Pressure also has an influence on the stability of the phases, i.e., equilibrium phase diagram. However, this parameter is not usu- ally taken into account, mainly in solid-state reactions, because its influence is limited. Some effects of the microstructure on electrical [2] and magnetic properties [3] of materials are widely known. However, the reverse is not true, except for high temperatures like in induction hardening, where this principle is used to heat the work piece [4]. The main objective of this preliminary investigation is to verify the effect of the voltage applied, by using a power source, in carbon steel samples during heat treatments