Abstract: Local dynamic equilibrium reaction process for the reactions involving complex inclusions,molten steel,slag and refractory materials in steelmaking of high carbon hard wire 82B steel melt was studied and the compositional variation of the inclusions using Mn,Si and Al deoxidation was discussed.The formation condition of plastic inclusions for the Al₂O₃-SiO₂-MgO-CaO-MnO system was calculated and analyzed by the thermodynamic software FactSage.The results reveal that the mass fractions of Al and O in molten steel are controlled at 25×10^-6 to 100×10^-6 and 5×10^-6 to 20×10^-6,respectively.In the low-melting point zone,the mass fraction of Si is controlled at 0.1% to 1.5% and that of Mn at 0.2% to 1%.