Numerical simulation of deformation-induced segregation in continuous casting of steel

Abstract

The deformation-induced macrosegregation in continuous casting of steel has been simulated using a finite-volume scheme. For that purpose, a two-dimensional heat-flow computation was first performed in a Eulerian reference frame attached to the mold, assuming a unique solidification path, i.e., a unique relationship between temperature and enthalpy. This gave the stationary enthalpy field in the longitudinal section of the slab. On the other hand, bulging of the slab between two rolls was calculated in the same section, assuming plane-strain deformation and using the ABAQUS code. The Lagrangian reference frame was attached to the slab, and the rolls were moved at the surface until a stationary, bulging deformation profile was reached. The bulging of the surface was then used as an input condition for the calculation of the velocity and pressure fields in the interdendritic liquid. Using a fairly simple hypothesis for the deformation of the solid skeleton, the mass conservation and Darcy equations were solved in a Eulerian reference frame. This calculation was performed in an iterative loop, within which the solute conservation equation was also solved. At convergence and using the enthalpy field, this calculation allowed to obtain the temperature, the volume fraction of solid, and the average concentration fields, in addition to the fluid velocity and pressure. It is shown that the positive centerline segregation of carbon in the slab is well reproduced with this model. The effects of shrinkage and soft reduction were also investigated.

A Two-dimensional Finite Element Thermomechanical Approach to a Global Stress-Strain Analysis of Steel Continuous Casting

“…close to the solidus isotherm), we can see that there is also an alternation, but opposite: the steel is in a tensile state (negative pressure of about Ϫ2 MPa) when passing in front of rolls, while it is in a compressive state in between, the value of pressure being around 2 to 3 MPa. These results are in agreement with previous structural analyses of the deformation of the solidified shell between rolls, such as those carried out in static conditions by Wünnenberg,20) Dalin and Chenot (in three dimensions), 8) Miyazawa and Schwerdtfeger, 1) or by Kajitani et al 21) on limited slab sections moving downstream between rolls and submitted to the metallurgical pressure onto the solidification front.…”

“…However, the averaged profile, as drawn on the figure, is shifted in the downstream direction, which is in agreement with the literature. 1,8,20,21) • Final Discussion and Conclusion…”

Dilatancy in semi-solid steels at high solid fraction

“…For example, unwanted deformation caused by bulging or roll misalignment leads to macrosegregation [3][4][5] and can cause internal cracking [1]. On the other hand, external deformation can be beneficial such as the application of a 'soft reduction', a small rolling reduction (e.g.…”

Analysis and Application of Soft Reduction Amount for Bloom Continuous Casting Process

“…[12][13][14][15][16] Recently, Menghuai Wu and et al 15,16) developed a two-phase columnar solidification model to describe the effect of shell deformation, melt flow, dendrite growth on the macro-segregation behavior, and revealed more detailed mechanism and principles of SR. However, due to the complicated coupled macro and micro factors and variable industrial process, it is still difficult to precisely quantify the SR amount, and more studies were carried out with industrial trial method.…”