COOLING METHOD OF LANCE FOR STIRRING MOLTEN METAL

PURPOSE:To extend the service life of a refractories-coated lance to be used for stirring and refining a molten metal and to reduce the cost ratio thereof by continuing to run gas in said lance even after the treatment thereby cooling the metallic pipe of the lance. CONSTITUTION:A lance 3 for stirring a molten metal which consists of metallic pipe 7 and covering refractories 8 enclosing the outside circumference thereof and is provided with a gas passage hole 7' is inserted into the molten iron 4 and slag 5 in a ladle 1 having a cover 2 and gas is bubbled 6, by which the molten iron 4 is stirred and refined. The gas is kept run for a specified time continuously even after the end of the treatment to cool the lance and prevent the rise of its temp. The difference in thermal expansion between the pipe 7 and the refractories 8 is thus decreased and the generation of crack and stripping in the refractories 8 as well as the bend, etc. of the metallic pipe is prevented. Thus, the service life of the lance 3 is extended.