1. What is 07Cr23Ni15Cu4NbN?
07Cr23Ni15Cu4NbN is a high-alloy, austenitic, heat-resistant stainless steel designed for high-temperature corrosive environments. Its composition includes:
23% chromium (Cr) – provides oxidation resistance;
15% nickel (Ni) – stabilizes the austenitic structure;
4% copper (Cu) – enhances resistance to sulfuric acid corrosion;
niobium (Nb) and nitrogen (N) – refine the grain size and improve high-temperature strength.
Internationally similar grades include UNS S31254 (a super austenitic stainless steel variant); the older domestic grade is 0Cr23Ni15Cu4NbN.
2. What are the core properties of this steel pipe? High-Temperature Resistance: Long-term operating temperatures reach 900-1000°C, making it suitable for high-temperature components such as heat exchangers and boilers.
Corrosion Resistance: Copper (Cu) significantly improves resistance to sulfuric acid and phosphoric acid corrosion, while niobium (Nb) prevents intergranular corrosion.
Mechanical Properties: Nitrogen (N) solid solution strengthening results in higher-temperature creep strength than standard 316L.
Weldability: Preheating (100-150°C) and the use of ERNiCrMo-3 welding consumables are required. Post-weld solution treatment (1050-1150°C with rapid cooling) is recommended.
3. What are its main applications?
Chemical Industry: Sulfuric acid production equipment, phosphoric acid reactor piping.
Energy and Power: Waste Heat Boilers, Flue Gas Desulfurization (FGD) Systems.
Marine Engineering: Seawater Desalination Plants, Chloride-Resistant Piping.
Environmental Protection Equipment: High-Temperature Flue Ducts in Waste Incinerators, Pickling Line Trunks.
4. How does it differ from 316L Stainless Steel (06Cr17Ni12Mo2)? High-Temperature Performance: The upper temperature resistance of 07Cr23Ni15Cu4NbN (1000°C) is much higher than that of 316L (approximately 800°C).
Corrosion Resistance: Copper (Cu) increases sulfuric acid corrosion resistance by over 50%, while niobium (Nb) prevents intergranular corrosion, a common problem in 316L.
Cost: Due to the presence of rare elements such as copper and niobium, the price is approximately two to three times that of 316L.
5. Procurement and Processing Considerations?
Standard Certification: ASTM A312/A213 or GB/T 14976 standard steel pipes are preferred.
Testing Requirements: High-temperature tensile data (e.g., strength at 800°C) and pitting corrosion tests (ASTM G48) are required.
Processing Recommendations:
Annealing is required during cold working to avoid cold-hardening cracking.
Avoid prolonged exposure to temperatures between 600°C and 850°C to prevent embrittlement caused by σ phase precipitation.
