# 310S24 Forgings, EN 1.4845 / AISI 310S / UNS S31008

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Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
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Reviewed: 2026-09-28

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. Equivalent designations

| Standard or system | Designation |
| --- | --- |
| EN material number | 1.4845 |
| EN name | X15CrNi25-21, also 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 |

ASTM A182 grade F310 is UNS S31000, carbon up to 0.25 %, minimum tensile strength 515 N/mm2 (75 ksi). 310S24 / S31008 is the low carbon version of the same 25Cr-20Ni chemistry.

## 2. Chemical composition, mass %, EN 10088-3

| 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 | 24.0-26.0 | 19.0-22.0 | balance |

ASTM A240 practice for 310S / S31008 works to C max 0.08 % and S max 0.030 %.

## 3. Mechanical properties at 20 C, solution treated, EN 10095

| Property | Value |
| --- | --- |
| Yield strength Rp0.2 | min 210 N/mm2 |
| Tensile strength Rm | 500-750 N/mm2 |
| Elongation A5 | min 35 % |
| Hardness | max 192 HB |
| Modulus of elasticity | 196 kN/mm2 |

## 4. Physical properties

| Property | Value |
| --- | --- |
| Density | 7.9 kg/dm3 at 20 C, also quoted as 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 (20-100 C), 17.1 (20-500 C), 18.9 (20-1000 C) |

## 5. Typical elevated temperature tensile data, 310S annealed

| Temperature | Yield | Tensile | 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, not guaranteed acceptance values.

## 6. Heat treatment and hot working

Solution treatment: 1050-1150 C, cooled in air or water. Some 310S practice specifies 1120-1175 C with about 30 minutes per inch of section.

Hot forming: 1150-800 C with air cooling. Published 310S practice: start 980-1120 C, finish not below 980 C, then rapid cooling to black heat.

Carbide and sigma phase: long exposure between 427 and 899 C can precipitate carbides or sigma phase. A full solution treatment is the corrective measure.

Hardening: not hardenable by heat treatment. Strength is raised only by cold or warm work, and that gain is not stable at service temperature.

## 7. Welding

Suitable for manual arc, TIG, MIG, MAG, submerged arc and laser beam welding. Gas welding is not used. Matching filler 1.4842 (X12CrNi25-20); low carbon fillers such as ER309L where tighter carbide control is wanted. Weld metal is fully austenitic with little or no ferrite, so hot cracking sensitivity is higher and silicon bearing fillers improve fluidity. As welded, the material is not resistant to intergranular corrosion, so heat tint and scale must be removed by stainless only brushing, grinding or nitric plus hydrofluoric acid pickling with a thorough rinse.

## 8. Applications

Industrial heat processing: radiant tubes, burners and burner nozzles, furnace linings, muffle sections, internal baffles, conveyor rollers, walking beam parts, heat treatment baskets, fixtures, retorts, trays, tube hangers and supports.

Chemical and process plant: hot nitric acid under oxidising conditions, ammonia bearing and cracked ammonia atmospheres, sulphur dioxide and other sulphur bearing combustion gases, carburising and mixed gas atmospheres.

Furnace construction and machinery: high temperature reactor structures, machine parts for high temperature, aerospace engine components, pressure vessels, tanks and pipelines.

Not suitable for: seawater, brine, chloride or strong acid service. Use 904L, A182 F44, A182 F55 or Sanicro 28. Above 1050 C use AISI 314 / 1.4841 or a nickel alloy such as Incoloy 800HT.

## 9. Forged product forms available in 310S24

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.

## 10. Melting, testing and certification

Melting: EAF plus VOD, with ESR refining available.

Ultrasonic testing: EN 10228-3, SEP 1921 or ASTM A388.

Certificates: EN 10204 3.1, or EN 10204 3.2 with third party endorsement.

Additional reports on request: mechanical and impact testing, ASTM A262 intergranular corrosion testing, PMI, dimensional.

Pricing: quotation on request against drawing or finished size. No list price is published for made-to-order forgings.

## 11. FAQ

**What is 310S24 steel?** A British Standard designation for 25Cr-20Ni heat resisting austenitic stainless steel, identical to EN 1.4845, AISI 310S and UNS S31008.

**What is 310S24 equivalent to?** EN 1.4845 / X15CrNi25-21, AISI 310S, SAE 310S, UNS S31008, JIS SUS310, AFNOR Z12CN25-20, GB 1Cr25Ni20Si2, UNI X6CrNi25-20, SS 2361, PN H23N18, AMS 5521 and 5651, ASTM A182 F310 for forgings.

**Maximum temperature?** Scaling resistant in air to 1050 C. Above that, AISI 314 / 1.4841. Some references quote continuous service to about 1100 C.

**Is it magnetic?** No, fully austenitic and not magnetisable in the solution treated condition.

**Can it be forged?** Yes. Hot formed 1150-800 C, then solution treated at 1050-1150 C.

**Seawater or chlorides?** No. Use 904L, A182 F44, A182 F53, A182 F55 or Sanicro 28.

**Sizes?** Forged to client drawing. Send drawing or finished size with standard, quantity, delivery condition and NDT requirement for price and lead time.