PURPOSE: To prevent the development of involution of defective shell into the obtd. continuous cast steel strip by giving fine vibration to long side weirs in a mold formed with both drums and side dams at the time of continuously casting the steel strip with twin drum type continuous casting method.
CONSTITUTION: Molten steel 2 in a tundish 1 is caused to flow into gap between drum 7A, 7B for cooling mutually rotated in the reverse direction A, B from a bottom nozzle 4 to form pouring basin 13 and the continuous cast strip 9 is continuously drawn while forming and developing solidified shells 8A, 8B with rotation of both drums 7A, 7B. The refractory-made long side weirs 15A, 15B are arranged in parallel to axes of both drums 7A, 7B in pouring basin 13 and at the time of starting the continuous casting, these are pulled upward and saved from both drums, and at the time, when the molten steel surface 2a in the pouring basin 13 comes to the stationary position, the long side weirs 15A, 15B are descended and set at 0.5-5mm gap from surfaces of the drums 7A, 7B. Then, the fine vibration of 10-200Hz frequency and 0.01-5mm amplitude commanded with electric hydraulic servo devices 18A, 18B is applied to the long side weirs 15A, 15B with a vibrating frame 16. Even if small solidified shell is developed in the long side weir, as this is dropped into the pouring basin with the vibration, defect caused by the involution of shell onto surface of the continuous cast strip 9 is not developed.
KIMURA TOMOAKI
TAKAKURA YOSHIO
HIRANO SATOSHI
MATSUNAGA SHIGERU
HANAWA TAKESHI
NISSHIN STEEL CO LTD