Wu Guorong

Key Technologies for Square/Round Billet Continuous Casting

According to the problems of bad castability of molten steel, surface longitudinal cracks and the difficulty of elimination for internal defects of billet in rolling process, the technologies of continuous casting process and quality control for square/round billet have been studied systematically. On this basis, integrated techniques of continuous casting process and quality control for billets are proposed, containing castability optimization, surface and internal quality improvement of billets. Large scale production application shows that the number of heats per sequence in a single tundish is increased from 4~5 heats to 7~8 heats. The non-defect rates of surface quality reach 98.91% and 97.81% for square billet and round billet, respectively. The comprehensive rates below level 1.0 of internal defects of center porosity, center segregation and center cracks are above 98.9%% and 98.5% for square billet and round billet, respectively. Furthermore, carbon segregation index is in the range of 0.93~1.09.