Teslevich S. New Technologies and Equipment for Production of Titanium Sponge and its Remelting into Ingot

The thesis considers solution of the problems of development of a fundamentally new unit for production of 3.8 MT titanium sponge per cycle, in comparison with the process of production of 0.87 MT per cycle that is available in the industry of Ukraine. New technologies for magnesium reduction of titanium tetrachloride and vacuum separation of the reaction mass formed in the reduction process to produce the highest-grade titanium sponge were developed on the basis of a package of general engineering, heat engineering and technological research. Another series of experiments consisted in melting of titanium sponge produced in the first phase of experiments was carried out. The correlation existing between increase in the chlorine content of titanium sponge and hydrogen concentration of the gas phase over the melt was established for the first time. It is shown that in induction melting the hydrogen content of an ingot follows the Sivert’s law. In plasma melting, the hydrogen concentration of metal is higher than the equilibrium level. The new technology was developed for melting of titanium sponge with the increased chlorine content (0.08-0.45 wt. %) to produce ingots. It comprises first remelting of titanium sponge in induction furnace with a sectional mould, and then second remelting, which can be carried out in vacuum arc, electron beam and plasma arc furnaces. Along with the development of commercial production of ingots from a new quality titanium sponge, the experiments were also conducted to produce shaped titanium castings using combined consumable electrodes in upgraded casting skull furnaces with a new design of the non-water-cooled titanium crucible.