| 摘要 |
PURPOSE:To obtain advantageously dead soft steel while inhibiting the oxidation of iron by carrying out refining only by bottom blowing at a restricted oxygen feeding rate after a low carbon range is attained. CONSTITUTION:Refining in a bottom blowing or top and bottom blowing type refining furnace is carried out while feeding oxygen at a conventional rate until a low carbon range (about 0.15-0.05% C) is attained, and the following refining carried out only by bottom blowing at <=1Nm<3>/min-t oxygen feeding rate. Oxygen to be fed in the latter stage may be mixed with an inert gas. Thus, the partial pressure of CO is reduced to inhibit the oxidation of iron, RH treatment or other stage is eliminated, and dead soft steel can be obtd. with high productivity. |
