The hot deformation behavior of 2304 lean duplex stainless steel was investigated by means of processing maps and physically based constitutive modeling in the temperature range of 850 °C to 1050 °C and strain rate of 0.1 to 15 s −1 . For all the processing maps developed for strains of 0.1 to 0.6, dynamic restoration mechanisms were efficient in preventing flow instability at low strain rates (1 to 4 s −1 ) in the studied temperature range. Hot deformation at medium strain rates of 5 to 7 s −1 results in the risk of flow instability. However, for typical industrial purposes, there is a possibility of hot working at higher strain rates (10 s −1 and above) at lower temperatures without the risk of instability by promoting dynamic recrystallization in the austenitic phase of the steel. The flow behavior of the steel can be accurately modeled by coupling the Estring-Mecking constitutive equation (for the work hardening and recovery region) with the Avrami model, which captures the dynamic recrystallization region.