Brief introduction of thickness control of high-quality baling steel belt during acceleration and deceleration

Brief introduction of thickness control of high-quality baling steel belt in acceleration and deceleration stage
An important sub-function in the AGC system of a reversible cold rolling mill is the thickness control during the acceleration and deceleration of the rolling mill. When the rolling mill accelerates and decelerates, because the rolling mill speed changes from the threading speed to the steady rolling speed or vice versa, the speed varies widely, so the following two phenomena will be caused:
　　 (1) Variation of oil film thickness of oil film bearing;
　　 (2) Changes in process lubrication conditions cause changes in the friction coefficient between the milk roller and the rolling material.
　　The change of oil film thickness will make the roll gap decrease with the increase speed, and the friction coefficient will decrease with the increase speed, so that the rolling pressure becomes smaller and the outlet thickness becomes thinner. Therefore, it is necessary to obtain the change law of these two parameters. Take the following measures:
　　 (1) When threading, add an additional tension to the tension setting value and gradually cancel it with the increase in speed.
　　 (2) Gradually lift up the seam when the speed is increasing.
　　 The curve followed by the gradual elimination of additional tension and the change curve of roll gap (up) should be consistent with the change curve of friction and the change curve of oil film thickness with speed.
　　The change curve of oil film thickness with speed and rolling force can be carried out at the same time during the stiffness test of the rolling mill. For this purpose, first fix the speed of pressing against the roll (low speed and carry out the stiffness pressing test on this basis, and then change The speed and rolling force of the rolling mill are measured under different speed and rolling force conditions, and the amount of change is the thickness of the oil film.
　　In the process of acceleration and deceleration, another important factor that affects the thickness difference is that the control accuracy of dynamic tension will be much lower than that of static tension, so the tension fluctuation will be larger. It is for these reasons that the current acceleration and deceleration The thickness accuracy that can be obtained during the process is much worse than that of the steady state rolling, and the thickness difference is about 2-2.5 times that of the steady state.