JPS57115914A - Method for controlling thickness of hot rolling mill - Google Patents

Abstract

PURPOSE: To constantly control the thickness of metallic plates without monitoring of attendants on the coating amount, by accurately controlling and driving brush rolls which are used for removing coating layers stuck on the surface of work rolls of a hot rolling mill of Al.

CONSTITUTION: When an Al material 21 is rolled with work rolls 2, a coating layer is gradually accumulated on the surface of the rolls 2. Therefore, brush rolls 3 are driven by motors 14 under a condition where the velocity of the brush roll 3 is controlled, and the peripheral speed VB of the brush roll 3 is controlled in a ratio with respect to the peripheral speed VR of the rolls 2. When the removed amount of the coating layer is defined as ΔQ, the relation between the peripheral speeds and the removed amount can be expressed by the formulaI(where, k₁ is a constant). On the other hand, the reduced amount Δh in thickness at the outlet side is expressed by the formula II (where, k₂ is a constant). Therefore, the formula III can be introduced from both formulaIand II. When the roll 3 is driven at a velocity VB of the formula IV obtained from the formula III in the case of thickness variation, an increased amount of the coating layer during the course of rolling can be removed and the coating amount is maintained constantly. Thus, a constant thickness is obtained.

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