| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection lance which is prevented from decreasing in its life due to the occurrence of a crack on a refractory covering a core metal of the lance, and consequently enables the cost of the lance to be reduced and the productivity thereof to be increased due to an increase in its life in the crack being a large portions of causes of damage to the injection lance. SOLUTION: The injection lance has the pipe-shaped metal-made core metal and the refractory disposed on the outer circumference thereof, wherein the constitution of at least a portion which immerses into molten iron, of the injection lance, is formed so as to satisfy an expression; 1.2≤R1/R3≤3 and an expression: R3≤R2<0.6×(R1+R3). In the expressions, R1: outer diameter (mm) of the injection lance, R2: outer diameter (mm) of the portion showing the maximum outer diameter in the metal-made core metal, and R3: outer diameter (mm) of the pipe used for metal-made core metal. COPYRIGHT: (C)2008,JPO&INPIT
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