To prevent a corner cracking of steel pieces such as a billet without lowering a casting velocity by cooling a portion which is within a given %, of the side length and apart from a corner by a given % or more of the side length per side of a steel piece cross section as a range to be directly cooled.
According to a continuous casting machine, after a molten steel in a ladle is once poured into a tundish, the molten steel is flowed into a mold via a nozzle per strand. Simultaneously with the solidification of a surface, a steel piece 16 is pulled out by a roller while being gradually cooled by a secondary cooling water 15 for carrying out continuous casting. At the time of secondary cooling of the steel piece 16 being cast by the continuous casting device, corner cracking of the steel piece 16 is prevented by cooling the portion which is within 80% of one side length W1 and apart from a corner portion 16a by 10% or more of the side length per side of the steel piece 16 cross section.
TAMASHIMA SEIJI
HORIUCHI YASUSHI
YAMAMURO TAKASHI
NITTETSU OSAKA ENGINEERING KK
Next Patent: MOLTEN PRESSURE MOLDING MACHINE