Sulfuric Acid Plant Heat Exchangers
Sulfuric acid plants tube their acid heat exchangers with N08825, cutting each straight length to the bundle drawing and holding outside diameter and wall to the band that fits the size.
ASTM B163 / ASME SB-163 / UNS N08825 / W.Nr. 2.4858
Incoloy 825 Seamless Tubes Manufacturer in Thailand
For condenser and heat-exchanger bundles, Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. makes Incoloy 825 seamless tubes at its Ban Bueng, Chonburi mill and releases them annealed and flare tested, lot by lot, under ASTM B163 / ASME SB-163. The alloy is UNS N08825, listed on European drawings as W.Nr. 2.4858, and within our Incoloy seamless tubes range it is the grade supplied to the condenser and heat-exchanger tube standard. Offers, certificates and export papers are handled by our office in Bang Phli, Samut Prakan.
Incoloy 825 seamless tubeUNS N08825 / W.Nr. 2.4858
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
ASTM B163 Incoloy 825 Seamless Tubes Specifications
Each tube we ship is held to the controls listed here: a single annealed condition, a flare sample drawn from every lot and a pressure or electric test on every length. The diameter, wall and length range on offer appears under sizes, next to the tolerance bands.
- Standard
- ASTM B163 / ASME SB-163
- Alloy
- UNS N08825 (Incoloy 825)
- Condition
- Annealed
- Manufacturing Route
- 1Hot extruded or hot pierced from billet
- 2Cold drawn or cold rolled
- 3Then annealed
- Ordering Basis
- Outside diameter with average wall or minimum wall, and cut length
- Finish
- Annealed with ground outside diameter, or annealed and pickled (not ground)
- Flare Test
- One end of 1% of finished lengths in each lot, at least one tube per lot
- Hydrostatic or Electric Test
- Every tube, by either method
- Mill's choice unless the order names one
- Lot Tests
- One chemical analysis and one tension test per lot
- Form
- Seamless
- Test Certificate
- EN 10204 3.13.2 on request
ASTM B163 is titled Standard Specification for Seamless Nickel and Nickel Alloy Condenser and Heat-Exchanger Tubes, and for Boiler and Pressure Vessel Code work it points to its related specification, ASME SB-163. The standard lists its alloys by UNS number, so an ASME SB-163 825 seamless tube is reported against N08825, while Incoloy 825 stays the commercial name on the material list. Exchanger tube is sized by actual outside diameter and wall; Incoloy 825 seamless pipes for process lines are ordered by NPS and schedule under a separate pipe standard.
A hydrostatic test or a nondestructive electric test proves every length, and a tube that leaks under pressure is rejected. One chemical analysis and one tension test represent each lot, and the flare test described below is drawn from the same lot. Results for each seamless Incoloy 825 tube shipment are reported on an EN 10204 3.1 (3.2 on request) material test certificate, and independent third-party inspection is available on request.
Flare Test on Seamless Incoloy 825 Tube
ASTM B163 makes flaring a standing requirement for this alloy, not an extra that the order has to add. One end of 1% of the finished tube lengths in each lot is flared, and a lot of fewer than 100 tubes still gives up one end of one length. The tool is an expanding cone with a 60° included angle, pushed in until the specified outside diameter has grown by 30%. The flared end passes when it shows no cracking through the wall.
A lot for flaring, as for the tension test, is all material of one heat, one nominal size apart from length, and one condition. Tube whose heat cannot be identified is grouped in lots of not more than 500 lb (230 kg). Chemical analysis is lotted by heat alone, so a heat drawn into several sizes is analyzed once but flared and tensile tested size by size.
UNS N08825 Seamless Tube Chemical Composition
Nickel at 38.0 to 46.0% and iron at 22.0% minimum make up the bulk of UNS N08825 seamless tube, with iron determined arithmetically by difference. Chromium is held at 19.5 to 23.5%, and molybdenum, copper and titanium are each set as a range rather than a ceiling. ASTM B163 places no limit on phosphorus for this alloy.
- NiNickel, 38.0 to 46.0
- CrChromium, 19.5 to 23.5
- FeIron, 22.0 min
- MoMolybdenum, 2.5 to 3.5
- CuCopper, 1.5 to 3.0
UNS N08825825
| Element | Limit per ASTM B163 / ASME SB-163 (%) |
|---|---|
| Ni (Nickel) | 38.0 to 46.0 |
| Cr (Chromium) | 19.5 to 23.5 |
| Fe (Iron) | 22.0 min |
| Mo (Molybdenum) | 2.5 to 3.5 |
| Cu (Copper) | 1.5 to 3.0 |
| Ti (Titanium) | 0.6 to 1.2 |
| Al (Aluminum) | 0.2 max |
| C (Carbon) | 0.05 max |
| Mn (Manganese) | 1.0 max |
| Si (Silicon) | 0.5 max |
| S (Sulfur) | 0.03 max |
ASME SB-163 825 Seamless Tube Tensile Requirements
The tube standard lists N08825 in one condition only, annealed, and gives it a single row of minimums that applies to every size and wall.
| Condition | Tensile Strength, min, ksi (MPa) | Yield Strength (0.2% offset), min, ksi (MPa) | Elongation in 2 in. or 50 mm (or 4D), min (%) |
|---|---|---|---|
| Annealed | 85 (586) | 35 (241) | 30 |
Swipe sideways to see the full table.
Pipe in this grade is split by finishing route, and only its cold-worked annealed row matches these figures; hot-finished annealed pipe carries a lower 75 ksi (517 MPa) tensile and 25 ksi (172 MPa) yield. An ASME SB-163 825 seamless tube therefore needs no condition entry beyond annealed. The higher-yield supplementary requirement of ASTM B163 names other alloys, not N08825, so 35 ksi (241 MPa) stays the yield floor on every order.
Equivalent Designations of Incoloy 825
European and Japanese drawings sometimes call Incoloy 825 by a national number instead of its UNS designation. ASTM B163 uses the UNS number alone, so the W.Nr. and JIS entries below help read such a callout and make no claim of conformity with those national standards.
- Commercial nameIncoloy 825, also written Alloy 825
- ASTM B163 / ASME SB-163 (USA)UNS N08825
- Europe (W.Nr.)2.4858
- Japan (JIS)NCF825
Whichever of these numbers a drawing uses, our offer and the certificate carry N08825 as the designation of record.
Sizes and Tolerances of Seamless WNR 2.4858 Tube
Seamless WNR 2.4858 tube is offered from 6 mm to 457 mm in outside diameter and from 1 mm to 65 mm in wall, in single lengths up to 22 m, with each size confirmed in our offer.
ASTM B163 prints the diameter and wall tolerances for this alloy in three bands of nominal outside diameter, covering the 1/2 to 3 in. (12.7 to 76.2 mm) heat-exchanger sizes:
| Nominal OD, in. (mm) | OD Tolerance, in. (mm) | Average Wall Tolerance | Minimum Wall Tolerance |
|---|---|---|---|
| 1/2 to 5/8 (12.7 to 15.9), excl | ±0.005 (0.13) | ±12.5% | +25.0% / 0 |
| 5/8 to 1 1/2 (15.9 to 38.1), incl | ±0.0075 (0.19) | ±10.0% | +20.0% / 0 |
| Over 1 1/2 to 3 (38.1 to 76.2), incl | ±0.010 (0.25) | ±10.0% | +22.0% / 0 |
Swipe sideways to see the full table.
The wall tolerance applies to the wall as ordered, either average or minimum, never to both. On thin-wall tube, where the wall is 3% of the outside diameter or less, the mean diameter must sit inside the table while single readings may exceed it by a further 1/2% of the nominal OD. Eccentricity is capped as well: across any one cross section, the wall may vary by no more than plus or minus 10% of that section's measured average wall. For a size outside the three printed bands, the applicable tolerance is written into our offer.
Cut Length and Straightness
A tube ordered cut to length is never shorter than specified and may run up to 1/8 in. (3.2 mm) over. For lengths above 30 ft (9.1 m), the permitted overrun widens to 1/4 in. (6.4 mm). Every length must also be reasonably straight and free of bends or kinks.
Supplementary Order Options for Alloy 825 Seamless Tube
ASTM B163 lists supplementary requirements that apply only when the purchase order calls them up by name. Two concern the shape in which Alloy 825 seamless tube is delivered:
U-bent tubes (S1): the standard links tube OD and average wall to a minimum bend radius, and for N08825 the radius column for annealed tube is the one that applies.
Coiled or unstraightened tubing (S3): material supplied this way is identified with a U suffix, as in UNS N08825-U.
Without either option on the order, the tube is supplied in straight cut lengths.
Choosing Seamless Nickel Alloy 825 Tube Against 925 and 904L
Incoloy 925 seamless tubes come under a different product standard that sets no flare test, and they are supplied solution annealed plus precipitation hardened. Their chemistry keeps the nickel, chromium, iron, molybdenum and copper windows of N08825 but raises titanium to 1.90 to 2.40% and aluminum to 0.10 to 0.50%, and the 925 range runs from 6.35 mm to 257 mm OD.
Where a duty does not call for a nickel alloy at all, stainless steel 904L seamless tubes are the lower-alloy option in our range. An exchanger specified to UNS N08825 stays on seamless nickel alloy 825 tube, because its flare-tested lots and its annealed strength row are what the certificate is checked against.
Applications of Seamless Alloy 2.4858 Tube
Seamless alloy 2.4858 tube serves acid-plant heat exchangers and evaporators, desalination exchangers, sour gas wellheads, flue gas scrubbers and pickling tank heaters.
Phosphoric Acid Evaporators
Wet-process phosphoric acid units use the alloy for evaporator tubes, where each lot arrives with its flare and tension results already reported on the certificate.
Desalination Heat Exchanger Tubing
MED and MSF desalination plants take the grade as heat exchanger tubing, ordered by outside diameter with an average or minimum wall instead of a nominal pipe size.
Sour Gas Wellhead Tubing
Oil and gas recovery puts the tube into wellhead tubing in sour gas service, where each lot of one heat, size and condition is traced to its certificate by the order number on the bundle.
Flue Gas Desulfurization Scrubbers
Pollution control plants fit the alloy in flue gas desulfurization scrubbers, which handle the sulfur-bearing acid formed during gas cleaning, with the ground or pickled finish stated on each line.
Pickling Tank Heaters
Acid production and metal pickling lines build tank heaters for sulfuric acid baths from the tube, ordering straight cut lengths in the annealed condition the standard prescribes.
Packing and Bundle Marking of Seamless 2.4858 Tube
Packing
Wooden cases with both tube ends capped, and the contents wrapped against moisture for the sea passage.
Bundle marking
Each bundle or shipping container carries the material name, condition (temper), ASTM B163, the size, the gross, tare and net weights, the consignor and consignee addresses and the contract or order number.
Documents
An EN 10204 3.1 (3.2 on request) material test certificate keyed to the heats of seamless 2.4858 tube in the case, with a packing list for every case.
Terms
FOB, CIF or CFR, with the port of loading named in the offer.
Timing
The mill slot and ship date are confirmed on the order acknowledgement.
Indicative Price per Kilogram
Seamless alloy 2.4858 tube is indicatively priced at USD 22 to 50 per kg. The nickel market sets most of where a quotation lands, with molybdenum and copper contributing to a smaller degree. Outside diameter, wall and cut length then fix the drawing and annealing cost per kilogram, so small-bore, thin-wall tube sits toward the top of the range, as do small lots and any added testing or inspection. A size list with tube counts brings a firm price.
Indicative price, Incoloy 825 Seamless Tubes
USD 22 to 50 per kg
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
- Outside diameter
- Wall thickness
- Length
- Testing and certification
- Nickel price
- Molybdenum price
- Copper price
Our Mill in Ban Bueng and Office in Bang Phli
Incoloy 825 seamless tubes are produced at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand, and offers, certificates and shipping papers are issued from 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. Projects in Thailand are supplied directly, and we export to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
Factory154 Moo.1 Map Phai, Ban Bueng,
Chonburi 20170, Thailand
Chonburi 20170, Thailand
Office89/18 Moo.15 Enterprize Park, Bangna-Trad Road,
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Exporting to
- Singapore
- Malaysia
- Vietnam
- Indonesia
- Philippines
- India
Incoloy 825 Seamless Tube FAQ
How many flare samples does a 300-tube order of N08825 need?
Three, if all 300 tubes share one heat, one size and the annealed condition, since 1% of the lengths in a lot is flared. Split the same order across two sizes and it becomes two lots, each flared separately, and any lot below 100 tubes still gives up one flared end.
Should exchanger tube be ordered on average wall or minimum wall?
Order on minimum wall when the thermal or pressure design uses the thinnest permitted wall. Between 5/8 and 1 1/2 in. (15.9 and 38.1 mm) OD, a minimum-wall order accepts nothing below the stated figure and up to 20.0% above it, while an average-wall order allows 10.0% either way.
What hydrostatic pressure does each tube see?
1000 psi (6.9 MPa) for tubes of 1/8 in. (3.2 mm) OD and larger with walls of 0.015 in. (0.38 mm) and over, provided the resulting wall stress stays within the allowable value the standard sets for the alloy. Unless the order names the method, the mill may use a nondestructive electric test instead.
How should cut lengths be set for long exchanger tubes?
At the shortest length the bundle drawing accepts, because the allowance runs one way only. Up to 30 ft (9.1 m) a tube may arrive 1/8 in. (3.2 mm) long, and above that up to 1/4 in. (6.4 mm) long, but never short. Single lengths are offered up to 22 m.
Can U-bent Alloy 825 seamless tube be ordered to ASTM B163?
The standard provides for it as supplementary requirement S1, which applies only when the purchase order names it. Bend radii come from the annealed column: for tube up to 1/2 in. (12.7 mm) OD with an average wall of 0.046 to 0.057 in. (1.17 to 1.45 mm), the minimum radius is 1 3/16 in. (30.2 mm).
Which grade gives more strength, 825 or 925?
925 does: in its solution annealed plus precipitation hardened condition it must reach 140 ksi (965 MPa) tensile, 110 ksi (758 MPa) yield and 18% elongation. Annealed 825 is held to 85 ksi (586 MPa), 35 ksi (241 MPa) and 30%, so it keeps the higher elongation, and only its lots are flare tested.
Is a material certificate part of every ASTM B163 order?
The standard requires one only when the purchase order or contract specifies it. We issue an EN 10204 3.1 (3.2 on request) certificate with every consignment anyway, reporting the heat analysis, the lot tension and flare results, and the hydrostatic or electric test applied to each tube.
Request a Quote for Incoloy 825 Seamless Tubes
or email sales@thaida.co.th