Modeling of the Nonuniform Microstructure and Microsegregation Formation of the Shell in Round Billet Continuous Casting

Abstract

To explore the influence of nonuniform heat transfer on the grain structure and microsegregation of carbon in shells inside the mold, a multiscale model considering heat conduction and dendritic growth is constructed for the round billet continuous casting. Adopting measured heat flux as the boundary conditions, heat conduction in the mold is solved by the finite difference scheme, and dendritic growth is modeled by the cellular automaton model. The temperature distribution of the round billet under measured heat flux is calculated, and the grain structure and the microsegregation of carbon in four selected regions are simulated. Herein, it is shown in the results that the different local heat fluxes lead to dissimilar variations in the surface temperature and grain structure of the shell. A close relationship exists between the carbon microsegregation and local heat flux; the carbon microsegregation decreases with heat flux. The high heat flux accelerates columnar dendritic growth and fines the columnar dendritic array so that the secondary arms are less developed and the microsegregation is improved.

Influence of the Specific Heat Capacity, Thermal Conductivity Coefficient, Density and Cooling Rate on Formation of Crystallization Centers in Metallic Melts

“…Synergetic methods allow a qualitatively new approach to solving the problem. Thus, for example, in [6][7][8][9][10], by using the method of analogies between the displacement of the liquid-solid interface and the propagation of a switching wave in a bistable trigger-type cellular automaton, a formula was proposed for determining the critical radius of the nucleus during crystallization: It should be emphasized that formula (1) takes into account the cooling rate of the metal during crystallization. This significantly distinguishes it from the classical formula:…”