Troyans'kyj O. Development scientific and technological fundamentals of electroarc and electroslag metals quality control

Dissertation is devoted to development of theoretical and technological fundamentals of metal quality control on the basis of creation of technological facilities and control systems (ACS) for processes of steel melting in electric furnaces, development of technology of casting of plates and plate ingots with specified structure, theoretical investigations in the field of mass transfer and methods of refining processes intensifying with the aim to obtain a high quality metal. System of monitoring of technological process status from information about the shape of instant arc voltage signal obtained with using of wavelet analysis and neural-network computing is developed. Items of thermal balance of superpower arc steelmaking furnace (ASF) were quantitatively evaluated and taken into account in the blocks of dynamic ACS. Main laws of horizontal ingots structure formation from metal of open melting and ESR method were established. Recommendations for quality control and organizing of their industrial producing were given. It was established positive influence of mechanical horizontal vibration oscillations in the range 78-123 Hz on refinement of dendrite structure of cast product. . It was shown the high level of mechanical properties of horizontal ingots as in cast as in deformed state. With the help of physical simulation the phenomenon of electrode metal film rupture at ESR even before the droplet formation stage and its fast rising through the tip of electrode was established. It provides the intensive liquid stirring. In analytical way with using of Higby's model the equations for mass transfer coefficients for components in the system "metal - slag" were obtained and method was developed and equations were obtained for determination of apparent activation energy of physical-chemical process, flowing in diffusion regime in two-phase system. The phenomenon of "self-vibration" of consumable electrode during ESR under the fluxes of system in the range of metal calcium content from 1 to 10% was established. New possibilities of electroslag remelting in chamber-type furnaces for utilization of wastes of titanium manufacturing were shown. Development works, presented in dissertation, were approbated in laboratory and industrial conditions and part of them, connected with on-line control, technological process monitoring and adaptive control systems of electric regime of ASF were implemented in practice.