What Are Alloy Pipes?
Per ASTM A335 and ASME SA335, alloy steel pipes are chrome-molybdenum (Cr-Mo) seamless pipes engineered for 400-600 °C service and pressures exceeding 100 bar. Chromium provides oxidation resistance; molybdenum enhances creep strength under sustained high-temperature load per ASME Section II Part D. They are the critical piping material in refinery heater circuits, power-plant main steam lines, and petrochemical reactors. We supply ASTM A335 grades (P11, P22, P91) with MTC and IBR certification.
- P11 (1¼Cr-½Mo): Standard grade for moderate-temperature service up to 540°C
- P22 (2¼Cr-1Mo): Higher creep strength for main steam and hot reheat lines up to 565°C
- P91 (9Cr-1Mo-V-Nb): Advanced grade for ultra-supercritical power plants up to 600°C
- All grades: Seamless, normalized and tempered, with MTC and IBR certification
Specifications We Stock
| Type | Seamless - hot-finished and cold-drawn |
|---|---|
| Size Range | NPS 1/2" to 24" in Schedules 40, 80, 120, 160, XXS |
| Grades | ASTM A335 P11, P22, P5, P9, P91, P92 |
| Temperature Rating | P11 up to 540°C, P22 up to 565°C, P91 up to 600°C |
| Certification | MTC 3.1/3.2, IBR Form III-C, NACE MR0175 (on request) |
Common Applications
- Power Generation: Main steam lines, hot reheat piping, boiler headers, economizer tubes.
- Refineries: Catalytic cracker piping, hydroprocessing units, heater tubes, furnace piping.
- Petrochemical: Reactor piping, reformer tubes, high-temperature process lines.
- Fertiliser Plants: Ammonia converter piping, synthesis gas lines.
Source Mills We Work With
We procure materials exclusively from highly reputed Indian and global steel mills, including:
Applicable Standards & Specifications
ASTM A335 grade selection guide
How to choose between the common A335 chrome-moly grades - chromium content drives high-temperature oxidation resistance; max metal temperature drives the typical service category.
| Grade | Chromium % | Max temp (°C) | Typical application | RP stock pattern |
|---|---|---|---|---|
| P11 | 1.0-1.5 | 580 | Steam piping, refinery low-temp circuits | Common |
| P22 | 2.0-2.5 | 600 | Superheater, reheater piping | Common |
| P91 | 8.0-9.5 | 625 | Ultra-supercritical boiler main steam | Indent |
| P92 | 8.5-9.5 | 650 | Advanced ultra-supercritical boiler | Indent |
P11 and P22 are stocked off-the-shelf in standard NPS / schedule combinations. P91 and P92 are rolled against indent - typical mill lead time 4-8 weeks depending on size and certification scope (IBR / NACE).
How To Order
- Specify ASTM A335 grade (P11/P22/P91), NPS, schedule, and length.
- Indicate certification requirements - MTC 3.1/3.2, IBR Form III-C, NACE.
- Provide quantity and delivery location for freight calculation.
- Approve quotation and PO - we dispatch from Kanpur stockyard.
Get a quote for Alloy Pipes
Share your sizes and grade. We reply with stock, pricing, and lead time.
Frequently Asked Questions
What is the difference between P11, P22, and P91?
Are alloy steel pipes available with IBR certification?
How do alloy pipes differ from carbon steel seamless pipes?
Related
- Calculate the weight of Alloy Steel Pipes for your BOQ Size, wall, and length to MT before requesting a quote.