Patent ID: 6017380
Filing Date: 2000-01-25
Classification: C21C

Abstract:
A top-blown refining method in a converter maintaining an excellent decarburization performance by efficiently carrying out the blowing for decarburization to remove carbon from the molten steel from the initial period to last period of blowing by using a top-blown lance, said top-blown lance having nozzles blowing oxygen gas on a surface of a molten steel bath thereby forming a cavity having a depth with respect to a static surface of the molten steel bath prior to blowing, said method comprising the steps of:finding a properly expanding absolute secondary pressure P.sub.0p of nozzles of said lance;effecting the blowing by changing an oxygen supplying rate of oxygen gas supplied from the nozzles of said lance by changing an absolute secondary pressure P.sub.0 of nozzles of said lance at least one time within an improperly expanding range which is from 0.7 to 2.5 times as great as said properly expanding absolute secondary pressure P.sub.0p of said nozzles; andadjusting the cavity depth in the surface of the molten steel formed by a jet of said oxygen gas produced by blowing.