ASTM A335 P9 Seamless Alloy Steel Tubes For Power Plants
Nov 06, 2025
The A335 P9 pipes are meant for high temperature applications. The sa335 p9 material chemically contains metals like Molybdenum and Chromium added to the alloy. By the addition of metals like Molybdenum and chromium, there is an increase in the tensile strength of the alloy. The yield strength of the a335 p9 welded pipe is 205 Mpa, while its tensile strength is 415 Mpa. The elongation percentage of the pipe is about 30%.
Both these elements are known to improve the pipe's resistance to wear, its impact qualities, hardenability, as well as its elastic limit. They also cause an increase in its mechanical properties like: the prevention of grain growth, reduced brittleness, the increase the creep strength at high temperatures and has excellent resistance to softening.
The chromium content in the a335 p9 pipe makes it highly resistant to corrosion. Therefore, the a335 p9, has excellent resistance to oxidation at elevated temperature. Besides chromium, astm a335 p9 alloy steel pipes that are externally coated with either Black oil paint or anti-corrosion oil show good resistance to corrosion. It could also be galvanized with zinc. Galvanization with zinc increases its resistance to atmospheric corrosion.
A335 P9 Pipes may be manufactured by forming them either through hot finishing or cold drawing. After forming, the pipes have to be finished with heat treatment that includes Full or Isothermal Annealing, Normalizing and Tempering. There are four types of sa335 grade p9 pipes that are manufactured - Welded, Fabricated, Seamless and ERW. The pipes are available in threaded ends, plain ends or bevel end. And both the ends of these pipes are protected by plastic caps. The asme sa335 grade p9 pipes and tubes are manufactured in several forms like – rectangle, coiled, round, square, hydraulics, U-shaped and pancake coils.
Key Features
Material Composition:
The P9 grade is an alloy steel that primarily contains chromium (Cr) and molybdenum (Mo), which enhance its strength, corrosion resistance, and high-temperature capabilities.
Typical composition includes:
Chromium (Cr): 8.0–10.0%
Molybdenum (Mo): 0.90–1.10%
Carbon (C): ≤ 0.15%
Manganese (Mn), Phosphorus (P), Sulfur (S), and Silicon (Si) in controlled amounts.
High-Temperature Strength:
With its chromium and molybdenum content, P9 tubes exhibit excellent resistance to oxidation, creep, and deformation even under extreme temperatures.
Corrosion Resistance:
Chromium provides superior resistance to oxidation and scaling, while molybdenum enhances corrosion resistance, particularly in acidic environments.
Seamless Construction:
The seamless design ensures superior strength, uniformity, and durability compared to welded tubes, making it ideal for critical applications.
Mechanical Properties (Typical)
| Property | Value |
|---|---|
| Tensile Strength | Minimum 415 MPa (60,200 psi) |
| Yield Strength | Minimum 205 MPa (29,700 psi) |
| Elongation | Minimum 20% |
| Hardness | ≤ 250 HBW (Brinell Hardness) |
Equivalent Grades&Standard
| Chrome Moly Pipes: Werkstoff vs EN vs ASTM | ||
|---|---|---|
| Werkstoff /DIN | EN | ASTM |
| 1.5415 | 16Mo3 | A335 Grade P1 |
| 1.7335 | 13CrMo4-5 | A335 Grade P11, P12 |
| 1.7380 | 10CrMo9-10 | A335 Grade P22 |
| 1.7362 | X11CrMo5 | A335 Grade P5 |
| A335 Grade P9 | ||
| 1.4903 | X10CrMoVNb9-1 | A335 Grade P91 |
Application of ASTM A335 P9 Seamless Alloy Steel Tubes For Boiler And Heat Exchanger Applications
1.Power generation: It is used in power plants for high-temperature steam pipelines, boiler tubes, and superheater tubes.
2.Petrochemical industry: ASTM A335 P9 finds applications in the petrochemical industry for high-temperature pipelines, heat exchangers, and process piping systems.
3.Refinery applications: It is used in refineries for hydrocarbon processing units, such as cracking units, cokers, and reformers.
4.Chemical industry: ASTM A335 P9 is suitable for various chemical processing applications where high-temperature and corrosion resistance are essential.
5.Heat recovery steam generators (HRSGs): It is employed in HRSGs, which are used to recover waste heat from gas turbines for power generation.
6.High-pressure boiler systems: ASTM A335 P9 is commonly used in high-pressure boiler systems for its strength and resistance to high temperatures.
Test and inspection
Packaging and shipping
