COMPONENT CONTROLLING METHOD OF MOLTEN IRON

摘要

PURPOSE:To prevent damaging of a blowing device by blowing component control agents together with a carrier gas into molten iron through a lance having a refractory material coating layer then pulling the lance upward while passing only the gas in succession and cooling the molten metal down to a predetermined temp. CONSTITUTION:Component control agents are blown together with a carrier gas into molten iron through a lance which has a refractory material coating layer and is immersed into the molten iron. In succession after the required component control agents are introduced therein, the lance is pulled up from the molten metal bath while only the gas is being passed. Thence, the cooling gas is kept supplied until the lance body is elevated of its temp. by the heat of the lance coating layer, and no more difference is produced in the thermal expansion between the lance body and the refractory material coating layer. Thereby, the occurrence of a slip phenomenon at the interface of the two is prevented and the damaging of the refractory material coating layer is prevented as well.