254 SMO
UNS S31254
Overview
Ultra-high molybdenum austenitic stainless steel with PREN ≥ 43 — approaching super duplex 2507 in pitting resistance while maintaining superior ductility and formability. The 6% Mo composition makes it one of the most corrosion-resistant stainless steels available, bridging the gap between standard 316L and expensive nickel alloys. Widely used in seawater handling, bleach plants, and FGD systems.
Chemical Composition (wt%)
| Element | Min | Max |
|---|---|---|
| C (Carbon) | — | 0.02 |
| Mn (Manganese) | — | 1 |
| Si (Silicon) | — | 0.8 |
| P (Phosphorus) | — | 0.03 |
| S (Sulfur) | — | 0.01 |
| Cr (Chromium) | 19.5 | 20.5 |
| Ni (Nickel) | 17.5 | 18.5 |
| Mo (Molybdenum) | 6 | 6.5 |
| N (Nitrogen) | 0.18 | 0.22 |
| Cu (Copper) | 0.5 | 1 |
Mechanical Properties
| Property | Value | Condition |
|---|---|---|
| Tensile Strength | ≥ 650 MPa (94 ksi) | — |
| Yield Strength (0.2%) | ≥ 300 MPa (44 ksi) | — |
| Elongation | ≥ 35% | — |
| Hardness | ≤ 96 HRB | annealed |
| Density | 8.0 g/cm³ | — |
Physical Properties
| Property | Value |
|---|---|
| Melting Range | 1320 – 1390 °C |
| Thermal Conductivity | 14.0 W/m·K (at 20°C) |
| PREN | 43 – 45 |
Corrosion Resistance
Outstanding pitting and crevice corrosion resistance (PREN ≥ 43) — approaching nickel alloy levels at a fraction of the cost. Excellent resistance to seawater, brine, and chloride-containing process streams even at elevated temperatures. Performs well in bleach plant environments and oxidizing chloride solutions. Resistant to stress corrosion cracking. Game-changing alloy where 316L/317L fail but full nickel alloys would be over-engineering.
Typical Applications
Related Standards
Available Products in This Material
Browse our product range manufactured in 254 SMO: