Analysis of metal mould heat transfer coefficients during continuous casting of steel

Abstract

Heat transfer coefficients in the mould were determined by the inverse method and they are related to both process conditions and carbon equivalents of steels. Experimental data were obtained from an industrial plant by temperatures measured in moulds of the continuous casting machine by thermocouples placed in the mould wall in known positions. The temperatures are compared to profiles of simulations by the numerical model of both solidification and heat transfer processes previously examined. As a result, the numerical model calculates the heat transfer coefficients in the metal/mould interface for heats cast with different process parameters. The results make possible the determination of expressions for the calculation of the interfacial metal/ mould heat transfer coefficients that include the effects of steels grades, mould faces, casting speed, mould taper, mould section and pouring temperatures for a range of process parameters.

The Interrelation between Casting Size, Steel Grade, and Temperature Evolution Along the Mold Length and at the Strand Surface during Continuous Casting of Steel

“…9, the thermocouple TC3 recorded the highest temperature, indicating that the meniscus level is deeper than those observed for the 180 and 240 molds. This behavior is in agreement with findings of previous studies which show that heat transfer is higher for medium and high carbon steels when compared with low carbon steel, and that the maximum heat flux values in the meniscus region are due to the best thermal contact between the liquid metal and the mold wall [23,40,41].…”

Element-Free Galerkin Formulation by Moving Least Squares for Internal Energy Balance in a Continuous Casting Process

“…On the basis of the aforementioned issues, it can be concluded that the solution of more complex 3‐D transient problems does not necessarily mean obtaining better results. Even today, several researchers are still conducting studies based on 1‐D pseudo‐transient models in order to analyze more specific issues regarding the CC process, such as: the convective heat transfer at the solid–liquid interface, and the convective coefficient for the Robin cooling condition through the solution of a mold‐slab coupled heat transfer problem . On the other hand, in the longitudinal section approach, the domain analysis implies explicitly the whole region of interest from the meniscus until the mold outlet, which results in a more accurate computation of boundary conditions and material properties .…”

“…On the other hand, the EFG solution presented in this work requires just 1st order differentiable shape functions and provides greater accuracy in computing the material properties at any domain position (not just at the nodal positions), since it has been formulated to solve the weak‐form presented at the integral Equation 15. The CC slab heat transfer model has been solved under the following assumptions: (i) An Eulerian Description is employed over the slab longitudinal thickness to solve the 2‐D heat transfer equation; (ii) The solution is acceptable for most of the slab wide face excluding the areas closest to the corners; (iii) There is not Newman heat flux q 0 condition on the boundaries but just a cooling Robin condition; (iv) The material properties and the cooling Robin condition exhibit a significant temperature dependence (nonlinear aspect); (v) Increased heat transport in the liquid core due to convection is taken into account by an effective thermal conductivity as proposed by Zhang et al; (vi) The temperature at the meniscus is uniform and assumed to be equal to the casting temperature; and (vii) The top and bottom surfaces of the mold are considered to be adiabatic, and heat absorption by the mold powder above the meniscus is negligible. The physical and transport properties are computed considering a Phase‐Fraction Model: …”

“…Several authors have carried out studies of control models for secondary cooling on the basis of FDM numerical models, including nonlinear aspects. Barcellos et al have conducted studies of metal mold heat transfer coefficients applying an inverse method where the one‐dimensional transient heat conduction equation is solved based on a FDM approach but considering constant physical, process, and transport properties. In the field of other conventional numerical method, Xia et al and Jian‐Xun et al have simulated the thermal–mechanical behavior in slabs and blooms employing total Lagrangian and mixed Eulerian–Lagrangian formulations, respectively.…”

Analysis of the heat transfer coefficients of the whole process of continuous casting of carbon steel

“…However, the main physical phenomena source that affects the continuous casting is the heat transfer in all three regions. For instance, irregularities in the cooling process at the boundaries of the mold may induce an uneven solid ingot shell, which can produce breakpoints at the mold exit or crack formation [1,5,8,10,11]. These problems directly influence the quality and cost of production.…”