Dual phase steels become more important every day due to the good combination of mechanical properties that offer the automotive industry being the main application, the combination of ferrite and martensite microstructure are responsible for producing changes in their mechanical properties. For this study, an AISI/SAE 1045 steel treated from intercritical temperatures which are ferrite and austenite and rapid cooling to make the martensite becomes used. The fractions of each phase vary with increasing temperature from which the treatment is performed. For these ratios the ASTM 562 standard was used, various microstructural analysis and hardness tests were performed. Upon water quenching and subsequent tempering from different temperatures in the intercritical range, it was found that in certain ranges had a substantial change in the analyzed properties after quenching tempering was performed 550 oC with times of 1, 2 and 4 hours, the metallographic show significant variation in the volume fraction of martensite, while the oil tempering the material showed the typical structure of a dual phase steel, where even in some cases the appearance of pearlite was evident.