• 30.06.2022 11:28:19

Duplex Stainless Steels

The corrosion performance of these steels, which generally contain equal proportions of ferrite and austenite in their microstructure, varies based on the alloys they contain.

As much as duplex stainless steels have a higher strength than austenitic stainless steels, they have better resistance to localized corrosion, especially to nucleation, crevice and stress corrosion, than austenitics. Duplex grades are also more durable than austenitics, thanks to their high content of chromium between 19-28%, molybdenum up to 5%, and nickel at lower rates than austenitics. The most significant limiting feature of duplex stainless steels is their brittleness at high temperatures and very low temperatures. Duplex steels become brittle and need to be annealed again, especially if they are worked above 300 °C and below -50 °C even for a short time. The most widely known duplex stainless steel grade is 2205 grade. Their structure is BCC for ferritic parts and FCC for austenitic parts.