| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a complex lance for vacuum degassing vessel, in which the preheating work can reliably be executed in a short time and also, the blowing of oxygen, the heat-up of molten steel and the heating of the vacuum degassing vessel itself can smoothly be executed. SOLUTION: The complex lance for vacuum degassing vessel is composed of an oxygen top-blown lance provided with a gaseous oxygen passage which is used by inserting into the vacuum degassing vessel and formed of a water- cooling cylindrical body and a nozzle 2 for blowing the oxygen onto the molten metal at the tip part of the oxygen passage, a water cooling outer cylinder 19 surrounding the periphery of the lance, plural passages 8 for fluid fuel 22 and combustion gas incorporated into a gap between the oxygen top-blown lance and the water cooling outer cylinder 19, combustion burners 6 arranged at the tip part in these passages and an ignition plug 9 arranged in at least one of the combustion burners 6.</p> |
