HT PIPE is a 6mo uns s31254 pipe supplier with 15+ export experience. Contact us for more information and quotes for free!
SS Alloy 254 SMO is a super austenitic alloy made of 6% molybdenum, chromium and nitrogen, with copper added for improved resistance to sulfuric acid. Excellent resistance to corrosion, crevice corrosion and pitting in both aqueous and acidic environments. Yield strength is nearly twice that of conventional austenitic grades such as 316L. Can be easily welded using standard methods such as TIG, MIG and hand welding.
254SMO Material Available Forms
- ASTM A240 Plate
- ASTM A276/479 Bars, rods
- ASTM A312/A213/A269 Pipe Tubes (welded and seamless)
- ASTM A182/A403 Fittings: Elbows, Tees, Stub Ends, Returns, Caps, Crossheads, Reducers, Couplings, Fittings, etc.
| Form & Format | ASTM / ASME Standards | International Equivalents & Codes |
| Seamless & Welded Pipe | ASTM A312 / ASME SA312 | UNS S31254 |
| Seamless & Welded Tube | ASTM A269, A213 / ASME SA213 | EN 1.4547 / X1CrNiMoCuN20-18-7 |
| Forgings & Flanges | ASTM A182 / ASME SA182 F44 | NORSOK M-630 / MDS R14 |
| Fittings (Butt-Weld) | ASTM A403 / ASME SA403 WP44 | Swedish SS 2378 |
| Plates, Sheets & Strips | ASTM A240 / ASME SA240 | Japanese SUS 312L |
Chemical Composition
- Chromium (Cr): 19.5–20.5%
- Nickel (Ni): 17.5–18.5%
- Molybdenum (Mo): 6.0–6.5%
- Nitrogen (N): 0.18–0.22%
- Copper (Cu): 0.5–1.0%
- Iron (Fe): Balance
Mechanical Properties
- Tensile strength: ≥ 650 MPa
- Yield strength: ≥ 300 MPa
- Elongation: ≥ 35%
- Hardness: ≤ 210 HBW
| Property | 316L | 2205 Duplex | 254 SMO |
|---|---|---|---|
| PREN | 23 | 35 | >42 |
| Yield Strength | 200 MPa | 450 MPa | 300 MPa |
| Applications | General use | Moderate chloride | Harsh chloride |
Corrosion Resistance
With a PREN (pitting resistance equivalent value) above 42, 254 SMO UNS S31254 Pipe performs significantly better than 316L and even duplex stainless steels.
Applications
Offshore Oil & Gas: Seawater cooling systems, firewater piping networks, and subsea hydraulic control lines.
Desalination Systems: High-pressure reverse osmosis (RO) piping arrays, heat exchangers, and brine concentration vessels.
Flue Gas Desulfurization (FGD): Scrubber units exposed to aggressive acidic condensates in coal-fired power infrastructure.
Pulp & Paper Processing: Bleach plant washers, drums, vat linings, and piping systems handling highly corrosive chlorine-based bleaching chemicals.
Precise Fabrication & Welding Guidelines
Because of its high alloy content, forming and joining 254 SMO demands specific procedural controls to avoid metallurgical defects.
- Welding Techniques: Gas Tungsten Arc Welding (GTAW/TIG), Gas Metal Arc Welding (GMAW/MIG), and Shielded Metal Arc Welding (SMAW) are standard.
- Filler Metal Requirements: Due to elemental segregation during cooling, welding without filler metal must be avoided. Autogenous welds suffer from molybdenum-depleted zones that act as paths for pitting. Always utilize an over-alloyed nickel-base filler metal such as Alloy 625 (ERNiCrMo-3) or Alloy C22 to ensure the weld zone achieves equal or superior corrosion resistance.
- Heat Input Control: Keep interpass temperatures below 300°F (150°C) to prevent micro-fissures and minimize time spent in the sensitization zone.
- Post-Weld Heat Treatment (PWHT): If heavy forming or autogenous welding is mandatory, process the components via solution annealing at 2100°F to 2150°F (1150°C to 1175°C) followed immediately by a rapid water quench.
Integrated Supply Capabilities by HT Pipeline
Zhengzhou Huitong Pipeline Equipment Co., Ltd. (HT Pipeline) offers comprehensive supply chains for certified Alloy 254 SMO configurations.
- Product Range Availability: Seamless and welded pipes, process tubing, heavy plates, sheets, and forged round bars in standard mill or precision cut-to-length options.
- Quality Assurance Documents: All shipments are delivered alongside a traceable EN 10204 3.1 Mill Test Certificate, displaying independent laboratory check analyses, mechanical performance metrics, and verified non-destructive testing (NDT) logs.
- One-Stop Procurement: We simplify project logistics by matching your 254 SMO raw materials with certified ASTM A403 WP44 pipe fittings, ASTM A182 F44 flanges, and custom machined components.
Are you engineering a high-salinity system or an aggressive chemical processing line? Contact our technical sales desk today to receive an accurate, competitive quotation tailored directly to your commercial specifications.
