Nippon Steel Corporation

Hideyuki Misumi

Akira Hashimoto

Junichi Nakagawa

Masafumi Zeze

Shiro Sukenari

Katsuhiro Maeda

Noriyuki Kanai

Hidetoshi Yuyama

Azumi Inaba

Tsuyoshi Okada

Shigeki Kashio

Atsuhiro Tokuda

Michiaki Kikunaga

Takashi Nishihara

Keisuke Fujisake

Tokinari Shirai

A method for improving the internal center segregation and center porosity of a continuously cast slab, wherein an unsolidified side edge portion and a given area at the upstream side of the cast slab during continuous casting are defined as a plane reducing zone; a holding means is provided having two sets of top and bottom walking plane reducing compressing means at the plane reducing zone, front and rear supporting shafts common to the sets, eccentric cams for each set arranged at the front and the rear supporting shafts for holding and releasing of the cast slab, and a front and a rear displacement mechanism; the cast slab holding position of the upper surface of the bottom side walking plane reducing means of each set is set within 0.5 mm of the deviation on a passline of a continuous casting machine; the cast slab holding position of the lower surface of the top walking plane reducing means of each set is set at a desired reduction taper having a plane reduction ratio of 0.5 to 5.0% in accordance with an amount of solidified shrinkage of an unsolidified cast slab in a longitudinal compressing plane reducing zone and an amount of the heat shrinkage of the solidified shell; said eccentric cam set and the front and the rear displacement mechanisms are driven to operate the holding, moving forward, opening, and moving backward alternately thereby compressively carrying the cast slab; wherein the improvement comprises the steps of measuring, for each the two sets of plane reducing means the holding distance of the cast slab at before and after the top and the bottom walking plane reducing means, obtaining reduction taper from the measured holding distances and predetermined distances of distance measured positions before and after the top and the bottom walking plane reducing means, obtaining the difference between the reduction taper, then controlling positions of the front and the rear supporting shafts so that each set of walking plane reducing means is given to the desired reduction taper when the obtained difference is 0.1 mm/m or less, and bringing the walking plane reducing means having the measured reduction taper least different from the desired reduction taper close to the other measured reduction taper by changing the plane reduction ratio within a range of 0.5 to 5.0% by controlling the amount of rotation for releasing the holding of the eccentric cams, when the difference is more than 0.1 mm/m and the reduction taper are all less than said desired reduction taper.

Method for improving internal center segregation and center porosity of

Injection apparatus and injection control method for high-speed thin

Growing community of inventors

Ohita, Japan

Hideyuki Misumi