309S, 310S heat-resistant steel series stainless steel coils

Core Property Comparison

• 309S (0Cr23Ni13): Contains 23% chromium and 13% nickel, with a recommended oxidation resistance temperature of ≤980°C. Its heat resistance is superior to 304 but inferior to 310S, and it has poor sulfidation resistance (prone to damage in sulfur-containing atmospheres). It is commonly used for medium to high-temperature components such as inner covers of continuous annealing furnaces, heat exchangers, and automotive exhaust manifolds.
• 310S (0Cr25Ni20): Contains 25% chromium and 20% nickel, with an oxidation resistance temperature of up to 1150°C, making it the "heat resistance ceiling" among austenitic stainless steels. It forms a dense oxide film at high temperatures and exhibits excellent creep resistance. It is mainly used in extreme high-temperature equipment such as muffle cans for heat treatment furnaces, boiler superheaters, and high-temperature thermocouple protection tubes.

???? How to Choose?

• Operating temperature ≤980°C and low sulfur content in the environment → Choose 309S for higher cost performance (about 20~30% cheaper than 310S).
• Long-term operating temperature >1000°C or resistance to severe thermal cycling required → 310S is a must; otherwise, the material will oxidize and peel off rapidly.

⚠️ Key Pitfalls to Avoid

1. Neither type can come into contact with halogens (such as fluorine and chlorine), as halogen corrosion will occur at high temperatures.
2. 309S should be used with caution in sulfur-containing atmospheres, as low-melting-point sulfides will form and damage the oxide film.
3. The corrosion resistance of both materials will decrease after welding. If post-weld use in corrosive media is required, solution treatment is recommended.