Influence of isothermal annealing in the 600 to 750 °C range on the degradation of SAF 2205 duplex stainless steelBurja, Jaka (Avtor) Žužek, Borut (Avtor) Šetina, Barbara (Avtor) duplex stainless steelsigma phaseprecipitation kineticsmechanical propertiesisothermal annealingWe studied the effect of isothermal annealing (600–750 °C, 1 to 1000 min) on the microstructure and mechanical properties of SAF 2205 duplex stainless steel. Impact toughness was found to be significantly more affected than hardness by annealing. Annealing at 750 °C for 1000 min resulted in a more than 90% decrease in impact toughness, while hardness only increased by 25%. Tensile strength increased up to 100 MPa, but elongation decreased by more than 50% under the same conditions. Sigma phase formation was minimal at lower temperatures (650 °C and below) but increased significantly at higher temperatures. At 750 °C and 1000 min of annealing, the ferrite content dropped from 50% to 16%. These findings suggest that annealing temperature and time need to be carefully controlled to avoid a reduction in impact toughness and ductility caused by sigma phase precipitation. The harmful effect of sigma phase precipitation on mechanical properties was directly shown. MDPI20242024-07-24 09:37:51Neznano19729Švicasl© 2024 by the authors