SU977077A1 - Method of controlling strip width in rolling mill - Google Patents

Description

(54) METHOD OF REGULATING THE STRIP THICKNESS ON A ROLLING MILL

The invention relates to the rolling of sheets and strips predominantly in reversing quarto cells. The closest to the technical support and the achieved result is a method of rolling in a quarto stand equipped with hydraulic cylinders for supporting cushion cushions, regulating fluid pressure in hydraulic cylinders for supporting cushions rolls, consisting in measuring, comparing with the set and stabilizing the rolling force 1.

The disadvantage of this method of adjusting the thickness of the strip is that eliminating the longitudinal thickness variation in the first passes increases the unevenness of the mechanical properties along the length of the strip that is inherent in any rolled products, which makes it difficult to further align the strip in thickness.

The purpose of the invention is the alignment of the mechanical properties and thickness variation of rolled products along the length of the strip.

The goal is achieved by the fact that in the method consisting in measuring, comparing with a given and stabilizing the rolling force, the regulation is performed in two

stages, before rolling down, 15–25% rolling is carried out with a constant rolling force, and at the second stage it is measured, compared with the target one and stabilized strip thickness.

FIG. 1 shows a block diagram of the apparatus: for implementing the method; FIG. 2 diagrams of pressure change versus thickness.

The device contains a storage box 1, a storage unit 2, a comparison unit 3, a sum.m10 unit 4, a relay unit 5, a frequency pulse modulator (PFM) 6, a transistor switch 7, a step motor control unit 8 / IM 9, a pressure regulator 10, thickness gauges 11, assembly 12 of the Direction of rolling, block 13 for adjusting the strip thickness according to the signals of the thickness gauge, sensor 14 of pulses installed on the motor shaft of the stand key 15, hydraulic cylinders 16 of the stand spreading.

The abscissas of the diagrams (Fig. 2) characterize the strip thickness, and the ordinates, the force acting on the strip and causing the deformation of the mill stand.

The abscissa of point A characterizes the thickness of the strip h after the rolling process at the initial thickness ho. If the initial thickness increases with HaShq, then the rolling force changes by the amount of dP. The new value of the thickness hi, in the output in this case is characterized by the abscissa of point B.

When maintaining the constant pressure (Ppr const), the force of the rolling roller will be reduced by the value of dP, which, in accordance with the diagram, will be the new value of the sandstone. In accordance with the diagram (Fig. 2), the different wavelengths will increase HI g,, or decrease h, h, due to a decrease in the pre-thrust force by uQ.

The abscissa of point C will correspond to the value of the strip thickness after the first stage of adjustment.

In this case, in the first case, the thickness difference slightly increases, while in the second case it slightly decreases, but in both cases, to a certain extent, the mechanical properties of the metal are equalized along the length of the strip. At the same time, in the first passes (with a reduction of x of the order of 15 -25 ° / o), intense metal work hardening occurs, and in subsequent passes, the work hardening intensity decreases significantly. Therefore, in the second control ethane (h -const), the mechanical properties change slightly.

In the second stage of adjustment, the strip thickness (h, -const) is kept constant, the output tlshin of the hi line corresponds to the point D dissociation, the ordinate of which on the diagram corresponds to the value of Rnr Pnr, and the dia diaplex is equal to

Pi f

If the initial thickness of the strip decreases by naShq, then the considered diagrams are shifted along the ordinate axis in the opposite direction.

Thus, according to the proposed method, the stage is controlled, in the beginning, in the first passes, the mechanical properties are aligned along the length of the strip, and the thickness difference can both increase and decrease, and then the thickness of the strip is equalized.

The method is implemented as follows.

Before starting the rolling mill, the initial pressure of the working fluid in the hydraulic cylinders 16 is established so that it is possible to regulate the pressure in both directions. In the process of filling the strip into the mill and installing an electromechanical pressure device of the required size of the strip, the voltage Up taken from the media doze 1 and proportional to the pressure in the stand Pj, which is equal to the sum of the rolling pressures Pf, p and thrust Pp, is written in hydraulic cylinders remains constant. At the first stage (in the first passes) during the rolling process, the signal of changing the thickness is taken

strips from the thickness gauge 11, installed at the mill outlet, through the rolling direction unit 12, in which a key control signal 15 is generated, prohibiting the passage of a signal to the input of the summing unit 4 produced by the unit

13 adjusting the strip thickness and sensor 14 pulses.

The force measured by the box 1 varies depending on the thickness of the rolled metal at the mill entrance and other possible disturbing influences. A change in the signal of the dose does lead to the appearance of the output of the error signal block 3, which passes through the current block 4. Signal UE. enters the input of ChIMA

6, which converts it into a sequence of rectangular pulses modulated in frequency and sign. When the signal Uc exceeds the specified deadband, the relay unit 5 is activated and

Q opens a transistor switch 7, through which the pulses from the output of the HIM come to the input of the control motor 8 of the stepper motor 9. Moving in the required direction, the rotor of the stepper motor acts on the pressure regulator 10. As a result, the pressure in the hydraulic cylinders 16 is changed until the signal at the output of the dose does not equal the set value PZ Up,. In this case, the relay unit 5 returns to the initial state, the key 7 is closed and the stepping motor 9 stops. When you repeatedly change the SI1-NALA Mesdozy automatic device works similarly. Thus, the pressure P in the stand, which acts on the mesdose, is stabilized. At this, the mechanical properties of the rolled strip are aligned and the thickness variation is partially corrected.

At the second stage (in the subsequent passages with a reduction of x over 15-25 ° / o) in

The rolling process in the rolling direction unit 12 generates a key control signal 15 that permits the passage of a signal proportional to the deviation of the thickness UuH formed by block 13

5 strip thickness adjustments and sensor

14 pulses. The signals LL and Unp are summed up in block 4.

In this case, in the summing unit 4, a new value of the signal LX is generated, PFM 6 converts the signal Ug into a modular sequence of square pulses in frequency and sign.

If the signal Ug exceeds a predetermined deadband, the relay unit is activated, a transistor switch opens, through which pulses from the output of the PFM arrive at the input of the stepper motor control unit 9. 9. The rotor of the stepper motor rotates and acts on the pressure regulator 10. The pressure in the hydraulic cylinders changes until the outlet thickness is equal to N of the set point.

Thus, at the second stage, the strip thickness variation is controlled in the h, const mode.

The proposed method of control significantly reduces the thickness variation of the strips and the non-uniformity of the mechanical properties of the rolled metal along the length.

Claims (1)

Invention Formula The method of adjusting the thickness of the strip in the rolling mill, which consists in measuring. Comparison with the set point and stabilization of the rolling force, characterized in that, in order to align the mechanical properties and the different thickness of the rolled products along the length, the regulation is carried out in two stages, and before rolling 15-25 / o-rolling is carried out under constant rolling force, and in the second stage, it is measured, compared with the target and stabilized strip thickness. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 488636, cl. B 21 B 37/00, 1974.