Sep 13, 2026Standards & Testing
ASTM A335 P22 Alloy Steel Pipe: Properties and High-Temperature Service
ASTM A335 P22 seamless alloy pipe for high-temperature, high-pressure service: characteristics, applications, selection points and buying FAQ.
Quick answer: ASTM A335 P22 is a chromium-molybdenum seamless alloy steel pipe for high-temperature, high-pressure service. It offers strong creep resistance, useful corrosion performance in hot gas and liquid media, and reliable mechanical strength, which is why it is common in power, petrochemical and refining work.
What is ASTM A335 P22 pipe?
ASTM A335 P22 is a seamless ferritic alloy steel pipe produced to the ASTM A335 specification for high-temperature service. P22 is a chromium-molybdenum grade, and the seamless route produces a smooth bore with no longitudinal weld, which supports stable performance under combined pressure and heat. It is commonly specified where service temperature and pressure exceed the practical range of plain carbon steel.
What are the main characteristics of P22 pipe?
Three characteristics stand out. First, high-temperature resistance: the chromium-molybdenum composition gives P22 pipe good stability in high-temperature and high-pressure environments. Second, corrosion resistance: it performs well in corrosive gas and liquid service. Third, mechanical performance: it combines high strength with good wear resistance for a long service life. The seamless process supports a smooth wall and the absence of weld defects, which matters for cyclic thermal service.
Where is P22 pipe used?
Typical applications include petroleum and natural gas service, where wells and pipelines must withstand high pressure and elevated temperature; power generation, where boilers, superheaters and heat exchangers carry high-temperature steam; chemical processing, where equipment and process piping handle aggressive media; and shipbuilding, where P22 is used in ship structures and on-board pipeline systems. In each case the grade and wall thickness should be matched to the design temperature and pressure rather than copied from an unrelated project.
For high-temperature service, grade selection should follow the design temperature and pressure rather than price alone; A335 P22 is specified where carbon steel reaches its practical limit.
How should P22 pipe be selected and maintained?
Selection starts with the service environment, because design temperature, pressure and medium determine the appropriate grade and wall thickness. Buyers should purchase from manufacturers with mature seamless production and a documented quality system. After installation, periodic inspection helps confirm that the pipe continues to operate safely; wall thickness checks, visual inspection and non-destructive testing are commonly used during maintenance. Any change in operating conditions should prompt a review of the material selection. Where the pipe is to be bent or welded, the qualified procedures and any required post-weld heat treatment should be confirmed at the ordering stage.
What is the outlook for P22 pipe?
Published industry commentary points to continued development in three directions: lower energy consumption and emissions in production, wider use across more industries, and the introduction of intelligent manufacturing to improve efficiency and product consistency. As a proven high-temperature material, P22 pipe is expected to remain in demand for power and process plants, including in retrofit and efficiency-upgrade projects.
FAQ
Is A335 P22 seamless or welded?
A335 P22 is normally supplied as seamless pipe. The seamless route avoids a longitudinal weld and gives a uniform wall for high-temperature pressure service.
What is the difference between P22 and plain carbon steel?
P22 contains chromium and molybdenum, which improve high-temperature strength and creep resistance compared with plain carbon steel. It is selected for elevated-temperature and high-pressure service where carbon steel would be limited.
Which industries use A335 P22 pipe most?
Power generation, petrochemical and refining, oil and gas, and shipbuilding are the most common industries, particularly for boilers, superheaters, heat exchangers and high-temperature process lines.
Can P22 pipe be supplied with third-party inspection?
Yes. Third-party inspection can be arranged with SGS, BV, TUV or TUBOSCOPE, and mill certificates are provided with shipment.
For a high-temperature alloy pipe requirement, send the grade, sizes, quantity and design conditions to the SPAI STEEL sales team for a quotation.
