1.4655 is a lean ferritic-austenitic (duplex) stainless steel — a copper-bearing variant of the 2304-type lean duplex family, with a microstructure of roughly equal ferrite and austenite. This datasheet presents the material within the European standard system.
With about 23% chromium, 4% nickel, only a little molybdenum (0.1-0.6%), a copper addition (1-3%) and controlled nitrogen (0.05-0.20%), 1.4655 is a lean, low-molybdenum, nickel-economical duplex grade. It offers roughly twice the proof strength of standard austenitic grades together with good resistance to chloride stress-corrosion cracking, at a lower alloy cost than the molybdenum-bearing 1.4462. Its PREN is modest (typically ~24-26), so it targets moderate-corrosivity service rather than the severe chloride duty of 1.4462. It must not be confused with the 3%-molybdenum standard duplex 1.4462.
Typical applications include structural and pressure components, hot-water tanks, building and construction elements, and process equipment in mild-to-moderate chloride environments.
Values for the solution-annealed condition, per EN reference data.
| Property | Value | Unit |
|---|---|---|
| Density | 7.8 | g/cm³ |
| Melting range | 1390-1450 | °C |
| Young's modulus (20 °C) | 200 | GPa |
| Thermal conductivity (20 °C) | 15 | W/m·K |
| Coefficient of thermal expansion (20-100 °C) | 13 | µm/m·°C |
| Specific heat (20 °C) | 480 | J/kg·K |
| Magnetic response | Ferromagnetic (duplex) | — |
Composition per EN 10088-2 (W.Nr. 1.4655, X2CrNiCuN23-4).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 22.0 | 24.0 | Ferrite former; corrosion resistance |
| Nickel | Ni | 3.5 | 5.5 | Austenite former; phase balance |
| Copper | Cu | 1.0 | 3.0 | Strength; acid resistance |
| Molybdenum | Mo | 0.1 | 0.6 | Minor pitting resistance (lean) |
| Nitrogen | N | 0.05 | 0.20 | Austenite former; strength; pitting |
| Manganese | Mn | — | 2.0 | Deoxidiser |
| Silicon | Si | — | 1.0 | Deoxidiser |
| Carbon | C | — | 0.030 | Low (intergranular resistance) |
| Phosphorus | P | — | 0.035 | Residual impurity |
| Sulphur | S | — | 0.015 | Residual impurity |
Nominal: lean 23Cr-4Ni-Cu-N duplex with only minor molybdenum. Distinct from the 3%-Mo standard duplex 1.4462.
Solution-annealed (+AT) condition, per EN 10088-2 for W.Nr. 1.4655.
| Property | Value | Unit |
|---|---|---|
| Tensile strength (Rm) | 650-850 | MPa |
| 0.2% proof strength (Rp0.2) | >=450 | MPa |
| Elongation at fracture | >=20 | % |
| Impact energy (KV, +20 °C) | >=60 | J |
| Brinell hardness | <=290 | HB |
Values per EN 10088-2. Confirm against the inspection certificate (EN 10204).
| Environment | Performance | Notes |
|---|---|---|
| Chloride SCC | Good | Duplex advantage over austenitics |
| Chloride pitting | Moderate | Lean (low Mo); PREN ~24-26 |
| Crevice corrosion | Moderate | Below 1.4462 |
| General (oxidizing) | Good | ~23% chromium |
| Acids | Fair-good | Copper assists in some media |
Suited to mild-to-moderate chloride service; for severe chloride duty use the molybdenum-bearing 1.4462.
Not hardenable by heat treatment; properties are set by solution annealing and phase balance.
Solution Anneal approximately 1000-1080 °C, followed by rapid water quench to retain the balanced ferrite-austenite structure and avoid embrittling intermetallic phases. Avoid prolonged exposure in the 300-1000 °C range (sigma-phase / 475 °C embrittlement).
Good weldability by common fusion methods; use a matching lean-duplex or 23 7-type filler and control heat input to maintain phase balance.
| Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Lean-duplex (23 7 N type) |
| GMAW / MIG | Good | Lean-duplex filler |
| SMAW / stick | Good | Matching duplex electrode |
No preheat; control interpass temperature and heat input; resistant to intergranular corrosion in the as-welded condition owing to the low carbon.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Duplex; carbide tools, moderate speeds, rigid setup |
| Work hardening | Significant; positive feeds, avoid dwelling |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Hot forming | ~1150-950 °C; solution anneal + quench afterward |
| Cold forming | Higher forces than austenitics (high duplex strength) |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Construction | Structural sections, rebar, plate | Strength + moderate corrosion resistance |
| Storage | Hot-water and chemical tanks | Cost-effective duplex |
| Process equipment | Vessels in mild chloride media | SCC resistance at lower cost |
| Water / municipal | Tanks, piping | Moderate chloride resistance |
| Product Form | Standard | Notes |
|---|---|---|
| Plate, sheet and strip | EN 10088-2 · W.Nr. 1.4655 | X2CrNiCuN23-4 |
| Bar, rod, wire and sections | EN 10088-3 · W.Nr. 1.4655 | — |
| Seamless / welded tube | EN 10216-5 / EN 10217-7 · W.Nr. 1.4655 | — |
| Sour service | ISO 15156-3 | Acid-gas applications |
Lean copper-bearing ferritic-austenitic (duplex) stainless steel. W.Nr. 1.4655; EN 10088-2.
| W.Nr. | Cr % | Ni % | Mo % | Cu % | N % | Best Used For |
|---|---|---|---|---|---|---|
| 1.4655 | 22-24 | 3.5-5.5 | 0.1-0.6 | 1-3 | 0.05-0.20 | Lean Cu-bearing duplex; moderate service |
| 1.4362 | 22-24 | 3.5-5.5 | 0.1-0.6 | 0.1-0.6 | 0.05-0.20 | Lean duplex (2304) |
| 1.4462 | 21-23 | 4.5-6.5 | 2.5-3.5 | — | 0.10-0.22 | Standard duplex (3% Mo) |
| 1.4410 | 24-26 | 6.0-8.0 | 3.0-4.5 | — | 0.24-0.35 | Super duplex |
| 1.4404 | 16.5-18.5 | 10-13 | 2.0-2.5 | — | — | Austenitic general service |




