We are Riddhi Siddhi Impex, a Mumbai-based Stainless Steel 309 Strips manufacturer and supplier, established in 2002. Our slitting lines produce UNS S30900 strip to ASTM A240 / ASME SA-240 in any width from 3 mm. As an ISO 9001, 14001, and 45001-certified company, we hold ready stock with a monthly supply capacity of 400-500 tonnes. We also provide EN 10204 Type 3.1 / 3.2 mill test certificates, shipped with orders on request.
Stainless Steel 309 strip belongs to a class of high-performance stainless steel strips, serving as a heat-resisting austenitic grade built around 22.0 to 24.0% chromium with 12.0 to 15.0% nickel. That chemistry grows a tight chromium oxide scale which holds to roughly 1095°C in continuous service and 980 °C where temperatures cycle. Density near 8.0 g/cm³. Typical uses of Stainless Steel 309 winding strip include furnace parts, heating elements, aircraft components, and high-temperature chemical processing equipment.
As a reliable 309 stainless steel strip supplier, we source the stainless steel coil and do the slitting ourselves. Material ships annealed to ASTM A240 in gauges from 0.03 mm to 5 mm and widths to 2000 mm. Inspection records follow each order from incoming coil to despatch, and Mumbai ready stock covers standard sizes.
We provide ASTM A240 Grade 309 strip in the annealed soft condition, with five finishes and four edge choices, precision-slit to width on our Mumbai lines.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240, ASTM A480, AMS 5523 |
| Thickness | 0.03 mm to 5 mm |
| Width | 3 mm to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Condition | Annealed (Soft) |
| Surface Finish | BA (Bright Annealed), 2B, Scotch-Brite, Matte, Matte PVC |
| Edge | Slit edge, Mill edge, Deburred edge, Round edge |
| Supply form | Hot rolled and Cold rolled |
Chromium carries this grade. At 22.0 to 24.0%, it rebuilds the protective scale faster than hot gas strips it, while 12.0 to 15.0% nickel keeps the structure fully austenitic. A240 limits follow.
| Element | Composition (%) |
|---|---|
| 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) | 22.0 to 24.0 |
| Nickel (Ni) | 12.0 to 15.0 |
| Iron (Fe) | Balance |
Annealed Type 309 strip opens at 515 MPa minimum tensile with 40% elongation, so it bends and draws without cracking. No spring-temper ladder applies here; the grade ships soft as standard.
| Property | Value |
|---|---|
|
Tensile Strength, minimum
|
515 MPa (75 ksi) |
|
Yield Strength (0.2% offset), minimum
|
205 MPa (30 ksi) |
|
Elongation in 50 mm, minimum
|
40% |
|
Hardness (Brinell), maximum
|
217 HBW |
|
Hardness (Rockwell B), maximum
|
95 HRB |
Cross-referencing SS 309 strips against regional standards is shown in the table given below. ASTM A240 lists the flat-rolled product under the 309S designation, UNS S30900, which our strip meets.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S30900 |
| Europe (EN) | X12CrNi23-13 |
| Germany (W.Nr) | 1.4833 |
| Japan (JIS) | SUS 309 |
| China (GB) | 06Cr23Ni13 |
| Russia (GOST) | 10Х23Н13 |
These 4 industries utilise 309 stainless strips we slit. Each one pays the chromium premium for scale resistance that 304 and 316 sections lose above 870 °C.
Heat treaters form SS 309 strip into conveyor belts, carburising baskets, radiant tube supports, and annealing box seals. Scale that flakes off the leaner grades contaminates the charge. On this grade, the oxide film stays anchored through door openings, quench cycles, and long soaks at temperature.
Boiler builders specify Alloy 309 strip for baffles, damper seals, burner shrouds, and superheater shielding exposed to combustion gas. The 12.0 to 15.0% nickel content resists thermal fatigue as load swings, which matters in plants that cycle daily.
Refineries and chemical plants fit Type 309 strips around fired heaters, sulphur recovery units, and flue ducting. Hot oxidising gas with moderate sulphur attacks low-alloy steel quickly. Thin slit sections of this grade line those zones at a fraction of nickel superalloy cost.
Exhaust fabricators wind 309 stainless strips into flexible bellows, heat shields, and manifold gaskets close to the engine, where temperatures beat what 409 or 304 tolerate. Slit coil at ±0.1 mm feeds forming presses directly, and deburred edges protect tooling.
Orders are issued from our Taloja and Mumbai warehouses in wooden cases or pallet packing, documented for export worldwide.
| 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 309 Strips price in India is nearly ₹300 to ₹520 per kg, around $3.2 to $5.5 for overseas buyers. The figure tracks nickel rates and moves with thickness, width, finish, and order volume. It sits below 310S at the same gauge. WhatsApp us your size for a firm quote.
The maximum service temperature for SS 309 strips is roughly 1095 °C in continuous exposure and 980 °C where duty cycles, since repeated heating spalls the protective scale.
Choose SS 309 strips once sustained temperatures pass about 870 °C. SS 304 scales heavily beyond that point, while the richer chromium and nickel in 309 stay serviceable another 200 °C.
SS 309 permits 0.20% carbon while SS 309S caps it at 0.08%. ASTM A240 covers the flat-rolled strip product as 309S (UNS S30908), so A240 strip carries the low-carbon limit and welds cleanly.
Finishes available on 309 stainless strips include BA, 2B, Scotch-Brite, Matte, and Matte PVC. Slit, mill, deburred, and round edges complete the options.
Custom-slit SS 309 strips dispatched within 4 to 5 days from ready stock. Urgent requirements move in 2 to 3 days from Mumbai.
You can buy Stainless Steel 309 strips in India directly from Riddhi Siddhi Impex. We hold S30900 coil at Mumbai and Taloja, slit to your width, and quote within 24 hours by phone or WhatsApp.
