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The paper describes the knowledge about and results of the experimental heats performed in an electric steel plant. The aim was to verify the possibilities of a controlled desulphurization of alloy steel in a VOD (Vacuum Oxygen Decarburization) device, particularly when using chemical heating through the OVD process (Oxygen Vacuum Deoxidation/Degassing), as well as the standard slag formers. Experimental procedures were used in the production of alloy tool steel. Both, the system of making the reducing slag and optimizing the composition of individual oxides in order to achieve the desired basicity, are complicated by the products of the chemical heating. Therefore, it was necessary to develop a new production technology that would eliminate such oxide products of chemical heating and, thus, the maximum degree of desulphurization could be achieved. The main principle of the technology is to create appropriate thermodynamic and kinetic conditions required for desulphurization. In particular, this concerns a low oxygen activity in the steel, the composition of refining slag, and an intense bath stirring with argon. Članek opisuje znanje in rezultate raziskave eksperimentalnih talin, izdelanih v elektrojeklarni. Namen je bil preveriti možnost kontroliranega razžvepljanja legiranega jekla v VOD (Vacuum Oxygen Decarburization)-napravi, posebno med uporabo kemijskega ogrevanja med OVD (Oxygen Vacuum Deoxidation/Degassing)-postopkom, kot tudi standardnih gradnikov žlindre. Eksperimentalni postopki so bili uporabljeni pri proizvodnji legiranega orodnega jekla. Oboje, tvorba reduktivne žlindre in optimalna sestava posameznih vključkov, z namenom doseganja želene bazičnosti, ovirajo produkti kemijskega ogrevanja. Zato je bilo potrebno razviti novo tehnologijo proizvodnje, ki bi preprečila oksidne produkte kemijskega ogrevanja, kar bi omogočilo doseganje maksimalne stopnje razžvepljanja. Osnovni princip nove tehnologije je zagotoviti ustrezne termodinamične in kinetične pogoje, potrebne za razžvepljanje. To pomeni nizko aktivnost kisika v jeklu, sestavo rafinacijske žlindre in intenzivno mešanje kopeli z argonom. |
