| 摘要 |
PURPOSE:To decrease the surface cracking and breakout, etc. of a billet and to obtain a billet having high accuracy by detecting the shape of a bath surface at the detecting end of the bath surface provided in a mold and smoothing the shape of the bath surface by blowing an inert gas. CONSTITUTION:The thickness of the molten powder layer in a mold 3 is measured by devices 11, 12 for measuring the thickness of the molten layer and the information on the thickness is transmitted to a signal processing unit 13. The unit 13 adjusts the rate of the gas to be blown from gas blowing parts 6, 7 installed dividedly in an immersion nozzle 2 by flow rate regulating valves 14, 15 for the blowing gas. The thickness of the molten powder layer in the mold 3 is maintained at an optimum value by adjusting the flow rate of the gas in the above-mentioned way. Surface defects, breakout, etc. of the billet are thus decreased. |
