Technological advances in steels heat treatment

Steels are the most important alloys utilized as structural material and this work shows technological advances in steels heat treatments. The structure and the microstructure of most steels are well known by now as well as the effects of the heat treatments in changing their mechanical properties. For instance, both martensite, obtained during rapid cooling and pearlite, obtained during slow cooling, comes from austenite. Therefore, both the steel microstructure and mechanical properties are related to steel thermal history. 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. The materials chosen were AISI 1020 and AISI 52100, which are well known steels with application in many areas of mechanical industry. The results showed that a great improvement could be reached by applying voltage during heat treatments. The effect of applying voltage seems to be similar to the temperature in the iron–carbon equilibrium system. Therefore, the microstructure and the mechanical properties of the steel to which a voltage was applied, were different from the other sample, of the same steel which had been heat-treated at the same temperature and cooled at the same cooling rate.