JPS5620112A - Production of low hydrogen steel - Google Patents

Abstract

PURPOSE:To make possible the production of low hydrogen content steel by changing over the cooling hydrocarbon from a bottom blowing lance to an Ar gas prior to decarbonizing to the target blowing-out carbon amount at the time of refining steel in an oxygen top blowing converter provided with a bottom blowing function. CONSTITUTION:At the time of performing decarbonization and refining in an oxygen top blowing converter provided with bottom blowing double lances in the furnace bottom, the oxygen from the bottom blowing nozzles is changed over to an inert gas such as Ar or mixed gases of O2 and inert gas when the carbon amount of molten metal becomes 0.8-1.0% in case the final blowing-out carbon amount is 0.50-0.40% and when the carbon amount of molten metal lowers to 0.30-0.50% in case the blowing-out carbon amount is <=0.10%. At the same time, an inert gas such as Ar is spouted in place of the cooling hydrocarbon from the bottom blowing lances. The absorption of the H2 gas produced by the decomposition of hydrocarbon at the end period of refining is less and the low hydrogen steel may be produced by dehydrogenation by the Ar gas.