Seamless
/glossary/seamlessPipe without weld seam, manufactured by hot-piercing solid steel billet.
Seamless pipe is formed from a solid billet that is pierced and then rolled or drawn, so the wall has no longitudinal weld. Kanpur sugar mills and Panki process shops order it when the drawing names ASTM A106, A53 Type S, SA192, SA210, or SA213. The seamless pipe price list bands A106 Grade B and A53 at ₹74-165 per kg ex-warehouse Kanpur as of 24 May 2026. GST sits at 18% extra on that steel line.
In detail
Seamless pipe or tube starts as a solid steel billet that is pierced and then rolled or drawn, so the finished wall has no longitudinal weld. Product identity comes from the ordered specification: ASTM A106, A53 Type S, ASME SA192, SA210, or SA213. Seamless construction does not by itself set pressure, temperature, or IBR acceptance. Indian boiler work uses Form III-A on steam pipes and Form III-B on tubes; Form III-C covers boiler mountings and fittings.
What seamless pipe is, and what it is not
A seamless hollow starts as a killed steel billet. The mill heats that round, pierces it, and rolls or draws the shell to the ordered OD and wall. The seamless price-list FAQ already states that route: piercing a solid billet, then finishing the wall with no weld seam.
ASTM A106/A106M-26 scope 1.1 covers seamless carbon steel pipe for high-temperature service in NPS 1/8 to NPS 48 (DN 6 to DN 1200), with nominal (average) wall as given in ASME B36.10M. The public abstract requires a seamless process. It does not print a piercing-mill brand or a universal temperature cap.
The BIS product manual for IS 1239 (Part 1):2004 (PM/1239 (Part 1)/4, Feb 2022) also lists seamless as a permitted manufacturing process beside ERW and HFIW. Class Light, Medium, or Heavy still governs that Indian tube when the BOQ is IS 1239. Seamless IS 1239 is not A106 process pipe.
Seamless is not ERW. It is not LSAW or HSAW. It is not a pressure rating. It is not automatic IBR approval. Commodity MS from the Kanpur yard does not become SA213 because the wall has no seam.
Who should order seamless, and who should stay on ERW
Order seamless when the approved drawing or piping class names a seamless-only specification. ASTM A106 is seamless-only. ASME SA192, SA210, and SA213 are seamless boiler or heat-exchanger tubes. A53 Type S is the seamless type under that general-purpose spec.
Panki process fabricators, about 12 km from the Bartan Bazar yard, take A106 Grade B on Sch 40 or Sch 80 when the isometric says so. Sugar mills in the Unnao and Bareilly belt take SA192 or SA210 on OD × minimum wall for generating banks, and SA213 T11 or T22 on superheater sections. Dada Nagar hydraulic shops, about 8 km away, take cold-drawn seamless barrel tube under DIN 2391 or EN 10305, not A106 pipe.
Stay on ERW for IS 1239 water, GI plumbing, JJM house connections, and most PWD distribution. The ERW versus seamless comparison treats the two routes as manufacturing methods, not quality tiers. A fire hydrant that NBC 2016 Part 4 sends to Heavy class GI does not become safer by swapping in seamless A106.
Do not buy seamless as a silent upgrade on an IS 1239 Medium BOQ. Do not fill a Type S line with Type E because the yard has ERW. Do not treat NACE lettering on a carton as sour-service qualification; that duty needs the project MR0175 / ISO 15156 route.
Seamless families on a Kanpur RFQ
Match the product form before comparing rupees. Pipe uses NPS and schedule. Boiler tube uses OD and minimum wall. Precision barrel tube uses OD × ID or OD × wall plus a bore class.
| Call-out | Product form | Usual size language | Kanpur use | Rupee band if listed |
|---|---|---|---|---|
| ASTM A106 Gr B | Seamless pipe | NPS × Sch 40 / 80 / 160 | Panki process headers | ₹74-165 / kg overall list |
| ASTM A53 Type S | Seamless pipe | NPS × schedule, black or GI | Utility where Type S is named | Same seamless list as A106 |
| SA192 | Min-wall boiler tube | OD × min wall, mm | Stationary boiler banks | ₹100-135 / kg on boiler list |
| SA210 A1 / C | Medium-carbon boiler tube | OD × min wall, mm | Water wall and carbon superheater | A1 ₹112-150; C ₹125-170 / kg |
| SA213 T11 / T22 | Alloy boiler tube | OD × min wall, mm | Chrome-moly superheater | Indent; no ₹/kg band |
| DIN 2391 / EN 10305 | Cold-drawn precision tube | OD × wall, H8 / H9 if finished | Dada Nagar barrels | ₹95-150 / kg precision list |
The overall seamless list span of ₹74-165 per kg is the Sch 40 / 80 / 160 envelope already printed for A106 Grade B and A53. A 2 inch Sch 40 row on that list is ₹80-98 per kg. Do not read a boiler-tube band as an A106 offer.
How to specify seamless pipe on an RFQ
A line that says only seamless Grade B produces mixed A53 Type E and A106 offers. Write the standard, the type, and the wall basis. Send the pack through the RFQ page. RP Sales returns a technical and commercial reply inside 4 working hours.
- Standard and grade: ASTM A106 A/B/C, A53 Type S A/B, SA192, SA210 A-1 or C, or SA213 T11/T12/T22.
- Size: NPS and schedule for pipe; OD and minimum wall in mm for boiler tube; OD × ID for a barrel.
- Condition: hot-finished or cold-drawn. End: plain, bevel, or threaded if the drawing shows threads.
- Length: 5.8 m or 6.0 m single random on the seamless list, DRL, or cut-to-length.
- Quantity in metres and MT. Coating: black, varnish, or hot-dip zinc only when the spec allows it.
- Documents: EN 10204 Type 3.1 MTC, heat stencil. Form III-A on an IBR steam pipe, Form III-B on a tube, Form III-C on a mounting or fitting.
- Inspection: mill, or a named TPI hold at the mill or at Bartan Bazar.
- Delivery: ex-warehouse Kanpur or a named FOR place. GST 18% extra. End caps and heat tags intact.
Worked mass for 2 inch Sch 40 from Kanpur
Plain-end planning mass on this entry is W = (OD − t) × t × 0.02466 kg/m (OD and wall in millimetres). That constant equals π × 7850 / 1,000,000, the carbon-steel density already used on the site weight tables.
The site schedule chart lists 2 inch NPS as 60.3 mm OD and Sch 40 wall 3.91 mm. W = (60.3 − 3.91) × 3.91 × 0.02466 = 56.39 × 3.91 × 0.02466 = 5.44 kg/m. A 6 m length is 32.6 kg. Sixty lengths are 1,958 kg (1.96 MT) before bevel waste or varnish.
The seamless pipe price list band for 2 inch Sch 40 is ₹80-98 per kg ex-warehouse Kanpur as of 24 May 2026. That steel line is 1,958 × 80 = ₹1,56,640 to 1,958 × 98 = ₹1,91,884 before GST and freight. Sch 80 on the same NPS is a different wall (5.54 mm) and a different band (₹95-118 per kg).
The glossary lead-time entry lists 3-7 days for stock, 14-21 days for mill-direct standard grades, and 21-30 days for mill-direct alloy such as SA213 T11/T22. A Panki shutdown that needs A106 next week belongs on the stock window, not on an alloy indent.
Common mistakes on seamless orders
In practice, the first failure is a welded offer against a seamless-only drawing. A53 Type E Grade B is not A106 Grade B. The stencil and the MTC must say seamless, Type S, or the SA grade the drawing named.
The second failure is ordering boiler tube as 2 inch Sch 40 pipe. SA192 at 50.8 mm OD is a different diameter from 60.3 mm NPS 2 pipe. Tube sheets and bend dies will not accept the swap.
The third failure is treating the MTC as Form III-B. The EN sheet records heat chemistry. The IBR form is the statutory manufacture-and-test certificate for that component. Order the form on the RFQ, not after the truck is loaded.
The fourth failure is a NACE sticker used as sour-service proof. Hardness, heat treatment, and the ISO 15156 environment statement come from the project specification. The piercing route alone does not qualify the heat.
The fifth failure is comparing a per-kg ERW rate with a per-kg seamless rate on different walls. Convert both lines to OD, wall, and kg/m first. See ERW versus seamless.
Standards that govern seamless pipe and tube
ASTM A106/A106M-26 is the seamless carbon-steel pipe specification for high-temperature service. Its store abstract retrieved for this site lists NPS 1/8 to NPS 48 and names tensile, bending, flattening, hydrostatic, and nondestructive electric tests. ASME publishes the same material as SA-106 in Section II Part A; write the designation the design actually uses.
ASTM A53/A53M-24 Type S is seamless general-purpose pipe in the same NPS 1/8 to NPS 26 range as Types E and F. Scope 1.3 of that abstract allows ordinary steam, water, gas, and air lines. It is still not A106.
ASME SA-192 covers seamless carbon-steel boiler tubes for high-pressure service, SA-210 covers seamless medium-carbon boiler and superheater tubes, and SA-213 covers seamless ferritic and austenitic alloy tubes for boiler, superheater and heat-exchanger duty. Order all three by OD and wall. The 1950 forms index maps steam pipe to Form III-A, tube to Form III-B, and a mounting or fitting to Form III-C.
IS 1239 (Part 1):2004 can be seamless or welded. The BIS product manual (PM/1239 (Part 1)/4, Feb 2022) says seamless tubes shall be made from tested-quality fully killed steel. Clause 13 leak-proof testing on that manual is 5 MPa on each tube, eddy-current or hydrostatic. DIN 2391-1:1994 and EN 10305-1:2016 govern cold-drawn precision tube used in Dada Nagar.
Buying seamless pipe in Kanpur
The origin yard is 83/124, Steel Market, Bartan Bazar, Afim Kothi, Basanti Nagar, Juhi, Kanpur 208014. Intra-city drops to Panki (about 12 km), Dada Nagar (about 8 km), Jajmau (about 10 km), Fazalganj, and Chakeri leave from that yard. See seamless steel pipes in Kanpur and the Kanpur steel market.
Trucks leave Kanpur each working day for Uttar Pradesh, Bihar, Madhya Pradesh, Delhi NCR, and Uttarakhand. Seamless pipes in Lucknow and steel pipes in Prayagraj describe those city drops. A Lucknow fabricator still writes the same NPS × schedule as a yard pickup.
Alloy and IBR tube is mill-direct more often than carbon A106. Name the live mill licence and the Inspecting Authority on the enquiry. Stock carbon pipe can move on the 3-7 day window listed under lead time.
PWD and JJM tenders almost never want A106. Keep those BOQs on IS 1239 and MS ERW from Kanpur. Hydraulic barrel RFQs stay on the precision pages, not on this pipe list.
Seamless versus ERW on the same NB
At 50 NB / 2 inch the outside diameter is 60.3 mm on both the class chart and the schedule chart. The walls are not the same. IS 1239 Medium is 3.6 mm (5.03 kg/m on the weight table). Sch 40 is 3.91 mm (5.44 kg/m). A rupee-per-kg fight that ignores those two walls is not a comparison.
ERW IS 1239 Medium at 50 NB sits on the MS ERW price list at ₹53-60 per kg as of 24 May 2026. Seamless 2 inch Sch 40 sits at ₹80-98 per kg on the seamless list the same date. The gap is process and specification, not a hidden quality grade.
Open Sch 40 versus Sch 80 when the isometric uses schedule language. Open the class thickness chart when the BOQ uses Light, Medium, or Heavy. Do not convert Medium into Sch 40 by nickname.
Papers that travel with a seamless heat
Every RP Sales dispatch already includes an MTC. RP Sales supplies EN 10204 Type 3.1 with each dispatch as its default sheet; Type 3.2 or a named TPI hold is added only when the purchase specification, tender, or ordering authority requires it on the PO. Heat number on the stencil, the certificate, and the dispatch challan must be the same number.
IBR steam pipe needs Form III-A in the same envelope. IBR tube needs Form III-B. A mounting or fitting needs Form III-C. Type 3.2 is not a substitute for any of those forms.
TPI by a named agency is a separate booking. The TPI process page lists SGS, Bureau Veritas, Lloyds, and TUV as the agencies this site already coordinates at the Kanpur yard when the RFQ names one. Book the witness before the mill dates the hydrotest.
Indent windows, GST, and yard pickup
Stock carbon seamless, when the size is on the floor, follows the 3-7 day ready-to-dispatch band on the lead-time entry. Mill-direct A106 or A53 Type S follows 14-21 days. SA213 alloy follows 21-30 days. Those bands are planning figures, not a promise on a named heat.
A contractor who can crane at Bartan Bazar collects against challan and invoice. Seamless invoices budget GST at 18% extra. HSN for seamless pipe sits under heading 7304 on the payment-terms pages already published on this site.
Cut-to-length, bevel, and TPI each add a line on the offer. Name them on the first RFQ so the 1.96 MT worked example above stays comparable across suppliers.
Where you'll meet this in procurement
You will meet Seamless when choosing process route and product family. Match Seamless to pressure, temperature, corrosion duty, and standard (IS, ASTM, ASME, or API) so the mill route and documentation line up with the application.
Related terms
Related resources
Key points
- Seamless means no longitudinal weld. The ordered specification still sets grade, wall, tests, and documents.
- A106 is seamless pipe by NPS and schedule. SA192 / SA210 / SA213 are tubes by OD and wall.
- 2 inch Sch 40 is 60.3 mm OD × 3.91 mm wall and 5.44 kg/m on the site formula.
- Seamless A106 / A53 bands are ₹74-165 per kg ex-warehouse Kanpur as of 24 May 2026; 2 inch Sch 40 is ₹80-98 per kg.
- IBR steam pipe uses Form III-A and IBR tube uses Form III-B. Form III-C is for mountings and fittings.
Frequently asked questions
Sources
- ASTM A106/A106M-26. Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service (public abstract, scope 1.1, NPS 1/8 to NPS 48, ASME B36.10M wall) (ASTM International)
- ASTM A53/A53M-24. Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless (Type S seamless; scope 1.1-1.3) (ASTM International)
- PM/1239 (Part 1)/4 Feb 2022. Product Manual for Steel Tubes according to IS 1239 (Part 1):2004: seamless permitted; Cl. 13 leak-proof 5 MPa; Cl. 8 dimensions; Cl. 9 thickness and mass tolerances (Bureau of Indian Standards)
- Indian Boiler Regulations, 1950. Forms index: III-A steam pipes, III-B tubes, III-C boiler mountings and fittings (Central Boilers Board, Government of India)
- ASME B36.10M. Welded and Seamless Wrought Steel Pipe (nominal OD and schedule walls used on this site) (American Society of Mechanical Engineers)