COMPARISON OF THE TEMPERATURE FIELDS OF CONTINUOUSLY CAST STEEL SLABS WITH DIFFERENT CHEMICAL COMPOSITIONS

The numerical model made by the authors was used for simulating the transient temperature fields of the continuously cast steel slabs with two different chemical compositions. The model solves the Fourier-Kirchhoff equation of the temperature fields of the slab-crystallizer system and the slab-ambient system with the following main thermophysical parameters: thermal conductivity, specific-heat capacity, density and enthalpy. When both melts follow each other closely, the critical state of the so-called breakout occurs at a certain point in the secondary cooling zone of a caster. It is probably a combination of surface defects. However, different chemical compositions of the two steels and their mixture are apparently decisive. Therefore, the temperature model simulated the temperature history of every point of a cross-section of a slab during its movement through the caster from the level of the melt in the crystallizer to the cutting torch for both melts and their mixture. The calculation of the temperature field of a slab is mainly focused on the part of the slab before the breakout and its surroundings. The results for the temperature field are used to set up a model of chemical heterogeneity of the steel supported by the material investigation of the samples taken from the breakout.