310S24 Forgings, EN 1.4845 / AISI 310S / UNS S31008
Forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets and bars in 25Cr-20Ni heat resisting austenitic stainless steel, produced to drawing by Jiangyin Jiangnan Metal Co., Ltd.
310S24 is a British Standard designation for a heat resisting austenitic stainless steel containing about 25 % chromium and 20 % nickel. It is the same material as EN 1.4845 (X15CrNi25-21), AISI 310S and UNS S31008. The steel is not magnetisable, is resistant to scaling in air up to 1050 C, and is specified for furnace internals, radiant tubes, heat treatment fixtures and high temperature plant components. It is not a wet corrosion grade and is not used for seawater or chloride service.
1. Designation and equivalent grades
310S24 belongs to the legacy British 310S series, which also includes 310S16 and 310S31. All three map to EN material number 1.4845. An order placed today as 310S24 is in practice an order for 25Cr-20Ni heat resisting austenitic stainless steel to EN 10095 and EN 10088-3 chemistry.
| Standard or system | Designation |
|---|---|
| EN material number | 1.4845 |
| EN name | X15CrNi25-21, also quoted as X15CrNiSi25-21 |
| BS, legacy | 310S16, 310S24, 310S31 |
| AISI / SAE | 310S |
| UNS / BSI | S31008 |
| JIS | SUS310 |
| AFNOR | Z12CN25-20 |
| GB | 1Cr25Ni20Si2 |
| UNI | X6CrNi25-20 |
| SS | 2361 |
| PN | H23N18 |
| AMS | 5521, 5651 |
| Product standards | EN 10095, EN 10088-3, ASTM A240, ASTM A182 F310 |
Note for forgings. ASTM A182 grade F310 is UNS S31000 and permits carbon up to 0.25 %, with a minimum tensile strength of 515 N/mm2 (75 ksi), whereas 310S24 / S31008 is the low carbon version of the same 25Cr-20Ni chemistry. If your enquiry is written to A182, state whether F310 or F310S applies so that the heat is melted to the correct carbon range.
2. Chemical composition
| C | Si | Mn | P | S | N | Cr | Ni | Fe |
|---|---|---|---|---|---|---|---|---|
| max 0.10 | max 1.50 | max 2.00 | max 0.045 | max 0.015 | max 0.11 | 24.0 to 26.0 | 19.0 to 22.0 | balance |
ASTM A240 practice for 310S / S31008 works to C max 0.08 % and S max 0.030 %. Where the order is placed to ASTM we melt to the ASTM limits. State the governing standard on the enquiry.
3. Mechanical and physical properties
| Yield strength Rp0.2 | min 210 N/mm2 |
|---|---|
| Tensile strength Rm | 500 to 750 N/mm2 |
| Elongation A5 | min 35 % |
| Hardness | max 192 HB |
| Modulus of elasticity | 196 kN/mm2 |
| Density | 7.9 kg/dm3 at 20 C. 310S data sheets also quote 8.03 g/cm3 |
|---|---|
| Thermal conductivity | 15 W/m K up to 20 C |
| Electrical resistivity | 0.85 ohm mm2/m at room temperature |
| Magnetisability | none |
| Thermal expansion | 15.9 um/m K (20 to 100 C), 17.1 (20 to 500 C), 18.9 (20 to 1000 C) |
Strength at temperature
Published 310S tensile data show useful strength through the furnace range, with elongation rising sharply above 900 C. That behaviour is normal for a fully austenitic steel and is the reason the grade tolerates thermal shock in cyclic heating service.
| Temperature | Yield strength | Tensile strength | Elongation |
|---|---|---|---|
| 25 C | 314 MPa | 624 MPa | 42.6 % |
| 204 C | 254 MPa | 533 MPa | 35.8 % |
| 427 C | 209 MPa | 508 MPa | 33.5 % |
| 538 C | 203 MPa | 484 MPa | 37.0 % |
| 649 C | 178 MPa | 393 MPa | 32.0 % |
| 760 C | 147 MPa | 260 MPa | 54.0 % |
| 871 C | 111 MPa | 155 MPa | 56.5 % |
| 982 C | 56 MPa | 81 MPa | 93.3 % |
| 1093 C | 27 MPa | 44 MPa | 121.0 % |
Typical values for design screening. They are not guaranteed acceptance values. Contractual properties are those tested and reported on the certificate issued with each forging.
4. Heat treatment and hot working
Solution treatment
Heat to 1050 to 1150 C, cool in air or water. This returns all carbides into solution and restores a carbide free austenitic structure. Some 310S practice specifies 1120 to 1175 C with about 30 minutes per inch of section. The cycle is agreed against the governing specification before treatment.
Hot forming
Hot forming range 1150 to 800 C with air cooling. Published 310S practice narrows this to a start of 980 to 1120 C and a finish not below 980 C, then rapid cooling to black heat. Forming above the range lowers hot ductility through ferrite formation. Forming below it risks carbide and sigma phase precipitation.
Carbide and sigma phase
Long exposure between 427 and 899 C can precipitate carbides or sigma phase even in the low carbon grade, with a loss of ductility. A full solution treatment is the corrective measure. Annealing scale is removed by blasting, stainless only grinding, or pickling in nitric and hydrofluoric acid followed by rinsing.
Hardening
310S24 cannot be hardened by heat treatment. Strength is raised only by cold or warm work, and that gain is not stable at service temperature. Cold worked parts intended for furnace duty are solution treated before long term hot exposure.
5. Welding
310S24 suits the common fusion processes, including manual arc, TIG, MIG and MAG, submerged arc and laser beam welding. Gas welding is not used on this grade. Filler 1.4842 (X12CrNi25-20) is a recognised matching consumable. Where tighter carbide control is wanted, low carbon fillers such as ER309L keep carbon down in the deposit.
Two points affect fabricated forgings. The weld metal solidifies fully austenitic with little or no ferrite, which raises hot cracking sensitivity and makes the pool sluggish, so silicon bearing fillers are used to improve fluidity. In the as welded condition the material is not resistant to intergranular corrosion, so heat tint and oxide scale are removed from the weld and the heat affected zone by stainless only brushing, grinding or pickling, with a thorough water rinse afterwards.
6. Applications of 310S24 forgings
Industrial heat processing
Radiant tubes, burners and burner nozzles, furnace linings, muffle sections and internal baffles, conveyor rollers and walking beam parts, heat treatment baskets, fixtures, retorts and trays, tube hangers and supports exposed to cyclic heating. Our forged rings, shafts, discs and sleeves go into these assemblies.
Chemical and process plant
Plant components that must carry high temperature while exposed to process chemicals, including hot nitric acid under oxidising conditions, ammonia bearing and cracked ammonia atmospheres, sulphur dioxide and other sulphur bearing combustion gases, and carburising or mixed gas atmospheres. Usual forged forms are flanges, tube sheets, nozzles, valve bodies and seat rings.
Furnace construction and machinery
High temperature reactor structures in furnace and blast furnace construction, machine parts that have to withstand high temperature, engine components in aerospace work, and pressure vessel, tank and pipeline components.
Where another grade is specified instead
Corrosion resistance is low in an oxidising atmosphere combined with reduced sulphur content, and the as welded material is not resistant to intergranular corrosion. For seawater, brine, chloride or strong acid duty see 904L, A182 F44, A182 F55 or Sanicro 28. Above 1050 C the usual step up is AISI 314 / 1.4841 or a nickel alloy such as Incoloy 800HT.
7. 310S24 forgings we produce
Everything below is forged to the client drawing or dimensional requirement, as single pieces or in series.
| Group | Forms |
|---|---|
| Rings | Forged rings, seamless rolled rings, ring gears, retaining rings, valve seat rings |
| Flanges and flat products | Forged flanges, blind flanges, tube sheets, discs, disks, blocks |
| Long products | Forged round bars, shafts, eccentric shafts, spindles, crankshafts, valve stems |
| Hollow products | Forged pipes, forged tubes, sleeves, bushings, hollow bars, nozzles |
| Valve and machine parts | Valve bodies, valve blocks and parts for ball, gate, globe, check and plug valves and strainers, gears, wheels, rolls, manifolds |
Melting, testing and certification
310S24 is melted by EAF plus VOD, with ESR refining available where the specification or the duty of the part calls for it. Non destructive examination is carried out to the standard nominated by the client, including ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388. Material certificates are issued to EN 10204 3.1, or to EN 10204 3.2 with third party endorsement. Mechanical and impact testing, intergranular corrosion testing to ASTM A262, PMI and dimensional reports are added to the inspection and test plan on request.
8. Questions we are asked about 310S24
What is 310S24 steel?
What is 310S24 equivalent to?
What is the maximum temperature for 310S24?
Is 310S24 magnetic?
Can 310S24 be forged and machined?
Can 310S24 be used in seawater or chlorides?
What sizes and weights can you forge?
What certificates are supplied?
Quick reference
310S24, EN 1.4845, X15CrNi25-21, AISI 310S, UNS S31008. Heat resisting austenitic stainless steel, Cr 24.0 to 26.0 %, Ni 19.0 to 22.0 %, C max 0.10 %. Rm 500 to 750 N/mm2, Rp0.2 min 210 N/mm2, A5 min 35 %, hardness max 192 HB, density 7.9 kg/dm3, not magnetisable. Scaling resistant in air to 1050 C. Solution treated 1050 to 1150 C, hot formed 1150 to 800 C. Used for furnace parts, radiant tubes, heat treatment fixtures and high temperature plant. Not used for seawater or chloride service.
Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. 310S24 forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets, bars and valve parts to drawing. EN 10204 3.1 or 3.2 certificates, ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388. Tel +86-189-2135-9659, email sales@steelforgepieces.com, www.steelforgepieces.com
Data on this page is compiled from EN 10095, EN 10088-3, ASTM A240 and ASTM A182 and from published 310S / 1.4845 data sheets. It is given for reference and design screening. Page reviewed 28 September 2026.
Request a 310S24 quotation
Send the size or the drawing of the 310S24 forging you need, whether ring, flange, shaft, disc, sleeve, tube sheet or bar, together with the governing standard, quantity, delivery condition and any NDT requirement. We will reply with price and lead time.