| 摘要 |
PURPOSE: To obtain a cast slab which makes the start of solidification the same time and effectively works the lubricating action with powder and can cast at high speed without developing breakout, in which uneven solidification and crack are not developed at the time of continuously casting a steel, by providing refractory thermal-spraying layer and metallic thermal-spraying layer with the specific thicknesses in the inner surface of a water-cooling copper mold, respectively. CONSTITUTION: On the inner surface of the water-cooling copper mold 1, the thermal-spraying layer 10 of ZrO2 -Y2 O3 base refractory having 100-150μm thickness is coated as a first layer, and on the upper surface thereof, the thermal-spraying layer 11 of stainless steel having 10-50μm thickness is coated as a second layer. Therefore, at the time of continuously casting, the solidified starting point is made to be the same time by rapidly cooling the molten steel 6 only at the time of starting the solidification with action of the metallic thermal-spraying layer 11. The lubricating function of the powder 8 can effectively be acted and the development of the breakout is eliminated and the casting at high speed can be executed. Further, since the molten steel in the mold is shifted to the slow cooling with the thermal-spraying layer 10 of the refractory just after starting the solidification, the uneven solidification is difficult to develop and the development of the crack on the cast slab 6c can be prevented.
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