Structural stainless steel is popular for its aesthetic appeal, flexibility, and durability. Duplex stainless steel is extensively utilized in concrete structures because of its exceptional corrosion resistance, robust structural properties, and widespread availability. These materials offer greater strength, enhanced strain hardening, and superior ductility compared to conventional carbon steel reinforcement. This study concentrated on the finite element analysis of the residual mechanical properties of hot-rolled duplex stainless-steel reinforcing bars, in comparison to experimental data. It involved evaluating user-defined material properties for an isotropic elasticity model and a multilinear isotropic hardening model across three distinct scenarios to validate with experimental data. This work found a close agreement between the experimental results and the numerical simulations and revealed only minor variations in the residual mechanical response of EN 1.4362H materials across different cooling methods. The study found that total maximum strain (mm/mm) and user-defined (the total elastic and total plastic strain) strain correlated strongly for the virgin temperature and across all examined heating temperatures and cooling modes. There was a relatively small percentage difference between experimental and numerical results which is (<1%) for ultimate tensile strength (fu) and (<5%) for proof strength (f0.2p) with the exception of six cases: 900 °C—rapid cooling in water (7.44%), 700 °C—intermediate cooling in air (10%), 800 °C—intermediate cooling in air (9.5%), 900 °C—intermediate cooling in air (12.5%), 600 °C—slow cooling inside the furnace (11.9%), and 900 °C—slow cooling in furnace (8.3%). The simulation data correlated well with the input data used for the engineering analysis across investigated temperatures and cooling modes.