PURPOSE: To efficiently form a large amt. of fine bubbles in molten metal by blowing a subsonic gas from a tuyere opened in the molten metal to generate bubbles and simultaneously allowing a supersonic gas jet to collide with the bubbles from another tuyere set in the tuyere.
CONSTITUTION: A gas supply pipe 52 having a refractory 54 and a permeable refractory 56 is dipped in molten metal 50 to form a first tuyere, plural through holes 58 having a small diameter (≤2mm) and piercing the permeable refractory 56 are formed in the permeable refractory 56 to form a second tuyere as the discharge hole 60 for a gas jet. When a subsonic gas 62 is blown from a gas supply pipe 52 and passed through the permeable refractory 56 under such a constitution, the deposited bubbles 66A are spread to a region A slightly away from the surface of the permeable refractory 56. Meanwhile, the gas jet 64 passed through the through hole 58 collides with the inner surface of the deposited bubble 66A to break through the deposited bubble 66A, hence fine bubbles 66B are formed in a region B, and the bubbles are diffused as far as a region C. Consequently, a large amt. of fine bubbles 66B are generated by this simple device, and the efficiency in removing the inclusion and the degasification efficiency are improved.
TAKASHIBA NOBUMOTO
KOJIMA SHINJI
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