We are Riddhi Siddhi Impex, a Mumbai-based supplier and stockist of SMO 254 Sheets & Plates, established in 2002. We stock this super austenitic 6Mo stainless steel to ASTM A240 / ASME SA-240 as cold rolled sheets from 3.8 mm and hot rolled plates in thicker gauges, in widths up to 2000 mm. Our ISO 9001, 14001, and 45001-certified firm ships worldwide with EN 10204 Type 3.1 / 3.2 certificates on request.
SMO 254 sheets and plates carry the 20-18-6 chemistry: 19.50 to 20.50% chromium, 17.50 to 18.50% nickel, and 6.00 to 6.50% molybdenum, with copper and a controlled nitrogen addition. That mix pushes the pitting resistance equivalent number to roughly 43, against about 25 for SS 316. Hot brine, wet chlorine dioxide, and seawater under deposits all sit inside the 6 Moly working envelope.
As a reliable 254 SMO Sheet supplier, every sheet we stock comes from reputed primary mills, annealed and certified to EN 10204 Type 3.1 / 3.2 upon request. Orders clear Mumbai and Taloja in 4 to 5 days. Buyers needing narrower panels get them slit in-house to ±0.1 mm; thinner 6Mo gauges move through our coil and foil ranges.
We provide ASTM A240 UNS S31254 sheets and plates from ready stock, annealed, in six surface finishes and two edge options.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240, ASTM A480 |
| Thickness (Sheets, CR) | 3.8 mm to 6 mm |
| Thickness (Plates, HR) | 6 mm and above |
| Width | Up to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Condition | Annealed (standard mill) |
| Surface Finish | 2B, BA (Bright Annealed), Scotch-Brite, Matte, Matte PVC, Skin Pass |
| Edge | Mill edge, Slit edge |
Nitrogen at 0.180 to 0.220%, it strengthens the austenite and holds the PREN near 43, while copper improves sulphuric acid performance.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.020 max |
| Manganese (Mn) | 1.00 max |
| Phosphorus (P) | 0.030 max |
| Sulphur (S) | 0.010 max |
| Silicon (Si) | 3.80 max |
| Chromium (Cr) | 19.50 to 20.50 |
| Nickel (Ni) | 17.50 to 18.50 |
| Molybdenum (Mo) | 6.00 to 6.50 |
| Copper (Cu) | 0.50 to 1.00 |
| Nitrogen (N) | 0.180 to 0.220 |
Annealed 254 SMO plate meets a 650 MPa minimum tensile strength, roughly a third above 316L, so designers can thin down vessel walls. No temper range applies.
| Property | Value |
|---|---|
|
Tensile Strength, minimum
|
650 MPa (94 ksi) |
|
Yield Strength (0.2% offset), minimum
|
300 MPa (44 ksi) |
|
Elongation in 50 mm, minimum
|
35% |
Check an overseas enquiry against the rows below. These are the recognised cross-references for Alloy 254. Note that the ranges are close but not identical.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S31254 |
| Europe (EN) | X1CrNiMoCuN20-18-7 |
| Germany (W.Nr) | 1.4547 |
| Japan (JIS) | SUS312L |
| France (AFNOR) | Z1 CNDU 20-18-06 Az |
| Sweden (SIS) | 2378 |
These 4 industries specify most of the 254 SMO plate leaving our warehouses, each specifying the grade because a pitted vessel wall costs far more than the alloy premium.
Desalination contractors use UNS S31254 plate in flash chamber linings, evaporator shells, and water boxes facing hot, concentrated brine. Standard duplex grades lose their margin once crevices form under scale deposits. A 6 Moly wall keeps its section through thermal cycling, stretching plant life between relines.
Power station scrubbers condense chloride-laden sulphuric acid onto every internal surface. FGD builders line absorber towers, outlet ducting, and quencher sections with 254 SMO sheet because the alloy passivates where 317L wastes away. Wallpaper cladding over carbon steel shells uses the same stock in thinner gauges.
Bleach plant washers run warm, acidic filtrate carrying chlorine dioxide, which strips the passive film off standard austenitics within a campaign. Mills fabricate drum washer decks, vats, and filtrate panels from UNS S31254 sheet for the C and D bleaching stages, where the combination of chloride, low pH, and chlorine dioxide is most aggressive.
Fabricators drill shell and tube exchanger tubesheets straight from 254 SMO plate, matching 6Mo tubing in seawater coolers and chemical condensers. Galvanic balance between tube and sheet removes one corrosion variable, and the 650 MPa minimum carries ligament stresses at thinner sections than 316L allows.
Flat stock travels in wooden cases or on pallets, loading at both our warehouses for sea.
| Parameter | Details |
|---|---|
| Packaging | Wooden cases, pallet packing |
| Incoterms | FOB, CIF, CFR, EXW |
| Dispatch Points | Mumbai and Taloja warehouses |
| Port | Mumbai |
| 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 |
SMO 254 Sheets & Plates price in India is around ₹356 to ₹1,300 per kg, or $4.35 to $15.87 for export buyers. Treat the band as indicative. Nickel and molybdenum surcharges set the base, then thickness, finish, and tonnage settle the final figure. WhatsApp us for a current quotation.
Cold-rolled UNS S31254 sheets run 3.8 mm to 6 mm and hot-rolled plates 6 mm and above, all in widths up to 2000 mm.
ASTM A240 / ASME SA-240 covers SMO 254 sheets and plates, while ASTM A480 covers flat-product tolerances. Our mill test certificates reference both.
Yes, SMO 254 plates call for an over-alloyed nickel filler such as ERNiCrMo-3. A matching-composition weld ends up leaner in molybdenum and pits first in chloride service.
The SMO 254 plate can carry warm aqueous streams but not furnace duty. Holding between 600 and 1000 °C precipitates intermetallic phases that cut toughness and pitting resistance.
254 SMO plate costs ₹356 to ₹1,300 per kg in India, about $4.35 to $15.87 on export terms. The rate moves with nickel and molybdenum markets, plus your size and quantity.
You can buy SMO 254 sheets and plates in India from us at Riddhi Siddhi Impex, a supplier, stockist, and exporter since 2002. WhatsApp your thickness, finish, and tonnage, and our team responds with a quote within 24 hours.
