What are the properties of T91 steel
Jan 07, 2026
T91 steel is a new generation of medium-alloy heat-resistant steel developed based on 9Cr1Mo(T9) steel using purification and fine-graining metallurgical techniques, as well as microalloying, controlled rolling, and controlled cooling processes. This steel possesses good comprehensive mechanical properties, stable microstructure after high-temperature aging, and excellent weldability and processability, making it suitable for high-temperature pressure-bearing components.
Chemical Composition of T91 Steel:
C content: 0.08~0.12%
Si content: 0.2~0.5%
Mn content: 0.3~0.6%
P content: <0.02%
S content: <0.01%
Ni content: <0.4%
Cr content: 8~9.5%
Mo content: 0.85~1.05%
Nb content: 0.06~0.1%
V content: Not specified.
Mechanical Properties:
Tensive strength of T91 steel >585MPa, yield strength >415MPa, elongation >20%. Its microstructure is typically tempered martensite or tempered sorbite.
Furthermore, the acceptable hardness range for the base metal of T91 steel is 180~250HB, and the acceptable hardness range for the welded joint is 185~290HB.
Application Areas
The properties of T91 material dictate its primary use in stationary industrial equipment with extremely high material performance requirements.
1. Power Plant Boilers: This is T91's most significant application area. It is commonly used in the manufacture of high-temperature, high-pressure steam pipes, headers, and superheater and reheater tube bundles in supercritical and ultra-supercritical thermal power generating units. These components operate under high-temperature, high-pressure steam environments for extended periods, demanding extremely high durability and oxidation resistance.
2. Petrochemical Equipment: In certain high-temperature, high-pressure chemical processes, such as some pipes and components in hydrocracking units, T91 is also used to cope with harsh operating conditions.
3. Other High-Temperature Industrial Applications: T91 may also be found in specific industrial applications requiring high temperatures and sustained material strength.
A213 T91 alloy steel pipe for boiler in stock
