METHOD FOR ACCURATELY PREDICTING DISSOLVED CARBON QUANTITY REMAINED IN MOLTEN STEEL AFTER VACUUM DEGASSING TREATMENT BY USING PARTIAL PRESSURE EQUILIBRIUM EXPRESSION FOR DECARBURIZATION

摘要

PURPOSE: To provide a method for accurately predicting dissolved carbon quantity remained in molten steel by measuring partial pressures of dissolved oxygen quantity and carbon monoxide after vacuum degassing treatment based on a partial pressure equilibrium expression for decarburization in vacuum degassing process, thereby substituting the measured partial pressures for the equilibrium expression. CONSTITUTION: The method for predicting dissolved carbon quantity in vacuum degassing process comprises first step of calculating an initial ratio of £C|/£O| in molten steel before vacuum degassing treatment, and performing recarburizing or decarburizing treatment so that the ratio of £C|/£O| is in the range of 0.7 to 1.3 if the ratio is deviated from a range of 0.7 to 1.3; second step of making vacuum degree of a vacuum degassing apparatus into the lowest vacuum degree required for decarburization within 8 minutes; and third step of obtaining dissolved carbon quantity by the following expression (1) by measuring treatment temperature, dissolved oxygen quantity in molten steel, and partial pressure of carbon monoxide after the vacuum degassing treatment.