A method for controlling the looper of a heavy plate finishing mill stand

Abstract

The application discloses a kind of thick plate empty pass finishing stand loop control method, first pre-set loop angle control program, when thick plate needs to empty pass certain stand when rolling, automatically trigger program to carry out the torque output of compensating loop;When strip steel has not entered the front stand of empty pass stand, the angle of control loop is P;When strip steel head passes through front stand and contacts loop, the loop torque required by the weight of the cross-sectional area of strip steel is compensated, and with the advance of strip steel, the loop torque is constantly adjusted according to the weight of strip steel pressed on loop;When strip steel enters the steel biting of empty pass stand and delays 0.5-10 seconds, the angle of loop is adjusted to Y;When the front stand throws steel, the angle of loop is adjusted to Z, until strip steel leaves loop.The method of the application realizes automatic feedback control of loop angle when thick plate is rolled by emptying pass stand, realizes that thick plate does not need manual pad gasket when emptying pass stand, reduces man-machine combination safety risk, and improves rolling efficiency simultaneously.

Description

Technical Field

[0001] This invention belongs to the field of hot continuous rolling finishing technology, specifically relating to a looper control method for thick plate blanking through a finishing mill stand. Background Technology

[0002] A conventional hot strip mill finishing mill mainly consists of seven stands, F1-F7, with six loopers between them. The loopers play a crucial role in balancing the flow rate between stands and maintaining constant tension during hot strip milling. The finishing mill loopers primarily control the looper angle and the tension between stands. Looper angle control mainly ensures sufficient looping volume between stands to guarantee flow rate balance during strip rolling.

[0003] Because the seven stands of the finishing mill (F1-F7) rationally allocate the reduction load of each stand based on the thickness of the incoming material and the thickness of the finished product, in the rolling process of thick plates (strip thickness greater than 12mm), the reduction load of the last stand of the finishing mill is relatively small due to the greater thickness of the finished product. Since the reduction load of the last stand is highly correlated with the performance of the thick plate, it is usually necessary to ensure a certain reduction rate on the last stand to guarantee the strip performance. Therefore, during the rolling of thick plates, the F7 stand is often skipped. To ensure that the strip exiting the F6 stand smoothly bites into the F7 skipped stand, operators usually need to retrieve shims from the control panel to fix the angle of the #6 looper, maintaining it at 11.5-13°. During specific operations, the rolling line area needs to be free of strip. The operator on the control panel selects to raise the angle of the #6 looper via the HMI screen, then the operator below the control panel places the shims into the base position of the #6 looper, and then the operator on the control panel lowers the #6 looper to raise its angle. The operation is cumbersome and poses safety risks due to the human-machine interaction. Furthermore, the process of placing the shims requires the rolling line to be free of strip steel, necessitating a halt to steel extraction from the heating furnace, which significantly impacts the rolling rhythm. Moreover, the required height at angle #6 often fails to meet specifications after shim placement, necessitating repeated shim placement. This frequent human-machine interaction significantly affects the stable and smooth operation of the rolling line. Summary of the Invention

[0004] The purpose of this invention is to provide a looper control method for thick plates passing through a finishing mill stand, which can realize automatic control of the looper angle and improve rolling efficiency.

[0005] The objective of this invention is achieved through the following technical solution: a looper control method for thick plate blanking through a finishing mill stand, characterized by comprising the following steps: (1) A preset looper angle control program is provided. When the rolling of thick plates requires passing through a certain stand, the program is automatically triggered to compensate for the torque output of the looper. (2) When the strip has not yet entered the front frame of the empty frame, adjust and control the initial angle of the corresponding looper to P, where P = 7-20°; (3) When the strip head passes the front frame and contacts the looper, the looper torque required to compensate for the weight of the strip cross-sectional area; (4) As the strip advances, the loop torque is continuously adjusted according to the amount of strip pressed onto the looper, so that the looper is maintained at the position of angle P. (5) When the strip enters the empty frame and bites the strip and delays for 0.5-10 seconds, control the increase of the looper torque and adjust the looper angle to Y, P+3°≤Y≤P+5°; (6) When the current frame throws steel, the angle of the looper is adjusted to Z, Y-4≤Z≤Y-2, until the strip leaves the looper.

[0006] Furthermore, in step (2), the angle of the 6# looper when it is in the waiting position is 11°.

[0007] Furthermore, in step (5), when the strip enters the empty frame and bites the strip and delays for 0.8 seconds, the angle of the looper is adjusted to Y.

[0008] Furthermore, in step (6), Z = 10°.

[0009] Furthermore, in step (5), Y = 14°.

[0010] The beneficial effects of this invention are: by increasing the torque output through looper control, this invention achieves automatic control of the looper angle, eliminating the need for manual shims when thick plates pass through the machine frame, reducing the safety risks of human-machine operation, and also reducing the impact of manual shim placement on rolling line efficiency. Attached Figure Description

[0011] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0013] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0014] Let the thickness of the finished strip be h (mm). When 12≤h≤25, in actual production, the strip is rolled through the F7 stand without any material during the rolling process. When h>25, the strip is rolled through both the F6 and F7 stands without any material at the same time.

[0015] The control method of the present invention will be described in detail below when the thickness of the finished strip steel is 12-25mm and it passes through an F7 frame. The specific method steps are as follows.

[0016] The preset looper angle control program automatically triggers to compensate for the torque output of the #6 looper when the rolling of thick plates requires passing through the F7 stand.

[0017] First stage: Before the strip enters the frame, control the No. 6 looper to be in the waiting position, with the initial angle of the looper being 11°.

[0018] (3) Second stage: When the strip passes through the F6 frame and is about to contact the 6# looper, the looper torque required to compensate for the weight of the strip cross-sectional area is first started.

[0019] (4) Third stage: As the strip moves forward, the total amount of strip pressed onto the looper changes continuously during the process between the F6 and F7 stands, requiring constant adjustment of the looper torque. The specific calculation method is as follows: When the head of the strip is between the F6 and F7 stands, let the length of the strip entering the looper be x, the thickness be h, the width be w, the density be p, and the gravitational acceleration be g. The corresponding looper torque compensation is F = xhwpg. In this way, the required looper torque is continuously adjusted by changing the length of the strip pressed onto the looper.

[0020] (5) Fourth stage: When the strip enters the F7 frame and bites the strip and delays for 0.8 seconds, control to increase the looper torque, adjust the looper angle to 14° and maintain it.

[0021] (6) Fifth stage: Continue until the F6 frame throws the steel, and lower the looper angle to 10° for control until the strip leaves the looper.

[0022] This invention controls the output of the looper torque to achieve angle control of the 6# looper during the rolling of thick plates without shims on the F7 stand, thus enabling the thick plates to pass through the F7 stand without shims. Therefore, by adopting the control method of this invention, since manual shim placement is not required, strip steel can be placed on the rolling line, and the heating furnace does not need to stop drawing steel, reducing the labor intensity of workers, ensuring production safety, and improving production efficiency. It has high potential for widespread application.

[0023] In summary, although the present invention has listed the above preferred embodiments, it should be noted that various changes and modifications can be made by those skilled in the art, and such changes and modifications should be included within the scope of protection of the present invention unless they deviate from the scope of the present invention.

Claims

1. A method for controlling the looper of a thick plate rolling mill stand without load, characterized in that, The thickness of the plate is 12-25mm, and it is rolled through the F7 stand without air, specifically including the following steps: (1) A preset looper angle control program is set up so that when the rolling of thick plates needs to pass through the F7 stand, the program is automatically triggered to compensate for the torque output of the looper. (2) When the strip has not yet entered the front frame of the empty frame, adjust and control the initial angle of the corresponding looper to P, where P = 7-20°; (3) When the strip head passes the front frame and contacts the looper, the looper torque required to compensate for the weight of the strip cross-sectional area; (4) As the strip advances, the looper torque is continuously adjusted according to the amount of strip pressing onto the looper; (5) When the strip enters the empty frame and bites the strip and delays for 0.5-10 seconds, control the increase of the looper torque and adjust the looper angle to Y, P+3°≤Y≤P+5°; (6) When the current frame throws steel, the angle of the looper is adjusted to Z, Y-4°≤Z≤Y-2°, until the strip leaves the looper.

2. The looper control method for thick plate passing through the finishing mill stand according to claim 1, wherein in step (2), the angle of looper #6 when it is in the waiting position is 11°.

3. The looper control method for thick plate blanking through a finishing mill stand according to claim 1, characterized in that: In step (5), when the strip enters the empty frame and bites the strip and delays for 0.8 seconds, the angle of the looper is adjusted to Y.

4. The looper control method for thick plate unloaded through a finishing mill stand according to claim 1, characterized in that: In step (6), Z = 10°.

5. The looper control method for thick plate unloaded through a finishing mill stand according to any one of claims 1-4, characterized in that: In step (5), Y = 14°.

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