1. What is 07Cr18Ni11Nb?
07Cr18Ni11Nb is an austenitic stainless steel, a heat-resistant and corrosion-resistant alloy steel. Its composition consists of approximately 18% chromium (Cr) and 11% nickel (Ni). Niobium (Nb) is added as a stabilizing element to improve resistance to intergranular corrosion. Similar grades include the domestic GB standard 0Cr18Ni11Nb (old grade) and the international ASTM standard 347H stainless steel.
2. What are the main characteristics of this steel pipe?
High-temperature resistance: It can be used for long periods of time below 800°C, making it suitable for high-temperature environments (such as boilers and heat exchangers).
Corrosion resistance: It resists oxidation and acid and alkali corrosion, and is particularly well-suited for environments containing sulfur.
Processability: The austenitic structure provides good plasticity and weldability, but care must be taken to avoid sensitization caused by carbide precipitation.
3. What are its main application areas? Energy Industry: Power plant boiler pipes and superheater tubes.
Chemical Equipment: Reactors and pipes transporting corrosive media.
Aerospace: High-temperature components or pressure-resistant structural parts.
4. How does it differ from ordinary 304 stainless steel?
Compositional differences: 304 does not contain niobium, while 07Cr18Ni11Nb is stabilized with niobium, providing greater resistance to intergranular corrosion.
High-temperature performance: 07Cr18Ni11Nb is more stable at high temperatures, while the long-term operating temperature of 304 generally does not exceed 600°C.
5. What parameters should I consider when purchasing?
Applicable standards: Such as GB/T 13296 (boiler tubes) and ASTM A213 (international standard).
Dimensional accuracy: Outer diameter and wall thickness tolerances must meet project requirements.
Test reports: Chemical composition analysis, mechanical properties testing (e.g., tensile strength ≥ 520 MPa), and non-destructive testing reports are required.
