Alloy Steel
Chrome-moly alloy steel P5, P9, P11, P22 and P91 in pipe, fitting, flange, plate and bar form — ASTM A335 / A182 / A234 WP with IBR and third-party inspection.
What is alloy steel?
Alloy steel is carbon steel with deliberate additions of chromium, molybdenum, nickel or vanadium to raise strength, creep resistance and high-temperature performance. In process plant the chrome-moly family dominates: ASTM A335 P11 (1¼Cr-½Mo), P22 (2¼Cr-1Mo), P5 (5Cr-½Mo), P9 (9Cr-1Mo) and P91 (9Cr-1Mo-V), used for steam lines and heaters up to about 650 °C.
Steelco Metal & Alloys supplies alloy steel from Mumbai in seamless pipe, buttweld fittings, forged flanges, plate and bar, with matching heat treatment (normalised and tempered), hardness reports and IBR certification for boiler service. Every dispatch leaves our Mumbai warehouse with an EN 10204 3.1 mill test certificate (3.2 with TUV, SGS, BV, Lloyd's, IRS or IBR witness on request), PMI verification and full heat-number traceability.
Alloy steel grades we stock.
Chrome-moly and engineering alloy steel grades held in ready stock in Mumbai.
Alloy Steel we hold in ready stock.
Seamless pipe
1/2" – 24" NB ASTM A335 P5 / P9 / P11 / P22 / P91, Sch 40 to XXS.
Buttweld fittings
ASTM A234 WP11 / WP22 / WP91 elbows, tees, reducers and caps.
Forged flanges
ASTM A182 F11 / F22 / F91 flanges 1/2" – 36", Class 150 – 2500.
Plate
ASTM A387 Gr 11 / 22 Class 2 pressure-vessel plate, 6 – 120 mm.
Round bar
EN 19, EN 24, EN 31, 4140 and 4340 bar, Ø 15 – 400 mm.
Tube
ASTM A213 T11 / T22 / T91 boiler and superheater tube.
Use our free metal weight calculator — bars, sheets, plates, pipes and sections.
Our alloy steel range
Ready stock across every mainstream form — dispatched with mill test certificates and full traceability from our Mumbai warehouse.
Pipe & Fittings
A335 P11 / P22 / P91 with WP fittings.
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Flanges
A182 F11 / F22 / F91, Class 150 – 2500.
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Plate
A387 Gr 11 / 22 Class 2, 6 – 120 mm.
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Round Bar
EN 19, EN 24, EN 31, Ø 15 – 400 mm.
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Boiler Tube
A213 T11 / T22 / T91 superheater tube.
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Forged Rings
F22 and F91 rolled rings and discs.
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Fasteners
A193 B7 / B16 studs and A194 2H nuts.
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Welding Consumables
E8018-B2, E9018-B3 and E9015-B9 electrodes.
ExploreAlloy Steel specifications.
Standards, sizes, thickness and condition we routinely supply across every product form.
| Product | Size Range | Thickness / Wall | Finish / Condition | Standards |
|---|---|---|---|---|
Seamless Pipe | 1/2" – 24" NB | Sch 40 – XXS | Black, normalised & tempered | ASTM A335 / ASME SA335 |
Boiler Tube | Ø 12 – 114 mm | 1.5 – 12 mm | Annealed / N&T | ASTM A213 T11 / T22 / T91 |
Plate | 1250 – 3000 mm wide | 6 – 120 mm | Normalised & tempered | ASTM A387 Gr 11 / 22 Cl 2 |
Buttweld Fittings | 1/2" – 36" | Sch 40 – XXS | Bevelled ends, N&T | ASTM A234 WP11 / WP22 / WP91 |
Flanges | 1/2" – 36" | Class 150 – 2500 | RF / RTJ machined | ASTM A182 F11 / F22 / F91 |
Round Bar | Ø 15 – 400 mm | — | Black, peeled, hardened & tempered | EN 19 / EN 24 / EN 31 |
Note: IBR certification, PWHT records and hardness testing available on request.
Where alloy steel is used.
Power Generation
Main steam lines, headers, superheater and reheater tubing in P22 and P91.
Refinery & Petrochemical
Hydrocracker and reformer piping, heater coils in P5, P9 and P11.
Boilers
IBR-certified boiler piping, tubes and drums.
Engineering & Tooling
Shafts, gears, spindles and dies in EN 19, EN 24 and EN 31.
Oil & Gas
High-pressure piping, valve bodies and forged components.
Fertiliser
Ammonia and urea plant piping under creep conditions.
Frequently asked questions.
Answers to the questions our Mumbai desk is asked most often.
What is the difference between P11, P22 and P91 pipe?
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The numbers describe chromium content and creep strength. P11 is 1¼Cr-½Mo for service to about 550 °C, P22 is 2¼Cr-1Mo for about 580 °C, and P91 is a modified 9Cr-1Mo-V grade with roughly double the creep rupture strength of P22, used in supercritical steam lines up to about 650 °C. P91 requires strictly controlled preheat and post-weld heat treatment.
Does alloy steel pipe need post-weld heat treatment?
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Yes for the chrome-moly grades. P11 and P22 need preheat and PWHT per ASME B31.1 / B31.3 depending on thickness, and P91 requires 200–250 °C preheat with PWHT at 750–780 °C. We supply pipe and fittings in the normalised and tempered condition with heat treatment charts.
Is alloy steel the same as stainless steel?
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No. Alloy steel carries small additions of chromium and molybdenum for strength and creep resistance but is not corrosion resistant and will rust. Stainless steel carries at least 10.5% chromium, which forms a passive film that prevents rusting.
Every dispatch is traceable, tested and certified.
Material is supplied with EN 10204 3.1 (3.2 on request) mill test certificates, PMI and spectro verification, and is open to third-party inspection by TUV, SGS, BV, Lloyd’s and IRS from our Mumbai warehouse.
EN 10204 3.1 / 3.2
Mill test certificate with every consignment.
PMI & Spectro
Positive material identification before dispatch.
Third-party Inspection
TUV · SGS · BV · Lloyd's · IRS welcome.
Export Documentation
Full set prepared for 40+ countries.
Other grades you may also need
Ready to price your requirement?
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