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| Grade | Code | UNS | Austenitic Stainless Steel |
| AISI 309S | X12CrNi23-13 | S30908 |
AISI 309S is an austenitic stainless steel grade designed to retain its mechanical integrity and surface stability under elevated-temperature conditions. Its main characteristics include strong resistance to oxidation at high temperatures, good weldability, and resistance to thermal cycling. In the annealed condition, it provides good ductility and formability, while its austenitic structure can cause noticeable work hardening during processing. AISI 309S is designed to perform more effectively in high-temperature service conditions than standard austenitic stainless steels.
| C % | Mn % | Si % | P % | S % | Cr % | Ni % | Fe % |
| ≤ 0.08 | ≤ 2.00 | ≤ 1.00 | ≤ 0.045 | ≤ 0.03 | 22.00 – 24.00 | 12.00 – 15.00 | Balance |
| Product Form | Rp0.2 [MPa] | Rm [MPa] | Elongation [%] | Hardness [HB] | Density [g/cm³] |
| Bar | ≥ 205 | ≥ 515 | ≥ 30 | — | 7.90 |
| Plate | ≥ 205 | ≥ 515 | ≥ 40 | ≤ 217 | 7.90 |
| Sheet | ≥ 205 | ≥ 515 | ≥ 40 | ≤ 217 | 7.90 |
* Mechanical properties for bar products are given based on ASTM A479/A479M.
** Mechanical properties for plate and sheet products are given based on ASTM A240/A240M.
| Sector | Most Common Products |
| Heat Treatment and Industrial Furnaces | Annealing boxes, retorts and muffles, furnace fans and shafts |
| Iron & Steel and Metallurgy | Radiant tubes, thermowells, furnace baffle plates |
| Energy and Incineration Plants | Boiler baffle plates, burner components, boiler tube hangers |
| Cement and Mineral Processing | Rotary kiln components, calciner components, high-temperature furnace equipment |
| Glass Industry | Glass forming equipment, annealing furnace components, thermowells |
| Industrial Process Equipment | Salt bath vessels, heat exchangers, high-temperature baffle plates |
AISI 309S is a stainless steel noted for its ability to operate for extended periods at elevated temperatures. It can be used in equipment exposed to repeated heating and cooling and is suitable for welded fabrication. However, it does not provide the same performance in every high-temperature environment; the service atmosphere, exposure time at temperature, and whether the component is under load are important factors in material selection. In addition, AISI 309S is intended for high-temperature service and therefore should not be selected as a direct substitute for corrosion-focused grades such as 316L, 904L, or similar materials in chloride-bearing or highly aggressive chemical environments.
AISI 309S, UNS S30908, 1.4833, X12CrNi23-13
| Product Form | ASTM Specification |
| Bar | ASTM A276/A276M, ASTM A479/A479M |
| Plate | ASTM A240/A240M |
| Sheet | ASTM A240/A240M |
AISI 310S – Offers higher temperature and oxidation resistance than 309S.
AISI 314 – A close alternative with strong resistance to oxidation at high temperatures.
316Ti – Its stabilized structure makes it suitable for consideration in certain hot-service and welded applications.
Note: The information contained in this datasheet is for informational purposes only; no liability is accepted.
