Investigation of chemical composition of quenching oil on cooling properties

U radu je opisan postupak kaljenja, kao jedan od najbitnijih postupaka za značajnije povećanje čvrstoće (tvrdoće) obrađivanog komada. U radu se prolazi kroz sve faze kaljenja, te se poseban naglasak stavlja na odabir sredstva za gašenje, koje utječe na dobivenu mikrostrukturu nakon kaljenja, te na mogućnost pojave pukotina i deformacija uslijed velikih zaostalih toplinskih naprezanja. Kao jedno od najpogodnijih, te isto tako najkorištenijih medija, detaljno se opisuje ulje za kaljenje. Naglašava se kako je izuzetno bitno odabrati odgovarajuće ulje, te analizirati karakteristike njegovog djelovanja. U eksperimentalnom dijelu rada prati se proces ohlađivanja odabranih uzoraka ulja za kaljenje. U svrhu ispitivanja svojstava medija za ohlađivanje koristi se metalna proba izrađena od legure Inconel 600 po normi ISO 9950. Ispitivanje je provedeno na 6 različitih ispitnih uzoraka ulja oznake: LAB305/19, LAB306/19, LAB307/19, LAB308/19, LAB309/19 i LAB310/19.In this work the process of quenching, which is one of the most important processes for substantial hardening of treated pieces, is described. This work goes through all stages of quenching emphasizing the selection of media for quenching which affect the acquired microstructure after quenching and the possibility of cracking and deformation due to big residual heat stresses. One of the most suitable and also most used media is quenching oil, which is described in detail. The importance of selecting the appropriate oil is emphasized as well as analysing the characteristics of its influence. The experimental part of this work follows the process of cooling of the selected samples of quenching oils. For testing of the medium's characteristics, a metal probe made of Inconel 600 alloy by the ISO 9950 norm is used. The experiment is conducted on 6 different oil test samples designated: LAB305/19, LAB306/19, LAB307/19, LAB308/19, LAB309/19 and LAB310/19