Modeling of crystallization of iron-carbon melts with alloying additives of Al, V, Ti taking into account chemical reactions

Solidification is one of the main links in the process of obtaining and processing metals. The structure and properties of the casting and ingot intended for further processing are determined mainly by the solidification process. Elimination or at least reduction of chemical heterogeneity and internal defects in the cast state allows to expand the scope of application of castings and reduce the number of defects, significantly improvethe mechanical properties of the products obtained. It should be noted that the processes of metal and alloy solidification and, in particular, primary crystallization have not been sufficiently studied at present. This is explained primarily by the complexity of the processes of nucleation and growth of primary crystallites and the large variety of variable factors that appear during the crystallization of technical alloys. The issue of heterogeneity and internal defects of cast metals and alloys continues to be the focus of attention of scientists and practitioners. The processes of steel production and subsequent processing are based on numerous and varied transformations. Among such transformations, which have a strong influence on the quality and operational properties of the finished steel, are reactions of formation and dissolution of non-metallic inclusions both in molten and solid metal. The efficiency of a particular technological operation of steelmaking ultimately depends on the completeness of the corresponding chemical reactions. The final concentrations of carbon and alloying elements in steel, as well as the concentrations of harmful impurities, depend on how far these reactions go. A physical model of cooling and crystallization for simulating solidification of multicomponent iron melts taking into account chemical reactions between the components and software have been developed. The model is based on the theory of a quasi-equilibrium two-phase zone. The law of conservation of mass is fully satisfied. The model uses a parameter that takes into account the diffusion coefficient of carbon in the solid phase, the distance between the second-order dendritic axes and the local solidification time. The chemical interactions during crystallization in the Fe-C-N-Al-V-Ti system have been simulated and it has been shown that taking into account chemical reactions and diffusion of components in the solid phase has a significant effect.