| 摘要 |
PROBLEM TO BE SOLVED: To provide a top-blowing lance for the refinement of a molten metal, which can not only reduce a variation of a dynamic pressure in a circumferential direction but also optimize a distribution of the dynamic pressure in a radial direction, and thereby further can reduce a spitting quantity. SOLUTION: The top-blowing lance 1 for the refinement of the molten metal has 3 or more holes of nozzles 2 arranged on the same circumference at equal spaces. In an XYZ rectangular coordinate system which is determined so that a lance center axis is regarded as a Z-axis and an outlets of the nozzles are positioned on an X-axis, when angles formed by respective projected lines of the nozzle axis onto a YZ plane and an XZ plane and Z axis are defined asαandβrespectively, the angles satisfy 0<tanα/tanβ<2.75, and a ratio of the cross sectional area of the center hole 3 arranged in the central part of the nozzles with respect to the total cross sectional area of the nozzles,γ=(d<SB>1</SB><SP>2</SP>/(d<SB>1</SB><SP>2</SP>+n×d<SB>2</SB><SP>2</SP>))×100, satisfies 3.2 to 10, wherein d<SB>1</SB>represents a diameter (mm) of the center hole; d<SB>2</SB>represents diameters (mm) of other holes; and n represents the number of other arranged holes. In the case of a lance with multiple holes having different diameters, in which the diameters of other holes are not equal, (d<SB>1</SB><SP>2</SP>+n×d<SB>2</SB><SP>2</SP>) is replaced with (d<SB>1</SB><SP>2</SP>+4S/π), where the total cross sectional area of the nozzles except the center hole is represented by S. COPYRIGHT: (C)2010,JPO&INPIT |
