Austenitic-ferritic also referred to as duplex stainless steels, combine many of the beneficial properties of ferritic and austenitic steels. Due to their high content of chromium and nitrogen, and molybdenum, these steels offer good resistance to local and uniform corrosion. The duplex microstructure contributes to their high strength and high resistance to stress corrosion cracking. Duplex steels also have good weldability.
Specifications
| Duplex 2205 – UNS S31803 | |
| Norm ASTM | |
| Seamless Tubes | A-789 A-790 |
| Welded Tubes | A-798 A-790 |
| Plates | A-240 |
| Bars | A-276 |
| Flanges | A-182 |
| Fittings | A-815 |
Chemical specifications %
| Duplex 2205 – UNS S31803 | ||
| Element | Simbol | Maximum % |
| Carbon | C | 0,030 |
| Manganese | Mn | 2,00 |
| Phosphorus | P | 0,030 |
| Sulfur | S | 0,020 |
| Silicon | Si | 1,0 |
| Nickel | Ni | 4,5-6,5 |
| Chrome | Cr | 21,0-23,0 |
| Molybdenum | Mo | 2,5-3,5 |
| Nitrogen | N | 0,08-0,20 |
Mechanical Properties
| 17.4PH – UNS S17400 | |||||||
| Norm | Rm min. | Rp 0,2% min. | E4d min.% | Z min.% | T.I.(J) | HR B | HB |
| A-182 | 90 (620) | 65 (450) | 25 | 45 | |||
| A-240 | 90 (620) | 65 (450) | 25 | 31 | 293 | ||
| A-276 | 90 (620) | 65 (450) | 25 | 290 | |||
| A-789 | 90 (620) | 65 (450) | 25 | 290 | |||
| A-790 | 90 (620) | 65 (450) | 25 | 290 | |||
| A-815 | 90 (620) | 65 (450) | 20 | 290 | |||
