About Alloy Pipes
Chrome-moly alloy steel pipes for temperature-dependent process and power piping service. ASTM A335 grades include P11, P22, P5, P9 and P91; any IBR inspection and documentation must be specified for the regulated order.
Use this page as a product and specification reference. The quotation must state the exact material grade, dimensions, manufacturer, certification or document scope, inspection, quantity, price, current availability, freight, and proposed delivery timing for the specific RFQ.
Specification reference
| 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 |
| Design Basis | Use the governing code allowable stresses, design temperature and pressure, dimensions, corrosion allowance and service environment |
| Documentation | State inspection-certificate type, IBR Form III-A scope where applicable, and any sour-service requirements in the order |
Confirm the exact grade, dimensions, tolerance, test certificate, and current availability for your requirement before ordering.
Common applications
These are enquiry contexts, not universal approvals. The project design and governing specification must approve the exact product, grade, dimensions, and service conditions.
- 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.
Who should specify alloy pipe, and who should avoid substitution
Alloy pipe belongs in a procurement package when the approved line class or equipment specification names an alloy grade. Power, refinery, petrochemical, fertiliser, and sugar-mill teams usually buy it against a piping material specification, isometric, shutdown list, or boiler requirement. The grade is tied to design conditions, welding controls, heat treatment, and inspection. Procurement should preserve that chain instead of choosing by a trade description.
General utility water, compressed air, structural fabrication, and ordinary plumbing usually do not justify an ASTM A335 alloy grade unless the engineer specifies one. Carbon steel seamless pipe, ERW pipe, GI pipe, or a boiler tube may fit those duties. Alloy pipe must not be substituted by matching outside diameter and wall alone. Similar dimensions do not establish material equivalence.
- Sugar-mill shutdown buyers should separate boiler tubes, headers, and steam-piping items because their governing specifications can differ.
- IBR applicability should be confirmed before the enquiry reaches the quotation stage.
- Maintenance contractors should provide the existing line class and verified material identification, not only a removed spool measurement.
- Welding consumables, preheat, post-weld heat treatment, and procedure approval belong with the project welding plan.
- Hydraulic and printing-cylinder shops should use their drawing-controlled tube grade rather than an alloy pipe grade chosen from availability.
Potential source references
The quotation must identify the proposed manufacturer, current availability, inspection documents, and delivery basis for the specific RFQ.
- ISMT Limited
- Maharashtra Seamless Limited (MSL)
- Jindal SAW
- Chandra Metal Enterprises
Applicable standards and specifications
ASTM A335 grade comparison inputs
These grades differ in chemistry, heat treatment and code properties. The table is a screening aid only; final selection comes from the governing code, design conditions, fabrication procedure and project material specification.
| Grade | Alloy family | Design check | Common project context | Quotation check |
|---|---|---|---|---|
| P11 | Lower Cr-Mo | Code allowable stress plus oxidation, corrosion and fabrication review | Process and steam piping where the design specification names P11 | Size, schedule, heat treatment, documents and current availability |
| P22 | 2¼Cr-1Mo family | Code allowable stress plus oxidation, corrosion and fabrication review | Steam, reheater and process duties where the design specification names P22 | Size, schedule, heat treatment, documents and current availability |
| P91 | Modified 9Cr-1Mo-V-Nb | Code design plus qualified welding and heat-treatment controls | Power piping where the engineering specification names P91 | Approved mill, heat treatment, tests, documents and current availability |
| P92 | Modified 9Cr-W grade | Code design plus qualified welding and heat-treatment controls | Specialised power piping where the engineering specification names P92 | Approved mill, heat treatment, tests, documents and current availability |
Do not infer stock, lead time or certification from the grade name. Require the Kanpur quotation to identify proposed mill, heat, size, schedule, heat treatment, inspection documents, IBR scope where applicable, current availability and delivery terms.
How Kanpur plant buyers write an alloy pipe RFQ
Open with ASTM A335 and the exact P-grade. Follow with NPS, schedule or minimum wall, length, end finish, heat-treatment condition, and quantity. State whether the material enters IBR-regulated service. Add the MTC, exact engineer-confirmed IBR form, TPI, positive material identification, testing, marking transfer, and packing required by the approved procurement specification.
A shutdown list may mix pipe, tube, fittings, and flanges. Keep each product on a separate line and name its material standard. A P22 pipe description does not automatically define the matching elbow, flange, or boiler tube. Ask engineering to approve the complete material set before comparing commercial offers.
- State grade and standard on every line rather than in a note below the BOQ.
- Use NPS and schedule for pipe, then show any minimum-wall or corrosion-allowance instruction separately.
- Identify plain or bevelled ends and any field-weld preparation requirement.
- List heat-number traceability and marking transfer for every cut length.
- Define inspection hold points before the supplier commits material to cutting or dispatch.
Worked weight example for an alloy pipe quantity
The carbon and low-alloy steel pipe formula provides a theoretical planning weight. Using 60.3 mm OD and 3.6 mm wall, weight = (OD - t) x t x 0.02466 kg/m. The calculation gives (60.3 - 3.6) x 3.6 x 0.02466 = 5.03 kg/m. A 6 m length is about 30.20 kg before coating, end preparation, and permitted dimensional variation.
Extend the result by the required metres to estimate MT for freight planning, then compare it with the supplier schedule. Do not use a weight calculation to select the schedule or prove design adequacy. The engineer-approved line class controls grade and wall. The PO should also state whether commercial billing follows actual weighment or a theoretical table.
Inspection failures that delay alloy pipe acceptance
Material identification is the first inspection gate. Match the stencil, heat number, grade, size, and schedule to the MTC before cutting. Where the PO calls for positive material identification or TPI, record the accepted heat and piece range. Mixed P-grades can share dimensions, so colour marks or bundle location alone are not enough for release.
Cutting creates another traceability risk. Short spools can lose the original marking unless the approved transfer method is followed. Check bevel condition, surface damage, straightness, length, and end caps before dispatch. Keep rejected and accepted pieces physically separated. Record the bundle schedule in the same order as the MTC set.
- Do not accept a material grade from paint colour alone.
- Do not combine heats under one unidentified cut-piece bundle.
- Do not treat an MTC, TPI record, and an IBR form as the same document.
- Do not approve a substitute P-grade without written engineering acceptance.
- Do not let inspection timing conflict with cutting, marking transfer, or vehicle booking.
ASTM A335, MTC, and IBR compliance
ASTM A335 is the material specification for seamless ferritic alloy-steel pipe used in high-temperature service. The catalogue lists P11, P22, P5, P9, P91, and P92. The purchase description still needs dimensions, heat treatment, supplementary requirements, inspection, and documentation. An ASTM code without a grade does not identify the material.
For applicable boiler and steam service, the project may require an IBR document in addition to the mill certificate. The official form index lists Form III-A for steam pipes, Form III-B for tubes, and Form III-C for boiler mountings and fittings. Confirm the exact requirement with the responsible engineer. TPI can witness the activities defined in the agreed inspection plan.
Kanpur dispatch planning for shutdown and project orders
Alloy-pipe buyers in Panki, Dada Nagar, Fazalganj, Jajmau, Chakeri, Kanpur Dehat, Unnao and elsewhere should require the quotation to identify proposed mill, grade, schedule, quantity, document package and current availability. The page itself does not prove local stock or regional service.
For destinations outside Kanpur, include the PIN code, site access, unloading equipment, cut-piece packing, and required document destination. Availability, inspection timing, freight, and the proposed dispatch date must be confirmed for the specific shutdown order.
What to include in the RFQ
- Specify the relevant standard or grade where known.
- Provide OD or NB, wall thickness or schedule, required length, and quantity.
- State the delivery city or PIN code and any unloading constraints.
- List MTC, IBR, TPI, marking, inspection, or other documentation requirements.
- Name ASTM A335 and the exact P-grade on each pipe line item.
- State NPS, schedule or minimum wall, length, bevel, surface condition, and quantity.
- Add heat treatment, marking, PMI, test, and supplementary requirements from the approved specification.
- Separate MTC, the engineer-confirmed IBR form, and TPI requirements.
- Specify cut-piece traceability, end protection, bundle segregation, packing, and inspection release.
- Define ex-warehouse Kanpur or delivered basis, destination, freight, unloading, and applicable taxes.
Key points for Kanpur buyers
- The approved piping material specification decides the A335 grade; procurement should not substitute by availability.
- Pipe, tube, fitting, and flange standards must remain separate within a shutdown BOQ.
- Heat-number traceability must survive cutting, inspection, packing, and site receipt.
- MTC, IBR, PMI, and TPI callouts describe different evidence and activities.
- Confirm each grade, schedule, document set, and dispatch basis against the Kanpur RFQ.
