Effect of 600°C reversion treatment to reabsorb α’ forged components made of F51 DSS

Duplex stainless steels encounter the precipitation of several secondary phases that are detrimental to both mechanical and corrosion properties when exposed to temperatures above 300°C. When embrittlement is caused by the α’ phase, heat treatment just above the miscibility gap responsible for α’ separation is sufficient to restore the lost properties, avoiding the most common solubilization at 1050°C. The aim of this study was to determine the optimal holding time for 600°C reversion treatment of 2205 DSS affected by α’. Optimization was performed by characterizing the material treated for different periods of time. To verify the soundness of this treatment, an analogous experimental campaign was conducted on the same material that was reverted at 550°C for different periods. From the research, the most effective holding time for 600°C reversion was found to be 2 h, as it gave the best results for elongation, corrosion rate, ductility, UTS, and Rp02. Lower times do not allow for complete recovery from embrittlement, whereas longer times cause the precipitation of detrimental secondary phases. In this study, conventional characterization techniques were coupled with double-loop electrochemical potentiodynamic reactivation to verify the reliability of this technique for the detection of detrimental secondary phases.