Papers by Author: Heli Kytönen

Abstract: Industrial data set with 400 CC (continuous casting) steel slabs were analysed by a statistical method for revealing the real connections between the technological parameters, heat transfer model results and the precisely determined centerline segregation index. Because of the poor correlations a new model was developed in which the shrinkage and deformations of the shells of the slabs can also be taken into account. It has been proved that the stopping of liquid movement below about 30 % liquid ratio plays an important role in the centerline segregation formation. The conclusions of the calculations are in good accordance with the results of the metallographical analysis.

Abstract: Industrial data set with 400 CC steel slabs were analysed by a statistical method for revealing the real connections between the technological parameters, heat transfer model results and the precisely determined centerline segregation index. Because of the poor correlations a new model was developed in which the shrinkage and deformations of the shells of the slabs can also be taken into account. It has been proved that the stopping of liquid movement below about 30 % liquid ratio plays an important role in the centerline segregation formation. The conclusions of the calculations are in good accordance with the results of the metallographical analysis.

Abstract: The inner structure of the continuously cast semis has a great importance from the point of view of further processing and application. The main reason for this is the very direct effect of the inner structure’s features (ie. porosity, macrosegregations, geometry of primary dendrites) on the technological characteristic features of the semis during further processing (ie. crack sensitivity, formability, etc.). The paper deals with the possible ways of macrostructure determination on the basis of the results of mathematical modeling of continuous casting process. We pay a special attention to the columnar-equiaxed transition as a function of heat parameters of the casting process and to the macrosegregation formation caused by the motion of solute enriched interdendritic liquid in the mushy zone.