Abstract
The main causes of deviation in the width of a transfer bar at a plate mill are listed in the paper. It was shown that one of the effective ways to improve the sheet shape is to form a double conical profile at the ends of the transfer bar during rolling. The authors introduced the modes of rolling with automatic profile control as an advance technology applied at modern rolling mills. One of the disadvantages noted in the paper is the discrepancy between the speed of the metal leaving the rolls and the linear speed of the rolling table before the roll stand in the process of moving the screw-down structures. Another disadvantage is low accuracy of the skew compensation of the roll gap along the rolling sides, which is determined by the setting of the aligning control of rolling. The authors examined the mechanism and the operating principle of the system of automatic strip thickness control of the convertible stand of the plate mill 5000. A method of control is suggested, which adjusts the speed of rolls in proportion to the displacement of the screw-down structures. The mechanism implementing this method in the structure of the operating system of the automatic strip thickness control is shown in the paper. The authors justified application of the proportional-differential RAC control and give some recommendations on its setting. Oscillograph records of rolling forces and correction signals on hydraulic screw-down structures are given and the decrease in the skew of the roll gap is confirmed. The research group considered the oscillograph records of screw-down structure coordinates and the velocity of electric drives in the process of forming inverted conic profile at the tail part of the transfer bar for the cases of design and recommended setting of the RAC control device. A conclusion was made about the decrease in the matching error of the gap at the side of the electric drive and at the side of the control pulpit. A number of recommendations on practical implementation of the suggested technical solutions are given.
Keywords
Plate mill, grooved rolling, convertible stand, system of automatic thickness control, electric drive, adjustment, hydraulic screw-down structures, gap, RAC control device, setting, experimental studies, recommendations.
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