Liu T. Research and development of oxygen-converter lances of rational design and increasing the efficiency of converter smelting during their operation. - Qualifying scientific work on the rights of manuscript

Thesis for the degree of Candidate of Technical Sciences in specialty 05.16.02 "Metallurgy of ferrous and non-ferrous metals and special alloys" - National Metallurgical Academy of Ukraine, Ministry of Education and Science of Ukraine. Dnipro 2020. The thesis is devoted to research of influence of oxygen-converter lance tip design on blast parameters of converter melting and technological indicators of process, study of hydrodynamics of lance tip cooling, development of rational design of oxygen-converter lance tip and new methods for its manufacturing. With the help of computational-analytical and experimental-industrial studies, results have been obtained on the organization of cooling of oxygen-converter tuyeres tips, depending on their design. New designs of tips based on a crown and a nozzle block with a guide plate and turbulators in the form of an Archimedes spiral on the inner surface of the crown and compensators for temperature loads have been developed.New methods and technologies for the manufacture of oxygen-converter tuyeres tips have been developed and experimentally substantiated. It is significant that the production costs of tips has been reduced by 30-40%, and their quality has been increased. Manufactured tips of rational design were used for blowing in 60 t and 160 t converters of Ukrainian factories and at the Chengde Steel plant (China). Operation has shown an average stability of the tips of 450-600 heats in the absence of nozzles erosion on the outer surface of a crown. Technological indicators of melting have been impoved. Key words: oxygen-converter lance tip, design and manufacture of the tip, cooling and tip stability, oxygen blowing, technological parameters, converter melting.