Continuous casting (CC) became one of the dominant steel production technologies throughout last decades. Better quality, energy savings and high production rates are the main aims of the research especially in the field of the thin slab casting (TSC). The electromagnetic brake (EMBr) is applied to control the highly turbulent flow after the fresh melt is fed through the ports of a submerged entry nozzle (SEN). The numerical modelling is a perfect tool to investigate the multiphase phenomena of the turbulent flow in the CC mold, heat transfer and solidification coupled with the effects of the magnetohydrodynamics (MHD). Traditionally the heat transfer in the CC mold during the numerical simulations is predefined by the heat flux profile which could be taken from the plant measurements, published data, or is described by the semi-empirical formulas. In all these cases the heat extraction in the CC mold cavity is strictly predefined and is not significantly influenced by the transient flow behavior. Moreover, the heat flux, used in a simulation, is frequently measured for the different flow pattern inside the mold. That is especially important when the EMBr effects on the solid shell formation are investigated. Thereby, the presented study considers the coupled heat transfer in the water-cooled copper mold, including the averaged thermal resistance between the slab and mold, implemented using OpenFOAM® open-source CFD software. The melt flow, the temperature field, and the induced electric current density are compared between the traditional approach (the applied heat flux) and the modelled heat transfer in the TSC mold. Different scenarios are studied without and with the applied magnetic field.