We are Riddhi Siddhi Impex, a Mumbai-based Stainless Steel 904L Foils manufacturer, supplier, and exporter, established in 2002. We slit UNS N08904 super austenitic foil to ASTM A240 / ASME SA-240 in gauges of 0.03 mm to 0.08 mm, while the width is held to ±0.1 mm tolerance. Our ISO 9001, 14001, and 45001-certified company carries ready stock, a supply capacity of 400-500 tons monthly, and EN 10204 Type 3.1 / 3.2 mill test certificates on request.
Stainless Steel 904L foil is thin-gauge, cold rolled stock of a super austenitic grade alloyed with 23 to 28% nickel, 19 to 23% chromium, 4 to 5% molybdenum, and 1 to 2% copper. Metallurgists balanced that chemistry for dilute sulphuric acid duty, and the copper addition holds the passive film where 316L corrodes freely. Fabricators use this material alongside standard stainless steel foils in spiral-wound gaskets and press it into diaphragms for phosphoric and sulphuric duty. Stainless Steel 904L foil is typically used to manufacture chemical diaphragms, heat exchangers, and gaskets for severe acidic environments.
As a reliable stainless steel 904L foil supplier, our slitting lines process every 904L foil in-house from source coils sourced from reputed primary mills. Material ships solution annealed to ASTM A240, cut anywhere between 3 mm and 2000 mm wide, with BA, 2B, and Matte surfaces and four edge options. Each coil carries traceability back to its heat, certified on request.
We provide SS 904L foil in annealed soft condition, cold rolled and precision-slit, with three surface finishes and four edge conditions, supplied in foil in custom slit widths.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240 |
| Thickness | 0.03 mm to 0.08 mm |
| Width | 3 mm to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Condition | Annealed (Soft) |
| Surface Finish | BA (Bright Annealed), 2B, Matte |
| Supply Forms | Cold rolled (CR), precision slit |
| Edge | Slit edge, Mill edge, Deburred edge, Round edge |
Nickel defines this grade. At 23.0 to 28.0%, UNS N08904 foil keeps a fully austenitic structure that resists chloride stress corrosion cracking, while molybdenum and copper hold the surface passive in reducing acids. Carbon is at 0.020% max to protect weld zones.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.020 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulphur (S) | 0.035 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 19.0 - 23.0 |
| Nickel (Ni) | 23.0 - 28.0 |
| Molybdenum (Mo) | 4.0 - 5.0 |
| Copper (Cu) | 1.0 - 2.0 |
| Nitrogen (N) | 0.10 max |
Ductility matters more than raw strength at foil gauges. Annealed ASTM A240 904L foil pairs 35% minimum elongation with 490 MPa tensile strength, so it wraps, winds, and presses without tearing. We ship it solution annealed only, and figures at very thin gauges are indicative.
| Property | Value |
|---|---|
|
Tensile Strength, minimum
|
490 MPa (71 ksi) |
|
Yield Strength (0.2% offset), minimum
|
220 MPa (31 ksi) |
|
Elongation in 50 mm, minimum
|
35% |
|
Hardness, maximum
|
90 HRB |
Alloy 904L foil answers to a different designation in each region. Match your specification against the table below; every row names the same copper-bearing super austenitic stainless steel.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | N08904 |
| Europe (EN) | X1NiCrMoCu25-20-5 |
| Germany (W.Nr.) | 1.4539 |
| Japan (JIS) | SUS890L |
| Sweden (SS) | 2562 |
These 4 industries specify the bulk of the EN 1.4539 foil we slit. Each one specifies the grade where sulphuric, phosphoric, or chloride-bearing media would destroy a standard austenitic foil.
Phosphoric acid plants making fertiliser work with some of the harshest process chemistry anywhere. 904L foil goes into gasket windings, expansion bellows, and instrument diaphragms across these circuits. It's 4 to 5% molybdenum, backed by copper, that keeps the foil passive in acid concentrations that perforate 316L within months.
Clean-in-place cycles hit pharma and food equipment with hot caustic and chloride sanitisers every day. SS 904L foil seals, diaphragms, and flexible connectors withstand repeated cleaning and thermal cycles without shedding corrosion products into the batch. Carbon capped at 0.020% keeps the structure stable through repeated cleaning and thermal cycles.
Refinery alkylation and amine units combine acids, chlorides, and heat in one stream. 904L foil suits gasket windings and sensing elements here because it resists the chloride stress corrosion cracking that splits ordinary austenitic foil under load, helping to maintain sealing performance between maintenance turnarounds.
Bleach plants circulate chlorine dioxide and hot acidic filtrate around the clock. Mills fit UNS N08904 foil in washer seals, gasketing, and sampling hardware through the bleaching sequence, where it outlasts 316 several times over without the cost of a full 6Mo alloy.
Foil coils are issued from Mumbai and Taloja, boxed in wooden cases or strapped to pallets, sea-worthy.
| Parameter | Details |
|---|---|
| Packaging | Wooden cases, pallet packing |
| Incoterms | FOB, CIF, CFR, EXW |
| Dispatch Points | Mumbai and Taloja warehouses |
| Port | Mumbai |
| Standard Lead Time | 4 to 5 days |
| Urgent Dispatch | 2 to 3 days |
| Payment Terms | Advance, credit, LC |
| Certification | EN 10204 Type 3.1 / 3.2 on request |
Stainless Steel 904L foils cost about ₹1,300-₹1,500 per kg in India, roughly $13.5-$15.7 per kg for export buyers. Thin gauges generally cost more to produce than standard thicknesses, and rates move with nickel, molybdenum, and copper markets, along with width, finish, and quantity. Call or WhatsApp us for a current quotation.
We offer Stainless Steel 904L Foils in thicknesses of 0.03 mm to 0.08 mm, slit to any width from 3 mm to 2000 mm at ±0.1 mm tolerance.
Stainless Steel 904L Foils are covered by ASTM A240 / ASME SA-240, the flat-rolled specification for this grade. We certify each consignment to it, with EN 10204 Type 3.1 / 3.2 documents on request.
Stainless Steel 904L Foils outperform 316L foils wherever sulphuric or phosphoric acid is present. Roughly double the nickel, more molybdenum, and a 1 to 2% copper addition give 904L a pitting resistance number near 35 against about 25 for 316L.
Stainless Steel 904L Foils do come in BA (Bright Annealed) finish, alongside 2B and Matte options. Any of them pairs with slit, mill, deburred, or round edges.
You can source Stainless Steel 904L Foils in India directly from us at Riddhi Siddhi Impex. We hold N08904 foil at our Mumbai warehouse ready for dispatch and export worldwide as a supplier, stockist, and dealer. Call or WhatsApp us, and your quote will be provided within 24 hours.
