Considerations Regarding the Evolution of the Solidified Crust at the Continuous Casting Steel

The continuous casting of the steel can cause cracks on the surface or inside, which arise due to thermal and mechanical stresses. To eliminate these defects, mathematical models are drawn up with which temperature fields, expansions and stresses can be determined. The purpose of making these models is to locate the areas with a high risk of cracking so that, finally, the continuous casting machines and working conditions can be modified, so as to eliminate, or at least diminish, the defects. The knowledge of the thermal state of the steel in the continuous casting machine is necessary for the transposition on mathematical bases of the technological process and the elaboration of some simulation models of the solidification, which would allow the optimization of the afferent plant. The proposed mathematical model takes into account when studying the heat transfer phenomena in the tundish the convective motion of the steel, which influences the thickness of the solidified crust and the evolution of the temperature in the section of the continuously cast steel thread. By running the simulation program were determined the variation of the thickness of the solidified crust as a function of time, overheating in the crystallizer and convection coefficient.