JPS5792121A - Method for estimation of phosphorus concentration of steel bath - Google Patents

Abstract

PURPOSE:To determine the effective amt. of oxygen used for oxidation of steel bath components accurately, estimate phosphorus concn. accurately and realize delicate dephosphorization control by analyzing the gases discharged from the steel bath in a converter. CONSTITUTION:An effective amt. of oxygen is determined in accordance with the amt. of O2 blown into a converter and the results of analysis of the gases discharged from the converter, that is, the respective concns. of CO, CO2, N2 and O2. On the other hand, the temp. of the steel bath and the amt. of C in the steel bath are determined by known sublance measurement during the course of blowing. The rate of decarbonization and the rate of desiliconization are determined from the amt. of C thus obtained, and the estimated value of the amt. of the molten steel, as well as the amts. of C and Si at the charging of the molten iron and the amt. of the molten iron, and further the amt. of O2 used for the decarbonization and desiliconization is calculated, from which the amt. of iron oxide in slag is calculated. From the amt. of iron oxide, and the temp. of the steel bath thus obtained, or further the amt. of quicklime charged as a slag making agent into the converter, the amt. of phosphorus contained in iron scraps, etc. charged as a coolant into the converter, etc., the phosphorus concn. in the steel bath at the time of the sublance measurement is estimated and calculated with high accuracy, for example, by utilizing the Balajiva's equilibrium equation.