CC-BY-NC-NDStamenković, UrošMarković, IvanaMladenović, SrbaMarjanović, SašaKovačević, AvramMitrović, MilijanaBasarabić, Filip2023-12-262023-12-262023978-86-6305-140-9https://ioc.tfbor.bg.ac.rs/public/2023/Proceedings_IOC_2023.pdfhttps://repozitorijum.tfbor.bg.ac.rs/handle/123456789/2511The subject of this paper was the investigation of the influence of different quenching media on the mechanical, thermal, and structural properties of C45 medium carbon steel. After normalization heat treatment, steel samples were austenitized at 880°C for 50 minutes. Austenitization was followed by quenching in different quenching media: pure water and different aqueous solutions (2–8%) of NaOH. After each heat treatment, hardness and thermal properties were determined, along with structural investigations using the optical microscope. After normalization, samples had the lowest hardness values, while thermal conductivity was the highest compared to the other tested samples. Metallographic analysis showed that the structure consists of fine-grained ferrite and perlite. Quenching in water and aqueous solutions, the values of hardness increased significantly, while the values of thermal properties decreased. Samples quenched in aqueous solutions exhibit extreme hardness. Metallographic analysis of the samples after quenching revealed fine needles of martensite.enquenchingaqueous salt solutionshardnessthermal conductivityconferenceObject