What are the properties of T91 material
Jan 06, 2026
T91 steel, officially named SA-213 T91, is an improved 9Cr-1Mo steel, belonging to the ferritic heat-resistant alloy steel category. Its chemical composition has been meticulously optimized to achieve excellent performance under high-temperature conditions. The main components are approximately as follows: carbon (C) content is approximately 0.08%-0.12%, a crucial element for ensuring steel strength; chromium (Cr) content is between 8.0%-9.5%, effectively improving the steel's oxidation and corrosion resistance; molybdenum (Mo) content is between 0.85%-1.05%, enhancing the steel's strength and toughness, especially under high-temperature conditions; in addition, it contains small amounts of vanadium (V), niobium (Nb), and nitrogen (N) to further improve the steel's overall performance.
These precise chemical proportions allow T91 steel to maintain sufficient toughness while possessing extremely high creep strength and endurance strength, making it particularly suitable for long-term use under high temperature and high pressure environments.
Characteristics:
Oxidation Resistance: In environments below 620℃, its resistance to high-temperature steam corrosion is superior to austenitic stainless steel; after long-term service, the oxide scale thickness is only 1/3 that of T9 steel.
Thermal Strength: The specified non-proportional elongation strength at 550℃ reaches 376MPa, the creep rupture life exceeds 100,000 hours, and the tensile strength is ≥585MPa.
Process Stability: Using a normalizing and tempering process, the tensile strength is ≥585MPa, and the specified non-proportional elongation strength at 550℃ reaches 376MPa.
Applications:
- Power Boilers: Primarily used in the main steam pipes of 600MW and above units. Compared to traditional P22 steel, it reduces wall thickness by 50%, lowers piping system weight by 35%, and reduces three-way power consumption by 65%.
- Nuclear Power Equipment: Used as heat transfer tubes in the secondary loop heat exchanger of the nuclear island, withstanding an operating environment of 550℃/20MPa.
- Petroleum Cracking Units: Suitable for furnace tubes in the radiant section of petroleum cracking units, with an upper service temperature limit of 650℃.
A213 T91 alloy steel pipe for heat exchanger in stock
