| 摘要 |
PURPOSE:To simply heat molten steel in a ladle with an extremely high heat efficiency, a high heating rate, by forming high temp. fire point in molten steel of a high forming while specifying the distance between top end of a top blow ing lance sand stand still surface of molten steel in dipping pipe. CONSTITUTION:A cap type dipping pipe 3 is set at upper surface of the molten steel 2 in the ladle 1, and a pipe 4 for feeding temp. raising material is connected above the pipe 3 with structural body following to up-and-down movement of the pipe 3. The top blowing lance 5 elevating independently of the pipe 3 is set. On the other hand, a porous plug 6 is embedded at bottom part of the ladle 1 for stirring the steel 2. In above constitution, the pipe 3 is dipped into the steel 2 while blowing 6 inert gas from ladle bottom and oxygen is blown into the pipe 3 through the lance 5. In this case, a distance L between top end of the lance 5 and stand still surface of molten steel in the pipe 3 is prescribed so that an inequality is satisfied. As a result, high speed heating with high heat efficiency, i.e. for instance 92% heat efficiency and 10 deg.C/min heating speed can be achieved and superior heating of molten steel in ladle can be carried out with extremely slight erosion of dipping pipe.
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