Austenitic, heat resisting, silicon bearing |
| UNS | S31400 |
| EN number | 1.4841 (X15CrNiSi25-21) |
| Chromium | 23 to 26 percent |
| Nickel | 19 to 22 percent |
| Silicon | 1.5 to 3 percent |
| Carbon | 0.25 percent max per AZoM, 0.20 percent max per EN |
| Scaling resistance in air | approximately 1150 C |
| Embrittlement band to avoid | 649 to 816 C prolonged exposure |
| Forging range | 1093 to 1232 C after a two stage heat |
| Annealing | 1038 to 1149 C, water quench or rapid air cool |
| Hardening | Not by heat treatment, only by cold working |
| Product standards | ASTM A276, A314, A473, A580, AMS 5522, AMS 5652 |
| Typical applications | Radiant tubes, furnace equipment, heat treatment components, annealing and carburising boxes |

## Designations and equivalents

| 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 correct one depends on which standard the drawing invokes.

## Chemical composition, weight percent, balance iron

| Element | AISI 314 per AZoM | 1.4841 per EN 10088-3 data |
|---|---|---|
| C | 0.25 max | 0.20 max |
| Si | 1.5 to 3 | 1.50 to 2.00 |
| Mn | 2 max | 2.00 max |
| P | 0.045 max | 0.045 max |
| S | 0.03 max | 0.015 max |
| N | not listed | 0.11 max |
| Cr | 23 to 26 | 24.0 to 26.0 |
| Ni | 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, state this on the order so the furnace aim is set to the tighter of the two. Molybdenum, titanium, niobium, aluminium, vanadium and copper are residuals in this grade, not alloyed additions.

## Mechanical properties, annealed

| Property | AISI 314 per AZoM | 1.4841 per EN 10095 practice |
|---|---|---|
| Tensile strength | 689 MPa (99900 psi) | 550 to 750 MPa |
| Yield strength | 345 MPa (50000 psi) | Rp0.2 230 MPa min, Rp1.0 270 MPa min |
| Elongation at break | 40 percent in 50 mm | 30 percent min, longitudinal |
| Modulus of elasticity | 200 GPa (29000 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 up to 160 mm in the solution annealed condition. Neither set is a guarantee for a particular forging.

## Physical properties

| Property | Value |
|---|---|
| Density | 7.9 kg/dm3 at 20 C |
| Thermal conductivity | approximately 15 W/(m K) at 20 C |
| Electrical resistivity | 0.9 ohm mm2/m at room temperature |
| PREN | 24.0 to 29.3 |
| Magnetic response | Not magnetisable as supplied. Slightly magnetisable after cold forming, increasing with the degree of cold work |

## Temperature map

| Temperature | Significance |
|---|---|
| 649 to 816 C | Embrittlement band. AZoM states the material can become very brittle after prolonged exposure here. The European data for the same steel describes sigma phase embrittlement and widens the window to avoid to 600 to 900 C |
| approximately 650 C | Limit of resistance to oxidising and reducing sulphurous gases |
| approximately 690 C | Creep limited service. Above this, creep rather than oxidation sets the design stress |
| approximately 900 C | Medium resistance against nitrogenous, carburising and low oxygen gases |
| 1038 to 1149 C | Annealing per AZoM, water quench or rapid air cool. European solution annealing 1050 to 1150 C |
| approximately 1150 C | Scaling resistance in air. Sustained practical service closer to 1100 C, cyclic duty lower again |
| 1093 to 1232 C | Forging window per AZoM. European practice gives 1175 down to 1000 C |

Every published scaling limit assumes continuous exposure. Thermal cycling cracks and spalls the protective oxide, so for fixtures, baskets, trays and hooks that see the full cycle several times a day, derate the continuous figure and expect a finite life. State the service cycle on the enquiry, because it changes the recommended section.

## Forging and annealing practice

| Operation | Practice |
|---|---|
| Heating for forging | Two stage heat per AZoM: heat slowly to 871 C (1600 F), soak thoroughly, then heat quickly to 1093 to 1232 C (2000 to 2250 F) to forge, flange or work. The slow first stage matters because this steel has roughly a third of the thermal conductivity of plain carbon steel and a heavy section taken straight to top heat will crack from the thermal gradient |
| Forging window | 1093 to 1232 C per AZoM. European practice 1175 down to 1000 C with rapid cooling in air or water afterwards. Open-die and drop forging are both feasible |
| Hot forming | 1150 down to 800 C, air cooled |
| Annealing | 1038 to 1149 C then water quench or rapid air cool per AZoM. European solution anneal 1050 to 1150 C, air or water cooled. The purpose of the rapid cool is to clear the embrittlement band quickly, not to harden |
| Hardening | Not possible by heat treatment. Hardenable only through cold working |
| 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 |

## Welding

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. Keep interpass temperature below 150 C. The grade is prone to hot cracking, so limit heat input; a weld metal with a low delta ferrite content, up to about 10 percent, reduces the tendency. Filler 1.4842 (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, since low thermal conductivity combines with a high expansion coefficient; prefer a double-V preparation above 12 mm thickness, with an included angle of 60 to 70 degrees, or about 50 degrees for MIG. The grade is susceptible to intergranular corrosion in the as welded condition, and corrosion resistance is reduced by welding. The material is also suitable for laser beam fusion cutting with nitrogen and flame cutting with oxygen.

## Machining

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, keep the feed positive so the tool cuts rather than burnishes, and provide sufficient coolant flow. Allow more machining stock than on a 304 or 316 forging. Because machining is the awkward part of this grade, 314 is normally supplied proof machined or finish machined from our own shop rather than as black forgings.

## Forged product forms

Seamless and contoured rolled rings from about 50 mm to 6000 mm outside diameter on the 6 m radial-axial mill, including retaining rings, gear rings, furnace door rings and seat rings. Weld neck, blind, slip-on, socket weld, lap joint, orifice, anchor, girth, swivel and long weld neck flanges, forged to drawing rather than cut from plate. Round, square, flat and hexagon bars and forged blocks. Solid and bored discs, tube sheets, covers and hubs machined to 5000 mm diameter. Sleeves, bushings, couplings, hollow cylinders and heavy wall pipe bored from solid to 1600 mm diameter by 10000 mm. Shafts, spindles, fan hubs and rolls turned to 14000 mm between centres. Furnace hardware including radiant tube components, annealing and carburising box parts, retort and muffle sections, burner grids and shields, walking beams, recuperator parts, conveyor components and hooks. Valve bodies, 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.

## Grade selection

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: https://www.steelforgepieces.com/Stainless-Steel/AISI-310S.html

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 and the EN mechanical minima, is at https://www.steelforgepieces.com/Stainless-Steel/1.4841.html

## Works, testing and commercial terms

Melting by EAF plus LF plus VOD, with protective atmosphere ESR on request, VIM and VAR available for remelted grades, 60 t maximum heat. Forging on hydraulic open-die presses of 6300 t, 4000 t and 2000 t and hammers of 5 t, 3 t, 2 t, 1 t and 750 kg, maximum single piece 30000 kg. Ring rolling on radial-axial mills of 6 m, 3 m and 1 m. Heat treatment in 14 furnaces including car bottom chambers to 8000 by 2000 by 2000 mm and two 15 m well type furnaces for vertical quenching. Machining on vertical lathes to 5000 mm swing, horizontal lathes to 14 m between centres and CNC deep hole drilling to 1600 mm by 10000 mm.

Ultrasonic testing 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. Optical emission spectrometry to ASTM E415, carbon and sulphur to ASTM E1019, positive material identification, 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, ASTM G28 and ASTM G48 are placed with an accredited third party laboratory.

Class approvals CCS, BV, DNV, LR and NK. EN 10204 3.1 as standard, EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer inspector on request. Traceability from melt number to shipment. 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.

## Enquiries

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. 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
Web: https://www.steelforgepieces.com/

## Questions and answers

**What is AISI 314 stainless steel?** A fully austenitic heat resisting steel with 23 to 26 percent chromium, 19 to 22 percent nickel and 1.5 to 3 percent 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 percent 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 1175 down to 1000 C with rapid cooling in air or water afterwards.

**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.

**Can AISI 314 be hardened by heat treatment?** No. 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.

## Notes and sources

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): https://www.azom.com/article.aspx?ArticleID=8259
- AGST, AISI 314 / 1.4841 / X15CrNiSi25-21 data sheet to DIN EN 10095: https://www.agst.de/4841?lang=en
- thyssenkrupp Materials UK, Stainless Steel 314 - 1.4841 Data Sheet: https://www.thyssenkrupp-materials.co.uk/stainless-steel-314-14841.html

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