Title: Simulation of segregation in continuous casting of high-carbon Fe-C alloys

Authors: B. Bozzine, M. Serra, A. Fanigliulo, L. Antonetti, M. Boniardi

Addresses: INFM-Dip. Ing. Innovaz., Universita di Lecce, V. Arnesano, 73100, Lecce, Italy. Dipartimento di Chimica Fisica Applicata, Politecnico di Milano, pz. L. da Vinci 32, 20132 Milano, Italy. Dipartimento di Meccanica, Politecnico di Milano, pz. L. da Vinci, 32, 20132 Milano, Italy. INFM-Dip. Ing. Innovaz., Universita di Lecce, V. Arnesano, 73100, Lecce, Italy. INFM-Dip. Ing. Innovaz., Universita di Lecce, V. Arnesano, 73100, Lecce, Italy

Abstract: In this paper, we propose a mathematical model devised to simulate the segregation profile on a cross-section of a high-carbon steel bloom produced by continuous casting, as a function of the operation conditions of the plant (withdrawal speed, superheat and coolant flow). The model consists of two coupled routines simulating the thermal and segregation behaviour of the system. The segregation routine is innovative, because (i) it simulates the segregation process accurately, and (ii) it can be used for on-line simulation of the behaviour of an industrial continuous casting process. In order to reduce the computational problem to a manageable degree of complexity, the physics of the process can be modelled with two time-dependent parameters describing (i) convective effects on the distribution of the solute (homogenisation parameter χ_o); (ii) displacements from thermodynamic equilibrium brought about by mass transport at the solid-liquid interface (effective partition coefficient κ_Pe), a function of the total liquid fraction χ_i,tot through the local thermal gradient ΔT). The numerical model is 2-D, but 3-D information is conveyed by the parameters χ_o); and κ_Pe. The mathematical model includes the flowing balances energy, mass, species and momentum; the overall system can be simplified by including convective effects through the time-and space-dependent homogenisation parameter χ_o. The number of equations is matched to the number of unknowns by correlating the liquid phase composition with the temperature through the linearised equilibrium Fe-C phase diagram. The results of the numerical simulation of the segregation profile are in good agreement with the experimental data available in the literature; the results of the thermal simulation are in excellent agreement with experimental data obtained in this work.

Keywords: solidification; segregation; high-carbon steel; continuous casting.

DOI: 10.1504/IJCAT.2002.000294

International Journal of Computer Applications in Technology, 2002 Vol.15 No.4/5, pp.186-194

Published online: 15 Jul 2003 *

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