Machining represents 50% of the production cost of mechanical components. The study of steels and their respective metallurgical aspects such as chemical composition, cold working, microstructure and inclusions have a marked effect on the machinability of this class of metallic material. The aim of this study is to evaluate the machinability of steel in relation to metallurgical aspects, by means of a survey of the literature. It was found that in cold working, in order to increase the hardness and decrease the ductility of steels, it is necessary to promote their hardening. It was also found that in terms of chemical composition and microstructure, it was possible to verify respectively that the phase change caused by heat treatment affects its machinability and that the increase in the sulphur content of the steel results in the formation of small chips during machining, favouring less flank wear of the cutting tool. It can be seen that knowing the machinability of steel, its characteristics and adding some alloying elements and knowing some process parameters can improve the process.