- Grade / Alloy
- 1.4652
- EN / W.Nr.
- 1.4652X1CrNiMoCuN24-22-8
- AISI / SAE
- —
- UNS
- S32654
- Family
- Austenitic
Chemical composition
Chemical composition
Composition limitsComposition limits for long products within EN 10088-3.
| Element | Content (% by mass) |
|---|---|
| CCarbon | ≤ 0.02 |
| SiSilicon | ≤ 0.5 |
| MnManganese | 2–4 |
| PPhosphorus | ≤ 0.03 |
| SSulfur | ≤ 0.005 |
| NNitrogen | 0.45–0.55 |
| CrChromium | 23–25 |
| CuCopper | 0.3–0.6 |
| MoMolybdenum | 7–8 |
| NiNickel | 21–23 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
What is 1.4652 / S32654?
1.4652 is a super-austenitic stainless steel distinguished by high molybdenum and nitrogen contents. Chromium and nickel are also central to its composition. Identified as UNS S32654, it serves applications requiring corrosion resistance beyond that of general-purpose stainless grades. It retains an austenitic structure despite the high alloy content. The commercial product known as 654 SMO is associated with this material identity.
How does it differ from 254 SMO?
254 SMO and 1.4652 belong to the same broad family, but they are different materials. The molybdenum, chromium and nitrogen levels in 1.4652 are higher. This contributes to resistance to localised attack, particularly in chloride-bearing environments. Similar commercial names do not remove the difference in alloy balance. Both can appear in seawater and chemical equipment, while temperature and chemical composition determine how significant their differences become.
Seawater and chemical equipment
Seawater systems, heat exchangers and different chemical-process surfaces are examples associated with this grade. Corrosion resistance is an important property where salt water remains in contact with metal. The family also serves some acidic fluids, but the name of an acid is not a complete description of the environment. Dilution, concentration, temperature and other substances change how a metal behaves. 1.4652 is therefore associated with demanding service, rather than with unlimited resistance to every chemical.
Between high-alloy stainless and nickel alloys
Super-austenitic stainless steels can be considered alongside nickel alloys in demanding corrosion applications. They share some equipment uses rather than a common material identity. 1.4652 is an iron-based stainless steel, whereas materials such as Alloy 625 are nickel-based. Their compositions, physical properties and behaviour in different media are not identical. This distinction helps explain why materials associated with a similar duty still have their own characteristics.
Typical application areas
Seawater equipment, chemical processing and gas cleaning.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.