Influence of isothermal aging on secondary phases precipitation and toughness of a duplex stainless steel SAF 2205

In this paper the results of secondary phases determination in a SAF 2205 duplex steel, heat treated at 780, 850 and 900 °C for 10–40 min, are presented. χ-phase is the first phase to precipitate at all the temperatures, followed by σ-phase. The main drop of toughness is related to very low contents of χ-phase and σ-phase. Hardness is not a sensitive parameter to low amounts of secondary phases.