| 摘要 |
PURPOSE:To make the use of inexpensive ore possible by charging pretreated molten iron into aconverter, and adding materials contg. Mn, Cr or Ni during oxygen blowing without adding any slag making agent thereby controlling the component concn. thereof. CONSTITUTION:The molten iron which is beforehand subjected to desiliconization, dephosphorization, and desulfurization is charged into a composite blowing furnace 1, and a lance 3 is inserted vertically through the upper opening thereof to blow gaseous pure oxygen to the molten metal, whereby oxygen blowing is accomplished. Mn-contg. materials, Cr-contg. materials or Ni-contg. materials which are crushed to lumps are contained in a hopper 4, and a slag making agent such as quick lime is contained in a hopper 6. At the suitable point of time after the start of the oxygen blowing, Mn ore and the like are charged into the furnace 1. The slag making agent is not added or if necessary, a small amt. thereof is added. An inert gas is introduced through a tyere 2 to stir the steel bath. Thereby, the concns. of Mn, Cr, Ni components of the molten iron are controlled by using inexpensive ore. |
