JPS55139107A - Controlling method for thickness of sheet - Google Patents

Abstract

PURPOSE: To high accurately control the thickness of sheet to the aimed value with high accuracy, at rolling the steel sheet by the low speed rolling method, by shifting the rolling roll to return to the former draft position correspondingly to deviation of the thickness at passing the sheet from the aimed thickness, when the normal rolling mode is to be restored after correcting the tip thickness of rolled material through the thickness correction mechanism.

CONSTITUTION: After the steel material 2 is bitten by the rolling mill 1, the thickness correction is started, and the value of correction is set in the digital setter 3. The memory device 4 memorizes the rolling force after biting the steel material as the set value. With respect to the rolling force thereafter, the value of correction from the set value is operated by the addition amplifier 5, and the value of correction of the roll gap is obtained through the factor operator 6. At the first method for this purpose, the controller 7 changes the set value of the rolling force memorized in the memory device 4, by using the restoration value set by the setter for thickness correction and restoration value 8, the mill constant setter 9, and the setter for rolled material's plasticity factor 10, the value of mill constant, and the rolled material's plasticity factor. At the second method, the restoration value of the draft position is operated by using above stated numerical values, and the result is added to the addition amplifier 11 as the command value. Hereby, the thickness of the steel sheet 2 is brought near the aimed value.

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