MELTING METHOD OF LOW PHOSPHORUS STEEL IN OXYGEN TOP BLOWING STEEL MAKING METHOD

摘要

PURPOSE:To make possible the production of low phosphorus steel with ease by blowing oxygen while blowing an inert gas through the furnace bottom at the time of performing iron making refining by the use of high basic molten slag with an oxygen top blowing converter provided with a bottom blowing function. CONSTITUTION:In making low phosphorus steel of =0.010% P with a converter by using low phosphorus iron of 0.080-0.150% P as raw material, slag of =2.5 basicity is used. In addition, the molten metal is agitated by blowing an inert gas of Ar or the like through the bottom nozzle of the converter at a rate of 5-50Nm3/Hr per ton of molten steel to improve the contact between the molten metal and the molten slag. Also, oxygen blowing is performed by using an oxygen gas of =46Nm3 per ton of the molten steel. By the oxidation action by this oxygen, FeO is contained at =12% as Fe in the molten slag, and this coupled with the high basicity of the molten slag accelerate the dephosphorization reaction of the molten steel, thus the low phosphorus steel of 0.010% P is easily produced.