Refractory steel refers to a group of steel alloys that can maintain their mechanical strength and chemical stability at high temperatures. This unique property makes refractory steels a primary choice for applications requiring optimal performance in high-temperature and corrosive environments. Their chemical composition includes key alloying elements such as chromium, nickel, molybdenum, and silicon, each playing a crucial role in enhancing their thermal and mechanical properties.
Chromium forms a protective chromium oxide layer on the steel’s surface, significantly improving its oxidation resistance. This layer prevents further oxidation at high temperatures, preserving the structure and properties of the steel. Nickel contributes to creep resistance and enhances mechanical performance under extreme heat. Molybdenum and silicon further strengthen the steel and improve its corrosion resistance, enhancing its overall durability.
Due to these exceptional properties, refractory steels are widely used in industries exposed to high temperatures and harsh environments. Common applications include furnace components, gas and steam turbines, and equipment in the chemical industry. In these applications, resistance to heat, creep, and oxidation is critical, and refractory steels play a key role in ensuring the efficiency and longevity of industrial equipment.
Overall, with their unique combination of mechanical and chemical properties, refractory steels are an ideal choice for demanding operational conditions and high-temperature environments, securing their place in advanced and specialized industries.
| Steel Grade | C (%) | Cr (%) | Ni (%) | Si (%) | Mn (%) | Other Elements (%) | Temperature Limit (°C) |
| AISI 309 | 0.2 max | 22-24 | 12-15 | 0.75 max | 2.0 max | – | ~1100 |
| AISI 310 | 0.25 max | 24-26 | 19-22 | 1.5 max | 2.0 max | – | ~1200 |
| AISI 446 | 0.20 max | 23-27 | – | 0.50 max | 1.5 max | – | ~1050 |
| 1.4841 (310S) | 0.02 max | 24-26 | 19-22 | 1.5 max | 2.0 max | – | ~1150 |
| AISI 321 | 0.08 max | 17-19 | 9-12 | 0.75 max | 2.0 max | – | ~850 |
| AISI 347 | 0.08 max | 17-19 | 9-13 | 0.75 max | 2.0 max | Nb: 10xC min, 1.0 max | ~900 |
| Inconel 600 | 0.15 max | 14-17 | 72 min | 0.50 max | 1.0 max | Fe: 6-10 | ~1150 |
| Inconel 625 | 0.10 max | 20-23 | 58 min | 0.50 max | 0.50 max | Mo: 8-10, Nb: 3.15-4.15 | ~980 |
| AISI 253MA | 0.05-0.10 | 20-22 | 10-12 | 1.4-2.0 | 0.8 max | N: 0.14-0.20, Ce: 0.03-0.08 | ~1150 |
| Alloy 601 | 0.10 max | 21-25 | 58-63 | 0.50 max | 1.0 max | Al: 1.0-1.7 | ~1200 |
| HK40 | 0.35 max | 24-26 | 19-22 | 1.50 max | 2.0 max | – | ~1100 |
| HP40 | 0.40 max | 24-27 | 33-37 | 1.00 max | 1.50 max | – | ~1200 |
| 1.4958 (Alloy 800H) | 0.05-0.10 | 19-23 | 30-35 | 1.0 max | 1.5 max | Al: 0.15-0.60, Ti: 0.15-0.60 | ~1100 |
| Alloy 825 | 0.05 max | 19.5-23.5 | 38-46 | 0.50 max | 1.0 max | Mo: 2.5-3.5, Cu: 1.5-3.0, Ti: 0.6-1.2 | ~1000 |
| 1.4724 | 0.10-0.20 | 11-13 | – | 1.5-2.0 | 0.8 max | Al: 0.70-1.30 | ~850 |
| 1.4742 | 0.10-0.20 | 17-19 | – | 1.5-2.5 | 0.8 max | Al: 0.70-1.20 | ~950 |
| 1.4828 | 0.20 max | 19-21 | 11-13 | 1.5-2.0 | 0.8 max | – | ~1100 |
| 1.4876 | 0.08 max | 19-23 | 30-35 | 1.0 max | 1.5 max | Al: 0.15-0.60, Ti: 0.15-0.60 | ~1100 |
| Alloy 718 | 0.08 max | 17-21 | 50-55 | 0.35 max | 0.35 max | Mo: 2.8-3.3, Nb+Ta: 4.75-5.50, Ti: 0.65-1.15 | ~980 |
| 1.4961 | 0.05-0.10 | 15-17 | 12-14 | 0.3-0.6 | 1.5 max | – | ~1100 |
| AISI 304 | 0.15 max | 18-20 | 8-10.5 | 1.0 max | 2.0 max | – | ~800 |
| AISI 304L | 0.03 max | 18-20 | 8-12 | 1.0 max | 2.0 max | – | ~800 |
| AISI 316 | 0.08 max | 16-18 | 10-14 | 1.0 max | 2.0 max | Mo: 2-3 | ~850 |
| AISI 316L | 0.03 max | 16-18 | 10-14 | 1.0 max | 2.0 max | Mo: 2-3 | ~850 |
| AISI 308 | 0.08 max | 19-21 | 10-12 | 1.0 max | 2.0 max | – | ~850 |
| AISI 420 | 0.15-0.45 | 12-14 | – | 1.0 max | 1.0 max | – | ~750 |
| 1.4848 | 0.3-0.5 | 24-26 | 19-22 | 1.0-2.5 | 0.5-1.5 | – | ~1150 |
| 1.4841 | 0.2max | 24-26 | 19-22 | 1.5 max | 2.0 max | – | ~1150 |
| 1.4828 | 0.20 max | 19-21 | 11-13 | 1.5-2.0 | 2.0max | – | ~1100 |
| 1.4837 | 0.3-0.5 | 24-26 | 11-14 | 1.0-2.5 | 0.5-1.5 | – | ~1150 |
| 1.4823 | 0.3-0.5 | 25-28 | 3.5-5.5 | 1.0-2.5 | 0.5-1.5 | – | ~1100 |
| 5830* | 0.70-0.90 | 24-26 | 2.5-3.5 | 1.0-2.0 | 0.6-1.0 | – | ~1000 |
Sepahan Foolad Atashgah Casting Industries Company, with over 30 years of experience in the casting industry, is committed to self-sufficiency by leveraging skilled personnel and experienced managers. The company proudly serves various industries, including steel, copper, mining, cement, and their related sectors, as well as producing cast iron balls required by different industries.
Isfahan – Najafabad – Najafabad Industrial Park 2 – Sanat Square – Doctor Hesabi Blvd – Sub-corner 28
