ASTM B622 / ASME SB-622 / UNS N10675 / W.Nr. 2.4600
From the Ban Bueng, Chonburi plant of Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd., ASTM B622 Alloy B3 seamless pipes go out to hydrochloric and sulfuric acid plants across Southeast Asia. The grade carries UNS N10675 and W.Nr. 2.4600, with chromium, iron and zirconium additions that keep its structure stable through welding and thermal cycling. It sits in our Hastelloy Seamless Pipes family, and quotations are issued by the Samut Prakan office at Bang Phli.
Alloy B3 seamless pipeUNS N10675 / W.Nr. 2.4600
EN 10204 3.1 certificate / 3.2 on request
Every ASTM B622 Alloy B3 seamless pipe we make sits inside the range below and is released against the lot test regime that specification sets. Match your line list to it, then tell us the quantity wanted per size.
ASTM B622, the Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube, is adopted as ASME SB-622, and it is the only product standard we certify this material to. The specification identifies the alloy by its UNS number and attaches no grade name, so Alloy B3 is a commercial name while UNS N10675 is what goes on the mark and the certificate. Each ASME SB-622 B3 seamless pipe is called off by standard pipe size and schedule, whereas Alloy B3 seamless tubes are called off by outside diameter, minimum or average wall thickness and length.
One chemical analysis covers each lot and one tension test stands for it, while no length is released before it has passed a hydrostatic test or, where the order specifies it, a nondestructive electric test. The EN 10204 3.1 (3.2 on request) material test certificate sets the heat analysis beside the ASTM B622 limits and prints the tension figures lot by lot. A raw material certificate, 100% PMI records and the heat treatment charts travel with it, and independent third-party inspection is arranged on request.
This is the one grade in its family whose nickel is written as a floor and not as the remainder. ASTM B622 fixes nickel at 65.0% minimum and holds nickel and molybdenum together between 94.0 and 98.0%, which leaves a narrow margin for everything else in the analysis.
The ASTM B622 / ASME SB-622 limits, against which every heat analysis is reported:
UNS N10675B3
| Element | Limit per ASTM B622 / ASME SB-622 (%) |
|---|---|
| Ni (Nickel) | 65.0 min |
| Mo (Molybdenum) | 27.0 to 32.0 |
| Ni (Nickel) + Mo (Molybdenum) | 94.0 to 98.0 |
| Cr (Chromium) | 1.0 to 3.0 |
| Fe (Iron) | 1.0 to 3.0 |
| W (Tungsten) | 3.0 max |
| Co (Cobalt) | 3.0 max |
| Mn (Manganese) | 3.0 max |
| Al (Aluminum) | 0.50 max |
| V (Vanadium) | 0.20 max |
| Ti (Titanium) | 0.20 max |
| Cu (Copper) | 0.20 max |
| Ta (Tantalum) | 0.20 max |
| Cb (Niobium) + Ta (Tantalum) | 0.20 max |
| Si (Silicon) | 0.10 max |
| Zr (Zirconium) | 0.10 max |
| P (Phosphorus) | 0.030 max |
| C (Carbon) | 0.01 max |
| S (Sulfur) | 0.010 max |
Carbon at 0.01% maximum and sulfur at 0.010% maximum keep carbide and sulfide films off the grain boundaries, which is what preserves corrosion resistance in the weld heat-affected zone. The chromium, iron and zirconium limits do the other half of the work, holding back the ordered phases that form in a nickel-molybdenum alloy left hot or cooled slowly.
One tension test represents each lot of seamless nickel alloy B3 pipe, and the room-temperature minimums below are the figures that test has to clear. ASTM B622 gives a single row for both product forms, so wall selection on a pipe line uses the same three values a tube order would.
| Property | Value | Unit |
|---|---|---|
| Tensile Strength, min | 760 (110) | MPa (ksi) |
| Yield Strength (0.2% offset), min | 350 (51) | MPa (ksi) |
| Elongation in 2 in. (50.8 mm) or 4D, min | 40 | % |
Across American and European practice the alloy is named in the ways set out here. The standard reaches only as far as the UNS number, which leaves the commercial name, the European number and the German number as cross-references: we print them beside N10675 where a drawing asks for them, and they assert no conformity to any European standard.
Testing on seamless Alloy B3 pipe is organized by lot rather than by piece, and the definition shifts with the test. A lot for chemical analysis is one heat. A lot for every other test is all the material from the same heat, the same nominal size with length left out of the comparison, and the same condition, so one tension result stands for pipe of one size out of one heat in one temper and for nothing wider than that.
Where the final heat treatment runs in a batch furnace, a lot covers only the lengths of one size and one heat that passed through the same furnace charge. Where it runs in a continuous furnace, a lot covers lengths of one size and heat treated at the same temperature, the same time at temperature and the same furnace speed inside a single production run. Either wording ties the lot to one thermal history, and that is the purpose of the rule.
No lot may exceed 9100 kg (20 000 lb), whatever its size and heat, so a heavy single-size order is divided into lots at that ceiling and each one is tested on its own. Where material cannot be identified by heat, the limit drops to 227 kg of one alloy in one condition and nominal size. No piece count is set anywhere in this specification: a lot is bounded by heat, size, condition, thermal history and that weight ceiling, never by a number of lengths.
A consignment of UNS N10675 seamless pipe is certified lot by lot, so the number of tension results shows how the order was grouped. Calling for all lengths of one size from a single heat keeps the consignment to one lot and one set of mechanical results, which is worth writing on the purchase order when a fabricated spool has to be built from matched material.
Both B-family grades are nickel-molybdenum alloys for reducing acids, and ASTM B622 gives them the same tensile, yield and elongation minimums, so strength is not the deciding factor. ASTM B622 holds UNS N10665 to 1.0% maximum chromium and 2.0% maximum iron and sets it no zirconium limit, while the same table gives UNS N10675 a 1.0 to 3.0% window on both chromium and iron and caps zirconium at 0.10%. Those additions, not strength, are why B3 is taken for welded spools and thermally cycled acid lines, and why Alloy B2 seamless pipes suit steadier duty. Once a stream turns oxidizing, or mixes oxidizing with reducing species, a B-family grade stops being the right answer and Alloy C22 seamless pipes take the service on the 20.0 to 22.5% chromium the same standard sets for UNS N06022.
Seamless 2.4600 pipe runs from 6 mm up to 457 mm in outside diameter, with wall from 1 mm through 65 mm, and single lengths reaching 18 m. Ordering under the specification means a standard pipe size with a schedule against it, so a line list already written that way is priced item by item, while a drawing giving outside diameter by wall is priced against the same envelope. Diameter and wall are held to these ASTM B622 cold-worked tolerances, read off the band the nominal diameter falls in.
Cold-worked diameter and wall limits by nominal outside diameter band
| Nominal OD | OD plus / minus | Wall, % of nominal, plus / minus |
|---|---|---|
| Up to 10 mm incl | 0.10 mm | 15.0 |
| Over 10 to 16 mm excl | 0.13 mm | 15.0 |
| 16 to 38 mm incl | 0.19 mm | 10.0 |
| Over 38 to 76 mm incl | 0.25 mm | 10.0 |
| Over 76 to 114 mm incl | 0.38 mm | 10.0 |
| Over 114 to 152 mm incl | 0.51 mm | 12.5 |
| Over 152 to 168 mm incl | 0.64 mm | 12.5 |
| Over 168 to 219 mm incl | 0.79 mm | 12.5 |
| Over 219 to 356 mm incl | plus 1.57 mm / minus 0.79 mm | plus 15.0 / minus 12.5 |
| Over 356 to 610 mm incl | plus 3.18 mm / minus 0.79 mm | plus 15.0 / minus 12.5 |
The last band keeps the boundary the specification prints, 610 mm, rather than stopping at the 457 mm ceiling quoted above, so a 60 mm line reads off the 38 to 76 mm band at 0.25 mm on diameter and 10.0% on nominal wall.
A seamless alloy 2.4600 pipe leaves the mill in the solution annealed and descaled condition, and where the anneal is run under atmosphere control no descaling is needed. Ends are plain, cut and deburred, and the material is reasonably straight and free of bends and kinks before it is measured and marked.
Alloy B-3 seamless pipe is specified where the stream is reducing and free of oxidizing species: hydrochloric, hydrobromic, sulfuric and organic acids, and the thermally cycled circuits that handle them.
Synthesis reactor piping, absorption column lines and condenser connections in hydrochloric acid plants run in this grade, which resists the acid over a wide span of concentrations where stainless steel pits and perforates.
Units recovering hydrochloric acid from steel pickling lines cycle their pipework through the thermal range that sensitizes a plain nickel-molybdenum alloy, which makes this the clearest case for choosing B3 over B2.
Concentration, distillation and transfer lines carrying sulfuric acid in its reducing range take B3 seamless pipe, where molybdenum rather than chromium does the corrosion work on the wetted bore.
Acetic and formic acid synthesis loops pipe their reactors and transfer legs in seamless alloy 2.4600 pipe, which holds up in pure organic acid streams that carry no oxidizing side stream.
Processing facilities in refineries and gas plants take UNS N10675 seamless pipe on tubular runs where a reducing acid stream is carried under pressure and the duty cycles thermally.
Process and transfer piping in pharmaceutical and fine chemical plants is specified in this alloy so that metal pickup from the acid side never reaches the product stream.
Every seamless WNR 2.4600 pipe is packed, marked and documented so that its lot stays identifiable on site.
Packing
Bundles with steel strapping for larger bores, wooden cases for small bores and short lengths, with plastic caps fitted to every end.
Marking
Manufacturer name, UNS N10675, the letters ASTM, the specification number, heat number and nominal size, so each length traces back to the lot that was tested for it.
Trade terms
FOB, CIF or CFR, with the port of discharge named in the offer.
Paperwork
The EN 10204 3.1 (3.2 on request) certificate covering every lot in the consignment, backed by heat treatment charts, a raw material certificate and a dimensional and surface report.
Further mill tests
100% PMI as standard, with impact and bend results, intergranular and pitting corrosion tests, and eddy current or ultrasonic examination printed on the manufacturer certificate where an order calls for them.
Delivery
From the sizes held at the works, or else on a production slot stated in the offer.
Indicative pricing for ASTM B622 Alloy B3 seamless pipes runs from USD 27 to 62 per kg. Small bores, heavy walls, part-lot quantities and added inspection move a quotation toward the upper end, and the band as a whole tracks the nickel and molybdenum markets on the day of pricing. Fewer mills hold billet in this grade, so project quantities and small-bore items sit at the top of the band. A firm figure comes back against the sizes you list.
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
This grade is extruded and drawn at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand. Offers, order files and certificates come out of 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. Thai sites take delivery straight from the works, and export consignments travel to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
For chemical analysis a lot is one heat; for every other test it is one heat, one nominal size with length disregarded, and one condition. The practical effect lands on the certificate: two sizes out of one heat give two tension results, and one size out of two heats gives two chemistries.
Because the specification writes it that way. ASTM B622 fixes 65.0% nickel as a floor for UNS N10675 and holds nickel plus molybdenum between 94.0 and 98.0%, so both are certified against stated limits. A table showing nickel as balance for this grade does not match the standard.
No more than 9100 kg (20 000 lb). That cap, rather than any piece count, is what decides how many tension results a large order carries, which matters when an inspection plan is being agreed. Material that cannot be identified by heat falls under a much smaller ceiling of 227 kg.
Yes. A batch-furnace lot cannot reach beyond a single furnace charge of one size and one heat, so the charge itself bounds the lot. A continuous-furnace lot can cover a whole production run, provided every length ran at the same temperature, the same time at temperature and the same furnace speed.
The specification sets no piece count at all, so a lot may hold a handful of lengths or a great many depending on the size ordered. Grouping follows heat, nominal size, condition and thermal history, and then the weight ceiling. Ask for the lot breakdown with the offer if a figure is needed.
Specify B3 where the line is welded or cycles through the sensitizing range, as a spent acid regeneration circuit does. Alloy B2 stays a sound choice where the duty is stable and the line is not repeatedly reheated. ASTM B622 gives both grades identical strength minimums, so thermal history decides.
Lot by lot: the heat analysis read against the ASTM B622 limits, that lot's tension figures, and a note that every length passed its hydrostatic or nondestructive electric test. UNS N10675 is the designation stated, and W.Nr. 2.4600 is cross-referenced where a drawing calls for it.
Outside diameters of 6 mm up to 457 mm, wall thickness of 1 mm up to 65 mm, and lengths as long as 18 m. Material is priced against a nominal size and schedule callout or against an outside diameter by wall callout, and ends are plain, cut and deburred.
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