Alloy Steel Seamless Pipes & Tubes
Giriraj Impex stocks, supplies and exports alloy steel seamless pipes and tubes – chrome-moly pipes to ASTM A335 in grades P5, P9, P11, P22 and P91, and boiler, superheater and heat-exchanger tubes to ASTM A213 in grades T5, T9, T11, T22 and T91. We supply alloy steel seamless pipes and tubes from approved mills, normalised and tempered, with mill test certificates and with IBR certification where the order requires it.
Alloy steel pipes and tubes are used where carbon steel would lose strength or suffer oxidation and hydrogen attack – high-temperature steam lines, boiler and superheater circuits, refinery heater and hydroprocessing lines.
Specifications
| Item | Pipes | Tubes |
|---|---|---|
| Standard | ASTM A335 / ASME SA335 | ASTM A213 / ASME SA213 |
| Grades | P5, P9, P11, P22, P91 | T5, T9, T11, T22, T91 |
| Dimensions | ASME B36.10M; NPS and schedule | OD and wall thickness (minimum or average) |
| Schedules / walls | SCH 40, 80, 120, 160, XS, XXS and others to order | Wall in mm, inches or BWG |
| Heat treatment | Normalised and tempered, or annealed, as the grade requires | |
| Ends | Plain or bevelled to ASME B16.25 | Plain, square cut |
| Documents | Mill test certificate (MTC); IBR certification and third-party inspection on request | |
ASTM A335 composition and properties
The ASTM A335 requirements for the main grades are shown below. Detailed pages: ASTM A335 P91 pipes and ASTM A335 P11 and P22 pipes.
| Grade | UNS | C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|---|
| P5 | K41545 | 0.15 | 0.30–0.60 | 0.025 | 0.025 | 0.50 | 4.00–6.00 | 0.45–0.65 |
| P9 | S50400 | 0.15 | 0.30–0.60 | 0.025 | 0.025 | 0.25–1.00 | 8.00–10.00 | 0.90–1.10 |
| P11 | K11597 | 0.05–0.15 | 0.30–0.60 | 0.025 | 0.025 | 0.50–1.00 | 1.00–1.50 | 0.44–0.65 |
| P22 | K21590 | 0.05–0.15 | 0.30–0.60 | 0.025 | 0.025 | 0.50 | 1.90–2.60 | 0.87–1.13 |
| P91 | K90901 | 0.08–0.12 | 0.30–0.60 | 0.020 | 0.010 | 0.20–0.50 | 8.00–9.50 | 0.85–1.05 |
P91 also has limits on V, Nb, N, Ni, Al and other elements, as given in the standard.
| Grade | Tensile strength, MPa (ksi) | Yield strength, MPa (ksi) |
|---|---|---|
| P5, P9, P11, P22 | 415 (60) | 205 (30) |
| P91 | 585 (85) | 415 (60) |
Elongation and P91 hardness requirements as given in the standard.
Pipes for steam lines, tubes for boilers
A335 pipe is ordered by nominal size and schedule and used for headers and interconnecting piping – main steam, hot reheat, feedwater heater extraction and refinery transfer lines. A213 tubes are ordered by outside diameter and wall thickness and used inside boilers, superheaters, reheaters, economisers and heat exchangers, where they are bent, swaged and welded into panels and coils. The same nominal composition is available in both forms – P22 pipe and T22 tube, for example – so a boiler and its piping can be built from matching material.
In refineries, A335 P5 and P9 pipes are used for heater outlet and transfer lines carrying hot, sulphur-bearing hydrocarbons, where their chromium content resists sulphidation. In hydroprocessing units, chrome-moly steels are selected with reference to the hydrogen partial pressure and temperature to avoid high-temperature hydrogen attack.
Testing and IBR certification
A335 and A213 require chemical analysis, tensile, flattening and flaring tests, hardness checks and a hydrostatic or non-destructive electric test on each length, with additional hardness requirements for P91/T91. For boiler and steam piping in India subject to the Indian Boiler Regulations, pipes and tubes are supplied with IBR certification when the order calls for it; please mention IBR in your enquiry so the documents and inspection are arranged. Third-party inspection and positive material identification can be added on request.
Handling and fabrication notes
Chrome-moly pipes and tubes look identical to carbon steel, so each length is marked with its grade and heat number and should be kept segregated. Welding requires preheat, interpass control and post-weld heat treatment to the design code, with the strictest controls for P91/T91. Bending of tubes and pipes may require heat treatment afterwards, depending on the strain and the grade.
Ordering
Please give the standard and grade, size and schedule (pipes) or OD and wall (tubes), length, quantity, and any IBR, hardness, inspection or end-finish requirement.
Applications and related products
Alloy steel pipes and tubes are used in thermal and combined-cycle power stations, industrial boilers and heat-recovery steam generators, refinery heaters, hydrocrackers and hydrotreaters, petrochemical crackers and fertiliser plants. They are matched with alloy steel flanges (A182 F11, F22, F91), alloy steel pipe fittings (A234 WP11, WP22, WP91), alloy steel fasteners, alloy steel plates to ASTM A387 and alloy steel round bars. See also boiler tubes, the alloy steel material page and all seamless pipes and tubes.
Frequently Asked Questions
ASTM A335 covers seamless ferritic alloy steel pipe for high-temperature service, ordered by nominal size and schedule. ASTM A213 covers seamless boiler, superheater and heat-exchanger tubes, ordered by outside diameter and wall thickness.
P22 has long been used for main steam and hot reheat lines, and P91 is now common in modern high-temperature power plants because its higher creep strength allows thinner walls.
Yes. Alloy steel pipes and tubes for boilers and steam lines can be supplied with IBR certification when the order requires it.
P91 gets its creep strength from a carefully controlled microstructure produced by normalising and tempering. Incorrect heat treatment, welding or post-weld heat treatment can reduce its strength, so procedures and hardness checks are strictly controlled.
Yes. ASTM A335 pipes are supplied normalised and tempered or annealed, as required for each grade, and the heat treatment is shown on the mill test certificate.
Please give the standard and grade, size and schedule or OD and wall, length, quantity, and any IBR, hardness, inspection or end-finish requirements.
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