Method for improving core toughness of thick plate by utilizing descaling box

The invention discloses a method for improving the core toughness of a thick plate by using a descaling box. The method comprises the following steps that (1) after a casting blank is discharged froma heating furnace, a first rough rolling pass begins to move forwards into the descaling box for large-strength cooling, and the first rough rolling pass is carried out within 15s after cooling; and (2) a casting blank rough rolling third pass starts to move forwards into the descaling box to be subjected to high-strength cooling, and rough rolling third pass rolling is conducted within 10 s aftercooling. According to the invention, on the conditions of not increasing the addition amount of the alloy elements and not changing the existing process equipment, the surface of a steel plate is subjected to high-strength cooling by utilizing the descaling box device before the steel plate enters the first rough rolling pass and the third rough rolling pass, the temperature gradient in the thickness direction of the stee