ASTM A106 is seamless carbon steel pipe for high-temperature service. The ASTM store listing retrieved on 2026-09-03 covers NPS 1/8 to NPS 48 (DN 6 to DN 1200). Kanpur industrial buyers often enquire for Grade B with Sch 40 or Sch 80 wall, but the approved design must set grade and wall. For an IBR steam-pipe route, the official forms index points to Form III-A, not Form III-C, and the competent authority must confirm the complete document set.
Overview
ASTM A106 is the ASTM specification for seamless carbon steel pipe for high-temperature service. It specifies Grades A, B and C, each with its own chemistry and mechanical-property requirements. The designation alone does not approve a grade, wall, condition or source for an Indian boiler or any other pressure system. Selection must follow the governing construction code, exact material line and edition, design temperature and pressure, allowable stress, service life, corrosion allowance, fabrication and welding requirements, and approved drawing. If the item is classified as an IBR steam pipe, the official forms index points to Form III-A. The competent authority must still confirm the full source, inspection, traceability, test and release route.
What ASTM A106 is, and what it is not
ASTM A106 is a seamless carbon steel pipe specification for high-temperature service. It is a pipe standard, ordered by NPS and schedule or wall, not a boiler-tube standard ordered by OD and minimum wall.
The ASTM store listing retrieved on 2026-09-03 titles it Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service. Scope 1.1 covers NPS 1/8 to NPS 48 inclusive, with nominal (average) wall as given in ASME B36.10M. Pipe must be suitable for bending, flanging and welding.
The same listing names Grade A, Grade B and Grade C. Grade A is the preferred grade for close coiling or cold bending, but that note does not forbid cold bending of Grade B seamless pipe.
A106 is not ASTM A53: A53 allows welded Type E and galvanized finish, while A106 is seamless only. A106 is also not SA192 boiler tube, since tube and pipe are different product forms.
This page's specs still cite ASTM A106/A106M-22. The store listing retrieved on 2026-09-03 also shows A106/A106M-26 as the active designation. Quote the revision written on the drawing, not a stockist habit.
Who should buy A106 in Kanpur, and who should not
Specify ASTM A106 only when the approved piping class, drawing or purchase specification names it. Grade B comes up often, but Grade A, B or C must be selected from the governing code material line and design calculation, not from a universal temperature hierarchy or a stock preference. Kanpur procurement teams should keep this as seamless pipe and distinguish it from boiler tube ordered by outside diameter and minimum wall.
Availability and lead time vary by grade, NPS, wall, condition, approved source, test scope, inspection route, quantity and mill schedule. Ask for the exact stock position, source identity, document set, release conditions and committed date in the current written quotation.
Do not buy A106 as a cheap substitute for IS 1239 water pipe: seamless high-temp pipe costs more and uses schedule walls, not Light/Medium/Heavy class.
Do not use A53 Type E welded pipe where the drawing says A106, and do not use IS 1239 ERW on an IBR steam line. If the item is a boiler generating-bank tube, the drawing likely wants SA192 or SA210, not A106 pipe.
Where the approved boiler design names SA-106 for a steam pipe, repeat that exact designation and ask the competent authority to confirm Form III-A and the supporting records. Do not promise a regulatory stamp from ordinary A106 stock.
Grade A vs Grade B vs Grade C: how to pick
Grade A has the lowest listed minimum strength of the three and its own chemistry limits. It may be selected where the governing design and fabrication requirements call for it, and procurement should not reject or substitute it on a market-frequency claim.
Grade B has higher listed minimum strength than Grade A and is frequently specified, but frequency does not make it a default. Verify the precise ASTM or ASME designation, edition, product form, wall basis, condition and code table line.
Grade C has the highest listed minimum strength of the three. That does not create a universal higher-temperature or higher-pressure approval. Welding controls, preheat, heat treatment, allowable stress, wall calculation and service suitability must come from the governing code, approved procedure and engineering review.
Chemical composition (as per ASTM A106)
- Grade A: Carbon 0.25% max, Manganese 0.27-0.93%, Phosphorus 0.035% max, Sulphur 0.035% max
- Grade B: Carbon 0.30% max, Manganese 0.29-1.06%, Phosphorus 0.035% max, Sulphur 0.035% max
- Grade C: Carbon 0.35% max, Manganese 0.29-1.06%, Phosphorus 0.035% max, Sulphur 0.035% max
- Copper, Nickel, Chromium, Molybdenum and Vanadium are restricted to 0.40% total maximum.
Mechanical properties (as per ASTM A106)
- Yield strength: Grade A = 205 MPa min, Grade B = 240 MPa min, Grade C = 275 MPa min
- Tensile strength: Grade A = 330 MPa min, Grade B = 415 MPa min, Grade C = 450 MPa min
- Elongation: 30% min in 50 mm (straight specimen), 20% min (strip specimen)
- All tubes undergo hydrotest at calculated pressure per ASTM A106 Section 5.
ASTM A106 vs ASME SA-106: is there a difference?
ASTM A106 and ASME SA-106 are published in different standards systems. Use the exact designation and edition named by the approved design. For an IBR steam pipe, verify the Form III-A route and supporting records with the competent authority.
ASTM A106 is the material specification published by ASTM International. ASME SA-106 is the same specification cross-referenced in the ASME Boiler and Pressure Vessel Code. The chemistry and mechanical requirements are virtually identical. The only distinction is that SA-106 carries the ASME certification mark, required for ASME-coded vessels.
Do not treat ASTM A106 and ASME SA-106 as automatically interchangeable. Use the designation and edition named by the governing design, and for an IBR steam pipe, confirm the component-specific Form III-A route.
How to specify A106 on an RFQ
A106 RFQs fail when they say "seamless pipe Grade B" and leave out edition, wall, condition, end finish, tests and any statutory route. Write every field needed to identify and verify one supply.
- Standard and revision: ASTM A106 / ASME SA-106, plus the revision on the drawing
- Grade: A, B or C exactly as selected by the governing design and code calculation
- Size: NPS and schedule, or OD × wall in mm. Sch 40, 80, 160 and XXS are the common walls
- Length: SRL 4.5-7 m or DRL 7-14 m, or cut-to-length
- End finish: plain end, beveled for welding, or T&C on small sizes
- Finish: black as-rolled, or normalized if the grade/order requires it
- Documents: the inspection certificate and test records named by the project; for an IBR steam pipe, confirm Form III-A and the approved authority route
- Inspection: mill, or named TPI if the PO requires EN 10204 3.2
- Tests: hydrotest per ASTM A106 Section 5, plus any supplementary S1-S7 extras
- Delivery: quantity in metres or MT, destination, ex-works Kanpur or delivered
A106 price is not fixed by schedule or this standards page. Ask for a current proforma stating grade, size, wall, condition, source, availability, quantity, tests, document and inspection scope, legally applicable tax, freight, processing, delivery basis and committed date.
Worked mass example: 2 inch NPS Sch 40 vs Sch 80
The pipe schedule chart on this site gives 2 inch NPS (DN 50) as OD 60.3 mm, Sch 40 wall 3.91 mm, Sch 80 wall 5.54 mm. Mass uses W = (OD - t) × t × 0.02466 kg/m.
Sch 40: (60.3 - 3.91) × 3.91 × 0.02466 = 56.39 × 3.91 × 0.02466 = 5.44 kg/m.
Sch 80: (60.3 - 5.54) × 5.54 × 0.02466 = 54.76 × 5.54 × 0.02466 = 7.48 kg/m.
One hundred lengths of 6 m in Sch 40 weigh 100 × 6 × 5.44 = 3,264 kg (3.26 MT). The same count in Sch 80 weighs 4,488 kg (4.49 MT).
Sch 80 uses more steel per metre than Sch 40 at this NPS. Price does not scale by a universal percentage, because grade, wall, quantity, source, tests, inspection and market conditions differ. Confirm the millimetre wall and get the actual commercial basis in the current quotation.
Common mistakes on A106 procurement
A grade gets selected or substituted from price or availability without returning to the governing code material line and approved design. Match the drawing and engineering record, not a stock or cost assumption.
A53 Type E is offered as "Grade B pipe". Grade B exists on both standards. Only Type S seamless A53 is even in the same family, and it is still not A106 high-temperature pipe.
The regulatory route comes up only after stock is allocated. Put the approved designation, component classification, required Form III-A where applicable, tests, traceability and authority scope on the enquiry before allocation.
Schedule is left off, so Sch 40 arrives against a Sch 80 isometric. NPS 2 inch looks the same on the rack, but wall 3.91 mm and 5.54 mm are not interchangeable.
SRL is assumed when the plot needs DRL, or cut-to-length is assumed without a written tolerance and commercial basis. State the required length and ask the current quotation to identify any processing charge and yield implication.
Standards and compliance for Indian jobs
The material specification is ASTM A106 / ASME SA-106. Dimensional walls come from ASME B36.10M, which this site's pipe schedule chart follows.
Hydrotest is per ASTM A106 Section 5 on this page's specs. Supplementary requirements S1 to S7 exist for buyers who need extra tests. Name them on the order if required.
Do not infer blanket IBR acceptance from the SA-106 designation. The approved design and current regulatory route must accept the exact material and condition. An EN 10204 inspection document is distinct from the prescribed Form III-A for a steam pipe.
Do not treat IS 1239 as an A106 equivalent. The A106 vs IS 1239 comparison on this site is the buyer check before any cross-standard substitution.
Key points
- A106 is seamless carbon steel pipe for high-temperature service, NPS 1/8 to NPS 48 on the ASTM store listing retrieved 2026-09-03.
- Grades A, B and C have different chemistry and minimum mechanical properties; use the exact grade selected by the approved design.
- 2 inch NPS Sch 40 is 3.91 mm wall and 5.44 kg/m; Sch 80 is 5.54 mm wall and 7.48 kg/m.
- For an IBR steam pipe, write the approved material designation and confirm Form III-A plus the required supporting records.
- A53 welded pipe and IS 1239 ERW are not A106 substitutes.