Alloy Steel Pipes — ASTM A335 P11, P22, P91

What is an Alloy Steel Pipe?

ASTM A335 covers seamless ferritic alloy-steel pipe for high-temperature service. Additions of chromium and molybdenum raise creep strength and resistance to oxidation and hydrogen attack, so these grades are used in boiler headers, main steam and hot reheat lines, superheaters and refinery heaters. P11 (1¼Cr-½Mo) and P22 (2¼Cr-1Mo) are common in power and process plants; P91 (9Cr-1Mo-V) gives higher strength at elevated temperature and allows thinner walls. Welding of these grades requires preheat and post-weld heat treatment per the code.

Key features

• Stockist and supplier — sourced from seamless alloy pipe mills; Teshi does not manufacture pipe
• Grades P1, P5, P9, P11, P12, P22, P91 and others against order
• Seamless only, per ASTM A335
• Wall thickness to ASME B36.10M schedules or calculated wall
• PMI checks when specified by the purchaser
• Matching alloy flanges (ASTM A182 F11, F22, F91) and fittings manufactured by Teshi

Specification

Applications

• Main steam and hot reheat lines in power plants
• Boiler headers and superheater links
• Refinery heater and hydro-processing lines
• High-temperature petrochemical service
• IBR steam piping