Dmytrenko I. The receiving of the fluoride-oxide fluxes for the processes of electroslag remelting of the metals

The analysis of methods for determination of total content of hydrogen in the fluoride-oxide systems has been carried out. The method for the analysis of hydrogen-containing gases to a single form in the form of molecular hydrogen and circuit implementation of this method were proposed. The design of the reaction tube, which eliminates the need for its frequent replacement was proposed, as well as composition of the converting reducing agent, which is self-recovery (manganese nitride, chopped fireclay and ferromanganese with ratio 1:1:1), which provides reliable operation of the reaction tube for a long time due to the presence of ferromanganese in a stream of nitrogen occurs the receiving of manganese nitride and its filling. The method of experimental study and quantification of the hydroprotective properties of the flux melts in the open remelting processes by means of dimensionless parameter is the index of accumulation of hydrogen of a remelted metal is developed. On the basis of the thermodynamic analysis it has been found that balance of reactions of pyrohydrolysis as a result of the slagging activity of silicon and aluminum oxides may be shifted towards formation of persistent chemical compounds. Termodynamically, the best ones are overall slag pyrohydrolysis reactions that give CaO·SiO2 in the fluoride-silicate systems, CaO·Al2O3 in the fluoride-aluminate systems and CaO·Al2O3·2SiO2 in the fluoride-alumosilicate ones. Calculations of the equilibrium composition of the gas phase over some of the fluoride-oxide melts for the temperatures within 1673...2073 K have been made. Calculations of activity of binary chemical compound CaO·Al2O3 in melts of the three-component CaO - CaF2 - Al2O3 have been made. Experimentally solubility of hydrogen in the fluoride-oxide melts in equilibrium with the atmosphere (HF + H2O)gas and (H2)gas within the range of temperatures from 1400 to 1700 Celsius degree has been studied. Regarding to the melting of steels were investigated the hydrogenprotective properties of some experimеntal fluxes, selected mainly on the basis of the system CaO-SiO2 and CaF2-CaO-SiO2. Were found original flux compounds that provide a reduction in the value of the index of accumulation of hydrogen of a remelted metal compared with the best standard fluxes. The last are recommended for the industrial development.