Board thickness controlling means of tandem mill

Abstract

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 1 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.Thus, the 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.

Description

Technical field [0001] The present invention relates to a method for controlling the thickness of a tandem rolling mill capable of reducing the thickness variation of the front end and the rear end of a material to be rolled. Background technique [0002] 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 of the feedback control by the exit side thickness gauge of the tandem mill cannot be used. Need to ensure board thickness accuracy. However, in the racks of the tandem mill, the rolling state immediately after the material to be rolled is bitten in and immediately before the tail end comes out changes all the time, exerting various influences on the exit plate thickness. As one of the main reasons for this, when the next stent bites in, there is an effect due to the occurrence of tension on the exit side. Before the next sten...

AI Technical Summary

Problems solved by technology

[0009] 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.

[0010] 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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