Integranular corrosion susceptibility analysis in austeno-ferritic (duplex) stainless steels

摘要

Duplex stainless steels (DSSs) are characterized by a really good generalized corrosion resistance in many environments and by really interesting mechanical properties, considering both static or quasi-static and cyclic loading conditions. DSSs are characterized by secondary phases, nitrides, and carbides precipitation phenomena, with consequent age hardening and embrittlement. These mainly occur inside ferritic grains and next to ferrite-austenite grain boundaries, with a consequent DSS susceptibility to intergranular and/or localized corrosion phenomena and the initiation and propagation of intergranular cracks. In this work, the influence of the secondary phases, nitrides, and carbides precipitation phenomena on intergranular and localized DSS corrosion resistance was investigated, considering both the lower and higher critical temperature ranges and steel chemical composition.