- Grade / Alloy
- 1.4578
- EN / W.Nr.
- 1.4578X3CrNiCuMo17-11-3-2
- AISI / SAE
- —
- UNS
- —
- Other names
- 316Cu
- Family
- Austenitic
Chemical composition
Chemical composition
Composition limitsComposition limits for long products within EN 10088-3:2023, kept separate from producer target analysis.
| Element | Content (% by mass) |
|---|---|
| CCarbon | ≤ 0.04 |
| SiSilicon | ≤ 1 |
| MnManganese | ≤ 1 |
| PPhosphorus | ≤ 0.045 |
| SSulfur | ≤ 0.015 |
| NNitrogen | ≤ 0.11 |
| CrChromium | 16.5–17.5 |
| NiNickel | 10–11 |
| MoMolybdenum | 2–2.5 |
| CuCopper | 3–3.5 |
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.
A stainless steel combining copper and molybdenum
The defining feature of 1.4578 is the combination of copper and molybdenum in a chromium-nickel austenitic structure. Copper contributes to formability in small fasteners and housings. Molybdenum is one of the elements distinguishing its corrosion behaviour from copper-bearing but molybdenum-free 1.4567. This combination explains its role in components that require forming capability as well as contact with process fluids.
Similar designation to 1.4598, different application purpose
Both 1.4578 and 1.4598 contain copper and molybdenum. Grade 1.4598, however, has a specified sulfur range and a separate machining focus. The low sulfur limit of 1.4578 belongs to its forming-oriented composition. A formed fastener and a small turned part may consequently have different material requirements. Similar-looking material numbers do not establish interchangeability.
Applications and weldability
Applications include connections in chemical and food equipment, formed mechanical components and small process housings. Molybdenum is useful in certain chloride-bearing environments, but the grade is not presented as a general seawater material. Its austenitic structure is suitable for welding. Surface condition and the service environment influence the corrosion behaviour of the finished component; copper content alone does not determine the outcome.
Reference mechanical values for solution-annealed material
The ranges below are references published in a producer long-product datasheet for longitudinal testing of solution-annealed material. They are not a universal acceptance table for all forms and dimensions. Cold deformation changes strength and elongation. The chemical table separately follows EN 10088-3:2023 long-product limits rather than merging them with the producer’s narrower target analysis.
| Property | Reference value |
|---|---|
| Tensile strength Rm | 450–650 MPa |
| Proof strength Rp0.2 | ≥ 175 MPa |
| Elongation A5, longitudinal | ≥ 45% |
Typical application areas
Formed fasteners, process components, food and chemical equipment.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.