A335 P22 Seamless Pipe

QS Pipe: Xiamen A335 P22 Seamless Pipe

ASTM A335 P22 seamless pipe in 2.25Cr-1Mo steel, supplied normalized and tempered for boiler, superheater and hot steam service.

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One-Minute Overview

Chrome-moly seamless pipe in ASTM A335 Grade P22 for high-temperature pressure service.
Sizes 1/2 to 24 inch, wall schedules Sch 40 to XXS, cut to the lengths your drawing calls for.
Supplied normalized and tempered, with plain or bevelled ends ready for field welding.
Built for boiler tubes, superheater lines, reheaters and refinery heater service.

A335 P22 seamless pipe is the 2.25Cr-1Mo chrome-moly tube specified for lines that stay hot. The chromium resists oxidation and graphitization, the molybdenum holds creep strength, and the seamless shell has no weld seam to soften under thermal cycling. Typical duty is boiler tubes, superheaters, reheaters, main steam piping and refinery heater coils. The pipe is supplied to ASTM A335 / ASME SA335 in the normalized and tempered condition, with chemistry and tensile results certified on the mill test report that travels with every heat.

Name: A335 P22 Seamless Pipe
Type: Seamless, hot finished or cold drawn
Size: 1/2-24 Inch
Schedule: Sch 40-XXS
Material: ASTM A335 P22 (2.25Cr-1Mo)
Standard: ASTM A335 / ASME SA335
End: Plain End or Bevel End
Feature: Normalized and tempered for creep service
Sizes, wall thicknesses and schedules are confirmed per inquiry, and a detailed specification sheet is available on request.

Welding P22 rewards patience. Use a matching filler metal, preheat in the range your welding procedure calls for, keep the interpass temperature steady, and plan post-weld heat treatment before the arc ever strikes — without it the heat affected zone can harden and crack. Run the root pass with care on thin schedules so the bead does not burn through, cap with a controlled weave, and let the joint cool slowly. Before the spool leaves the shop, confirm the fit-up, the bead profile and the numbers stamped on the pipe body.

Inspection follows the service code. Hydrostatic test every pipe, add ultrasonic or radiographic examination where the design demands it, and run positive material identification on the alloy before it joins the line, because a mislabelled heat is far cheaper to catch on the floor than in a shutdown. Store tubes capped and dry, keep the bevels protected with end caps during transport, and segregate P22 from carbon steel so nobody grabs the wrong grade in the rush of a turnaround.

FAQ

Q1. Why specify P22 instead of carbon steel on a hot line?

P22 adds 2.25% chromium and 1% molybdenum to the steel, which raises creep strength and oxidation resistance well above carbon steel. In steam and heater service above roughly 400°C, carbon steel loses strength quickly, while P22 keeps its load-carrying ability and tolerates the oxide scale that forms on the surface. Below that band, carbon steel is often the cheaper answer.

Q2. Do I really have to preheat and PWHT a P22 weld?

Yes, really. P22 hardens in the heat affected zone, and a cold, rushed weld is exactly how cracks start. Preheat as your welding procedure says, keep the interpass steady, then post-well heat treat the joint. Skip those steps and you may pass the visual check today only to find a crack at the next shutdown.

Q3. What paperwork comes with the pipe — or do we just hope?

No hoping required. Each heat ships with a mill test report covering chemistry, tensile results and heat treatment, and we can add hydrostatic, ultrasonic or radiographic records plus positive material identification to the file. If your project wants a third-party witness or an EN10204 3.1 certificate, say so with the inquiry and it goes into the scope.

Q4. What's the minimum I can order?

Standard flange insulation gasket kits start at one set, and standard gaskets, studs, washers and sleeves start at one piece. Kits made to your drawing or for a non-standard bolt pattern are quoted individually, because the minimum really depends on the material and the tooling involved.

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