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Seamless
ASTM A335 Alloy Steel Pipe

ASTM A335 seamless ferritic alloy-steel pipe for high-temperature service — P5, P9, P11, P22, P91 grades for power plants, refineries, and petrochemical facilities.
ASTM A335 alloy steel pipe
OVERVIEW

The chrome-moly standard for high-temperature piping.

ASTM A335 covers seamless ferritic alloy-steel pipe for high-temperature service in power plants, refineries, and petrochemical facilities. The specification spans grades from P5 (5Cr-0.5Mo) through P91 (9Cr-1Mo-V), each engineered for a specific temperature-pressure-corrosion envelope.
Global Seamless manufactures A335 pipe in all standard grades with in-house normalising, tempering, and quench-and-temper heat treatment. Every pipe ships with documented heat treatment parameters, full mechanical properties, and Mill Test Certificates to EN 10204 3.1 or 3.2.
✓   Grades: P5, P9, P11, P12, P22, P91
✓   Sizes: NPS 1/2" through NPS 24"
✓   Schedules: Std through XXS and custom wall
✓   N+T and Q+T heat treatment in-house
✓   IBR and PED certified
ASTM A335 chrome-moly pipe
DIMENSIONAL SPECIFICATIONS

Available size range.

Cold Drawn Seamless (CDS)

GradeCompositionMax Service TempMin Yield (MPa)
P55Cr-0.5Mo~590°C205
P99Cr-1Mo~595°C205
P111.25Cr-0.5Mo~540°C205
P222.25Cr-1Mo~580°C205
P919Cr-1Mo-V~620°C415
APPLICATIONS & INDUSTRIES

Where these tubes get used.

Main steam, hot reheat, and header piping in thermal power plants.
Reactor circuit piping, transfer lines, and high-temperature process piping.
Furnace piping, ethylene cracker transfer lines, and reformer headers.
Co-generation, waste heat recovery, and industrial boiler steam piping.
MATERIAL GRADES

Chrome-moly grades for every temperature.

LOW ALLOY

P11 · P12

1-1.25Cr grades for subcritical steam piping up to 540°C.
MEDIUM ALLOY

P22 · P5 · P9

2.25-9Cr grades for elevated temperature and sulfidation resistance.
ADVANCED

P91

9Cr-1Mo-V for supercritical steam piping up to 620°C.
TECHNICAL ARTICLES

Latest insights on alloy steel pipe.

ARTICLE

P11 vs P22 Chrome-Moly Selection

Comparing 1Cr and 2.25Cr for your temperature range.
ARTICLE

P91 T91 Supercritical Applications

Advanced 9Cr-1Mo-V for next-generation power plants.
ARTICLE

Heat Treatment of Alloy Steel

Normalising, tempering, and Q&T for chrome-moly grades.
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