Heat Exchanger and Boiler Bundles
Shell-and-tube bundles and boiler circuits are the service A213 was drafted around, and a stabilized grade gets specified when the joint at the tubesheet stays hot from one shutdown to the next.
ASTM A213 / ASME SA-213 / UNS S32100 / W.Nr. 1.4541
Stainless Steel 321 Seamless Tubes Manufacturer in Thailand
Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. runs a seamless tube mill in Ban Bueng, Chonburi, Thailand, where ASTM A213 TP321 stainless steel seamless tubes are pierced from billet, drawn to size and solution treated for boiler, exchanger and furnace work. The grade carries UNS S32100, and EN 1.4541 names the same titanium-bearing steel in Europe, one of the stabilized grades in our range of stainless steel seamless tubes. Our Bang Phli, Samut Prakan office turns a size list into a quotation.
Stainless Steel 321 seamless tubeUNS S32100 / W.Nr. 1.4541
- 6.35 to 257 mmOutside diameter
- 0.89 to 12.7 mmWall thickness
- Up to 22 mLength
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
Supply Range of ASTM A213 TP321 Stainless Steel Seamless Tubes
An order here turns on two figures, outside diameter and wall. A213 treats the wall as a minimum unless average wall is named, and the delivery condition settles the rest, because hot finished and cold finished tube answer to different dimensional limits.
- Product Standard
- ASTM A213 / ASME SA-213, grade TP321
- Designation
- UNS S32100, with EN 1.4541 (X6CrNiTi18-10) as the European cross-reference
- Diameter Range
- 6.35 to 257 mm
- Wall
- 0.89 mm to 12.7 mm, ordered on a minimum-wall or average-wall basis
- Length
- Straight tube up to 22 m, cut as your order lists
- Delivery Condition
- Hot finished or cold finished, named on the order
- Route
- 1Billet heated and pierced
- 2Worked over a mandrel
- 3Then cold drawn where cold finished tube is ordered
- Stabilizing Element
- Titanium, 5 x (C + N) minimum and 0.70% maximum
- Heat Treatment
- Solution treated at 1040 °C (1900 °F) or hotter, then water or other rapid cool
- Surface
- Pickled free of scaleor bright annealed with no pickling required
- Every Tube
- Hydrostatic test, or the nondestructive electric test in its place
- Every Lot
- Tension, hardness, flattening and flaring
- Certificate
- EN 10204 3.13.2 on request
The title of A213 names boiler, superheater and heat-exchanger tube, and TP321 is one of its austenitic grades, so a single purchase line carries the chemistry, the anneal, the test plan, the finish and the marking. Stainless steel 321 seamless tubes leave the mill pickled free of scale, or bright annealed where that is asked for, and both conditions reach the same solution treatment first. Items drawn up by NPS and schedule number belong instead with our stainless steel 321 seamless pipes, a different ASTM specification with its own tolerance set.
Release Testing on Each SS 321 Seamless Tube
A213 builds its test plan on three levels, and all three reach the certificate. Heat level comes first: an analysis is taken from a billet or from a finished length out of every heat, so the titanium, carbon and nitrogen results describe metal that really went down the mill. Lot level follows, a lot being one size drawn from one heat. Tension testing claims one tube where a lot numbers 50 or under and a second as soon as it runs past that; a pair of tubes gives the hardness readings; and flattening and flaring are run on two different finished tubes, each sampled at both of its ends. Wall thickness decides the hardness scale. Brinell, Rockwell and Vickers all serve from 5.1 mm of wall upward; thinner than that and down to 1.65 mm the reading is taken on the Rockwell or Vickers scale; under 1.65 mm it is waived altogether. Tube level closes the plan, since every SS 321 seamless tube goes under hydrostatic pressure or through a nondestructive electric examination instead, and that pick is ours wherever the order leaves it open. An independent inspection body attends the lot testing on request, and the finished record issues as an EN 10204 3.1 (3.2 on request) certificate.
Heat Analysis Limits for UNS S32100 Seamless Tube
Titanium is the one element written as a ratio instead of a flat band: it has to reach five times the carbon plus nitrogen content, and 0.70% is the ceiling. A213 sets no nitrogen limit for TP321 and asks nothing of molybdenum or niobium, so the heat behind a UNS S32100 seamless tube is judged on the eight limits set out below, in weight percent:
- CrChromium, 17.0 to 19.0
- NiNickel, 9.0 to 12.0
- TiTitanium, 5 x (C + N) min, 0.70 max
- MnManganese, 2.00 max
- SiSilicon, 1.00 max
UNS S32100321
| Element | TP321 Limit, % |
|---|---|
| C (Carbon) | 0.08 max |
| Mn (Manganese) | 2.00 max |
| P (Phosphorus) | 0.045 max |
| S (Sulfur) | 0.030 max |
| Si (Silicon) | 1.00 max |
| Cr (Chromium) | 17.0 to 19.0 |
| Ni (Nickel) | 9.0 to 12.0 |
| Ti (Titanium) | 5 x (C + N) min to 0.70 max |
What the Titanium Ratio Buys in Seamless 1.4541 Stainless Steel Tube
Carbon left loose in an austenitic steel finds chromium at the grain boundaries once the metal passes through the sensitizing range, whether in a weld heat-affected zone or in service, and the chromium-poor band it leaves is where intergranular attack begins. Pinning that carbon to titanium at the ratio the grade specifies keeps the chromium in solution and the boundaries sound, which is why a fabricator calls up grade 321 rather than an unstabilized chromium-nickel steel. Since the mechanism is a ratio, a certificate for seamless 1.4541 stainless steel tube has to be read as a set, carbon and nitrogen alongside titanium. Molybdenum is absent from the grade, so chloride pitting is not the problem it is bought to solve.
One Strength Level at Every Wall of Seamless S32100 Stainless Steel Tube
Stabilization changes how the steel behaves after heat, not what it owes a tension test. A213 gives TP321 a single row of requirements, and each lot of seamless S32100 stainless steel tube is tested against it after solution treatment:
| Property | A213 Requirement for TP321 |
|---|---|
| Tensile Strength, min | 515 MPa (75 ksi) |
| Yield Strength, min | 205 MPa (30 ksi) |
| Elongation on a 50 mm (2 in.) Gauge, min | 35% |
| Hardness Ceiling | 192 HBW / 200 HV, and 90 HRB |
| Solution Treatment, min | 1040 °C (1900 °F), water or other rapid cool |
There is no heavy-wall step in the tube standard, so a thick boiler tube is accepted against the same 515 and 205 MPa minimums as a thin exchanger tube. One row, read the same way from the thinnest wall the mill draws to the heaviest, is what holds a mixed size list on a single acceptance criterion. Note the word minimum against the anneal: 1040 °C (1900 °F) is a floor with no upper figure attached to it, and the water quench or equivalent rapid cool behind it counts as part of the treatment. The hardness ceiling is what keeps the tube soft enough to roll into a tubesheet or bend into a furnace coil.
Designation Equivalents for Grade 321
Drawings arrive with grade 321 written half a dozen ways. The mill order runs on UNS S32100 with the A213 grade, and the rest of the table exists to tie a foreign designation back to those two.
- UNSS32100
- ASTM / ASME seamless tube gradeTP321 (A213 / SA-213)
- WNR1.4541
- EN / ISO nameX6CrNiTi18-10
- Japan (JIS)SUS321
- China (GB)S32168 (ISC) / 06Cr18Ni10Ti
- Russia (GOST)08X18H10T
A requisition raised for seamless WNR 1.4541 tube and one raised for TP321 reach the same production order. We mark and certify to UNS S32100 with the A213 grade, carrying 1.4541 on the certificate purely as the cross-reference a European drawing needs, without claiming conformity to a European product standard.
Sizes and Permitted Variations for 321 Stainless Steel Seamless Tube
Diameters of 6.35 mm to 257 mm, walls of 0.89 mm to 12.7 mm and single straight runs out to 22 m bound what the mill draws in 321 stainless steel seamless tube. Boiler and furnace-part items usually sit in the small and middle diameters of that envelope, where one cut length repeats right across a consignment. Diameter limits go into the quotation size by size. What follows instead is the average-wall rule carried by our A213 seamless tubing, the basis to use whenever a drawing states a nominal thickness.
Average-Wall Variations on Hot-Formed Seamless Tube
| Specified Outside Diameter | Wall as a Fraction of Diameter | Permitted Variation |
|---|---|---|
| 10.3 to 73.0 mm (0.405 to 2.875 in.) incl. | any | +20% / -12.5% |
| Above 73.0 mm (2.875 in.) | 5% or less | +22.5% / -12.5% |
| Above 73.0 mm (2.875 in.) | over 5% | +15% / -12.5% |
Average wall is only one of the two bases. Ask for minimum wall instead and the whole variation sits on the plus side, so nothing in the consignment finishes thinner than the figure your calculation produced. Cold-formed tube ordered to average wall is simpler again: one band of +/-10% covers every size and every wall. State the basis against each item, because an order that stays silent is taken as minimum wall.
Titanium or Niobium: Grade 321 Against 321H and 347
Three A213 grades carry a stabilizer, and carbon is the first fork between them. TP321 holds carbon to 0.08% maximum with no floor under it. TP321H raises that to a 0.04 to 0.10% window, relaxes the titanium ratio to four times carbon plus nitrogen, adds a grain size of ASTM No. 7 or coarser and anneals hotter, a package aimed at creep-rupture strength. A superheater element sized on creep therefore belongs in 321H seamless tubes, while a welded assembly that merely passes through the sensitizing range belongs on this grade.
The stabilizing element is the second fork. A213 stabilizes TP347 with niobium at ten times carbon up to 1.10% maximum and gives it a wider chromium band of 17.0 to 20.0%, and a line that stays in the sensitizing range for long periods is often written to 347 seamless tubes. Titanium stabilization remains the established answer for exhaust, bellows and expansion work, where forming and welding follow each other on the same part.
Where Seamless Stainless Steel 321 Tube Is Used
Titanium went into the grade because heat and welding so often arrive on the same component, and every duty listed below brings the two together.
Furnace Parts and Radiant Elements
Radiant tubes, muffles and internal supports climb from cold to working heat at every start-up, and a stabilized structure is what holds the welds in those parts together through the cycling.
Thin-Wall Aircraft Exhaust Manifolds
Exhaust manifolds are formed and welded from thin-wall seamless 1.4541 stainless steel tube that then heats and cools on every flight, so each weld zone has to keep its corrosion resistance with no later anneal.
Bellows
Convolutions are rolled or hydroformed from the finished tube, which makes an even wall and a ductile structure matter as much as the chemistry; thin-wall cold finished tube is the usual starting stock.
Expansion Joints
Collars, liners and tie rods in an expansion joint are welded up and then strained at temperature in service, so they are cut from stabilized tube to keep every joint behaving like the parent metal.
Electric Heating Elements
Sheath and support tubing for electric heating elements runs hot continuously and is usually welded into an assembly, which places it squarely in the duty this grade is specified for.
High-Temperature Mineral Processing Screens
Hot screening duty in mineral processing puts the frames and support tubing under the same heat as the deck, and we supply the seamless tube stock for that fabrication.
Packing and Dispatch of Seamless WNR 1.4541 Tube
Bundles
One size and one heat to a bundle, banded over edge protection, each tube capped at the bore.
Marking
Our mark with the specification and grade, the finishing condition, the wall basis and your item number where the order gives one.
Thin walls
Bellows and exhaust stock rides in cases on closely set battens, since a thin-wall tube takes a set more readily than a heavy one.
Documents
The EN 10204 3.1 (3.2 on request) certificate, solution-anneal charts, PMI readings, a packing list built size by size, and the certificate for the billets behind the heat.
Terms
FOB, CIF or CFR, fixed in the quotation.
Dispatch
Trucks to plant sites anywhere inside Thailand, containerized sea freight on export items.
What Sets the Price per kg of ASTM A213 Stainless Steel 321 Seamless Tube
Expect USD 3.75 to 7 per kg as the indicative figure on an ASTM A213 TP321 stainless steel seamless tube. Nickel at 9.0 to 12.0% sets the floor, and stabilizing the steel with titanium adds to it over a plain chromium-nickel grade, while small diameters, thin walls, short drawing runs, bright annealing and a widened test scope move a line toward the top of the band. Send the size list and each item comes back with a firm figure.
Indicative price, Stainless Steel 321 Seamless Tubes
USD 3.75 to 7 per kg
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
- Outside diameter
- Wall thickness
- Quantity
- Testing and certification
- Nickel price
- Chromium price
- Titanium price
Manufacturing and Export of Stainless Steel 321 Seamless Tubes
Piercing, drawing, solution treatment and release testing all run on one shop floor, 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand. The commercial side of an order, quotation through certificate to export paperwork, is handled out of 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. Plants inside Thailand are served direct, and ASTM A213 stainless steel 321 seamless tubes travel on from there 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
Questions Engineers Ask About Grade 321 Seamless Tube
What does the titanium in a 321 seamless tube do at a weld?
It reaches the carbon before the chromium can. Heating a stabilized austenitic steel forms titanium carbides rather than chromium carbides, so the grain boundaries beside the weld keep their chromium and their resistance to intergranular attack, with no anneal needed on the finished fabrication.
Does a heavy wall lower the strength minimums of a 321 seamless tube?
No. A213 prints one row for TP321, and it governs at 0.89 mm of wall just as it does at 12.7 mm, so the tested values on a certificate are read against the same 515 and 205 MPa whatever the item. Heavier wall therefore buys pressure capacity and corrosion allowance, never a different acceptance figure.
Which wall basis suits a 321 seamless tube order, average or minimum?
Minimum wall whenever the thickness comes out of a pressure calculation, because nothing then arrives under your figure. Average wall when the drawing quotes a nominal thickness and variation either way is acceptable. Whichever you pick is marked on the tube itself under A213, so the basis stays visible long after delivery.
Which extra heat treatments can be ordered on a seamless 321 tube?
Two, and each has to be named on the order. A stress-relieved anneal at 815 to 900 °C follows roll straightening, with no mechanical straightening after it, for chloride stress corrosion service. A stabilizing anneal is also listed for TP321, held under the solution anneal at whatever temperature we settle with you.
Is grade 321 or grade 347 the better stabilized seamless tube for a hot line?
Both are stabilized austenitic grades of A213. Titanium in 321 suits welded fabrications that cycle through the sensitizing range, while niobium in TP347, specified at ten times carbon up to 1.10% maximum, is the usual pick for a line that sits in that range for long periods. Send the duty and we will confirm.
Can a seamless 321 tube be solution treated hotter than 1065 °C?
It can, with one caution attached by A213: above 1065 °C the resistance to intergranular corrosion after a sensitizing exposure may be impaired, and a lower-temperature stabilization or re-solution anneal then follows when the order specifies it. Our standard treatment is 1040 °C (1900 °F) minimum with a rapid cool.
Is a spiral-welded version of grade 321 available for burner and flue duty?
Burner and flue work is served here as seamless 321 tube, made by the seamless process A213 requires and then cut and bent to the fabrication drawing. Oxidation resistance and titanium stabilization are what put the grade on that duty in the first place.
What appears on the certificate for a 321 seamless tube?
Chemistry leads: the heat analysis plus the product analysis A213 requires of every heat, with titanium read against carbon and nitrogen. Lot figures come next, four of them: tension, hardness, flattening, flaring. After those sit the per-tube test result and the anneal record. The level is EN 10204 3.1 (3.2 on request).
Request a Quote for Stainless Steel 321 Seamless Tubes
or email sales@thaida.co.th