# Chemical composition of stainless steels II

## According to standard DIN EN ISO 3506

| **Steel group** | **Steel grade** | **Chemical composition (mass%)1)** |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| **C** | **Si** | **Mn** | **P** | **S** | **Cr** | **Mo** | **Ni** | **Cu** | **Notes** |  |  |
| Austenitic | **A1** | 0,12 | 1 | 6,5 | 0,20 | 0,15 – 0,35 | 16 – 19 | 0,7 | 5 – 10 | 1,75 – 2,25 | 2), 3), 4) |
| **A2** | 0,1 | 1 | 2 | 0,05 | 0,03 | 15 – 20 | *5) | 8 – 19 | 4 | 6), 7), 8) |  |
| **A3** | 0,08 | 1 | 2 | 0,045 | 0,03 | 17 – 19 | *5) | 9 – 12 | 1 | 6), 9) |  |
| **A4** | 0,08 | 1 | 2 | 0,045 | 0,03 | 16 – 18,5 | 2-3 | 10 – 15 | 1 | 10), 8) |  |
| **A5** | 0,08 | 1 | 2 | 0,045 | 0,03 | 16 – 18,5 | 2-3 | 10,5 – 14 | 1 | 9), 10) |  |
| Martensitic | **C1** | 0,09 – 0,15 | 1 | 1 | 0,05 | 0,03 | 11,5 – 14 | – | 1 | – | 10) |
| **C3** | 0,17 – 0,25 | 1 | 1 | 0,04 | 0,03 | 16 – 18 | – | 1,5 – 2,5 | – | – |  |
| **C4** | 0,08 – 0,15 | 1 | 1,5 | 0,06 | 0,15 – 0,35 | 12 – 14 | 0,6 | 1 | – | 2), 10) |  |
| ****Ferritic**** | **F1** | 0,12 | 1 | 1 | 0,04 | 0,03 | 15 – 18 | *6) | 1 | – | 11), 12) |

1. Maximum value
2. Sulphur may be replaced by selenium.
3. If the mass fraction of nickel falls below 8%, the mass fraction of manganese must be at least 5%.
4. There is no minimum limit for the mass fraction of copper if the mass fraction of nickel is more than 8%.
5. A deviation regarding the molybdenum content is permissible. At the same time, for certain applications the molybdenum content must be limited. These must be stated for customers when ordering.
6. A deviation regarding the molybdenum content is permissible.
7. If the mass fraction of chromium falls below 17%, the mass fraction of nickel must be at least 12 %.
8. For austenitic steels, with a carbon mass fraction of at most 0,03 %, nitrogen may be contained up to 0,22%.
9. It must contain stabilising titanium in an amount corresponding to five times the carbon content, up to a maximum of 0,8 %, and may be supplemented according to this table, or stabilising niobium and/or tantalum in an amount corresponding to 10 times the carbon content, up to a maximum of 1 %.
10. The carbon content may be higher at the manufacturer’s choice, in so far as this may be necessary at a larger diameter to achieve the specified mechanical properties, however for austenitic steels it is not more than 0,12%.
11. The titanium may be in an amount of up to five times the carbon content, but may not exceed 0,8 %.
12. The niobium and/or tantalum may be in an amount of up to 10 times the carbon content, but may not exceed 1 %.

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