2007 年 78 巻 1 号 p. 41-47
The steel making section in Chita plant, Daido Steel Co., Ltd. has many facilities, five electric arc furnaces, many kinds of refining devices, and two continuous casting machines, No.1CC, and No.2CC, and produce approximately 140 k tons a month crude steel which covers more than 90 % of that of Daido Steel. Forever, the ladle transportation delay due to the lack of the number of ladle crane and ladle transportation line cause the amount of CC production which is less than that of their ability to decrease. New ladle crane in CC shop, and new ladle transportation line from refining yard to CC shop have been introduced in order to solve the problems in Oct. 2004, and Jan. 2006. The effects of these works are the following. 1) Both No.1CC and No.2CC productivity increased (+18 ton/hr) because of the reduce of process time from the end of LF to CC start. 2) Power consumption of EAF and LF reduced because of decreasing of the molten steel temperature after refining. 3) CC tundish refractory life increased because of decreasing of continuous casting time and molten steel temperature in tundish.