1. What is this material?
07Cr22Ni25W3Cu3Co2MoNbN is an ultra-high-grade austenitic heat-resistant stainless steel designed for extreme high-temperature, high-pressure, and highly corrosive environments. Its composition includes chromium (22%), nickel (25%), tungsten (3%), copper (3%), cobalt (2%), molybdenum, niobium, and nitrogen, and its overall performance far exceeds that of conventional stainless steel. Similar international grades include UNS S31050 and DIN 1.4959. The older domestic designation is 0Cr22Ni25W3Cu3Co2MoNbN (GB/T 20878).
2. What are its core properties?
Ultra-high-temperature resistance: It can withstand long-term operating temperatures up to 1100°C and short-term temperatures up to 1200°C, making it suitable for extreme environments such as cracking furnaces and boilers. Strong corrosion resistance: High chromium and nickel provide oxidation resistance, while molybdenum and copper enhance resistance to sulfuric acid and chloride corrosion, making it suitable for petrochemical and marine environments.
Excellent mechanical properties: Tungsten and cobalt significantly enhance high-temperature creep strength, while niobium and nitrogen refine grain size and improve toughness.
Weldability: Preheating (150-200°C) and the use of specialized welding consumables (such as ERNiCrMo-3) are required. Post-weld solution treatment is recommended.
3. Typical applications?
Petrochemical industry: Ethylene cracking furnace tubes, catalytic reforming units, and high-temperature reactors.
Energy and power: Ultra-supercritical power plant boiler piping and gas turbine hot-end components.
Special environments: Some nuclear power structural components (requires irradiation performance verification) and chemical transportation of highly corrosive media.
4. How does it differ from 310S stainless steel (25Cr20Ni)? 07Cr22Ni25W3Cu3Co2MoNbN significantly surpasses 310S in high-temperature strength (tungsten-cobalt strengthening) and corrosion resistance (molybdenum-copper resistance to localized corrosion) by adding elements such as tungsten, cobalt, and copper. 310S relies solely on chromium and nickel for oxidation resistance, resulting in lower cost but limited performance, making it suitable for general high-temperature oxidizing environments.
5. Procurement and Processing Key Points
Standard Certification: Steel pipes complying with ASTM A213 (high-pressure boiler tubes) or GB/T 5310 are preferred.
Key Testing: High-temperature tensile data (e.g., strength at 600°C), intergranular corrosion testing (ASTM A262-E), and ultrasonic testing reports are required.
Processing Notes:
Cold working requires a large bend radius (≥4 times the pipe diameter) to prevent cracking.
Avoid prolonged exposure to temperatures between 450°C and 850°C to prevent embrittlement caused by σ phase precipitation.
