Duplex Steel Products

Duplex steel is called “duplex” because they have a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel. The picture shows the yellow austenitic phase as “islands” surrounded by the blue ferritic phase.  When duplex stainless steel is melted it solidifies from the liquid phase to a completely ferritic structure.  As the material cools to room temperature, about half of the ferritic grains transform to austenitic grains (“islands”).  The result is a microstructure of roughly 50% austenite and 50% ferrite.