PURPOSE: To provide a billet having high quality with extremely little segregation in the stage of casting continuously the billet of a specific size by providing a light screw-down device consisting of plural diametrally opposed split type roll groups having a specified roll pitch in the final solidifying region.
CONSTITUTION: A molten high-purity carbon steel consisting of ≤0.008% P and ≤0.003% S is continuously cast to the billet size of 200W500mm thickness and ≥1,000mm width by using a vertical type continuous casting machine. A light screw-down device of ≥4m overall length consisting of plural diametrally opposed split type roll groups having ≤300mm roll pitch is disposed in the final solidifying region in this stage. A slab is successively drawn and rolled down in such a way that the space between the rolls facing each other satisfies the relation 67≤δ.D≤210 (δ; the drawing rate of the rolls mm/min, D; the thickness of the billet mm).
NIIMI HIDETOSHI
MIWA HIDEKAZU
YOSHIDA TAKAHARU
| JPS5438978B2 | 1979-11-24 | |||
| JPS594943A | 1984-01-11 |