Tube enquiries come to us differently than pipe enquiries. They arrive with a drawing attached. Metinox Overseas is a stainless steel 304 tube manufacturer and supplier in Mumbai, and most of what we produce against those drawings is heat exchanger, boiler and instrumentation tubing to ASTM A213, A249 and A269, shipped to fabricators across India, the USA, the Middle East and Africa. The grade is UNS S30400, the same 18-8 chemistry the industry runs on. What changes with tube is precision. Exact OD, exact wall, tolerances in tenths of a millimetre, because a tube that will not seat in a tube sheet is scrap. The full range starts on our Stainless Steel Tubes page.
And a caution that saves buyers money every week. Tube is not pipe. Tube sells on actual OD and wall thickness; pipe sells on nominal bore and schedule, with looser tolerances and a different price logic altogether. Order one when you need the other and the material arrives correct on paper, wrong on the bench. If your job is really NB-and-schedule work, our SS 304 Pipes page is where you want to be.
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What Is Stainless Steel 304 Tube?
In trade terms, stainless steel 304 tube is UNS S30400 (EN 1.4301, JIS SUS 304) supplied to a tube standard rather than a pipe standard, and the standard follows the job. A213 seamless tube goes into boilers, superheaters and heat exchangers. A249 is its welded counterpart for the same equipment. A269 covers general-service and instrumentation tube in both forms. A270 is sanitary tube for food, dairy and pharma with a polished bore. A554 is mechanical and ornamental tube, never pressure duty.
Walls are quoted in millimetres or in BWG, the old Birmingham gauge that heat exchanger people still speak fluently. 16 BWG is 1.65 mm, and a fabricator asking for three-quarter inch 16 gauge expects exactly that, not something close. We supply straight lengths, U-bends formed and stress relieved for exchanger bundles, coils for instrument runs, and bright annealed tube where the bore has to stay mirror clean. Long single lengths are worth asking about too. Every tube-to-tubesheet joint you delete from a bundle is a leak path that no longer exists.
ASTM A213 / A249 / A269 TP304 Tube Specifications
| Specification | Details |
|---|---|
| Material Grade | Stainless Steel 304 (TP304) |
| UNS Number | S30400 |
| EN / Werkstoff No. | 1.4301 (X5CrNi18-10) · JIS: SUS 304 |
| Standards | ASTM A213 / ASME SA213 (seamless boiler & heat exchanger) · A249 / SA249 (welded heat exchanger) · A269 (general service & instrumentation) · A270 (sanitary) · A554 (mechanical & ornamental) |
| Forms | Seamless, Welded (ERW), U-Bend, Coil |
| OD Range | 6.35 mm to 101.6 mm (¼" to 4") |
| Wall Thickness | 0.5 mm to 6 mm (20 BWG and heavier) |
| Length | Straight lengths to 6 m standard, longer against order; U-bends formed to drawing |
| Finish | Annealed & pickled · bright annealed · polished bore (A270) |
| Ends | Plain, deburred |
Every tube is supplied heat treated and traceable, with the test regime of its governing standard completed before dispatch.
Where 304 Stainless Steel Tube Works, and Where It Does Not
304 tube earns its default status in most exchanger and instrument work. It also fails in predictable places, so here is the straight version.
- Excellent in: fresh and demineralized cooling water, steam and condensate, food, dairy and brewery lines, instrument air and gas, and cryogenic duty down to -196°C.
- The U-bend caveat: forming leaves residual stress in the bend, and residual stress plus hot chlorides is exactly the recipe for stress corrosion cracking. Stress relieving the bends helps. Changing grade helps more.
- Cooling water reality: brackish or seawater condenser duty pits 304, sometimes within a season. It is the wrong tube for that water, full stop.
Where the water or the process stream carries chlorides, quote us the duty honestly and we will price SS 316/316L Tubes alongside, or Super Duplex UNS S32750 Tubes for seawater condensers where pitting resistance is the whole game. We stock all of them, so nothing pushes us to sell 304 into water it cannot survive.
Stainless Steel 304 Tube Applications
- Heat Exchangers & Condensers: straight and U-bend bundles to A213 and A249, the largest share of what we ship.
- Boilers & Superheaters: A213 tube, with 304H specified where sustained temperature calls for it.
- Instrumentation & Impulse Lines: A269 straight and coiled tube for Gulf EPC and refinery instrument packages.
- Food, Dairy & Brewery: A270 sanitary tube with polished bore for product-contact and CIP circuits.
- Sugar & Distillery: evaporator and juice heater tubing for mills across India and Africa.
- Pharmaceuticals: utility and process tubing in plants standardized on austenitic stainless.
- Automotive & General Engineering: A269 and A554 tube for fabrication and machine building.
- Architectural & Ornamental: A554 polished tube for railings, facades and interiors.
SS 304 Tube Testing, Certification & Export to USA, Middle East & Africa
Every tube is tested to ASTM A1016 general requirements: hydrostatic or eddy current examination on each length, plus the flattening, flaring and hardness tests its governing standard demands. Intergranular corrosion testing to ASTM A262 and PMI verification are done on request. An EN 10204 3.1 mill test certificate ships with every order, and 3.2 witnessed certification through BV, SGS or TUV can be arranged at order stage. Metinox Overseas is an ISO 9001 and PED certified company supplying material approved to the procurement standards of SABIC, ADNOC, KNPC, EIL, IOCL and BPCL, which is why Middle East EPC buyers already know our paperwork clears; the full program is on our Quality Policy page. Exports move in regular consolidations to the USA, the Middle East and Africa, with tubes crated, end-capped and packed as described on our Packing and Dispatch page. Ex-stock sizes dispatch in 7 to 14 working days. Made-to-order sizes and U-bend sets take 4 to 6 weeks.
Related SS 304 Products
- SS 304 Pipes – the NB-and-schedule side of the same grade
- SS 304L Tubes – low-carbon tube for as-welded service
- SS 304H Tubes – high-carbon tube for superheater and reheater duty
- SS 316/316L Tubes – the molybdenum upgrade for chloride-bearing water
- Bright Annealed Tube 316L (ASTM A269 BA) – mirror-bore tube for instrumentation and analytical lines
- Super Duplex UNS S32750 Tubes – seawater condenser and high-chloride exchanger tube
- SS 304 Flanges – matching flanges in the same grade
- SS 304 Pipe Fittings – buttweld fittings to ASTM A403 WP304
SS 304 Tubes: Frequently Asked Questions
Sizing and tolerance. Tube is ordered on actual OD and wall thickness and held to tighter tolerances; pipe is ordered on nominal bore and schedule. A 1 inch tube measures 25.4 mm outside, a 1 inch pipe measures 33.4 mm. The two are not interchangeable, and heat exchangers, instruments and tube sheets are all designed around tube.
It follows the job. A213 is seamless boiler, superheater and heat exchanger tube. A249 is the welded version for the same equipment. A269 covers general-service and instrumentation tube in both forms. Sanitary lines take A270, and ornamental or structural work takes A554.
Yes. U-bends are formed to drawing for exchanger bundles and can be stress relieved after bending, which matters because bend-zone residual stress is where chloride cracking likes to start. Coiled tube is supplied for instrumentation and impulse lines.
Yes, and it is the industry default. Order it as ASTM A270 sanitary tube with a polished bore for product-contact and CIP lines. For high-temperature CIP circuits using chlorinated cleaning agents, discuss the duty with us first; some plants step up to 316L there.
An EN 10204 3.1 mill test certificate with every order, heat-number traceable to A213, A249 or A269 as applicable. Test reports cover hydrostatic or eddy current examination plus the mechanical tests, and 3.2 witnessed certification through BV, SGS or TUV can be arranged for project orders.
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