METHOD OF SMELTING LOW-P STEEL BY TOP AND BOTTOM-BLOWN CONVERTER

摘要

PURPOSE:To enable to smelt low-P steel by a single slag method and to shorten a time for making steel, by controlling the amount of bottom-blown gas to be changed by the basicity of slag and C content in steel melt at a predetermined value, and rinsing the steel melt after the completion of blowing. CONSTITUTION:Under the operational condition of the basicity (CaO/SiO2) of slag =4, the amount of bottom-blown gas is held =0.07Nm3/min.ton from the start of blowing until C content in steel melt is lowered to 0.4% at most. In succession, the amount of bottom-blown gas is held =0.05Nm3/min.ton until C content in the steel melt comes to an objective value. After the completion of blowing, the further injection of bottom-blown gas only is executed. Hence low- P steel is smelted by the single slag method, and a time for making steel is shortened.