Abstract
Currently, the main part of car body parts is made of IF steel (Interstitial Free) - steel without free embedding atoms, with a very low content of carbon and nitrogen in the solid solution (ferrite). Its carbon content is less than 0.003%. The article analyzes the melting of IF-steels carried out in the oxygen-converter shop with vacuum decarburization, deoxidation, and titanium alloying of the metal during metal vacuum in a RH-type vacuum unit. An analysis of previously smelted IF-steels was conducted, and based on it, a balance calculation of the change in carbon content in the metal during its decarburization in a vacuum was performed. The main part of the oxygen that dissolves in the liquid metal enters the metal when it is blown in an oxygen converter. In this case, the author identified additional sources of oxygen supply to the metal during vacuum treatment. The main additional source of oxygen can be considered to be oxygen, which enters along with the transporting gas - argon. It was also established that part of the dissolved carbon interacts with residual elements (chromium, titanium, vanadium, niobium, and others), which are present as carbides in the liquid solution of the metal.
Keywords:
IF-steels, vacuuming, carbides, metal oxidation, argon purity