Alloy Steel Pipe Supplier in India — ASTM A335 P91, P22, P11

P91 (9Cr-1Mo-V-Nb) has higher creep strength than P22 (2.25Cr-1Mo), allowing thinner walls and lighter piping systems at the same temperature and pressure. P91 is used for main steam lines in supercritical and ultra-supercritical power plants (up to 600°C). P22 is used for lower-temperature headers and HRSG piping (up to 565°C). P91 requires strict heat treatment control — normalise at 1040-1080°C followed by temper at 730-780°C.

Both are 9% chromium creep-strength-enhanced ferritic steels, and the difference is the alloying route used to reach that creep strength. P91 is 9Cr-1Mo-V-Nb. P92 keeps the same chromium base but adds roughly 1.8% tungsten and reduces molybdenum, which raises creep rupture strength further at the same temperature. In practice that means P92 allows thinner walls than P91 for an equivalent duty, which lowers weight and reduces thermal stress at welds — the reason it is specified for ultra-supercritical boiler and main steam service where P91 would need excessive wall thickness. Both require closely controlled normalising and tempering, and P92 is the less forgiving of the two on heat treatment and welding procedure. We stock P91 and supply P92 against project requirements, both with IBR Form III-C and heat treatment certificates.

IBR (Indian Boiler Regulations) certification is mandatory for pipes used in boilers and pressure vessels in India. IBR Form III-C is the material manufacturer certificate confirming the pipe meets IBR requirements. It includes chemical composition, mechanical properties, heat treatment, and NDT results. Only IBR-approved manufacturers can issue Form III-C. We supply all P-grades with valid IBR Form III-C documentation.

We source from world-class mills: Sumitomo Metal Industries (Japan) — premium P91/P92; Vallourec (France/Germany) — P91, P22, P11; ISMT India — P11, P22, P5, P9; Chelpipe (Russia); Maharashtra Seamless; and Jindal SAW. All pipes come with original Mill Test Certificate (MTC) per EN 10204 3.1/3.2 with full heat traceability.

We stock ASTM A335 alloy steel seamless pipe from 1/2 inch (15NB) to 24 inches (600NB) in schedules SCH 40, 60, 80, 100, 120, 140, 160 and XXS. Standard random lengths 5-7 metres. Fixed length and cut-to-length available. For P91 and P22, we maintain heavy-wall stock up to SCH XXS for main steam applications.

P91 (9Cr-1Mo-V-Nb) derives its superior creep strength from a precise tempered martensitic microstructure formed by normalising at 1040-1080°C (air cooled to below 100°C) followed by tempering at 730-780°C. Incorrect heat treatment — over-tempering, under-normalising, or improper cooling — produces ferrite/bainite instead of martensite, drastically reducing creep life. All our P91 pipe is supplied with heat treatment certificates confirming N+T parameters.