Formation zone of fluorine-free mold fluxes for slab continuous casting of low carbon steel

In order to develop fluorine-free mold fluxes into stable properties for slab continuous casting of low carbon steel, the formation regions of fluorine-free mold fluxes were investigated. Based on the test of the physical properties of traditional fluorine containing (F-&le3%) fluxes, the slag samples, fitting to the compositional characteristics of mold fluxes, were designed by using the mathematical complex method in the slag system of CaO-SiO2-Al2O3- Fe2O3-MgO-Li2O-TiO2- Na2O-MnO-B2O3. By fixing some variable components step by step, the multidimensional composition space was transformed into two-dimensional plain grids, from which the nodal points were used as compositions of fluxes. Compared with the properties of fluorine containing fluxes, three formation regions of fluorine-free fluxes, with a lower basicity, melting point, viscosity and breaking temperature, and solidified in the glassy state, were found. The typical components in one of the regions were CaO 31.2%, SiO2 36.8%, Al2O3 3%, Fe2O3 1%, MgO 2%, Li2O 2%, TiO2 6%, Na2O 7%-12%, MnO 3%-8%, and B2O3 0-3%.