COOLING METHOD OF LANCE FOR STIRRING MOLTEN METAL

摘要

PURPOSE:To extend the service life of a lance for stirring a molten metal and to reduce the cost ratio thereof by forming largely the inside diameter of the metallic pipe of said lance and running cooling gas in succession even after the treatment in use, thereby cooling effectively the metallic pipe. CONSTITUTION:The ratio between the inside diameter of a metallic pipe 7 having a gas passage hole 7' and the outside diameter of covering refractories 8 is determined at 0.3-0.6 to increase the heat transmission area on the inside surface of the pipe 7 and cooling gas is kept flowing in succession even after the treatment in the stage of use in a method for supplying gas and flux to the molten iron 4 in a ladle 1 by a lance 3 for stirring a molten metal formed by covering the metallic pipe 7 with the refractories 8 and stirring and refinng the molen iron. The pipe 7 is thus effectively cooled, by which the difference in thermal expansion between the pipe 7 and the refractories 8 is decreased and the generation of the crack and stripping in the refractories 8 and the bend, etc. of the pipe 7 is prevented and the service life of the lance 3 is extended.