(EOSC_031)Kinetic assessment of decarburization of Stainless steelmaking process using Hot metal by coupled reaction model with oxygen blowing

摘要

In the converter for decarburization of stainless steel, the precise control of temperature by the oxidation of C and Cr is quite important. The optimum conditions for decarburization operation are necessary to prevent the significant oxidation of Cr in the molten steel because the oxygen potential to oxidize Cr is very close to that to oxidize C. Previously many researchers reported the condition to suppress the oxidation of Cr in low carbon region. On the other hand, in the actual operation, the oxidation of Cr occurs not only in the low carbon region but also in the initial stage of the decarburization because of the low temperature. Based on the thermodynamic calculation, when the Cr content in the molten phase increases before temperature reaches high, the preferential oxidation of Cr would occur in the region of high carbon content. This situation occurs when the ferrochromium alloy is added to the dephosphorised hot metal in low temperature, or when the charging temperature of the Cr containing hot metal made by smelting reduction is not enough high. In order to investigate the optimum conditions to prevent the preferential oxidation of Cr, we developed the kinetic model to simulate the decarburization in the converter process of stainless steel using coupled reaction model with oxygen blowing. By the experimental results of 300 kg of hot metal, the simulation results were compared with the measured changes in the content of Si, C and Cr, and the temperature. By the developed model, the influence of oxygen blowing conditions on the preferential oxidation of Cr were investigated.