| 摘要 |
PURPOSE:To eliminate burning and breakout and to obtain a cast slab having good surface characteristic without oscillating operation by making the specific value or more of an amplitude of ultrasonic vibration and making the specific value of a viscosity of molten powder charged on surface of molten metal. CONSTITUTION:At the time of pouring the molten metal 8 into a mold 1 from a submerged nozzle 5, the molten metal 8 is cooled to make the cast slab 7, and it is drawn downward. The thickness of circumferential wall at the part near upper end of the mold 1 is made to thin, and the width of thin part 1a is equal to half length of wave length of plane wave from the ultrasonic vibrator 3a. Ten vibrator transmitted rods 2a, etc., are screwed-connected with wall face of the thin part 1a at whole around of corresponding part to the meniscus by screw parts 4a, etc., of the one ends thereof. A frequency signal from an oscillator is transmitted to the mold 1 from the ultrasonic vibrator 3a, etc., through the vibration transmitting rod 2a, etc. The oscillator is adjusted, so that the vibrating amplitude to the mold 1 becomes >=4mum. Further, the molten powder 6 having 0.5-3.0 poise of the viscosity at 1,300 deg.C is charged as a lubricator, to prevent the burning between the molten steel 8 and the mold 1. |
