Method for controlling thickness in tandem mill

Abstract

The invention relates to a thickness control method in a tandem mill by which the thickness variation due to the generation of inlet-side tension when a material is bitten with the next stand and the elimination of the inlet-side tension when the material is tailed off is suppressed very small. In this thickness control method, in any stand of the tandem mill, the variation of rolling load of the stand and the thickness variation on the outlet side which are caused by the generation of tension on the outlet side of the stand when the nose of a material to be rolled reaches a stand on the downstream side or a winding reel are predicted and the roll gap of the stand is manipulated by matching to the timing of the generation of the outlet-side tension so that the variation of the outlet-side thickness is offset on the basis of these predicted values.

Description

[0001] This application is a divisional application of the invention patent application with the application number "200510081455.1" and the invention title "plate thickness control method for tandem rolling mill" submitted by the applicant on June 22, 2005. technical field [0002] The present invention relates to a thickness control method of a tandem rolling mill capable of reducing the variation in the thickness of the front end portion and the rear end portion of a material to be rolled. Background technique [0003] In the thickness control of the tandem mill, from the viewpoint of improving the yield, not only the stable part in the longitudinal direction of the material to be rolled, but also the front and rear ends that cannot be used for feedback control by the thickness gauge on the exit side of the tandem mill The plate thickness accuracy needs to be ensured. However, in each stand of the tandem rolling mill, the rolling state immediately after the bite of the ma...

AI Technical Summary

Problems solved by technology

[0010] However, in the case of storing the change amount of the roll gap in advance in the former check table and using the method of manipulating the roll gap in accordance with the time when the tension occurs or disappears, the temperature of the rolled material and other conditions in the actual rolling Changes occur every moment, so there is a problem that excessive or insufficient gap change due to changes in these conditions cannot be avoided.

[0011] In addition, in the method corresponding to the latter automatic thickness control function (AGC) based on the feedback of the load detection value, a certain degree of thickness deviation remains due to the hysteresis of the AGC control response, and there are cases where the thickness deviation exceeds The problem that the yield rate decreases due to the tolerance range

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