| 摘要 |
PURPOSE:To prevent the development of surface crack caused by friction between continuously cast slab and blocks by applying ultrasonic vibration to the blocks at position, where molten steel is started to solidify, at the time of producing the continuously cast slab by using the block type synchronous mold. CONSTITUTION:Many inverted L-shape type metallic blocks 2, 4 are endlessly shifted toward the same direction and the molten steel is poured in the mold space 7 formed by both blocks 2, 4 from a nozzle 8 and rapidly cooled by the metallic blocks 2, 4, to draw toward C direction as the thin continuously cast slab 11. In this case, the molten steel in the mold 7 is started to solidify near the end of nozzle 8, to form the solidified shell and this thickness is gradually increased, to draw from the continuous casting apparatus, while remaining non-solidified molten steel in the internal part. The ultrasonic vibrator 19 and coiled spring 20 are fitted at one end of the mold 7 composed of the metallic blocks 2, 4 through a contacting terminal 18 having rolling ball and >= about 10 KHz of ultrasonic vibration is applied to the mold 7 through the vibrator 19. By this vibration, the friction resistance between the inner face of mold and the solidified shell in the continuously cast slab 11, is reduced and the development of surface crack caused by the friction between the cast slab aud the blocks is prevented. |
