In the present work, the influence of different thermomechanical treatments in the final microstructure of a multiphase-steel (0.2%C-1.5%Mn-1.5%Si) through of morphological characterization of the transformation products was studied. The goal of this work was to investigate the volumetric fraction variation and phase distribution present in the microstructure. The steel was submitted to intercritic annealing treatment (alpha + gamma) with and without previous reheating after the hot-rolling. The microstructure was observed by optical microscopy and mechanical properties were measured by Vickers microhardness. The results show a typical microstructure of multiphase steel ("dual-phase") with increase of the martensite volumetric fraction and hardness values when the steel was submitted to intercritic annealing without reheating after the hot-rolling.