We are Riddhi Siddhi Impex, a Mumbai-based SMO 254 shims manufacturer and supplier, established in 2002. We slit UNS S31254 super austenitic stainless steel shim stock to ASTM A240 / ASME SA-240 in thicknesses from 0.03 mm to 5 mm. Our ISO 9001, 14001, and 45001-certified facility carries ready stock, with a monthly supply capacity of 400 to 500 tonnes, ships worldwide, and issues EN 10204 Type 3.1 mill test certificates as standard, with Type 3.2 on request.
SMO 254 shims are thin, flat spacers slit from a super austenitic stainless steel that runs about 20% chromium, 18% nickel, and 6% molybdenum, with a controlled nitrogen addition. That chemistry gives a pitting resistance number near 43, so the grade holds up in warm seawater and acidic chloride service where 316L pits. Engineers fit these shims to set clearances and align mating faces in corrosion-critical equipment.
We process every 254 SMO shim in-house on our own slitting lines. Material leaves our facility in the solution annealed condition to ASTM A240, in any width from 3 mm to 2000 mm. Buyers choose No.1, BA, 2B, or Matte surfaces with slit, deburred, or round edges. A documented quality system covers each stage, from source coil inspection through final dispatch.
We provide ASTM A240 super austenitic stainless steel shims in the solution annealed condition, with four surface finishes and three edge options, supplied in coil to match your production line.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240 |
| General Requirements | ASTM A480 |
| Thickness | 0.03 mm to 5 mm |
| Width | 3 mm to 2000 mm |
| Width Tolerance | ±0.1 mm on narrow slit widths |
| Condition | Solution annealed per ASTM A240 |
| Surface Finish | No.1, BA (Bright Annealed), 2B, Matte |
| Edge | Slit edge, Deburred edge, Round edge |
| Supply Forms | Hot Rolled and Cold Rolled |
Molybdenum defines this grade. UNS S31254 shim sheets carry 6.0 to 6.5% molybdenum, roughly double the level in SS 316, and that content drives the alloy's resistance to pitting and crevice attack. Nitrogen and copper additions support it. The nominal composition of UNS S31254 to ASTM A240 appears below.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.020 max |
| Manganese (Mn) | 1.00 max |
| Phosphorus (P) | 0.030 max |
| Sulphur (S) | 0.010 max |
| Silicon (Si) | 0.80 max |
| Chromium (Cr) | 19.50 to 20.50 |
| Nickel (Ni) | 17.50 to 18.50 |
| Molybdenum (Mo) | 6.00 to 6.50 |
| Nitrogen (N) | 0.180 to 0.220 |
| Copper (Cu) | 0.50 to 1.00 |
| Iron (Fe) | Balance |
Solution annealed S31254 shims pair a 650 MPa minimum tensile strength with 35% elongation, and yield strength around 75% higher than 316L, while still forming and punching cleanly. Values for thin gauges are indicative and vary with thickness.
| Property | Value |
|---|---|
|
Tensile Strength, minimum
|
650 MPa (94 ksi) |
|
Yield Strength (0.2% offset), minimum
|
300 MPa (44 ksi) |
|
Elongation in 50.8 mm (2 in.), minimum
|
35% |
|
Hardness, maximum
|
223 HBW / 96 HRB |
International buyers can cross-reference UNS S31254 shims against their regional standard using the table below. The shims we slit correspond to the designations shown for cross-reference.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S31254 |
| Europe (EN) | X1CrNiMoCuN20-18-7 |
| Germany (W.Nr) | 1.4547 |
| France (AFNOR) | Z1 CNDU 20-18-06 Az (legacy) |
| Sweden (SIS) | 2378 |
These four industries use most of the 6 Moly shims we slit. In each case, buyers select the grade for chloride corrosion resistance rather than strength, because a failed spacer means downtime, and few other stainless grades survive this service.
Acid and halide plants use 254 SMO Stainless Steel shims around reactor flanges, heat exchanger bundles, and pump housings. The 6% molybdenum content resists sulphuric and phosphoric acids and warm chloride solutions that pit 316L. Precise spacing keeps sealing faces true, so operators avoid leaks that stop a corrosive line.
Platforms and subsea equipment run in seawater, among the toughest chloride services. 254 SMO shims align valve internals, riser clamps, and instrument mounts, resisting pitting and crevice attack under gaskets. The grade's stress corrosion cracking resistance matters where warm brine and load meet, keeping shimmed joints stable through long maintenance intervals.
Multi-stage flash and reverse osmosis plants push hot, high-chloride brine through heat exchangers and pumps. S31254 shims set clearances in this equipment, where 316 falls short and standard duplex grades reach their limits in the hottest brine. The alloy holds dimensional accuracy across thermal cycling, helping alignment stay in tolerance between shutdowns.
Bleach plants generate chlorine dioxide and wet chloride conditions that attack most stainless grades. 6Mo shims align equipment across washers, digesters, and bleaching towers in these lines. The grade's pitting resistance lets a mill run its most corrosive stages without the frequent spacer replacement that carbon steel or 316 would force on the maintenance crew.
Export orders leave Mumbai and Taloja, packed in wooden cases or on pallets, ready for sea freight.
| 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 standard; Type 3.2 on request |
The SMO 254 shims price in India is around ₹1,200 to ₹1,500 per kg, or roughly $14 to $17 per kg for international buyers. The figure moves with global nickel and molybdenum rates, since this is a premium 6% moly grade. Thickness, width, quantity, and finish all affect the final price. Volume discounts apply to bulk and wholesale orders, so call or WhatsApp us for today's rate.
We slit SMO 254 shim stock from 0.03 mm to 5 mm thick and to any width between 3 mm and 2000 mm. Foil gauges from 0.03 mm to 0.08 mm also fall under our SMO 254 foils range.
SMO 254 shims hold about 6% molybdenum against 2 to 3% in SS 316, so their pitting resistance is far higher. In warm chloride and acidic service, 6Mo shims last where 316 pits and fails.
Available surface finishes include No.1, BA, 2B, and Matte. Round or deburred edges suit winding and gasket work where a sharp slit edge would damage adjacent parts.
You can source SMO 254 shims in India from us at Riddhi Siddhi Impex. Our Mumbai warehouse holds S31254 shim inventory in stock, ready for immediate dispatch. As a stockist, manufacturer, and supplier, we serve buyers across India and export overseas. Phone or WhatsApp us; get a quote within 24 hours.
