| 摘要 |
PURPOSE:To improve the quality of a billet by using a single hole type immersion nozzle and disposing a static magnetic field generator to a discharge flow region of a molten steel to decelerate the discharge flow of the molten steel. CONSTITUTION:The single hole type immersion nozzle 2 is disposed to a mold 1 and an electromagnetic brake 3 for the molten steel as the static magnetic field generator is disposed in the region where the discharge flow of the molten steel is formed. Since the N and S poles of the brake 3 are disposed to face each other, the static magnetic field is generated in the molten steel which is not yet solidified, thereby forming lines of magnetic force from the N pole toward the S pole. The discharge flow of the molten steel from the nozzle 2 perpendicularly cross the static magnetic field and therefore the induced current is generated in the molten steel. The molten steel flow is thus decelerated by the cross effect of the current and magnetic field, by which the intrusion depth of the molten steel is kept low. The development of the gas in the billet to a blowhole defect is prevented by the above-mentioned method and therefore the quality of the billet is prevented. |
