CONTROLLING METHOD OF CENTRAL SEGREGATION IN CONTINUOUS CASTING

摘要

PURPOSE:To control the casting condition for a billet and to prevent effectively central segregation by calculating the suction index of the thickened molten steel from the area in the non-flowing region of the unsolidified molten steel in the top end part of the solidified steel and the bulging amt. in said part and predicting the rate of central segregation. CONSTITUTION:The area S in the non-flowing region of the unsolidified molten steel at the top end part of the solidified steel and the bulging rate deltab in said part are determined in accordance with the solidification profile of a continuously cast billet. The suction index Q of the thickened molten steel is calculated in accordance with the equation Q=2/3.beta.(S+deltab).a(beta: the coefft. of volume expansion in the stage of solidification, a: the length in the non-flowing region) from said values and the rate of central segregation is predicted from said index. The casting condition for the billet is controlled by the prescribed equation according to said index Q.