| 摘要 |
PROBLEM TO BE SOLVED: To dissolve such problem as clogging of a slit with respect to a slit type gas blowing plug. SOLUTION: Relating to the dense brick-made gas blowing plug having slit passages 18 extended in the axial direction as the blowing passage for blowing the gas into molten metal, the slit passages 18 are formed in the axial direction of trapezoidal cone shaped refractry 10 made of the dense brick. The surface roughness on the inner wall surface forming the slit passages 18 is regulated to <=36.9μm in the max. roughness and 1.9-3.7μm in the average roughness.
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