SS 904L Pipe & TubeASTM A312 UNS N08904 · Manufacturer, stockist & exporter, India
Also sold as Alloy 904L · UNS N08904 · W.Nr 1.4539 · 2RK65
SS 904L pipe is supplied seamless to ASTM A312 (N08904) and welded to ASTM A312 (N08904), in ASME pipe sizes and schedules, with tube to ASTM A269 · A213 where supported (N08904). It is a super-austenitic stainless steel with high nickel, molybdenum and copper, chosen for dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water. Kanak Steel & Engineering Co. supplies it with EN 10204 3.1 mill certificates from Mumbai to buyers across India, the Gulf, South-East Asia, South America, Europe, the UK and the USA.
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is SS 904L Pipe & Tube?
SS 904L pipe & tube is a super-austenitic stainless steel with high nickel, molybdenum and copper supplied as pipe & tube to ASTM A312 (N08904) (UNS N08904). Buyers specify it for dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water. It is also sold as Alloy 904L, UNS N08904, W.Nr 1.4539.
- What it is
- Super-austenitic stainless steel with high nickel, molybdenum and copper
- Seamless
- ASTM A312 (N08904)
- Welded
- ASTM A312 (N08904)
- Sizes
- NPS ⅛" – 24" · OD tube to order
- Schedules
- 5S · 10S · 40S · 80S · 160 · XXS
- Best at
- Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water
SS 904L Pipe & Tube Specification & Sizes
| Seamless pipe | ASTM A312 (N08904) |
|---|---|
| Welded pipe | ASTM A312 (N08904) |
| Tube | ASTM A269 · A213 where supported (N08904) |
| Grade | SS 904L · UNS N08904 · W.Nr 1.4539 |
| Size & schedule | NPS ⅛" to 24" to ASME B36.19 / B36.10; OD × wall for tube |
| Length | Single random, double random, or cut lengths |
| Ends | Plain end · bevelled end (for welding) · threaded |
| Testing | Hydrostatic or eddy-current · PMI · flattening & flaring · IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
SS 904L Pipe: Seamless, Welded or Tube?
Three different specifications cover 904L tubular products. Pick the route first — it decides price, test requirements and lead time. General requirements (tolerances, hydrostatic or electric testing) come from ASTM A999. Schedules, the −12.5% wall tolerance and the B31.3 wall formula are explained in the pipe guide.
- 904L pipe is ordered to ASTM A312 (UNS N08904, often written TP904L), seamless or welded.
- Older piping classes may still name the nickel-alloy specifications B677 (seamless) or B673 / B674 (welded). Those listed N08904 in earlier editions; current editions do not, so confirm the edition with your client.
- State which specification your piping class names — they differ in testing and general requirements.
- Japanese projects specify SUS890L to JIS G 3459 (pipe) or G 3463 (tube) — see the Japan section below.
| Route | Specification | Use it for |
|---|---|---|
| Seamless pipe | ASTM A312 (N08904) | Pressure and critical service; no weld seam to inspect. |
| Welded pipe | ASTM A312 (N08904) | Economical in larger diameters and thinner walls where the code allows it. |
| Tube | ASTM A269 · A213 where supported (N08904) | Heat exchangers and instruments; ordered by exact OD × wall. |
904L Pipe for Japan — SUS890LTP / SUS890LTB
In Japan, 904L is SUS890L. Pipe is specified as SUS890LTP to JIS G 3459 and heat-exchanger tube as SUS890LTB to JIS G 3463. SUS890L is equivalent to UNS N08904, so material made to ASTM A312 can be offered with certificates showing both designations where your project accepts dual certification.
For shipments to Yokohama, Tokyo, Kobe, Osaka or Nagoya we send the EN 10204 3.1 certificate and PMI report; where the tariff line carries duty and you claim preference, we apply for the India–Japan CEPA certificate of origin from the issuing authority.
More on standards, documents and shipping: exporting to Japan.
| ASTM | JIS | |
|---|---|---|
| Grade | UNS N08904 (904L) | SUS890L |
| Seamless pipe | ASTM A312 (N08904) | JIS G 3459 · SUS890LTP |
| Heat-exchanger tube | ASTM A213 / A269 (N08904) | JIS G 3463 · SUS890LTB |
| Plate & sheet | ASTM A240 | JIS G 4304 / G 4305 · SUS890L |
SS 904L Pipe Wall & Weight by Schedule
For the same size, the schedule sets the wall — and the weight you pay for. Cross-sections are drawn to scale for 2" NPS (OD 60.33 mm, ASME B36.19); weights use the density of SS 904L, 7.95 g/cm³.
Other sizes: pipe schedule chart and weight calculator.
SS 904L Pipe & Tube Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel | As specified |
| Chromium | As specified |
| Molybdenum | As specified |
| Copper | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Nitrogen | As specified |
| Phosphorus | As specified |
| Sulphur | As specified |
| Iron | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A240 for UNS N08904.
SS 904L Pipe & Tube Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
| Hardness | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM A240 for UNS N08904 — Annealed plate & sheet.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 7.95 g/cm³ |
| Melting range | 1300 – 1390 °C |
| Magnetic | Non-magnetic (annealed) |
| PREN (approx.) | ≈ 35 |
SS 904L Equivalent Grades
SS 904L Pipe Weight Chart (kg/m)
Weight per metre (kg/m) = (OD − WT) × WT × 0.02498, with OD and wall thickness in mm. The factor comes from SS 904L's density of 7.95 g/cm³.
Example: 4" Sch 40S (114.30 × 6.02 mm)
(114.30 − 6.02) × 6.02 × 0.02498 = 16.28 kg/m
| NPS | OD mm | Sch 10S kg/m | Sch 40S kg/m |
|---|---|---|---|
| ½" | 21.34 | 1.01 | 1.28 |
| 1" | 33.40 | 2.12 | 2.53 |
| 2" | 60.33 | 3.98 | 5.51 |
| 3" | 88.90 | 6.54 | 11.44 |
| 4" | 114.30 | 8.47 | 16.28 |
| 6" | 168.28 | 14.00 | 28.62 |
| 8" | 219.08 | 20.22 | 43.09 |
Six-digit Harmonized System heading (iron and steel, chapter 72–73). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify SS 904L Pipe & Tube with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. SS 904L is most often mixed up with Inconel 825 — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen; those come from the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | SS 904L | Inconel 825 |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | As specified | As specified |
| Copper | As specified | As specified |
| Titanium | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
SS 904L Pipe & Tube Price — What Decides It
Two quotes for "904L pipe & tube" can differ by 20% and both be fair. We quote 904L pipe & tube per kg for full sizes and per piece for cut sizes. These six things move the price per kg, so you can compare offers like for like.
SS 904L Pipe & Tube Applications
SS 904L is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
SS 904L Pipe & Tube vs 316L, 2205 and 825
| Grade | Pipe & Tube standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| SS 316 / 316L | ASTM A312 TP316L | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| Inconel 825 | ASTM B423 | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| Duplex 2205 | ASTM A790 | ≈ 35 | Strength with chloride resistance at a stainless-steel budget |
| SS 904L | ASTM A312 (N08904) | ≈ 35 | Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
SS 904L Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 904L fits.
Elevated nickel gives far better resistance to chloride cracking than 316L.
Molybdenum lifts pitting resistance well above ordinary austenitic grades (screening PREN on the grade page).
Copper is what makes 904L the stainless steel of choice for dilute sulphuric acid.
Very low carbon limits carbide precipitation, so welds keep their corrosion resistance.
How your 904L pipe & tube order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI before processing is available on request.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Standards on this page
Welding & Fabricating SS 904L Pipe & Tube
SS 904L welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ER385 (AWS A5.9) |
|---|---|
| Over-alloyed filler | ERNiCrMo-3 for severe chloride service |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 904L fittings and 904L flanges for the matching pipe-system parts.
How to Order SS 904L Pipe & Tube: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Seamless or welded, and the standard
- NPS and schedule (or OD × wall for tube)
- Length — random or cut, and number of lengths
- End finish — plain, bevelled or threaded
- Certificate type and extra tests
- Delivery port, Incoterm and required date
SS 904L pipe & tube for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 904L pipe & tube — questions buyers ask
Is SS 904L the same as Alloy 904L?
Alloy 904L, UNS N08904, W.Nr 1.4539 are names used for SS 904L (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order), and pipe & tube is ordered to ASTM A312 (N08904) whichever name is on the enquiry.
What is the difference between SS 904L pipe and tube?
Pipe is ordered by nominal pipe size and schedule, for carrying fluids. Tube is ordered by exact outside diameter and wall, for heat exchangers and instruments, and is held to tighter tolerances.
Seamless or welded SS 904L pipe — which should I buy?
Seamless (ASTM A312 (N08904)) is the default for pressure and critical service. Welded (ASTM A312 (N08904)) is cheaper in larger diameters and thinner walls and is accepted where the design code allows it.
What is the wall-thickness tolerance on SS 904L pipe?
Seamless pipe is normally allowed −12.5% on nominal wall under its general-requirements standard (ASTM A999). Allow for it in the pressure calculation or order on minimum wall.
Can SS 904L pipe be welded to carbon-steel pipe?
Yes, with the right filler: ER309L (or E309L electrode) is the usual filler when joining it to carbon steel. Follow a qualified WPS.
Is 904L the same as SUS890L?
They are equivalent: SUS890L is the Japanese (JIS) designation corresponding to UNS N08904, with minor differences in limits. Pipe is SUS890LTP to JIS G 3459; tube is SUS890LTB to JIS G 3463.
SS 904L or Inconel 825 — which should I choose?
SS 904L is chosen for dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water. Inconel 825 is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026