Steel Pipe & Tube Glossary

API specification for seamless and welded steel line pipe in oil and gas transportation.

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API Specification 5L covers seamless and welded steel line pipe for pipeline transportation. The grades this site tabulates run B through X70 by specified minimum yield strength, with X42 at 289 MPa and X70 at 483 MPa. The adopted edition sets two product specification levels, PSL 1 and PSL 2. Sour service is a project add-on: name the H2S environment and the ISO 15156 or Annex H route the operator selected. The designation alone does not set pressure, fluid, or location class.

American standard for seamless carbon steel pipe for high-temperature service.

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ASTM A106/A106M specifies seamless carbon steel pipe for high-temperature service in NPS 1/8 to NPS 48. It covers three grades (A, B, and C) with rising minimum tensile strength of 330, 415, and 450 MPa. Mechanical testing on the ASTM abstract includes tensile, bending, flattening, hydrostatic, and nondestructive electric tests. Grade, wall, condition, and inspection must follow the approved design and purchased edition; the designation alone is not a pressure or temperature approval.

American standard for welded and seamless black and hot-dipped galvanized steel pipe.

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ASTM A53/A53M is the specification for black and hot-dipped, zinc-coated, welded and seamless steel pipe. The A53/A53M-24 store abstract covers NPS 1/8 to NPS 26 (DN 6 to DN 650) in Type F, Type E, and Type S, Grades A and B. Scope 1.3 names mechanical and pressure service and ordinary steam, water, gas, and air lines. Type F is not intended for flanging. Grade A is preferred for close coiling or cold bending. The designation does not set a universal pressure, casing depth, or substitution approval.

Indian Boiler Regulations certificate for boiler mountings and fittings; tubes use Form III-B and steam pipes use Form III-A.

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Form III-C is the Indian Boiler Regulations certificate of manufacture and test for boiler mountings and fittings. The official forms index assigns Form III-A to steam pipes and Form III-B to tubes. The Boilers Act, 2025 has been in force since 1 May 2025; Section 45 keeps earlier regulations and forms in force until replaced. Match the form to the component, approved drawing, lot identity, tests, and Inspecting Authority stamp.

BIS series for steel tubes and tubulars, and matching wrought-steel fittings, used for water, gas, air and steam.

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IS 1239 is a two-part BIS series. Part 1:2004 (reaffirmed 2019) covers steel tubes; Part 2:2011 (reaffirmed 2021) covers wrought-steel pipe fittings. Part 2 is not a size extension of Part 1. Part 1 orders tubes by nominal bore and Light, Medium, or Heavy class. The series name alone is not a pressure rating. Select part, edition, class, coating, ends, joining, and authority requirements from the approved design.

BIS specification for steel water and sewage pipes from 168.3 mm to 2540 mm OD.

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IS 3589:2001 is the Bureau of Indian Standards specification titled Steel Pipes for Water and Sewage (168.3 to 2540 mm Outside Diameter). The May 2020 product manual records four amendments and groups manufacture as seamless, ERW, or SAW in grades Fe 330, Fe 410, and Fe 450. Wall, lining, coating, ends, and hydraulic-test details come from the purchased edition and the order. The standard is not IS 1239 class tube, not API 5L line pipe, and not a boiler specification. Kanpur and UP municipal tenders use it once the design leaves the small-bore NB series.

AMPP / ISO materials-selection standard for metallic equipment in H2S oil and gas production.

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NACE MR0175 is published with ISO 15156. ISO 15156-1:2020 sets general principles for metallic materials in H2S-containing oil and gas production and natural-gas sweetening plants. It supplements design codes and addresses cracking: sulfide stress cracking, stress corrosion cracking, hydrogen-induced cracking, stepwise cracking, SOHIC, soft-zone cracking, and galvanically induced hydrogen stress cracking. Part 2 covers carbon and low-alloy steels and cast irons. Part 3 covers corrosion-resistant alloys. PSL2 or a 22 HRC stamp does not qualify a pipe for every sour envelope.

ASME specification for seamless carbon steel boiler tubes for high-pressure service.

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SA-192 is the ASME Boiler and Pressure Vessel Code Section II material specification for minimum-wall seamless carbon steel boiler and superheater tubes for high-pressure service. Usual furnished sizes on the ASTM A192 abstract are 12.7 to 177.8 mm OD with 2.2 to 25.4 mm minimum wall. Order it by OD and minimum wall against the approved drawing. Where the tube is an Indian boiler pressure part, the IBR certificate is Form III-B.

ASME specification for seamless medium-carbon steel boiler and superheater tubes.

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SA-210 is the ASME specification for seamless medium-carbon steel boiler and superheater tubes in Grade A-1 and Grade C. Grade A-1 tensile on this site is 415 MPa min; Grade C is 485 MPa min. ASTM A210/A210M-26 usually furnishes 12.7 to 127 mm OD and 0.9 to 12.7 mm minimum wall. The approved boiler drawing selects the grade. IBR tubes take Form III-B; Form III-C covers boiler mountings and fittings.

ASME specification for seamless ferritic and austenitic alloy steel boiler tubes.

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SA-213 is the ASME specification for seamless ferritic and austenitic alloy steel boiler, superheater, and heat-exchanger tubes. It covers multiple grades including T11 (1.25Cr-0.5Mo), T12 (1Cr-0.5Mo), and T22 (2.25Cr-1Mo). The standard mandates stringent chemical analysis, mechanical testing, and non-destructive examination, making it essential for superheater and reheater tubes in thermal power stations and high-pressure process plants.

Pipe or tube end machined to a defined weld preparation for a butt-weld joint.

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Bevel end means a pipe or tube end machined to a defined weld preparation. ASME B16.25-2022 covers buttwelding-end geometry, including single-angle and compound bevels, internal and external shaping of heavy-wall components, and GTAW root-pass details. API Specification 5L lists a 30° bevel when that end finish is ordered. Angle, root face, land, and internal transition come from the approved joint detail and welding procedure. V, compound, J, and U preparations are not interchangeable defaults.

Liquid-pressure test of a pipe or assembled line under the governing product standard or approved procedure.

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Hydrotest pressure is the liquid pressure applied to a pipe length, tube, or assembled system under a written procedure. A mill test follows the purchased product standard. The BIS product-manual certificate for IS 1239 (Part 1):2004 states each steel tube is eddy-current or hydrostatically tested to 5 MPa. ASTM A530/A530M-18 Section 22 sets mill hydrostatic pressure for specialised carbon and alloy pipe as P = 2St/D, with S at 60 percent of specified minimum yield for carbon and ferritic grades, then applies the stated caps and a minimum 5 s hold. A site leak test follows the design code, not that mill clause. Record the actual pressure, medium, duration, and result on the inspection document.

Nominal size label for selecting pipe, fittings and flanges; not the measured inside diameter.

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Nominal Bore (NB) is the size label Indian BOQs use to pick steel tube, fittings and flanges. It is not a micrometer reading of the inside. NPS is the ASME B36.10M counterpart and DN is the ISO 6708 alphanumeric size. IS 1239 Part 1 lists 6 to 150 mm NB in the site's BIS preview record; the product manual's stocked series and this site's class chart run 15 to 150 mm NB. Once the drawing leaves that series it usually orders OD under IS 3589. Wall still comes from Light, Medium or Heavy class, or from a millimetre thickness.

Measured outside diameter of a pipe or tube, in millimetres or inches, used for fit-up.

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Outside Diameter (OD) is the measured distance across the external surface of a pipe or tube. Indian water-tube charts list it in millimetres (48.3 mm, 60.3 mm, 114.3 mm). ASME B36.10M lists the same series against NPS and DN. The permissible deviation is taken from the product standard and the ordered size, not from a single commercial plus-or-minus. Put the exact OD on the drawing, then check the delivered pieces under the receiving plan.

ASME B36.10 wall-thickness designation that must be paired with NPS, material, and the design code.

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Schedule is a standardised wall-thickness designation for welded and seamless wrought steel pipe under ASME B36.10-2022. The 2022 edition revises B36.10M-2018 and standardises dimensions for high or low temperatures and pressures; it does not assign a working-pressure rating by itself. Size, actual minimum wall, material allowable stress at design temperature, corrosion allowance, joint efficiency, fittings, and the governing code set the rating. On the site schedule chart, 2 inch NPS is 60.3 mm OD with Sch 40 wall 3.91 mm and Sch 80 wall 5.54 mm. State NPS or DN, the schedule or exact millimetre wall, the material specification, and the code edition on the PO.

Named dimensional-deviation band under a cited product standard, size range, and drawing limit.

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A tolerance class names the permitted variation on a stated dimension (OD, wall, length, or bore) under one product standard and size range. IS 1239 Class A, B, and C on this site are Light, Medium, and Heavy wall series, not an OD millimetre band. Kanpur hydraulic drawings still write DIN 2391 T1 through T4 as OD-class labels. EN 10305-1:2016 instead publishes size-and-condition tables for seamless cold-drawn tubes with outside diameter D of 380 mm or less. Copy the millimetre limits from the invoked edition. A class letter from welded utility tube does not travel onto a precision barrel.

Radial steel between the bore and the outside diameter of a pipe or tube.

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Wall thickness (WT) is the radial distance between the inner and outer surfaces of a pipe or tube. It enters mass, geometry, and design calculations, but it is not the only input to pressure or structural capacity. Indian class pipe uses Light, Medium, and Heavy walls by NB. ASTM and ASME pipe uses schedule or a stated millimetre wall. Tolerances sit in the product standard: IS 1239 Part 1 clause 9 for class tube, ASTM A530/A530M-18 Table 1 for the pipe specifications that invoke it. Write OD or NB together with the wall or class.

Pipe formed by rolling steel strip and welding the seam using electric resistance heat.

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Electric Resistance Welded (ERW) pipe is made by forming steel strip into a cylinder and joining the longitudinal seam with resistance heating and pressure. Product range, heat treatment, examination, dimensions, grade, and permitted service come from the product standard and mill capability. ERW construction alone does not set a pressure rating. Select it through the governing code, the design calculation, the approved material line, and the inspection plan.

Steel pipe coated with zinc layer for corrosion resistance in outdoor and wet environments.

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Galvanised (GI) pipe is steel tube with a hot-dip zinc coating. The tube follows its own product standard, usually IS 1239 Part 1 for NB 15 to 150, and the coating follows IS 4736, whose amended minimum is 360 g/m². Zinc gives sacrificial corrosion protection, but service life depends on exposure, water chemistry, jointing, and maintenance. GI suits plumbing, water distribution, fencing, and selected fire-system work only where the approved specification calls for galvanized steel.

Spiral-welded pipe formed by helical winding of steel coil with submerged arc welding.

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Helical Submerged Arc Welded (HSAW), or spiral SAW, pipe is made by helically forming coil and submerged-arc welding the seam. Available diameter, wall, grade, seam examination, dimensional controls, and permitted application depend on the manufacturing specification, mill qualification, and project requirements. A spiral seam does not create one universal pressure limit or an automatic ranking against LSAW. Use the exact product standard, design code, approved calculation, and inspection plan.

Plate-formed pipe with a straight longitudinal submerged-arc weld seam.

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Longitudinal Submerged Arc Welded (LSAW) pipe is made by forming steel plate into a cylinder and submerged-arc welding the longitudinal seam. Forming is commonly JCOE or UOE. The straight seam does not by itself approve a pressure, fluid, or project duty. Grade, wall, examination, coating, and mill qualification come from the purchased specification. Feasible OD and wall remain mill- and procedure-specific.

Pipe without weld seam, manufactured by hot-piercing solid steel billet.

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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.

Tube drawn through tooling below recrystallisation temperature to the ordered standard and condition.

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Cold-drawn seamless tube is produced by drawing a prepared hollow through a die and over a mandrel below the steel's recrystallisation temperature, then applying the delivery-condition treatments named by the product specification. EN 10305-1:2016 covers seamless cold-drawn precision tubes with outside diameter D ≤ 380 mm and a specified maximum surface roughness. ASTM A179/A179M-24 covers seamless cold-drawn low-carbon heat-exchanger tubes from 3.2 to 76.2 mm OD. Tolerance, roughness, and strength follow the ordered standard, grade, and condition, not the words cold drawn.

Internal surface finished by abrasive honing to precise diameter and surface roughness.

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Honed bore is an internal surface finished with abrasive stones to a controlled geometry and, when specified, a cross-hatch that holds oil. Hydraulic-cylinder pages on this site treat a finished barrel as H8 or H9 with Ra 0.2-0.4 μm after honing or SRB; those figures belong on the drawing, not on the process name. The mother tube is usually DIN 2391 ST52 or EN 10305-1 E355, then honed. Honing is not a substitute for skiving unless the drawing allows it.

Seamless pipe or tube pierced from a heated billet and sized while the steel is still hot.

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Hot-finished seamless product is formed from a heated round billet, pierced over a plug, then rolled and sized while hot. Site process copy places that pierce near 1200 °C. ASTM A213/A213M-25 requires seamless tubes to be hot finished or cold finished as specified; Grade TP347HFG shall be cold finished. The A213 abstract keeps heat treatment off the pierce heat. SA179 is cold-drawn only. SA210 tubes are marked hot-finished or cold-finished. Do not apply one OD or wall percentage across products.

Surface treated with phosphate coating for corrosion resistance and lubricant retention.

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Phosphating is a chemical surface treatment that converts steel surface into an insoluble phosphate coating (typically manganese or zinc phosphate). The crystalline coating provides corrosion protection during storage, improves paint adhesion, and retains lubricating oil for subsequent forming operations. Phosphated tubes are specified for hydraulic systems (oil retention), automotive components, and as a pretreatment before painting or powder coating. The process follows cleaning and acid pickling in the surface preparation sequence.

Internal surface machined by cutting tool to remove imperfections and improve finish.

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Skiving is a machining process that uses a cutting tool to remove a thin layer from the internal surface of a tube, eliminating internal weld beads, scale, or surface imperfections. Unlike honing which abrades the surface, skiving cuts with defined geometry. Skived and roller burnished (SRB) tubes combine skiving with cold working for superior internal finish. The process is used for hydraulic cylinders, honed tube pre-processing, and applications requiring specific internal surface characteristics.

Alphanumeric designator that identifies one steelmaking heat on the pipe and on the MTC.

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A heat number is the alpha, numeric, or alphanumeric designator used to identify a specific heat of steel. ASTM A941 defines a heat as a specific lot of steel based on steelmaking and casting considerations, and may mean a primary heat, a multiple heat, or a remelted heat. The number on the stencil, the bundle tag, the [MTC](/glossary/mtc), and the dispatch challan must be the same number. When they diverge, the lot fails traceability and stays on hold. Kanpur PWD, JJM, and sugar-mill stores check that match before they cut the first length.

Detailed test results document covering chemistry, mechanicals, and dimensional compliance.

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Material Test Report (MTR) is the comprehensive document detailing all test results for a specific heat of steel, including chemical composition analysis (C, Si, Mn, P, S, Cr, Mo, Ni), mechanical test results (yield strength, tensile strength, elongation, hardness), and dimensional verification. MTR is synonymous with MTC in common usage, though technically MTR refers specifically to the test data portion. The MTR provides the evidence of compliance to specified grades like SA192, SA210, or ASTM A53.

Manufacturer document certifying chemical composition, mechanical properties, and test results.

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A Mill Test Certificate (MTC), also called a Mill Test Report (MTR), records declared material identity, heat or lot traceability, and the test results the mill ran on that unit. EN 10204:2004 defines Type 2.1 (compliance statement), Type 2.2 (non-specific test results), Type 3.1 (specific results validated by the manufacturer's authorized inspection representative independent of manufacturing), and Type 3.2 (specific results with a second validation by the purchaser or an officially designated inspector). The purchase specification picks the type. An EN 10204 sheet does not replace a BIS mark or an IBR form. RP Sales already attaches an MTC to each dispatch.

Formal documentation of non-conforming material to be returned or replaced by supplier.

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Rejection Note is the formal documentation issued by a buyer to a supplier identifying material that fails to meet specification requirements. It details the nature of non-conformance (dimensional out-of-tolerance, chemical deviation, mechanical failure, surface defects), references the MTC heat number, and states disposition (return for credit, replacement, or scrap). Rejection notes trigger supplier corrective action and are essential for quality tracking and supplier performance evaluation in B2B procurement.

Independent inspection by a named agency against an inspection and test plan, not a mill MTC.

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Third-Party Inspection (TPI) is independent verification of a named lot against the purchase order and inspection plan. Indian projects may name SGS, Bureau Veritas, Lloyds, or TUV. TPI is not automatic on every API, PWD, or IBR order. TPI witnesses or reviews the tests; it does not sign the IBR tube form itself. RP Sales coordinates TPI at the Kanpur yard when the RFQ names the agency.

Incoterms 2020 any-mode rule: seller delivers on the arriving vehicle, ready for unloading, at the named place.

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DAP (Delivered at Place) is an Incoterms 2020 any-mode rule. The seller delivers, and risk transfers, when the goods sit at the buyer's disposal on the arriving means of transport, ready for unloading, at the named place of destination. The seller clears export and arranges carriage. The buyer unloads and, where applicable, clears import. DAP is not FOR, not DPU, and not DDP.

Document accompanying goods dispatch detailing items, quantities, and delivery information.

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A dispatch challan is the packing list that travels with a steel-pipe load. It records sizes, lengths, piece count, heat numbers, and the PO or invoice reference so the consignee can check the truck. Under GST it is distinct from the tax invoice. CGST Rule 55 allows a serially numbered delivery challan in lieu of an invoice for listed movements such as job work or non-supply transport; Rule 138 then uses that challan, or the invoice, to value the e-way bill. Buyers sign the challan on receipt as the count and condition record.

Incoterm where buyer collects goods from seller premises, bearing all transport costs.

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EXW (Ex Works) is an Incoterms 2020 rule under which the seller delivers by placing the goods at the buyer's disposal at the named place, not loaded on the collecting vehicle. The buyer contracts carriage from that place and bears risk from delivery under A2. RP Sales names EXW at the Bartan Bazar / Basanti Nagar (208014) yard when that is the collection point. EXW is one of eleven Incoterms 2020 rules. It is not FOR, and the rule itself does not set the lowest rupee price.

Domestic delivery label that can mean Free on Rail; not one of the eleven Incoterms 2020 rules.

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FOR can mean Free on Rail in Indian steel trade, but it is not one of the eleven Incoterms 2020 rules. Parties also write FOR Kanpur or FOR destination for road dispatch. The quotation must name the station or yard, who loads, who pays freight, when risk transfers, and which document (railway receipt or dispatch challan) proves handover. FOR is not DAP, not EXW, and not FOB.

Bank-issued payment guarantee providing security for buyer and supplier in large transactions.

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Letter of Credit (LC) is a bank undertaking to honour a complying presentation of documents (UCP 600 Article 2). The LC substitutes bank credit for buyer credit, reducing supplier risk in large or first-time transactions. Types include irrevocable, confirmed, and transferable LCs. Document wording on the credit must match the PO. RP Sales accepts LC for export orders and large public-sector contracts.

Interval from an agreed commercial trigger to a named readiness or delivery event.

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Lead time runs from an agreed trigger (accepted PO and cleared payment, or approved drawings) to a named event (ready for collection at the Kanpur yard, or delivered to a named place). This glossary publishes three planning bands used across the site: stock 3-7 days, mill-direct standard grades 14-21 days, and mill-direct alloy SA213 T11/T22 21-30 days. TPI visits and IBR form issue sit after mill readiness. Form III-B is the tube certificate; Form III-C covers boiler mountings and fittings.

Smallest quantity a supplier will accept for an order, often measured in metric tonnes.

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Minimum Order Quantity (MOQ) is the smallest quantity a supplier accepts for one order line or production campaign. It is a commercial condition set by the mill or stockist, not a clause of IS 1239 or any ASTM or ASME grade. A Kanpur stockist may sell identified lengths from yard stock, while a mill production lot needs a quoted minimum with quantity tolerance. State quantity in MT on the RFQ and ask the quotation to confirm the accepted minimum, invoice mass basis, and call-off terms.

Buyer document requesting supplier pricing for specified pipe requirements.

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A Request for Quotation asks a supplier for a written technical and commercial offer against named pipe or tube lines. A complete steel-tube RFQ lists standard edition, process, grade, OD or NB, wall or class, length, quantity, end finish, coating, MTC, inspection, packing, collection or delivery point, freight basis, and requested date. Where IBR applies, name the component: Form III-B for tubes, Form III-C for boiler mountings and fittings. RP Sales responds to RFQs within 4 working hours with a technical and commercial offer.