SS 904L CoilASTM A240 UNS N08904 · Manufacturer, stockist & exporter, India
Also sold as Alloy 904L · UNS N08904 · W.Nr 1.4539 · 2RK65
SS 904L coil is supplied as full-width mother coil, slit coil or precision strip to ASTM A240. 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 every heat
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is SS 904L Coil?
SS 904L coil is a super-austenitic stainless steel with high nickel, molybdenum and copper supplied as coil to ASTM A240 (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
- Standard
- ASTM A240
- Forms
- Mother coil · slit coil · strip
- Density
- 7.95 g/cm³
- Finish
- 2B · BA · No.4
- Best at
- Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water
SS 904L Coil Specification & Sizes
| Material standard | ASTM A240 |
|---|---|
| Grade | SS 904L |
| Thickness | 0.1 mm to 6 mm, depending on mill route |
| Width | Mill width, or slit from 10 mm upwards |
| Coil weight & ID | To order — state maximum coil weight and inner diameter |
| Finish | 2B · BA · No.4 · 2D |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
SS 904L Coil: Slitting & Cut-to-Length Specification
904L coil is bought for a production line, so state thickness, slit width, inner diameter and maximum coil weight with the grade.
| Standard | ASTM A240 |
|---|---|
| Thickness tolerance | Per ASTM A480 |
| Finish | 2B · BA · No.4 · 2D |
ID, coil weight, edge, camber and interleaving: see the coil guide.
SS 904L Coil Chemical Composition
| Element | Weight % |
|---|---|
| Nickel | 23.0 – 28.0 |
| Chromium | 19.0 – 23.0 |
| Molybdenum | 4.0 – 5.0 |
| Copper | 1.0 – 2.0 |
| Carbon | 0.020 max |
| Manganese | 2.00 max |
| Silicon | 1.00 max |
| Nitrogen | 0.10 max |
| Phosphorus | 0.045 max |
| Sulphur | 0.035 max |
| Iron | Balance |
SS 904L Coil Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 490 MPa · 71 ksi |
| Yield strength 0.2% | 220 MPa · 31 ksi |
| Elongation | 35% |
| Hardness | 90 HRB max |
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
Values follow ASTM A240 for UNS N08904. Always check against the edition named on your purchase order.
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 Coil 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. We PMI-test nickel alloys as standard and any grade on request.
| Element | SS 904L | Inconel 825 |
|---|---|---|
| Nickel | 23.0 – 28.0 | 38.0 – 46.0 |
| Chromium | 19.0 – 23.0 | 19.5 – 23.5 |
| Molybdenum | 4.0 – 5.0 | 2.5 – 3.5 |
| Copper | 1.0 – 2.0 | 1.5 – 3.0 |
| Titanium | residual | 0.6 – 1.2 |
| Iron | Balance | 22.0 min |
| Manganese | 2.00 max | 1.0 max |
SS 904L Coil 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 Coil vs 316L, 2205 and 825
| Grade | Coil standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| SS 316 / 316L | ASTM A240 | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| Inconel 825 | ASTM B424 | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas |
| Duplex 2205 | ASTM A240 | ≈ 35 | Strength with chloride resistance at a stainless-steel budget |
| SS 904L | ASTM A240 | ≈ 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.
About 25% nickel gives far better resistance to chloride cracking than 316L.
4–5% molybdenum lifts pitting resistance to a PREN of about 35.
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 coil order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked and material is PMI-tested before processing.
- 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.
Welding & Fabricating SS 904L Coil
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 Coil: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Thickness and width
- Coil weight and inner diameter
- Finish and edge (mill or slit)
- Certificate type
- Delivery port and date
SS 904L coil for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 904L coil — questions buyers ask
Is SS 904L the same as Alloy 904L?
Yes. Alloy 904L, UNS N08904, W.Nr 1.4539 all refer to the same material, and coil is ordered to ASTM A240 whichever name is on the enquiry.
Can SS 904L coil be slit to width?
Yes. Coils can be slit to narrow widths for stamping, tube making and spring work; state width tolerance and coil weight on the enquiry.
What inner diameter do SS 904L coils have?
508 mm (20") and 610 mm (24") are the common IDs. Tell us your decoiler ID and maximum coil weight and we slit to suit.
Can I order SS 904L cut-to-length sheets from coil?
Yes. Coil can be levelled and cut to length; state length tolerance and flatness.
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