What material is P9 boiler tube
Jan 06, 2026
ASME SA335/ASTM A335 P9 is a type of ferritic alloy seamless steel tube designed for high-temperature applications. Its primary manufacturing purpose is to serve high-temperature, high-pressure, and ultra-high-pressure boilers, and it is widely used in the manufacture of critical components such as superheater tubes, reheater tubes, steam pipes, and main steam pipes. In the petrochemical industry, the manufacture of high-temperature boilers, superheaters, heat exchangers, and fittings also relies heavily on P9 high-temperature alloy tubes. It maintains stable physical and chemical properties under high-temperature conditions, ensuring the safe and efficient operation of related equipment.
A335 P9 Alloy Tube Chemical Composition:
ASTM A335 P9 alloy seamless steel tubes adhere to strict chemical composition standards:
C: ≤0.15%, precise control of carbon content is crucial for balancing the strength and hardness of the steel.
Si: 0.25~1.00%, silicon helps improve the strength and hardness of the steel.
Mn: 0.30~0.60%, manganese plays a key role in improving the strength and hardenability of the steel.
Phosphorus (P) ≤ 0.025%, strictly controlling phosphorus content ensures stable steel performance.
S ≤ 0.025%, a reasonable sulfur content reduces the hot brittleness of steel.
Cr: 8.00~10.00%, chromium significantly enhances the corrosion resistance and oxidation resistance of steel.
Mo: 0.90~1.10%, molybdenum further improves the strength, hardenability, and hot strength of steel.
Mechanical properties of P9 alloy seamless steel pipe:
Tensile strength ≥ 415 MPa, ensuring it is not easily broken under tensile force.
Yield strength ≥ 205 MPa, demonstrating good resistance to deformation.
Elongation ≥ 22%, indicating that the material has certain ductility.
A335 P9 boiler tube delivery condition and specifications:
Delivery condition: Usually fully annealed or isothermal annealed, normalized + tempered. These delivery conditions ensure that the steel pipe has good performance upon delivery, meeting the requirements of subsequent processing and use.
Specifications and dimensions: Covering a range of 60.3 - 765*2 - 120. Commonly used diameters include 60.3, 73, 88.9, 114.3, 168.3, 219.1, 273.1, 323.9, 355.6, 406.4, 457.2, 508, 559, 610, 660, 711, and 762. Of course, other sizes can be customized according to customer specifications to meet diverse project requirements.
A335 P9 alloy steel boiler tube factory
