We are Riddhi Siddhi Impex, a Mumbai-based supplier and stockist of Stainless Steel 347 Coils, established in 2002. As an ISO 9001, 14001, and 45001 certified company, we hold niobium-stabilised austenitic coils to ASTM A240 / ASME SA-240, slit to ±0.1 mm, and export to 60+ countries. Supply capacity runs 400 to 500 tonnes monthly, with EN 10204 Type 3.1 / 3.2 mill test certificates on request.
Stainless Steel 347 coils are flat-rolled austenitic stainless steel stabilised with niobium, historically called columbium, at ten times the carbon content minimum. Niobium ties carbon up as stable carbide, so chromium stays free, and the grade resists intergranular attack through the 427 to 816 °C sensitisation band. General corrosion resistance tracks Type 304, while creep strength runs well past it. Fabricators reach for 347 wherever welded parts run hot. These Stainless Steel Coils are widely specified in aerospace, power generation, and petrochemical industries.
As a reliable Stainless Steel 347 Coil supplier, we source parent coils from reputed primary mills and slitting to width in-house. Material ships annealed, hot rolled, or cold rolled, in 2B, BA, Matte, or Scotch-Brite finish, with test documentation on request.
We provide ASTM A240 Type 347 coils in the annealed mill condition, with four surface finishes and three edge options.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240, AMS 5512 |
| Thickness | 0.03 mm to 5 mm |
| Width | Up to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Coil ID | 150 mm to 610 mm |
| Coil OD | Up to 1800 mm |
| Condition | Annealed (standard mill) |
| Surface Finish | 2B, BA (Bright Annealed), Matte, Scotch-Brite |
| Supply Forms | Hot rolled and Cold rolled |
| Edge | Mill edge, Slit edge, Deburred edge |
Niobium sets this grade apart. Added at ten times the carbon minimum, it forms carbides before chromium can, so the 17 to 19% chromium stays on corrosion duty.
| 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) | 17.00 to 19.00 |
| Nickel (Ni) | 9.00 to 13.00 |
| Niobium (Nb) | 10xC min, 1.00 max |
| Iron (Fe) | Balance |
Annealed SS 347 coils reach 515 MPa minimum tensile strength with 40% elongation, so they draw, bend, and form without cracking. Coils ship annealed only.
| Property | Value (Annealed) |
|---|---|
|
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
|
201 HBW / 92 HRB |
International buyers can match UNS S34700 coils to their regional standard using the table below. Every designation listed covers the same niobium-stabilised austenitic composition.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S34700 |
| Europe (EN) | X6CrNiNb18-10 |
| Germany (W.Nr) | 1.4550 |
| Japan (JIS) | SUS347 |
| China (GB) | 06Cr18Ni11Nb |
| Russia (GOST) | 08Х18Н12Б |
These 4 industries specify the 347 SS coils we supply. Buyers pick the grade for weld-zone stability, creep strength, and resistance to intergranular corrosion under sustained heat.
Refiners specify 347 SS coils for fluid catalytic cracking internals, recovery equipment, and exchanger components that idle and restart. The grade resists polythionic acid stress corrosion cracking during shutdowns, a failure mode that catches unstabilised grades once sulphide scale meets air and moisture.
Boiler fabricators run Stainless Steel 347 Coils into superheater casings, expansion bellows, and flue components that hold shape through years of thermal load. Creep strength across the 427 to 816 °C band keeps welded assemblies sound without any post-weld anneal.
Aerospace shops press Alloy 347 coils into exhaust manifolds, collector rings, and engine ducting covered by AMS 5512. Niobium stabilisation preserves weld-seam corrosion resistance through repeated heat cycling, and the material keeps its strength where plain austenitic grades begin to soften.
Chemical and pharmaceutical plants form Type 347 stainless steel coils into reactor linings, mixing vessels, and transfer piping that carry hot oxidising media. Weld zones stay immune to acid attack because the stabilised structure never gives up its grain-boundary chromium.
Export orders leave Mumbai and Taloja in wooden cases or on pallets, documented end-to-end.
| 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 mill test certificates on request |
Stainless Steel 347 Coils price in India is around ₹250-₹400 per kg, roughly $3.50-$4.20 per kg for export buyers. Nickel and niobium surcharges move the rate, along with thickness, finish, and volume. Call or WhatsApp us for today's figure.
We supply Stainless Steel 347 Coils in thicknesses from 0.03 mm to 5 mm and widths up to 2000 mm, slit to ±0.1 mm. Coil ID spans 150 mm to 610 mm, with OD up to 1800 mm.
The difference between SS 347 coils and SS 321 coils comes down to the stabiliser. Type 347 uses niobium while Type 321 uses titanium. Niobium carbides hold together at higher temperatures, so 347 keeps its intergranular corrosion resistance longer in service above 700 °C.
SS 347 coils outperform SS 304 coils wherever service falls between 427 and 816 °C. Type 304 sensitises in that band as chromium carbides form at grain boundaries. The niobium in 347 absorbs the carbon first, so welded or heat-cycled parts stay corrosion-resistant.
The maximum service temperature for Stainless Steel 347 Coils is around 870 °C continuous. Intermittent exposure runs slightly higher, and creep strength stays useful through the 427 to 816 °C band.
Available finishes for SS 347 coils include 2B, BA (Bright Annealed), Matte, and Scotch-Brite. We supply both hot-rolled and cold-rolled material, with mill, slit, or deburred edges.
You can source Stainless Steel 347 Coils in India from us at Riddhi Siddhi Impex. Our Mumbai and Taloja warehouses hold 1.4550 stainless steel coils ready for dispatch in 4 to 5 days, or 2 to 3 days for urgent needs. Phone or WhatsApp us, and get a quote within 24 hours.
