Received: Oct 27, 2020 / Published: Dec 31, 2021
In order to select an appropriate heat treatment process for an industrial application of S45C medium carbon steel, it is necessary to investigate the influence of technological parameters during the heat treatment process such as heating temperature, holding time and cooling medium on the microstructure and mechanical properties. In this study, the experiments were conducted in various heating temperatures, holding times and cooling mediums for specimens made of S45C steel. Then, the relationship between the microstructure and the hardness of the steel was examined. The obtained results show that the heating temperature and cooling medium strongly affect the microstructure of this steel, leading to considerable changes in the hardness. The hardness of S45C steel was markedly improved when heated above 800oC and cooled in water. Moreover, the holding time needs to be carefully calculated to obtain finer grain structure to prevent an increase in the brittleness.