QUENCHING OF STEELS

Tema ovoga rada je toplinska obrada čelika postupkom kaljenja. Na početku ovoga rada je ukratko objašnjen opći dijagram toplinske obrade te njegove faze. Dalje u radu detaljnije je opisan postupak kaljenja sa svim njegovim fazama, objašnjen je izbor parametara postupka kaljenja, dana su sredstva za hlađenje te objašnjeni načini hlađenja. Na kraju teorijskog dijela ukratko su objašnjeni pojmovi kaljivost, zakaljivost i prokaljivost te su spomenuti postupci kaljenja čelika i ukratko je svaki od njih objašnjen. U eksperimentalnom dijelu rada provedeno je kaljenje na uzorku izrađenom od čelika C45. Potrebno je pripremiti ispitni uzorak, ispitati njegovu tvrdoću i mikrostrukturu prije kaljenja, kaljenje ispitnog uzorka, ispitivanje tvrdoće i mikrostrukture nakon kaljenja te analiza rezultata ispitivanja prije i poslije kaljenja.The topic of this paper is the heat treatment of steel by the process of hardening. At the beginning of this paper, a general diagram of the heat treatment and its phases are briefly explained. Further in the paper, the process of hardening with all its phases is described in more detail. The selection of the parameters of the hardening process is explained, cooling agents are given and the cooling modes are explained. At the end of the theoretical part, the concepts of hardenability are briefly explained, and the processes of quenching of steels are mentioned and briefly each of them is explained. In the experimental part, the process of hardening was carried out on the sample made of C45 steel. It is necessary to prepare the test sample, examine its hardness and microstructure prior to hardening, and then after the process of hardening the same tests of hardness and microstructure are done on the test sample. After all tests are done, results of analysis are given and compared with each other