Chemical Plant Exchangers and Columns
Heat exchangers, distillation columns and reactor vessels in chemical plants are tubed in this alloy for acetic and phosphoric acid service, with S2 or S3 testing added where the plant specification requires it.
ASTM B444 / ASME SB-444 / UNS N06625 / W.Nr. 2.4856
Inconel 625 Seamless Tubes Manufacturer in Thailand
ASTM B444 / ASME SB-444 governs the Inconel 625 seamless tubes that Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. draws or pilgers and then heat treats at its Ban Bueng, Chonburi mill. The alloy is UNS N06625, or W.Nr. 2.4856 in Europe, and these tubes belong to our Inconel seamless tubes range in the annealed Grade 1 or solution-annealed Grade 2 condition. Grain size, intergranular and pitting tests are added only on order, and each quotation comes from our Bang Phli, Samut Prakan office.
Inconel 625 seamless tubeUNS N06625 / W.Nr. 2.4856
- 6 to 257 mmOutside diameter
- 1 to 35 mmWall thickness
- Up to 22 mLength
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
Seamless Inconel 625 Tube Specifications Under ASTM B444
Use these limits to check a tube line item before it goes out: the OD, wall and length we draw, the two heat-treated grades, how the wall is stated, the release tests on each lot and each tube, and the three tests only an order can add.
- Standard
- ASTM B444 / ASME SB-444
- Designation
- UNS N06625
- Product Scope
- Cold-worked seamless tube
- Grades
- Grade 1 (annealed) or Grade 2 (solution annealed)
- Grade 1 by default
- Outside Diameter
- 6 to 257 mm
- Wall Thickness
- 1 to 35 mmordered as nominal or minimum wall
- Length
- Up to 22 m
- Production Route
- 1Hot-extruded hollow
- 2Cold drawn or pilgered
- 3Then heat treated to the grade
- Finish
- Normally supplied ground OD (12.7 mm to 102 mm OD) or pickled, not ground (12.7 mm to 168 mm OD); finish for other sizes agreed at quotation
- Release Tests
- Chemical analysis and tension test per lot
- Hydrostatic or nondestructive electric test on each tube
- Supplementary Tests
- S1 grain size, S2 intergranular corrosion, S3 pitting and crevice corrosion, when ordered
- Test Certificate
- EN 10204 3.13.2 on request
ASTM B444 limits its scope to cold-worked seamless pipe and tube, so each tube we release under it has been drawn or pilgered before the final heat treatment, and ASME SB-444 is the counterpart named in boiler and pressure vessel code designs. The standard identifies the alloy by UNS number alone, so N06625 is what we mark on each UNS N06625 seamless tube or its bundle tag and print on the certificate. A tube item states the outside diameter with either a nominal or a minimum wall, whereas Inconel 625 seamless pipes under the same specification are listed by nominal pipe size and schedule.
A lot groups tube from a single heat, of the same nominal size and condition, and is capped at 9100 kg (20 000 lb). One chemical analysis and one tension test stand for each lot, while each tube goes through a hydrostatic check or an electric nondestructive examination, selected by the mill unless the order specifies one. Lot results are issued on an EN 10204 3.1 (3.2 on request) material test certificate, and an inspector you appoint can witness release whenever the order provides for it.
Supplementary Grain Size and Corrosion Tests in ASTM B444
Three supplementary requirements close the text of ASTM B444, and none of them belongs to a standard release. Each becomes binding only when the purchase order names it, so the order states which of S1, S2 and S3 apply, and the purchaser may also set a test frequency other than the one the requirement provides.
| Requirement | What It Checks | Test Method | Acceptance Criterion |
|---|---|---|---|
| S1 Grain Size | Average grain size of the finished tube | ASTM E112 intercept method, on each heat-treatment lot | 5.0 or finer |
| S2 Intergranular Corrosion | Resistance to intergranular attack | ASTM G28 Method A | Corrosion rate 0.003 ipm (0.914 mm/yr) maximum |
| S3 Pitting and Crevice Corrosion | Resistance to pitting and crevice attack | ASTM G48 Method C; test temperature 75 °C (167 °F) ± 1 °C; exposure 72 h | No visible pitting deeper than 0.001 in. (0.025 mm) at 20× magnification, and weight loss under 1.0 g/m2 |
Swipe sideways to see the full table.
S1 is determined on every heat-treatment lot. In an ASTM B444 tube lot, annealed material comes from a single batch-furnace charge, or from one continuous-furnace run at one temperature, time and speed, so a single grain size result covers tube that shared the same anneal. If you order Grade 2 with the optional stabilization anneal, which the standard includes to increase resistance to sensitization, S2 can be written into the same order. The 75 °C in S3 is a laboratory condition of the test and says nothing about the temperature the tube may see in service.
Name the tests on the order line, for example "ASTM B444 Grade 1 with S1 and S3", and add a frequency if your specification asks for more than the requirement gives. Each report travels with the lot data, and the quotation gives a delivery date that already allows for the extra testing.
Chemical Composition of UNS N06625 Seamless Tube
Every lot is covered by one heat analysis against the limits below. The nickel figure of 58.0% minimum is the balance left once every other element has been determined, so it is calculated rather than read directly. ASTM B444 notes that columbium and niobium name the same element; here it shares a single 3.15 to 4.15% limit with tantalum.
- NiNickel, 58.0 min
- CrChromium, 20.0 to 23.0
- MoMolybdenum, 8.0 to 10.0
- FeIron, 5.0 max
- NbNb (Niobium) + Ta (Tantalum), 3.15 to 4.15
UNS N06625625
| Element | ASTM B444 Limit (%) |
|---|---|
| Ni (Nickel) | 58.0 min |
| Cr (Chromium) | 20.0 to 23.0 |
| Mo (Molybdenum) | 8.0 to 10.0 |
| Nb (Niobium) + Ta (Tantalum) | 3.15 to 4.15 |
| Fe (Iron) | 5.0 max |
| Co (Cobalt), if determined | 1.0 max |
| C (Carbon) | 0.10 max |
| Mn (Manganese) | 0.50 max |
| Si (Silicon) | 0.50 max |
| P (Phosphorus) | 0.015 max |
| S (Sulfur) | 0.015 max |
| Al (Aluminum) | 0.40 max |
| Ti (Titanium) | 0.40 max |
Grade 1 and Grade 2 Heat Treatment of ASME SB-444 625 Seamless Tube
Both grades share one chemistry. What separates them is the mill heat treatment and, with it, the room-temperature minimums that the tension test on each lot has to meet.
| Grade | Required Heat Treatment | Tensile Strength, min, MPa (ksi) | Yield Strength (0.2% offset), min, MPa (ksi) | Elongation in 2 in. (50.8 mm) or 4D, min, % |
|---|---|---|---|---|
| Grade 1 (annealed) | Annealed at 871 °C (1600 °F) minimum | 827 (120) | 414 (60) | 30 |
| Grade 2 (solution annealed) | Solution annealed at 1093 °C (2000 °F) minimum; optional stabilization anneal at 982 °C (1800 °F) minimum | 690 (100) | 276 (40) | 30 |
Swipe sideways to see the full table.
These strength minimums apply to tubing in straight lengths. An order that names neither grade is filled as Grade 1. Grade 2, solution annealed, is the grade for designs that need creep and rupture resistance, and its stabilization anneal is a separate choice you add to an ASME SB-444 625 seamless tube order when you want it.
Equivalent Designations of Inconel 625
An exchanger datasheet may call for Inconel 625 under any of the designations below, depending on where it was drawn up. ASTM B444 itself assigns the UNS number and nothing else. The W.Nr. and JIS rows below are cross-references for drawings prepared in Europe or Japan, and the commercial name sits in a row of its own.
- Commercial nameInconel 625, also written Alloy 625
- ASTM B444 / ASME SB-444 (USA)UNS N06625
- Europe (W.Nr.)2.4856
- Japan (JIS)NCF625
Where a datasheet quotes 2.4856 or NCF625, we enter the item as N06625, and that is the designation the certificate reports.
Size Range and Cold-Worked Tolerances of Seamless WNR 2.4856 Tube
We draw seamless WNR 2.4856 tube between 6 mm and 257 mm OD, in wall thicknesses from 1 mm through 35 mm and lengths reaching 22 m. The wall is ordered either as nominal, with a plus and minus allowance, or as minimum, with the whole allowance on the plus side, so read the column that matches the wall basis on your order. Small-bore seamless alloy 2.4856 tube up to 76 mm OD is held to these ASTM B444 cold-worked limits:
| Nominal OD, in. (mm) | OD Plus, in. (mm) | OD Minus, in. (mm) | Nominal Wall, % | Minimum Wall, % |
|---|---|---|---|---|
| Up to 0.400 (10), incl | 0.004 (0.10) | 0.004 (0.10) | +15.0 / -15.0 | +30 / 0 |
| Over 0.400 (10) to 5/8 (16), excl | 0.005 (0.13) | 0.005 (0.13) | +15.0 / -15.0 | +30 / 0 |
| 5/8 (16) to 1 1/2 (38), incl | 0.0075 (0.19) | 0.0075 (0.19) | +10.0 / -10.0 | +22 / 0 |
| Over 1 1/2 (38) to 3 (76), incl | 0.010 (0.25) | 0.010 (0.25) | +10.0 / -10.0 | +22 / 0 |
Swipe sideways to see the full table.
Single OD readings include ovality, and the wall figures include eccentricity. On thin-wall tube, where wall thickness is no more than 3% of the diameter, the band governs the mean OD and single readings are allowed an extra 0.5% of nominal OD on top. Tube from 76 mm up to our 257 mm limit falls in wider cold-worked bands, which the quotation states size by size. Ends are supplied plain cut and deburred, and random-length orders are settled at quotation.
Seamless Nickel Alloy 625 Tube Compared with 600 and C276
Inconel 600 seamless tubes are a nickel-chromium-iron alloy with 72.0% nickel minimum, 14.0 to 17.0% chromium and no molybdenum requirement, supplied annealed with minimums of 552 MPa tensile and 241 MPa yield strength. Seamless nickel alloy 625 tube brings molybdenum at 8.0 to 10.0% and a combined niobium and tantalum content of 3.15 to 4.15%, and its Grade 1 minimums rise to 827 MPa and 414 MPa.
Alloy C276 seamless tubes are a separate alloy with their own UNS number and product standard, so the datasheet, the order and the certificate all change with the material. For 625, S2 and S3 results give the corrosion side of that choice a measured basis. Send the process media and the test you intend to specify, and we build it into the 625 quotation.
Industrial Applications of Inconel 625 Seamless Tubes
The duties below come from chemical, power, desalination, aerospace and semiconductor equipment.
Steam Generator and Superheater Tubing
Power plants order the alloy as steam generator tubing and superheater tubes, choosing Grade 1 or Grade 2 according to the strength, or the creep and rupture resistance, that the design calls for.
Heat Recovery Units and Condensers
Heat recovery systems and condensers in power generation take straight seamless lengths, with the heat number on each length or on its bundle tag, matching the certificate.
Desalination Heat Exchangers
Desalination plants tube their heat exchangers in this alloy where seawater is the cooling or feed medium, and the same grade serves the seawater piping that supplies those units.
Aircraft Fuel Lines and Thrust Reversers
Aircraft engine components, exhaust systems, fuel lines and thrust reverser systems are built from this tube, each length leaving with its lot chemistry and tension results on the certificate.
Semiconductor and Vacuum Equipment
Chambers for chemical vapor deposition, vacuum systems and other semiconductor fabrication equipment take this tube, with a ground OD or a pickled finish chosen on the order to suit the assembly.
Packing and Dispatch of Seamless 2.4856 Tube
Packing
Small-bore seamless 2.4856 tube in wooden cases, larger OD in strapped bundles, with every tube end capped.
Identification
Each tube, or the tag on its bundle, shows the UNS number, heat number and size, and the case label states whether the contents are Grade 1 or Grade 2.
Terms
Shipment on FOB, CIF or CFR terms.
Documents
EN 10204 3.1 (3.2 on request) certificate with the lot results, any S1, S2 or S3 report that was ordered, and the heat treatment charts.
Timing
Ex-stock, or from a mill production date fixed in the quotation.
Price of Alloy 625 Seamless Tube per kg
For Alloy 625 seamless tube to ASTM B444, plan on an indicative USD 26 to 60 per kg. The nickel, molybdenum and niobium markets move the whole band; within it, the grade ordered, the OD, wall and cut length all shift the figure, while small bores, small lots and any supplementary test you add move it toward the top. Your item list turns that band into a firm price.
Indicative price, Inconel 625 Seamless Tubes
USD 26 to 60 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
Drawn in Ban Bueng, Quoted from Bang Phli
Tube for this specification is extruded, drawn or pilgered and heat treated at our factory, 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand. Quotation, order review and export paperwork are handled at our office, 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. We deliver within Thailand and ship export orders 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
Seamless Alloy 2.4856 Tube FAQ
Which supplementary tests can I add to ASTM B444 Inconel 625 seamless tubes?
Three, each tied to a different risk: S1 for grain size after the final anneal, S2 for intergranular attack and S3 for pitting and crevice corrosion. Pick them by the failure mode your design must rule out; one, two or all three can sit on the same order line, and each returns a separate report with the certificate.
What grain size does S1 require on UNS N06625 seamless tube?
An average of 5.0 or finer, determined by the ASTM E112 intercept method on every heat-treatment lot. Ask for it when your exchanger or vessel specification sets a grain size limit, because without S1 on the order, grain size is not a release requirement for this tube.
What does the S3 pitting test demand of seamless Inconel 625 tube?
Specimens spend 72 h in ASTM G48 Method C at a test temperature of 75 °C (167 °F) ± 1 °C. A pass means no visible pit deeper than 0.025 mm at 20× magnification and a weight loss below 1.0 g/m2. Order it when chloride pitting is the deciding risk on your process side.
How tight is the OD tolerance on small-bore seamless alloy 2.4856 tube?
It depends on the band: ±0.10 mm up to 10 mm OD, ±0.13 mm from there to under 16 mm, ±0.19 mm from 16 mm to 38 mm and ±0.25 mm from 38 mm to 76 mm. At 19.0 mm OD (3/4 in.), that means ±0.19 mm, with ±10% on nominal wall or +22/0% on minimum wall.
How do I decide between Alloy 625 and C276 for a chloride-bearing exchanger duty?
Let the process media decide. Send the fluid, its chloride content and the corrosion test your specification names, and we price both alloys, each to its own standard. On the 625 side, ordering S2 or S3 gives the order a measured corrosion result to set against the requirement before the bundle is built.
Which ASTM B444 grade suits an exchanger bundle?
Grade 1, unless the design calls for creep and rupture resistance. Grade 1 is annealed, carries a 414 MPa yield minimum against 276 MPa for Grade 2, and is what the mill ships when an order is silent. Either way, the strength minimums apply to tube in straight lengths.
Is every ASTM B444 seamless tube cold worked?
Yes. ASTM B444 has no hot-finished category, so the OD and wall limits measured on arrival are the cold-worked bands at every size. If the tube is to be hot formed after delivery, ask for hot forming quality: it is released on chemistry and a surface check alone, and no tensile minimum applies.
What paperwork comes with an Alloy 625 seamless tube delivery?
An EN 10204 3.1 (3.2 on request) material test certificate showing the heat, the grade, the lot chemistry, the tension results and the record of the hydrostatic or electric test, plus heat treatment charts. Any S1, S2 or S3 report you ordered joins the same package, and a third-party inspection report is included when your order calls for one.
Request a Quote for Inconel 625 Seamless Tubes
or email sales@thaida.co.th