Speed ​​control method of looper false frame in hot continuous rolling thin gauge steel mill

Abstract

A speed control method for a loop virtual sleeving rack of a hot continuous rolling thin-steel-plate rolling mill is characterized in that when a rack loop torque deviation value is larger than or equal to 2000 Nm, the final speed reference value of the rack is correspondingly reduced; and when the rack loop actual torque is larger than or equal to set torque 1000 Nm (that is the torque when the rack loop torque deviation value is smaller than or equal to -1000 Nm), an integral control formula is applied to enable the torque to quit out of the above speed additional value. According to the method, off tracking, rolling rejects and major risks to mechanical equipment due to loop virtual sleeving are eliminated, the failure time is shortened, the product quality is improved, and good benefits are achieved.

Description

Technical field [0001] The invention belongs to the field of automatic control loops of hot strip steel rolling lines, and is mainly adapted to thin gauge steel plates with a thickness of less than 2.5 mm. Background technique [0002] Under normal circumstances, the looper control between the frames after the looper is set is torque control. Even if the deviation between the given moment of the looper and the actual moment of the strip is used for control, it can solve the control problem of looper adjustment. [0003] In the rolling process of thin gauge steel plate, due to the large changes in external conditions, especially when the looper is at a low position, it is easy to produce strip steel virtual sleeve, that is, the actual torque of the strip steel is less than the given torque of the strip steel. The set torque servo valve control setting cannot be satisfied. Due to the fast rolling speed, the slippery scrap between the racks caused by the false sleeve of the looper is...

AI Technical Summary

Problems solved by technology

[0003] During the rolling process of thin-gauge steel plates, due to large changes in external conditions, especially when the looper is at a low position, false looping of the strip is very easy to occur, that is, the actual moment of the strip is less than the given moment of the strip. The control setting of the torque servo valve cannot be satisfied. Due to the high rolling speed, the scrap steel between the racks is caused by the false loop of the looper.

[0004] As the thin gauge billet increases and the rolling speed increases, as long as the strip temperature and shape change between the finishing stands and the looper servo valve is a proportional servo valve, the response speed is slightly poor, and the strip virtual sleeve will appear. When the looper adjustment is slow, especially the 3#, 4#, 5# looper control of the rear frame, the strip steel is easy to run off and crushed, resulting in poor quality of the strip steel product, and in severe cases, direct scrap steel between the frames, It affects the normal production of the rolling line and brings great economic losses to our factory