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Optimum Load Distribution Feedforward, Feedback Gauge Control Of A Rolling Mill

IP.com Disclosure Number: IPCOM000096763D
Original Publication Date: 1963-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Related People

Wu, WS: AUTHOR

Abstract

In this hot strip rolling mill control system, the control computer stores a set of equations. These express all the characteristics of mill behavior and the constraint conditions. The equations are descriptive of the relationship which exists between drive motor power, roll separating force, rolling speed, material composition, material temperature, material dimension, draft, strip tension, etc. In addition, the equations can specify limits of bite angle, drive motor overload, separating force, reduction allowable within limits of product quality strip tension, etc. Within the framework of these equations two specific control functions are performed.

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Optimum Load Distribution Feedforward, Feedback Gauge Control Of A Rolling Mill

In this hot strip rolling mill control system, the control computer stores a set of equations. These express all the characteristics of mill behavior and the constraint conditions. The equations are descriptive of the relationship which exists between drive motor power, roll separating force, rolling speed, material composition, material temperature, material dimension, draft, strip tension, etc. In addition, the equations can specify limits of bite angle, drive motor overload, separating force, reduction allowable within limits of product quality strip tension, etc. Within the framework of these equations two specific control functions are performed.

In the first control function, the screw down settings, speed and other variables are computed to provide a mode of operation in which the maximum allowable power is delivered from each of the main drive motors.

The second control function is directed to gauge control. Based on measurements of thickness, temperature, and other data relating to the slab, an optimum setting for the mill is computed and performed on the mill prior to the actual entry of the slab into the mill.

Since the measurements and mathematical relationships are not absolute, the computed settings may not result in finished strip of the desired gauge. Correction of such errors as may exist is done according to the relationship h = S + F/M where h = output gauge of a stand, S = screw down position or roll gap without load, M = Hook's constant or mill modules of the stand, and F = roll force or separation force of the stand.

This equation means that the output thickness of the strip is equal to the gap opening between two rollers plus the amount of yield of the stand due to the reaction force (separation force) of the strip being squeezed. S is obtained accurately by calibration. Stand modulus can also be measured and is a constant. The only variable which is obtained for an exact...