[en] The thesis deals with a numerical model based on the finite element method applied to the continuous casting of steel. The model is developed using the LAGAMINE finite element code and two industrial applications of steel casting are presented to illustrate the capabilities of the model.
The first chapter introduces the continuous casting process, defining the essential terminology and the industrial challenges. Then, the objectives of the model are detailed: the model is applied to the upper part of the caster (in the mould region) as well as to the bending and straightening zones.
Chapters two, three and four are dedicated to the theoretical developments of thermal aspects (phase transformations, thermal contraction, heat flow and thermal boundary conditions), mechanical aspects (generalized plain strain state, material constitutive law, ferrostatic pressure and mechanical contact) and the staggered analysis used for thermal / mechanical coupling.
In the two next chapters, some numerical results are presented. The model has been first applied to a 125mm square billet in the mould region. The industrial goal is to evaluate the effect of the mould taper on the cooling of the billet (temperature evolution, solid shell growing, stress and strain development). The second application focuses on the risk of transverse cracking during straightening of steel slabs and the effect of some local defects (reduction of secondary cooling, locking or misalignment of rolls).
The thesis ends with some concluding remarks and perspectives for the model.
