We are Riddhi Siddhi Impex, a Mumbai-based Stainless Steel 304 Foils manufacturer, supplier, and stockist, established in 2002. We supply AISI 304 stainless steel foil produced from strip conforming to ASTM A240 / ASME SA-240 (annealed) and ASTM A666 (cold-worked tempers), in thicknesses from 0.03 mm to 0.08 mm. Our ISO 9001, 14001, and 45001-certified facility keeps ready stock, with a monthly supply capacity of 400 to 500 tonnes across our product range, and issues EN 10204 Type 3.1 mill test certificates as standard, with Type 3.2 on request.
Stainless Steel 304 foils are thin-rolled flat products of austenitic chromium-nickel steel, traded as 18/8 stainless steel foil for its 18.0 to 20.0% chromium and 8.0 to 10.5% nickel. The grade offers corrosion resistance in food processing, atmospheric exposure, and mild chemical environments. It resists oxidation in intermittent service up to about 870 °C and in continuous service up to about 925 °C, draws deeply, and responds well to bright annealing. Designers specify 304 SS foil for gasket layers, shielding, liners, and flat spring elements wherever a thin, corrosion-resistant material is required.
Each foil we offer undergoes processing on our own slitting lines in Mumbai. Material leaves in six temper conditions, from Soft (annealed) through Spring, with BA, 2B, Scotch-Brite, Matte, Matte PVC, or Skin Pass surfaces. Quality records track each order from source coil to final dispatch.
Temper is the first detail we confirm on every enquiry after grade and thickness, because it decides how far the foil can be formed before it cracks. Each cold rolling pass beyond the anneal raises strength and reduces ductility. We stock SS 304 foil in six conditions. Quarter hard and half hard carry ASTM A666 minimums; the three harder conditions are mill tempers rolled to tensile ranges agreed at order stage, since A666 stops at half hard for grade 304.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240 (annealed); ASTM A666 (1/4H, 1/2H); harder tempers to agreed values |
| General Requirements | ASTM A480 |
| Thickness | 0.03 mm to 0.08 mm |
| Width | 3 mm to 2000 mm (width availability depends on thickness) |
| Width Tolerance | ±0.1 mm on narrow slit widths |
| Condition | Soft (Annealed), 1/4 Hard, 1/2 Hard, 3/4 Hard, Full Hard, Spring |
| Surface Finish | BA (Bright Annealed), 2B, Scotch-Brite, Matte, Matte PVC, Skin Pass |
| Edge | Slit edge, Mill edge, Deburred edge, Round edge |
Soft 304 foil suits work that involves folding, pleating, or drawing. The annealed condition pairs the grade's 75 ksi (515 MPa) tensile floor with the highest ductility of the range, so it forms into corrugated tower packing and conforms to uneven gasket flanges. Dairy and pharmaceutical fabricators usually order it with a BA finish for cleanability. Soft foil is prone to denting during handling, so we interleave paper on narrow slit coils before dispatch.
Quarter hard 304 foil suits parts that must stay flat after blanking, a common limitation of soft foil. A light cold reduction lifts tensile strength to 125 ksi (860 MPa) minimum with 75 ksi (515 MPa) yield under ASTM A666, while the foil still accepts moderate bends and shallow draws. EMI shielding cans, formed shim blanks, and trim sections are produced in this temper. For deep drawing, soft foil remains the better choice, as quarter hard tends to thin during the draw.
Half hard is the strongest 304 temper covered by an ASTM A666 certificate; the standard stops at this condition for the grade. It carries 150 ksi (1035 MPa) minimum tensile strength against 110 ksi (760 MPa) yield. The temper blanks cleanly with minimal burr, which makes it a regular choice for washer and flat shim production. Bends should be kept simple with generous radii, and tooling should allow for springback, which is noticeably higher than in quarter hard.
Three quarter hard sits outside ASTM A666 for grade 304, so we supply it as a mill temper with the tensile target, typically towards 175 ksi (1207 MPa), agreed at order stage and reported on the EN 10204 certificate. It is generally selected for stiffener strips and flat spring elements where a higher strength level is needed than half hard provides. The temper should be treated as a flat product; bending beyond a slight deflection risks cracking along the bend line.
Full hard 304 foil is supplied as a mill temper rolled towards 185 ksi (1276 MPa), with the agreed minimum recorded on the test certificate rather than drawn from a standard table. Feeler stock, doctor blades, flat shims, and wear liners use it exactly as slit, without further forming. One point we state clearly to buyers: where a design needs full hard strength together with guaranteed elongation, grade 301 is the correct selection, because A666 publishes full hard minimums for 301 and not for 304.
Spring temper is the hardest condition we produce in grade 304, and the least standardised: no ASTM table covers it for this grade, so the tensile target, typically towards 190 to 200 ksi, is agreed before the coil is scheduled. The temper resists taking a permanent set under load, which suits spring contacts, snap elements, and retaining clips formed flat or nearly flat. Most spring applications are still supplied in grade 301; buyers select 304 spring temper when the end user's specification is written around 304 chemistry.
Specifications of Stainless Steel 304 Foils
We provide Type 304 foil in six tempers, six surface finishes, and four edge options, delivered as SS 304 foil coil. Annealed material is certified to ASTM A240; quarter hard and half hard to ASTM A666; harder tempers to tensile ranges agreed at order stage.
Chromium builds the passive oxide film on 304 SS foil. The 18.0 to 20.0% band reforms that layer after scratching, while 8.0 to 10.5% nickel keeps the structure austenitic. Nickel is shown to the tighter ASTM A666 window; the current edition of ASTM A240 permits 8.0 to 11.0% for this grade.
| Element | Composition (% by weight) |
|---|---|
| Carbon (C) | 0.08 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulphur (S) | 0.030 max |
| Silicon (Si) | 0.75 max |
| Chromium (Cr) | 18.0 to 20.0 |
| Nickel (Ni) | 8.0 to 10.5 |
| Nitrogen (N) | 0.10 max |
| Iron (Fe) | Balance |
Annealed Type 304 foil pairs 515 MPa minimum tensile strength with 40% elongation on standard gauges. Cold work lifts strength through the tempers: 1/4 hard and 1/2 hard carry ASTM A666 minimums, while 3/4 hard, full hard, and spring are mill tempers rolled to agreed values. ASTM A666 publishes separate, lower elongation minimums for gauges under 0.38 mm; where the standard publishes a thin-gauge value we show it, and mill-temper figures are indicative.
| Temper | Tensile strength | Yield strength | Elongation | Hardness (indicative) |
|---|---|---|---|---|
|
Annealed (A240/A666)
|
75 ksi min (515 MPa) | 30 ksi min (205 MPa) (standard gauges) | 40% (standard gauges); 20% min in 25.4 mm below 0.38 mm (A240) | 92 HRB max |
|
1/4 hard (A666)
|
125 ksi min (860 MPa) | 75 ksi min (515 MPa) | 10% min below 0.38 mm (A666) | ≈ HRC 20 to 25 |
|
1/2 hard (A666)
|
150 ksi min (1035 MPa) | 110 ksi min (760 MPa) | 6% min below 0.38 mm (A666) | ≈ HRC 25 to 32 |
|
3/4 hard (mill temper)
|
towards 175 ksi (1207 MPa), as agreed | as agreed | ~3% (indicative) | ≈ HRC 32 to 37 |
|
Full hard (mill temper)
|
towards 185 ksi (1276 MPa), as agreed | as agreed | ~1% (indicative) | ≈ HRC 37 to 42 |
|
Spring (mill temper)
|
towards 190 to 200 ksi, as agreed | as agreed | ~1% (indicative) | ≈ HRC 42+ |
Procurement teams abroad can match AISI 304 stainless steel foil or SUS 304 foil against their regional standard here. The foil we stock corresponds to the designations shown for cross-reference.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S30400 (AISI 304) |
| Europe (EN) | X5CrNi18-10 |
| Germany (W.Nr) | 1.4301 |
| Japan (JIS) | SUS 304 |
| China (GB) | 06Cr19Ni10 |
| UK (BS) | 304S31 |
| Russia (GOST) | 08Kh18N10 (08Х18Н10) |
These five industries use most of the 304 stainless steel foil leaving our slitters. Buyers in each one balance hygiene, formability, and heat tolerance against strength when they pick this grade.
Exhaust heat shields, sensor housings, and shim stock consume Alloy 304 foil in vehicle plants. The grade holds strength through repeated thermal cycling. Annealed coil can be ordered with AMS 5513 traceability, subject to availability, for airframe and engine work, while hardened tempers serve as flat spring and shim material. Every heat ships with a mill test certificate.
Dairies, breweries, and packaging plants line contact surfaces with 304 stainless steel foil. The grade is accepted for food-contact use under FDA and EU frameworks. The surface withstands hot caustic washdowns, and the metal does not taint flavour. Conveyor wear strips and hygienic enclosure panels use the same material.
Surgical instrument components and pharmaceutical equipment liners start as precision-slit SS 304 foil. Cleanability drives the choice here. A BA surface leaves no crevice for residue, and the alloy survives repeated autoclave sterilisation. Diaphragms and instrument shims in the harder tempers hold their shape through repeated handling.
EMI shielding cans, spring contacts, and camera components rely on Type 304 foil across the electronics sector. Thin gauge matters most here. At 0.03 mm thickness, the foil screens stray fields and will not add measurable weight to a board. Watch and instrument makers run the same coils for bands and diaphragms.
Heat exchanger liners, bellows, gasket cores, and tower packing all begin as 304 SS foil in chemical plants. The chromium oxide film handles most process media, and the foil folds into corrugated packing shapes. Where chlorides concentrate, we advise 316 foil instead.
As a Stainless Steel 304 Foils exporter, we ship to 60+ countries from Mumbai and Taloja in sea-worthy packing.
| Parameter | Details |
|---|---|
| Packaging | Wooden cases, pallet packing |
| Incoterms | FOB, CIF, CFR, EXW Mumbai |
| Dispatch Points | Mumbai and Taloja warehouses |
| Standard Lead Time | 4 to 5 days |
| Urgent Dispatch | 2 to 3 days |
| Payment Terms | Advance, credit, LC |
| Certification | EN 10204 Type 3.1 standard; Type 3.2 on request |
Stainless Steel 304 foils in India sit around ₹150 to ₹250 per kg for standard items, which converts to roughly $1.8 to $3.0 per kg for export enquiries. Thin gauges and hard tempers occupy the upper end. Thickness, width, finish, and quantity all affect the final price, so WhatsApp us for the current rate.
We stock SS 304 foil in thicknesses from 0.03 mm to 0.08 mm, slit to widths between 3 mm and 2000 mm depending on gauge. Thicker gauges fall under our stainless steel 304 strips range.
304 stainless steel foil can be supplied in six temper conditions: Soft (annealed), 1/4 Hard, 1/2 Hard, 3/4 Hard, Full Hard, and Spring. Cold reduction sets each temper. The mill test certificate records tensile values to ASTM A666 for 1/4 hard and 1/2 hard, and to the agreed order values for the harder mill tempers.
The main difference between SS 304 foil and SS 316 foil is molybdenum, which SS 316 carries for chloride and pitting resistance. 304 costs less and performs well in atmospheric, food-contact, and mild chemical service.
You can source Stainless Steel 304 Foils in India from us at Riddhi Siddhi Impex. We keep ready stock in our Mumbai warehouse and dispatch in 4 to 5 days, or 2 to 3 days when urgent. As a manufacture, r supplier, exporter, and stockist, we serve buyers across India and overseas. Phone or WhatsApp us; we provide a quotation within 24 hours.
