Biktagirov F. Electroslag technologies with a non-consumable graphite electrode used in melting and refining of steels and alloys

The thesis is devoted to the investigation of physical – chemical, metallurgical and thermophysical laws applied to electroslag melting with a non-consumable graphite electrode, development of new and updating of known electroslag technologies of heating, treatment and melting of metals. It was established that to limit the metal carburization, it is necessary to use a slag with a definite ratio of СaO and SiO2 concentration, and to keep the temperature of slag melt lower than the temperature of formation of carbides of calcium and silicon. Procedure has been developed and sulphide capacity of melts of CaF2-CaO-Al2O3-SiO2 system. Thermophysical features of formation of ingots in electroslag casting (ESC) and portion electroslag casting (PESC) were defined. Technologies of production of ESC and PESC ingots of up to 75 tons were developed. It is shown that these methods allow improving greatly the quality of forged ingots designed for manufacture of critical products with higher service characteristics.Technology of elecrtoslag melting and refining (ESMR) from a non-compact charge of manganese – copper alloys with damping properties at the level of the best samples for the similar metal, including the case of use of metallurgical manganese instead of electrolytic manganese, has been developed. Technology of elecroslag melting from converter vanadium slag of vanadium-containing master alloys with 95-97% degree of vanadium extraction and high technical-economical characteristics has been developed and realized.