A method and system for adjusting the roll gap deviation of a rolling mill

Abstract

This invention discloses a method and system for adjusting the roll gap deviation of a rolling mill. The method includes the following steps: (1) Based on the vertical roll biting signal, calculate the roll gap deviation S between the working side and the drive side of the current i-th stand. i (2) The roll gap deviation S i The data is distributed to the i-th frame based on the roll gap deviation S. i To adjust the roll gap of the i-th frame; roll gap deviation S i The roll gap deviation base value S required by the difference in rolling force between the zero-adjustment operation side and the drive side 1i The primary roll gap deviation compensation value ΔS required to eliminate the asymmetry factor of the intermediate billet 1i and for roll gap deviation S 1i +ΔS 1i Compensation value ΔS for secondary roll gap deviation 2i Composition. Based on the zero-adjustment rolling force difference and the camber of the intermediate billet head, the roll gap deviation of each rolling mill is automatically calculated and distributed, effectively reducing the impact of the zero-adjustment rolling force difference and the camber of the roughing mill on the deviation of the finishing mill, greatly reducing the degree of operator intervention, and improving the stability of the rolling process.

Description

Technical Field

[0001] This invention belongs to the field of hot rolling technology, and more specifically, this invention relates to a method and system for adjusting the roll gap deviation of a rolling mill. Background Technology

[0002] With the rapid development of science and technology in recent decades, the steel industry has made certain achievements in its overall level. However, there is still considerable room for improvement in the steel industry, mainly in the fact that it cannot meet the requirements of high-tech equipment in terms of high-quality and high-precision steel strip.

[0003] In the finishing mill area, asymmetric factors can cause strip misalignment and quality issues such as waviness and wedge-shaped defects. On-site, operators rely primarily on their years of experience to observe the condition of the incoming strip head, press the roll gap reduction control buttons on both sides of the rolls, and adjust the roll gaps on both sides of the finishing mill stand to pre-level the strip head, correcting asymmetric shape defects that occur during the finishing mill process.

[0004] However, the problem of strip defects caused by asymmetric factors is a multi-factor coupled process. Various asymmetric factors on site will cause asymmetric defects in strip. Relying solely on the operator's years of experience to pre-level the roll gap has a large degree of subjectivity and results in low rolling stability. Summary of the Invention

[0005] This invention provides a method for adjusting the roll gap deviation of a rolling mill, aiming to improve the above-mentioned problems.

[0006] This invention is implemented as follows: a method for adjusting the roll gap deviation of a rolling mill, the method comprising the following steps:

[0007] (1) Based on the vertical roll biting signal, calculate the roll gap deviation S between the working side and the drive side of each frame i. i ;

[0008] (2) The roll gap deviation S i The data is distributed to the i-th frame based on the roll gap deviation S. i To adjust the roll gap of the i-th frame.

[0009] In some embodiments, the formula for calculating the roll gap deviation is as follows:

[0010] S i =S 1i +ΔS 1i +ΔS 2i ;

[0011] S 1i The roll gap deviation base value required for the difference in rolling force between the operating side and the drive side during zero adjustment, ΔS 1iThe primary roll gap deviation compensation value required to eliminate or reduce the influence of intermediate billet asymmetry factors, ΔS 2i For use with roll gap deviation S 1i +ΔS 1i The compensation value for the secondary roll gap deviation.

[0012] In some embodiments, the roll gap deviation base value S of the i-th frame 1i The specific calculation formula is as follows:

[0013] S 1i =α i *ΔF;

[0014] Where ΔF is the difference in rolling force between the operating side and the transmission side after zeroing, and α i The pre-swing roll gap influence coefficient is given.

[0015] In some embodiments, the primary roll gap deviation compensation value ΔS for the i-th frame 1i The specific calculation formula is as follows:

[0016]

[0017] Where, η i Let L be the correction coefficient for the camber of the intermediate billet in the i-th frame, L be the bending length of the intermediate billet head, H be the thickness of the intermediate billet, B be the width of the intermediate billet, and y be the bending amount of the intermediate billet.

[0018] In some embodiments, the influence of intermediate billet asymmetry factors is eliminated or reduced by the first roll gap deviation compensation value of the first three stands, η1=-0.02, η2=-0.015, η3=-0.01, η4=η5=η6=η7=0.

[0019] In some embodiments, the secondary roll gap deviation compensation value ΔS 2i The specific method for obtaining it is as follows:

[0020] For the first coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for:

[0021] ΔS 2i =0;

[0022] For the second coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for:

[0023]

[0024] Wherein, β1 and β2 are the self-learning coefficients of the threading roller gap, β1 = 0.1 and β2 = 0.06.

[0025] In some embodiments, after triggering the memory leveling mode, the current roll gap deviation S of each frame is saved. i This allows operators to monitor the stored roll gap deviation S. i Make corrections and save the data, and save the roll gap deviation S. i Distribute to the corresponding rack.

[0026] In some embodiments, after a 2-second delay following the most recent steel throwing on the i-th stand, the saved roll gap deviation S is... i Distribute to the i-th rack.

[0027] This invention is implemented as follows: a rolling mill roll gap deviation adjustment system, the system comprising:

[0028] K racks, and K racks are connected to the PLC controller for communication;

[0029] Upon receiving the vertical roll biting signal, the PLC controller calculates the current roll gap deviation value for each stand based on the aforementioned mill roll gap deviation adjustment method and sends it to the corresponding stand.

[0030] This invention automatically calculates and distributes the roll gap deviation of each rolling mill based on the zero-adjustment rolling force difference and the camber of the intermediate billet head. This effectively reduces the impact of the zero-adjustment rolling force difference and the camber of the roughing mill on the deviation of the finishing mill, greatly reduces the degree of operator intervention, and improves the stability of the rolling process. Attached Figure Description

[0031] Figure 1 A flowchart of a mill roll gap deviation adjustment method provided in an embodiment of the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0033] Figure 1 The flowchart of the mill roll gap deviation adjustment method provided in the embodiment of the present invention is as follows:

[0034] (1) Based on the vertical roll biting signal, calculate the roll gap deviation S between the working side and the drive side of the current i-th frame. i The value of i ranges from 1 to 7;

[0035] Among them, the roll gap deviation S i It consists of three parts, including the roll gap deviation base value S required for the rolling force difference between the zero-adjustment operation side and the drive side. 1i The primary roll gap deviation compensation value ΔS required to eliminate the asymmetry factor of the intermediate billet 1iand for roll gap deviation S 1i +ΔS 1i Compensation value ΔS for secondary roll gap deviation 2i Ultimately, the roll gap deviation S i =S 1i +ΔS 1i +ΔS 2i .

[0036] (2) The roll gap deviation S i The data is distributed to the i-th frame based on the roll gap deviation S. i To adjust the roll gap of the i-th frame.

[0037] (11) After the rolling mill changes rolls, the rolls need to be zeroed, that is, the gap between the upper and lower work rolls is zeroed based on the zeroing signal. The rolling force difference ΔF between the operating side and the drive side is recorded during the zeroing. The roll gap deviation base value S of the i-th stand is calculated based on the rolling force difference ΔF. 1i The specific calculation formula is as follows:

[0038] S 1i =α i *ΔF;

[0039] Where, α i The pre-swing roll gap influence coefficient is expressed in mm / kN.

[0040] Since a hot rolling mill may consist of five, six, or seven stands, and based on the assumption that a hot rolling mill can consist of a maximum of seven stands, pre-sway roll gap influence coefficients α1 to α7 are set. Historical data is analyzed, with α1 = 0.0004, α2 = 0.0004, α3 = 0.0004, α4 = 0.0003, α5 = 0.0003, α6 = 0.0002, and α7 = 0.0001. When the current hot rolling mill consists of six stands, the roll gap deviation base value S for the corresponding stand is determined based on the pre-sway roll gap influence coefficients α1 to α6. 11 ~S 16 calculate.

[0041] (12) When the strip reaches the vertical roll, the system sends a vertical roll bite signal. The vertical roll is located before the first stand. Based on the vertical roll bite signal, the system calculates the primary roll gap deviation compensation value ΔS for each stand. 1i The first roll gap deviation compensation value ΔS 1i Primarily used to eliminate or reduce the influence of asymmetric factors in intermediate billets, the primary roll gap deviation compensation value ΔS for the i-th stand. 1i The specific calculation formula is as follows:

[0042]

[0043] Where, η iLet η1 = -0.02, η2 = -0.015, η3 = -0.01, η4 = η5 = η6 = η7 = 0. Here, L is the bending length of the intermediate billet head (mm); H is the thickness of the intermediate billet (mm); B is the width of the intermediate billet (mm); and y is the bending amount of the intermediate billet (mm). L, H, B, and y are the relevant detection values ​​of the current intermediate billet. This invention eliminates or reduces the influence of asymmetric factors on the intermediate billet by using the roll gap deviation compensation values ​​of the first three stands. Therefore, η1 = -0.02, η2 = -0.015, η3 = -0.01, η4 = η5 = η6 = η7 = 0.

[0044] (13) The current roll gap deviation S is calculated based on the second coil of strip after the work roll change. 1i +ΔS 1i Perform further compensation, that is, generate the secondary roll gap deviation compensation value ΔS for each frame. 2i Secondary roll gap deviation compensation value ΔS 2i The specific method for obtaining it is as follows:

[0045] For the first coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for:

[0046] ΔS 2i =0;

[0047] For the second coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for:

[0048]

[0049] Wherein, β1 and β2 are the self-learning coefficients of the threading roller gap, β1 = 0.1, β2 = 0.06;

[0050] For the first coil of strip after the work roll change, ΔS 2i =0, therefore, the roll gap deviation value S output by the program is 0. i =S 1i +ΔS 1i If the roll gap deviation value S output by the program at this time i The roll gap deviation value S is the result of manual intervention and input. i_man If the adjustment directions are the same (i.e., in the same direction), both increasing or decreasing, then ΔS 2i =β1·S i If the roll gap deviation value S output by the program at this time i The roll gap deviation value S is the result of manual intervention and input. i_man If the adjustment directions are opposite (i.e., opposite), then ΔS 2i =β2·S i_manFor the strip after the second roll of strip following the work roll change, the secondary roll gap deviation compensation value for each stand remains the same as the secondary roll gap deviation compensation value set when the second roll of strip was produced.

[0051] Due to the influence of the production environment in winter, the measured values ​​of relevant parameters L, H, B, and y of the strip steel show greater deviations, resulting in a decrease in the calculated primary roll gap deviation compensation value ΔS. 1i There is a significant deviation; therefore, this invention incorporates a memory leveling mode. Upon triggering the memory leveling mode, the current roll gap deviation S of each frame is saved. i It allows operators to correct the current roll gap deviation based on different incoming material conditions such as steel grade, width, and thickness. After correction, the deviation is saved, and the roll gap deviation S of each stand is saved. i Distribute to the corresponding rack.

[0052] It should be noted that in some areas, the rolling pace is quite fast, and there are situations where the strip has already bitten the steel in stand F1 before stand F7 has even finished stripping. Issuing a uniform pre-swing roll gap could easily cause accidents. To adapt to the faster rolling pace, after triggering the memory leveling mode, the currently saved roll gap deviation is sent to the corresponding stand 2 seconds after the most recent stripping resolution. That is, 2 seconds after stand F1 strips the steel, the saved roll gap deviation S1 is sent to stand F1, and so on, stopping after 1 second. Because significant roll gap fluctuations occur during strip biting and stripping processes in each stand, the memory leveling mode is only triggered in the stages when there is no strip on each stand and when all stands are biting the steel; it cannot be triggered in other stages.

[0053] This invention uses a seven-stand mill as an example to illustrate the calculation process of the roll gap deviation for the first coil of strip steel, as detailed below:

[0054] At the end of the zero-adjustment, the rolling force difference ΔF between the operating side and the drive side of each stand is read from the PLC: {358,1343,-492,109,-1259,439,384}. Since α1=0.0004, α2=0.0004, α3=0.0004, α4=0.0003, α5=0.0003, α6=0.0002, α7=0.0001, at this time, the roll gap deviation base values ​​of the 1st to 7th stands are respectively: S 11 =0.143mm, S 12 =0.537mm, S 13 = -0.197mm, S 14 =0.033mm, S 15 = -0.378mm, S 16 =0.088mm, S 17 =0.038mm;

[0055] Since this is the first roll of strip steel after the work roll has been replaced, the secondary roll gap deviation compensation value ΔS 2i =0. Read the relevant parameters of the intermediate billet, including the bending length of the intermediate billet head L = 3052.258 mm, the set thickness of the intermediate billet incoming material H = 42.69 mm, and the strip width B = 1238 mm; the incoming material bending amount y = -58.486 mm. When the vertical roll bite signal rises, calculate the primary roll gap deviation compensation value ΔS for the i-th stand. 1i Since the intermediate billet camber correction coefficients η1 = -0.002, η2 = -0.0015, and η1 = -0.001, based on the formula... The secondary roll gap deviation compensation values ​​for the first, second, and third stands were calculated to be ΔS. 11 =0.031mm, ΔS 12 =0.023mm, ΔS 13 =0.016mm. Therefore, the roll gap deviations for the 1st to 7th frames are S1=0.174mm, S2=0.560mm, S3=-0.181mm, S4=0.032mm, S5=-0.377mm, S6=0.088mm, and S7=0.038mm, respectively. These roll gap deviations are then assigned to the corresponding frames.

[0056] After rolling the fourth coil of strip, the incoming steel grade was changed. During the rolling process, the operator adjusted the roll gaps of stand F6 and stand F7 to 0.07mm and 0.06mm respectively based on experience. Observing that subsequent rolling plans were all for the same steel grade, the operator pressed the memory leveling button, triggering the memory leveling mode. The program calculated the current roll gap deviation values ​​of the seven stands {0.17, 0.56, -0.18, 0.03, -0.38, 0.07, 0.06}, displayed them on the interface, and sent them to the corresponding stands.

[0057] This invention also provides a mill roll gap deviation adjustment system, the system comprising:

[0058] K racks are connected to the PLC controller for communication, where K can be 5, 6 or 7;

[0059] Upon receiving the vertical roll biting signal, the PLC controller calculates the current roll gap deviation value for each stand based on the aforementioned mill roll gap deviation adjustment method and sends it to the corresponding stand.

[0060] This invention automatically calculates and distributes the roll gap deviation to each rolling mill based on the zero-adjustment rolling force difference and the camber of the intermediate billet head. This effectively reduces the impact of the zero-adjustment rolling force difference and the camber of the roughing mill on the deviation of the finishing mill, greatly reduces the degree of operator intervention, and improves the stability of the rolling process. The memory leveling mode allows operators to correct the current roll gap deviation based on the current roll gap deviation and their years of manual leveling experience, according to different incoming material conditions such as steel grade, width, and thickness, thereby improving the accuracy of plate shape control.

[0061] The present invention has been described by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for adjusting the roll gap deviation of a rolling mill, characterized in that, The method includes the following steps: (1) Based on the vertical roll biting signal, calculate the roll gap deviation S between the operating side and the drive side of the current i-th frame. i Where i takes values ​​from 1 to 7; (2) The roll gap deviation S i The data is distributed to the i-th frame based on the roll gap deviation S. i To adjust the roll gap of the i-th frame; The specific formula for calculating roll gap deviation is as follows: S i =S 1i +ΔS 1i +ΔS 2i ; S 1i The roll gap deviation base value required for the difference in rolling force between the operating side and the drive side during zero adjustment, ΔS 1i The primary roll gap deviation compensation value required to eliminate or reduce the influence of intermediate billet asymmetry factors, ΔS 2i For use with roll gap deviation S 1i +ΔS 1i The compensation value for the secondary roll gap deviation; The roll gap deviation base value S of the i-th frame 1i The specific calculation formula is as follows: S 1i =α i *ΔF; Where ΔF is the difference in rolling force between the operating side and the transmission side after zeroing, and α i The pre-swing roll gap influence coefficient; The primary roll gap deviation compensation value ΔS for the i-th frame 1i The specific calculation formula is as follows: Where, η i Let L be the camber correction coefficient for the intermediate billet of the i-th frame, L be the bending length of the intermediate billet head, H be the thickness of the intermediate billet, B be the width of the intermediate billet, and y be the bending amount of the intermediate billet. The influence of intermediate billet asymmetry factors is eliminated or reduced by the first roll gap deviation compensation value of the first three stands, η1=-0.02, η2=-0.015, η3=-0.01, η4=η5=η6=η7=0; Secondary roll gap deviation compensation value ΔS 2i The specific method for obtaining it is as follows: For the first coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for: ΔS 2i =0; For the second coil of strip after the work roll change, the secondary roll gap deviation compensation value ΔS of the i-th stand is... 2i for: Wherein, β1 and β2 are the self-learning coefficients of the threading roller gap, β1 = 0.1 and β2 = 0.

06.

2. The method for adjusting the roll gap deviation of a rolling mill as described in claim 1, characterized in that, After triggering the memory leveling mode, the current roll gap deviation S of each stand is saved. i This allows operators to monitor the stored roll gap deviation S. i Make corrections and save the data, and save the roll gap deviation S. i Distribute to the corresponding rack.

3. The method for adjusting the roll gap deviation of a rolling mill as described in claim 2, characterized in that, After a 2-second delay following the most recent steel throwing operation on the i-th stand, the saved roll gap deviation S is... i Distribute to the i-th rack.

4. A rolling mill roll gap deviation adjustment system, characterized in that, The system includes: Seven racks, all of which are connected to the PLC controller. Upon receiving the vertical roll biting signal, the PLC controller calculates the current roll gap deviation of each stand based on the mill roll gap deviation adjustment method described in any one of claims 1 to 3, and sends the result to the corresponding stand.

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