The aim of the following master thesis is the proper simulation of the BOF pre-process. In particular it starts at the charging point of the materials when added into the converter and ends at the start of blowing. The program is based on the former investigations and developments of Lytvynyuk [1] and Bundschuh [2].The used compiler for the calculation is MatLabTM®2014b. Process steps like the time depended mass flow during the charging of hot metal and the influence of tilting the converter are investigated and mathematically described. For example the already mentioned tilting of the converter influences the bath level and the number of bottom tuyeres in action. Also the behaviour of hot metal was examined, especially the formation phase of a frozen hot metal shell at the surface of cold scrap, whilst charging and right before start of blowing. The already implemented diffusive melting module for scrap designed by Lommel and Chalmers [3,4] was changed to the model of Zhang and Oeters et al. [5]. Further it was enhanced through the calculation and installation of liquidus projections in FactSageTMVersion 7.0 for varying chemical compositions of scrap. This improves the description of the melting behavior because the calculated liquidus carbon content influences the driving force of the reaction. The heat transfer coefficient (HTC) for the description of convective scrap melting was also investigated. Therefore several empirical equations were compared and rated. Additionally a self designed model was developed. This model is based on the calculation of the bath velocity via the dissipation energy and the following description of the HTC using the Nusselt number. The post combustion is described by the comparison of polynomial functions of CO and CO2, which are based on data from the industry [1]Y. Lytvynyuk, Thermodynamic and kinetic modeling of metallurgical reactions, Dissertation, Leoben, 2013. [2]Philip Bundschuh, Modelling of the LD-process, Dissertation, Leoben, 2017(in Print).