Key Features:
Through a unique "micro-alloying" design (high chromium, high nickel, and the addition of nitrogen, cerium, etc.), it achieves high-temperature strength and oxidation resistance far exceeding that of ordinary austenitic heat-resistant steels (such as 310S) while maintaining excellent processing performance.
Simply put, 253MA is "an enhanced version of 310S designed for extreme oxidation environments above 1100°C".
Chemical Composition and Design Logic:
High Chromium, High Nickel Base: Chromium (~21%) and nickel (~11%) provide an excellent oxidation resistance base. Although the nickel content is lower than that of 310S, its performance is significantly enhanced by other elements.
Key Strengthening Elements:
Nitrogen: High content (~0.17%). Nitrogen is a powerful austenite-forming element and solid solution strengthening agent, which can significantly improve room temperature and high-temperature strength, hardness, and creep resistance, and its cost is much lower than that of nickel.
Cerium: A small amount of the rare earth element cerium (Ce) is added. Cerium refines and stabilizes the chromium oxide protective film at high temperatures, making it denser and more adhesive, thus significantly improving resistance to high-temperature cyclic oxidation (i.e., resistance to oxide scale peeling due to thermal expansion and contraction).
Higher silicon and carbon content: Silicon (~1.7%) further enhances oxidation and carburization resistance; higher carbon content (~0.08%) contributes to high-temperature strength.
Balanced design: This compositional combination (partially replacing nickel with nitrogen and adding cerium) is a classic “nickel-saving, high-strength” heat-resistant steel design, achieving top performance while controlling costs.
Key performance characteristics:
Extremely high-temperature strength: Its creep resistance and endurance strength far surpass 310S in the 800°C - 1150°C range. This means that under the same temperature and load, 253MA exhibits less deformation and a longer service life.
Excellent high-temperature oxidation resistance:
Maximum continuous service temperature up to 1150°C, short-term service temperature up to 1250°C.
In particular, it exhibits exceptional resistance to cyclic oxidation, making it ideal for operating conditions with frequent temperature fluctuations.
Good resistance to carburizing and sulfidation: The addition of high silicon and cerium ensures good performance even in reducing and carburizing atmospheres.
Good weldability and formability: Despite its high strength, it retains the good machinability of austenitic steel.
