Importance

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Abstract

In an arrangement for a tandem cold mill in order to compensate for 'speed effect,' each stand has a roll force memory unit and an oil film roll force controller unit which operate together, and in conjunction with a tensiometer, to maintain a relatively constant roll gap during the acceleration and deceleration phases of the mill. In threading, in tailing out, and in a full run speed of the mill, the roll force memory unit is constantly operating to obtain a 'lock on' roll force reference for the stand prior to the acceleration or deceleration phase. A roll force error signal, which is the difference between a roll force reference of the roll force memory unit and an instantaneous roll force, enters the oil film roll controller. A proportional integrator type controller in the oil film roll force controller unit changes the roll force error signal within a limit of +25% of the desired tension. This oil film roll controller produces a tension reference signal which is compared to the desired tension and selectively with the actual tension to produce a tension error signal used to control the roll gap control system of the stand or used to provide a speed change reference for the downstream stand.

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First Claim