CONTINUOUS CASTING METHOD

摘要

PURPOSE:To prevent sticking of a solidified shell and to make the quality of a billet higher and an operation stabler by cooling the surface of a molten steel prior to cooling of the molten steel by a mold connected to the lower nozzle of a tundish and repeating quick drawing and slow drawing without interruption. CONSTITUTION:A nozzle ring 4 connected to a lower nozzle 3 is a cylindrical sealing body made of ceramics, has a smooth inside surface and has poor wettability and lubricity. The heat conductivity thereof is <=1/3 the heat conductivity of a mold 6. The ring is formed to the length (l) longer than the length of one pitch of a pinch roller 9. The ring is cooled by a cooling jacket 12 and three thermocouples 13 are provided just before the jacket to detect the temp. at the point where a solidified shell 7 is formed. The quick drawing and slow drawing of the shell 7 are continuously repeated without interruption. Sticking of the shell 7 in the ring 4 is accordingly avoided and the generation of a cold shut mark and cold shut crack is entirely eliminated.