1. Material Definition and Standard Specifications
S31009 is a high-chromium-nickel austenitic heat-resistant stainless steel (corresponding to the Chinese designation 06Cr25Ni20NbN). Its core features include:
Composition Design:
High-chromium nickel base (Cr 24.0-26.0%, Ni 19.0-22.0%) + niobium-nitrogen composite strengthening (Nb ≥ 0.10%, Ni 0.10-0.20%);
Ultra-low carbon (C ≤ 0.08%), strictly controlled phosphorus and sulfur (P ≤ 0.040%, S ≤ 0.030%);
Implementation Standards: GB/T 5310 (for boiler tubes), ASTM A213/A312 (American Standard). 2. Core Performance Advantages
High-Temperature Performance:
Continuous operating temperature 1100°C (short-term 1200°C);
Tensile strength ≥ 60 MPa at 1000°C (baseline for long-term strength);
Oxidation Resistance: Oxidation weight gain < 1.5 mg/cm² (100 hours) at 1100°C;
Processing Characteristics: Welding requires ER310Nb wire, followed by post-weld solution treatment (1150°C rapid cooling).
3. Typical Applications
Energy Equipment:
Ultra-supercritical boiler final stage superheater;
Molten salt reactor main heat exchange piping;
Industrial Furnaces:
Heat-resistant slide rails for steel rolling furnaces;
Ceramic sintering furnace rollers;
Special Applications: Aerospace engine tail nozzle liners.
4. Comparison with Similar Materials
vs. S31008 (310S):
Niobium-nitrogen strengthening increases high-temperature strength by 40%;
Carburization resistance doubled;
vs. RA330:
Lower nickel content, only 60% of the cost;
Comparable performance in oxidizing environments. 5. Procurement and Testing Key Points
Key Certificates: A high-temperature endurance test report (1000°C/100,000 hours extrapolated) is required.
Processing Notes:
Hot forming finish rolling temperature ≥ 950°C.
The use of sulfur-containing cutting fluids is prohibited.
