We are Riddhi Siddhi Impex, a Mumbai-based manufacturer and supplier of Stainless Steel 439 Foils, established in 2002. Our own slitting lines cut source coil into titanium-stabilised ferritic foil to ASTM A240 / ASME SA-240, from 0.03 mm to 0.08 mm thick. Our ISO 9001, 14001, and 45001 certified company keeps a ready stock with a supply capacity of 400-500 tonnes for a month and also provides EN 10204 Type 3.1 / 3.2 certificates on request.
Stainless Steel 439 foil is a thin-gauge ferritic stainless steel holding 17 to 19% chromium, stabilised with titanium. The titanium binds carbon and nitrogen as carbonitrides, so welded joints resist intergranular attack with no post-weld anneal. Nickel stays at 0.50% max, shielding these Stainless Steel Foils from chloride stress corrosion cracking. That near-zero nickel content keeps its price under austenitic foil, while corrosion resistance is close to Type 304. Typical uses of Stainless Steel 439 foil include heat exchangers, automotive mufflers, appliance trim, and catalytic converter components.
As a reliable 439 stainless steel foil supplier, we slit every coil of 439 ferritic stainless steel foil in-house from Stainless Steel coil, never buying in finished narrow stock. Material ships annealed soft to ASTM A240; the grade is ferromagnetic and carries no hardness temper ladder. Gauges reach the ultra-thin range below 0.10 mm, in widths from 3 mm to 2000 mm, and four surface finishes.
We provide ASTM A240 Type 439 Foil in the annealed soft condition, slit from ready stock to your exact width, with the finish, edge, and coil dimensions listed below.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240 |
| Thickness | 0.03 mm to 0.08 mm |
| Width | 3 mm to 2000 mm (custom slit) |
| Width Tolerance | ±0.1 mm |
| Condition | Annealed (Soft) |
| Surface Finish | 2B, BA (Bright Annealed), Matte, Scotch-Brite |
| Edge | Slit edge, Deburred edge, Round edge, Mill edge |
Chromium provides the corrosion resistance in Type 439 stainless steel foil, and titanium keeps it available: the 0.20 + 4(C+N) minimum captures interstitials before they form chromium carbides at weld seams.
| Element | Composition (% by weight) |
|---|---|
| Carbon (C) | 0.030 max |
| Manganese (Mn) | 1.00 max |
| Phosphorus (P) | 0.040 max |
| Sulphur (S) | 0.030 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 17.00 to 19.00 |
| Nickel (Ni) | 0.50 max |
| Titanium (Ti) | 0.20 + 4(C+N) min, 1.10 max |
| Nitrogen (N) | 0.030 max |
| Iron (Fe) | Balance |
| Aluminium (Al) | 0.15 max |
Type 439 Foil offers formability. Annealed material pairs a 415 MPa minimum tensile strength with 22% elongation, so it presses and folds cleanly. Below roughly 0.38 mm, treat elongation as indicative; the foil ships soft only.
| Property | Value (Annealed) |
|---|---|
|
Tensile Strength, minimum
|
415 MPa (60 ksi) |
|
Yield Strength (0.2% offset), minimum
|
205 MPa (30 ksi) |
|
Elongation in 50 mm, minimum
|
22% |
|
Hardness, maximum
|
89 HRB |
Buyers ordering against a regional code can match UNS S43035 Foil to the designations below. Each row covers the same titanium-stabilised 17 to 19% chromium ferritic analysis.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S43035 |
| Europe (EN) | X3CrTi17 |
| Germany (W.Nr) | 1.4510 |
| Japan (JIS) | SUS430LX |
| China (GB) | 06Cr17Ti |
4 industries widely utilise 439 stainless steel foil issued from our slitters: automotive exhaust, heat exchange, gasket stamping, and architectural trim.
Exhaust fabricators wrap Type 439 foil into flexible coupling liners, cold-end silencer internals, and converter heat barriers. Chromium at 17 to 19% holds surface oxidation back through repeated thermal cycles, and the stabilised chemistry keeps spot and helps maintain ductility in spot and seam welds. One caution applies: prolonged soaking near 475 °C embrittles any ferritic grade through alpha-prime precipitation.
Water-heater and heat-exchanger builders specify SS 439 foils for fins, baffle wraps, and tank liners. Ferritic steel conducts heat faster than austenitic alternatives and expands less on heating, so brazed thin-gauge assemblies stay flat in service. The stabilised surface performs well in typical hot chlorinated water service found in water-heating systems.
Gasket producers press exhaust flange seals, sensor housings, and layered sealing beads from annealed AISI 439 Foil. The 22% minimum elongation survives sharp bend radii. A width slit to ±0.1 mm feeds straight into progressive dies with no secondary trimming, and gauges under 0.10 mm stack into multi-layer beads.
Interior fit-out contractors edge panels, lift surrounds, and signage with bright-annealed 439 foil. The BA surface keeps its tone indoors, and the magnetic ferritic base suits clip fixing. Nickel-free chemistry prices the trim below austenitic equivalents, with deburred or round edges safe to handle.
Foil coils are issued from our Taloja and Mumbai warehouses in export-worthy packing, booked by sea.
| 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 / 3.2 on request |
Stainless Steel 439 foils in India are typically around ₹135-₹265 per kg, while export buyers generally pay about $1.6-$3.2 per kg. Ferrochrome surcharges move the market month to month, while thickness, width, finish, and quantity set the final rate. WhatsApp or call us for today's quotation.
We manufacture SS 439 foils from 0.03 mm to 0.08 mm thick, slit to any width between 3 mm and 2000 mm at ±0.1 mm tolerance.
439 stainless steel foil carries 17 to 19% chromium against 10.5 to 11.7% in 409, so it resists oxidation and staining at higher temperatures and costs a little more per kg.
Yes, Stainless Steel 439 Foils can be welded without post-weld annealing. Titanium stabilisation stops chromium carbide formation in the heat-affected zone, so joints keep their corrosion resistance as welded.
SS 439 foil is ferromagnetic in every condition. The body-centred cubic ferritic structure stays magnetic whether the material is annealed or skin-passed.
2B, BA (Bright Annealed), Matte, and Scotch-Brite finishes are available on 439 foil, paired with slit, deburred, round, or mill edge conditions.
You can buy Stainless Steel 439 Foils in India from us at Riddhi Siddhi Impex. Mumbai and Taloja stock covers standard gauges, and quotes will be provided within 24 hours. Call or WhatsApp our team with your size.
