We are Riddhi Siddhi Impex, a Mumbai-based supplier and stockist of Stainless Steel 321 Coil, established in 2002. Our warehouse holds ASTM A240 / ASME SA-240 coils from 0.03 mm to 5 mm thick, slit in-house. The ISO 9001, 14001, and 45001-certified company with a monthly supply capacity of 400-500 tons keeps ready stock and exports worldwide with EN 10204 Type 3.1 / 3.2 mill test certificates on request.
Stainless Steel 321 coils are flat-rolled lengths of titanium-stabilised austenitic steel, wound for continuous feeding into presses, tube mills, and forming lines. The grade carries the designation UNS S32100. Chromium at 17.0-19.0% forms the passive surface film, and 9.0-12.0% nickel holds the austenitic structure. Titanium, added at five times the combined carbon and nitrogen content, binds carbon before it can form chromium carbides. Welds and parts held between 425 °C and 870 °C, therefore, keep their corrosion resistance. These Stainless Steel Coils are used in power generation and heat exchangers.
As a reliable Stainless Steel Coil supplier, we buy prime coils from reputed primary mills and hold every gauge in stock. Each coil can be slit to a width between 3 mm and 2000 mm (after slitting) on our own lines. Material ships in annealed soft condition, and standard orders dispatch in 4 to 5 days.
We provide SS 321 coils to ASTM A240 / ASME SA-240 in hot rolled and cold rolled form, covering five surface finishes, four edge types, and widths slit to order.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240, ASTM A480 / ASME SA-480 |
| Thickness | 0.03 mm to 5 mm |
| Width (post-slitting) | 3 mm to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Coil ID | 150 mm to 610 mm |
| Coil OD | Up to 1800 mm |
| Condition | Annealed (Soft) |
| Surface Finish | 2B, BA (Bright Annealed), Matte, Matte PVC, Scotch-Brite |
| Supply Form | Hot Rolled (HR), Cold Rolled (CR) |
| Edge | Slit edge, Mill edge, Deburred edge, Round edge |
Titanium separates this grade from the rest of the 300 series. ASTM A240 sets the titanium floor at five times the sum of carbon and nitrogen, with a 0.70% cap, which stops sensitisation during welding and hot service.
| 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) | 17.0-19.0 |
| Nickel (Ni) | 9.0-12.0 |
| Titanium (Ti) | 5 x (C + N) min, 0.70 max |
| Nitrogen (N) | 0.10 max |
| Iron (Fe) | Balance |
Annealed Type 321 coils reach 515 MPa minimum tensile strength with 40% elongation, so deep drawing and tight bending won't crack the strip. ASTM A240 caps hardness at 217 HBW.
| 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, maximum
|
217 HBW / 95 HRB |
Buyers working to European, Japanese, or Chinese specifications can match AISI 321 coils against their national standard in the table below. Every row names the same titanium-stabilised alloy.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S32100 |
| Europe (EN) | X6CrNiTi18-10 |
| Germany (W.Nr) | 1.4541 |
| Japan (JIS) | SUS 321 |
| China (GB) | 06Cr18Ni11Ti |
| UK (BS) | 321S31 |
| Russia (GOST) | 08Kh18N10T |
These 4 industries specify most of the Alloy 321 coils we supply. Each runs equipment through the heat range where unstabilised grades sensitise, and coil form feeds their lines directly.
Refineries specify 321 stainless steel coils for heater shrouds, flare components, and hot-process ducting. Sustained heat in these units would pull chromium out of a standard austenitic grade at the grain boundaries. The titanium addition locks carbon away, so fabricated parts stay serviceable through years of thermal cycling between shutdowns.
Boiler fabricators press casing panels and expansion joints from SS 321 coils; superheater shielding comes off the same stock. Flue-gas paths hold metal at red heat for long stretches. Grade 321 keeps both its strength and its grain-boundary chromium under that load, so power plants pick it over 304 for hot-gas hardware.
Exhaust component makers draw manifolds, bellows, flexible couplings, and heat shields from UNS S32100 coil. Temperatures swing from ambient to above 800 °C within minutes of a cold start. The alloy doesn't embrittle under that cycling, and thin slit coil suits deep-drawn bellows convolutions.
Exchanger builders form tube-side baffles and fins from thin-gauge 321 SS coil, some under 0.5 mm. Welded seams resist intergranular attack without any post-weld anneal, so tube bundles go straight into service. We slit stock to the exact fin or baffle width at ±0.1 mm.
Stainless Steel Coils leave our Mumbai and Taloja warehouses in sea-worthy wooden cases or on pallets, marked to your instructions.
| 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 321 coils price in India runs between roughly ₹280 and ₹450 per kg. Export buyers pay about $3.50 to $5.50 per kg depending on destination.
We stock SS 321 coils from 0.03 mm to 5 mm thick and slit widths from 3 mm to 2000 mm (after slitting) at ±0.1 mm tolerance. Narrow precision requirements fall under our stainless steel 321 strips range.
The main difference between 321 and 304 coils is the titanium. Grade 321 carries a titanium addition of at least five times its carbon plus nitrogen content, while 304 has none, so prolonged exposure to 425 °C to 870 °C sensitises 304 yet leaves 321 resistant to intergranular corrosion.
The maximum service temperature for 321 stainless steel coils is approximately 870 °C (1600 °F). Titanium stabilisation carries the grade through the 425 °C to 870 °C carbide precipitation range.
You can source Stainless Steel 321 coils in India from us at Riddhi Siddhi Impex. Our Mumbai warehouse keeps SS321 coils ready for dispatch, supply covers all of India, and we export to 60+ countries. Phone or WhatsApp your requirement; get a quote within 24 hours.
