| 摘要 |
<p>PURPOSE:To control blowing oxygen rate and molten steel temp. and to assume C content at the end point of refining under good accuracy by submerging the specific construction of an Mn sensor into the molten steel with a sub-lance at the time of refining the molten steel wit less slag oxygen blowing in a converter and assuming the Mn content in the molten steel from electromotive force and the molten steel temp. obtd. from the sensor. CONSTITUTION:Molten iron tapped fro a blast furnace is pre-desiliconized and dephosphorized by oxidizing with scale, etc., on the casting floor in front of the furnace and by executing the less slag oxygen bowing in the converter, the molten iron is refined into the molten steel with decarbonizing reaction. In this case, the Mn sensor having a solid electrolyte 4 of ZnO2+7% MgO, normal electrode 2 and a Mo-made measuring electrodes 1, 1' and having MnO or Mn3O4 coat 5 on the surface of the solid electrolyte 4, and a thermocouple 7 are fitted to the sub-lance and submerged into the molten-metal 8. Mn activated value in the molten metal is calculated from voltage between both electrodes 1, 1' for the sensor and the measured temp. with the thermocouple 7 for measuring the molten metal temp., and the Mn content in the molten metal 8 is assumed from this value, and further, Mn oxidizing loss at the end period of the blowing is assumed, to control the O2 blowing rate and the molten metal temp., and the content at the end point of the refining is assumed and hit to the aimed value at high accuracy.</p> |
