Rough rolling sickle bend first pass control method

Abstract

The invention provides a rough rolling camber first pass control method. The rough rolling camber first pass control method comprises the following steps that rough rolling camber related technological parameters are collected, and data preprocessing is carried out; according to the total rolling pass of the upper steel block and the bending amount of each pass, the influence weight of the odd number of passes is taken and recorded as a matrix A; according to the camber bending amount of the ith pass of the upper steel block, the first-pass camber regulation and control amount of the steel block is calculated; the first-pass camber leveling value of the steel block is calculated; and the first-pass camber leveling value of the steel block is issued to a rolling foundation automatic control system, and camber first-pass automatic control is achieved. The purpose of automatically controlling the rough rolling camber first pass is achieved, and the camber problem and follow-up accidents are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of slab camber control in the hot rolling and rough rolling stage of plate and strip rolling, and in particular to a rough rolling camber first pass control method. Background Art

[0002] Slab camber is a common plate shape defect in the hot rolling process. Slab camber has a great impact on the control and stability of subsequent finishing and final rolling accuracy, and seriously affects strip production. There are many factors that affect slab camber. During the on-site rolling process, there will always be some asymmetric factors that cause changes in the rolling process parameters, mainly including the incoming material factor, equipment factor and working condition factor. These factors will lead to the asymmetric rolling state along the roller axis direction, resulting in differences in the reduction rate along the width direction of the rolling mill, thus generating and affecting camber.

[0003] As the mainstream research direction in the field of modern plate and strip rolling, slab sickle control has always attracted much attention. Hot rough rolling is a continuous and reversible rolling process. Under normal circumstances, on-site operators often do not adjust the sickle leveling value of the first pass of slab rolling too much. They all inherit the normal sickle leveling value of the first pass of the previous steel. After the first pass is completed, targeted adjustments are made in subsequent passes based on the rolling effect. However, due to many complex factors on site, a large sickle will appear in the first pass of the slab, which may easily cause the risk of hitting the side guide plate. In addition, in the hot rough rolling production process, if the manual control intervention of the sickle of the slab in the first pass is not timely, it is easy to cause a large sickle to impact the side guide plate, and even a steel pile accident may occur. Summary of the invention

[0004] The present invention is made in view of the above-mentioned problems, and its purpose is to provide a method for controlling the first pass of roughing sickle bending. First, the relevant process parameters of roughing sickle bending are collected and data preprocessing is performed; secondly, the influence weight of the bending amount of each pass of the previous steel block on the first pass bending amount of the current steel block is calculated; then, the first pass sickle bending control amount of the current steel block and the first pass sickle bending leveling value of the current steel block are calculated; finally, the first pass sickle bending leveling value of the current steel block is sent to the basic rolling automation control system, so as to achieve the purpose of automatic control of the first pass of roughing sickle bending and reduce the occurrence of sickle bending problems and subsequent accidents.

[0005] Specifically, a first aspect of the present invention provides a roughing sickle bending pass control method, comprising the following steps:

[0006] Step 1: Collect the relevant process parameters of rough rolling sickle bending and perform data preprocessing;

[0007] Step 2: According to the total rolling pass N′ of the previous steel block and the bending amount of each pass, the influence weight of the bending amount of the i-th pass of the previous steel block on the bending amount of the first pass of the current steel block is obtained, which is recorded as ai , i is the number of passes, take the influence weight of the odd passes, and record it as matrix A;

[0008] According to a large amount of historical rolling data, when the bending amount of the upper block of steel in the i-th pass exceeds the normal range, different degrees of adjustment are given according to the degree of bending. The effect on the first pass of the lower block of steel is observed and statistically analyzed to obtain the influence weight of the bending amount of the i-th pass of the upper block of steel on the bending amount of the first pass of the current block of steel.

[0009] Step 3: According to the sickle bending amount C of the i-th pass of the upper steel i , calculate the first pass sickle bending control amount of this piece of steel, the formula is as follows:

[0010] ΔT1=AB T ;

[0011] B=[b1 b3 b5 b7] T ;

[0012]

[0013] Among them: ΔT1 is the first pass sickle bending control value of this piece of steel;

[0014] A is the weight matrix of the influence of the odd-numbered bending amount of the previous steel block on the first-pass bending amount of the current steel block;

[0015] B T is the transpose of the bending value matrix of the upper steel head;

[0016] B is the bending value matrix of the upper steel head;

[0017] C i is the bending amount of the ith pass of the previous steel piece;

[0018] b i is the value of the head bending amount of the upper steel piece in the i-th pass;

[0019] C′ i is the set sickle bending threshold of the i-th pass;

[0020] i is the number of passes;

[0021] Step 4: Calculate the first pass sickle bend leveling value of this piece of steel. The formula is as follows:

[0022] T = T1′ + ΔT1;

[0023] Where: T is the first sickle bend leveling value of this piece of steel;

[0024] ΔT1 is the first pass sickle bending control value of this piece of steel;

[0025] T1′ is the actual leveling value of the first sickle bend of the upper steel block;

[0026] Step 5: Send the first pass sickle bend leveling value of this piece of steel to the basic rolling automation control system to realize automatic control of the first pass of sickle bend.

[0027] There is a significant difference in the effect of odd and even passes on the amount of sickle bending in rough rolling. During the rolling process with odd passes, due to the switching of speed direction, the rolled piece may deviate due to the instantaneous inconsistency of the front and rear speeds of the rollers, especially during the reversible rolling process. Since the front and rear side guides of R2 are both electrically driven, the correction capacity of the slab is insufficient, and the odd number of rolling passes may cause sickle bending.

[0028] In contrast, when rolling with even-numbered passes, the order of acceleration and deceleration of the rolling mill is the same as that of odd-numbered passes, except that the direction of the speed setting is exactly opposite to that of odd-numbered passes. The finishing mill generally rolls the rolled piece for 5 to 7 passes, and the rolling with even-numbered passes is usually straightened later to reduce the generation of sickle camber. Therefore, the present invention studies the influence of odd-numbered passes on the bending amount of sickle camber in order to reduce the generation of sickle camber.

[0029] Furthermore, the rough rolling sickle bend related process parameters specifically include: the total rolling passes of the previous piece of steel, the total rolling passes of the current piece of steel, the rolling pass number, the head bending amount of each pass of the previous piece of steel, and the actual leveling value of the sickle bend of the first pass of the previous piece of steel.

[0030] Furthermore, the data preprocessing is to remove outliers in the collected data using the Laida criterion.

[0031] Furthermore, the matrix A in step 2 is expressed as:

[0032] When the total rolling pass number N' of the upper steel piece is 7:

[0033] A=[a1 a3 a5 a7];

[0034] When the total rolling pass number N' of the upper steel piece is 5:

[0035] A=[a1 a3 a5 0];

[0036] Among them: a i is the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

[0037] Furthermore, the size range of the data in the matrix A is:

[0038] 0.02≤a1<a3<a5<a7≤0.09;

[0039] Among them: a iis the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

[0040] In a second aspect, the present invention further provides a computing device, which has the function of implementing the method described in the first aspect above. The beneficial effects can be found in the description of the first aspect, which will not be repeated here. The functions can be implemented by hardware, or by executing corresponding software through hardware. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the structure of the device includes an acquisition module, a training module, and optionally, a construction module. These modules can implement the functions of the training node in the method example of the first aspect above. Please refer to the detailed description in the method example for details, which will not be repeated here.

[0041] In a third aspect, the present invention further provides a computing device, which is used to implement the functions of the method described in the first aspect above. The beneficial effects can be found in the description of the first aspect and will not be repeated here. The structure of the computing device includes a processor and a memory, and the memory is used to store instructions and / or data. The memory is coupled to the processor, and when the processor executes the program instructions stored in the memory, the function of the training node in the example of the first aspect above can be implemented. The structure of the computing device also includes a communication interface for communicating with other devices.

[0042] In a fourth aspect, the present invention further provides a computer-readable storage medium, in which instructions are stored, and when the computer-readable storage medium is run on a computer, the computer executes the method in the above-mentioned first aspect and various possible designs of the first aspect.

[0043] In a fifth aspect, the present invention further provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method in the above-mentioned first aspect and various possible designs of the first aspect.

[0044] In a sixth aspect, the present invention further provides a computing chip, which is connected to a memory, and is used to read and execute a software program stored in the memory, and to execute the methods in the above-mentioned first aspect and various possible implementations of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0046] Figure 1It is a flow chart of the steps of the present invention.

[0047] The purpose, features and advantages of this figure will be further described in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0049] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0050] In order to better understand the solutions of the embodiments of the present invention, some relevant terms and concepts that may be involved in the embodiments of the present invention are first introduced below.

[0051] (1) Rough rolling is a metal processing process that is mainly used to initially deform the billet or slab through a rolling mill to achieve the required basic size and shape. The main task of rough rolling is to widen the slab or ingot to the required width and perform large compression and extension to provide a suitable intermediate billet for the subsequent finishing rolling process.

[0052] (2) Roughing sickle bend refers to the phenomenon that the plate and strip bend in the length direction due to various factors during the rough rolling stage of the hot-rolled plate and strip. This bending usually manifests itself as the two sides of the plate and strip bending to the same side, resembling a sickle, hence the name. The causes of sickle bend are complex and varied, including roll crossing, incoming material wedge, difference in stiffness on both sides of the rolling mill, uneven temperature, uneven roll wear and other factors. Sickle bend not only affects the quality of the plate and strip, but also affects the subsequent finishing process and the processing performance of the product. For example, sickle bend can cause the strip to deviate and scrape during the cold rolling process, seriously affecting product quality. Therefore, in actual production, it is very important to control and eliminate sickle bend.

[0053] (3) The Laida criterion, also known as the three sigma criterion, is a statistical method used to identify and eliminate gross errors. This criterion is based on the assumption of normal distribution. It determines an interval by calculating the standard deviation. It is believed that errors exceeding this interval are not random errors but gross errors and should be eliminated. Specifically, the Laida criterion assumes that a set of test data contains only random errors and calculates the standard deviation. Then, based on the characteristics of the normal distribution, an interval is determined, usually the mean plus or minus three times the standard deviation. Data outside this interval are considered to be outliers or bad values ​​and should be eliminated.

[0054] (4) The amount of sickle bending control refers to the amount of adjustment made during the hot rolling process to control the sickle bending of the slab. Specifically, the calculation and adjustment of the amount of sickle bending control involves multiple factors, including the wedge shape of the incoming material, the roll crossing angle, the roll gap ratio, the amount of reduction, and the thickness of the slab.

[0055] In this embodiment, Figure 1 As shown, a rough rolling sickle bending first pass control method includes the following steps:

[0056] Step 1: Collect the relevant process parameters of rough rolling sickle bending and perform data preprocessing;

[0057] Step 2: According to the total rolling pass N′ of the previous steel block and the bending amount of each pass, the influence weight of the bending amount of the i-th pass of the previous steel block on the bending amount of the first pass of the current steel block is obtained, which is recorded as a i , i is the number of passes, take the influence weight of the odd passes, and record it as matrix A;

[0058] According to a large amount of historical rolling data, when the bending amount of the upper block of steel in the i-th pass exceeds the normal range, different degrees of adjustment are given according to the degree of bending. The effect on the first pass of the lower block of steel is observed and statistically analyzed to obtain the influence weight of the bending amount of the i-th pass of the upper block of steel on the bending amount of the first pass of the current block of steel.

[0059] Step 3: According to the sickle bending amount C of the i-th pass of the upper steel i , calculate the first pass sickle bending control amount of this piece of steel, the formula is as follows:

[0060] ΔT1=AB T ;

[0061] B=[b1 b3 b5 b 7 ];

[0062]

[0063] Among them: ΔT1 is the first pass sickle bending control value of this piece of steel;

[0064] A is the weight matrix of the influence of the odd-numbered bending amount of the previous steel block on the first-pass bending amount of the current steel block;

[0065] B T is the transpose of the bending value matrix of the upper steel head;

[0066] B is the bending value matrix of the upper steel head;

[0067] C i is the bending amount of the ith pass of the previous steel piece;

[0068] b i is the value of the head bending amount of the upper steel piece in the i-th pass;

[0069] C′ i is the set sickle bending threshold of the i-th pass;

[0070] i is the number of passes;

[0071] Step 4: Calculate the first pass sickle bend leveling value of this piece of steel. The formula is as follows:

[0072] T = T′1 + ΔT1;

[0073] Where: T is the first sickle bend leveling value of this piece of steel;

[0074] ΔT1 is the first pass sickle bending control value of this piece of steel;

[0075] T′1 is the actual leveling value of the first sickle bend of the upper steel block;

[0076] Step 5: Send the first pass sickle bend leveling value of this piece of steel to the basic rolling automation control system to realize automatic control of the first pass of sickle bend.

[0077] There is a significant difference in the effect of odd and even passes on the amount of sickle bending in rough rolling. During the rolling process with odd passes, due to the switching of speed direction, the rolled piece may deviate due to the instantaneous inconsistency of the front and rear speeds of the rollers, especially during the reversible rolling process. Since the front and rear side guides of R2 are both electrically driven, the correction capacity of the slab is insufficient, and the odd number of rolling passes may cause sickle bending.

[0078] In contrast, when rolling with even-numbered passes, the order of acceleration and deceleration of the rolling mill is the same as that of odd-numbered passes, except that the direction of the speed setting is exactly opposite to that of odd-numbered passes. The finishing mill generally rolls the rolled piece for 5 to 7 passes, and the rolling with even-numbered passes is usually straightened later to reduce the generation of sickle camber. Therefore, the present invention studies the influence of odd-numbered passes on the bending amount of sickle camber in order to reduce the generation of sickle camber.

[0079] Furthermore, the rough rolling sickle bend related process parameters specifically include: the total rolling passes of the previous piece of steel, the total rolling passes of the current piece of steel, the rolling pass number, the head bending amount of each pass of the previous piece of steel, and the actual leveling value of the sickle bend of the first pass of the previous piece of steel.

[0080] Furthermore, the data preprocessing is to remove outliers in the collected data using the Laida criterion.

[0081] The Laida criterion, also known as the Three Sigma criterion, is a statistical method used to identify and eliminate gross errors. The criterion is based on the assumption of normal distribution and determines an interval by calculating the standard deviation. It is believed that errors exceeding this interval are not random errors but gross errors and should be eliminated.

[0082] Specifically, the Laida criterion assumes that a set of test data contains only random errors and calculates the standard deviation. Then, based on the characteristics of the normal distribution, an interval is determined, usually the mean plus or minus three times the standard deviation. Data outside this interval are considered outliers or bad values ​​and should be eliminated.

[0083] Furthermore, the matrix A in step 2 is expressed as:

[0084] When the total rolling pass number N' of the upper steel piece is 7:

[0085] A=[a1 a3 a5 a7];

[0086] When the total rolling pass number N' of the upper steel piece is 5:

[0087] A=[a1 a3 a5 0];

[0088] Among them: a i is the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

[0089] Furthermore, the size range of the data in the matrix A is:

[0090] 0.02≤a1<a3<a5<a7≤0.09;

[0091] Among them: a i is the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

[0092] In this embodiment, the total number of rolling passes of the upper steel block is 7, that is, N′=7, and the matrix A is expressed as:

[0093] A=[a1 a3 a5 a7];

[0094] The actual matrix A is:

[0095] A = [0.09 0.05 0.03 0.02];

[0096] The bending value of the upper steel sickle is:

[0097] C1=45, C3=32, C5=23, C7=10;

[0098] The threshold value of the sickle bend set for the i-th pass is:

[0099] C′1=40, C′3=30, C′5=C′7=25;

[0100] Then the bending value matrix B of the upper steel head is obtained as follows:

[0101] B = [1 1 0 0];

[0102] According to the formula, the first pass sickle bending control value ΔT1 of this steel is calculated as:

[0103] ΔT1=0.14;

[0104] The total number of rolling passes for this piece of steel is 5, that is, N = 5. The actual leveling value of the first pass of the previous piece of steel, T'1, that is, the first pass reference value of this piece of steel, is 0.1. The first pass of the sickle bend leveling value T of this piece of steel is calculated according to the formula:

[0105] T = T′1 + ΔT1;

[0106] T=0.24 is obtained. According to the calculation result, the first pass sickle bending leveling value of this piece of steel is sent to the basic rolling automation control system to complete the automatic control of the first pass of the slab sickle bending, reducing the sickle bending situation in the first pass of rough rolling by more than 85%.

[0107] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A rough rolling sickle bending pass control method, characterized in that: The following steps are involved: Step 1: Collect the relevant process parameters of rough rolling sickle bending and perform data preprocessing; Step 2: According to the total rolling pass N′ of the previous steel block and the bending amount of each pass, the influence weight of the bending amount of the i-th pass of the previous steel block on the bending amount of the first pass of the current steel block is obtained, which is recorded as a i , i is the number of passes, take the influence weight of the odd passes, and record it as matrix A; Step 3: According to the sickle bending amount C of the i-th pass of the upper steel i , calculate the first pass sickle bending control amount of this piece of steel, the formula is as follows: ΔT1=AB T ; B = [b1 b3 b5 b7]; Among them: ΔT1 is the first pass sickle bending control value of this piece of steel; A is the weight matrix of the influence of the odd-numbered bending amount of the previous steel block on the first-pass bending amount of the current steel block; B T is the transpose of the bending value matrix of the upper steel head; B is the bending value matrix of the upper steel head; C i is the bending amount of the ith pass of the previous steel piece; b i is the value of the head bending amount of the upper steel piece in the i-th pass; C′ i is the set sickle bending threshold of the i-th pass; i is the number of passes; Step 4: Calculate the first pass sickle bend leveling value of this piece of steel. The formula is as follows: T = T′1 + ΔT1; Where: T is the first sickle bend leveling value of this piece of steel; ΔT1 is the first pass sickle bending control value of this piece of steel; T1′ is the actual leveling value of the first sickle bend of the upper steel block; Step 5: Send the first pass sickle bend leveling value of this piece of steel to the basic rolling automation control system to realize automatic control of the first pass of sickle bend.

2. A rough rolling sickle bending pass control method according to claim 1, characterized in that: The rough rolling sickle bend related process parameters specifically include: the total rolling passes of the previous piece of steel, the total rolling passes of the current piece of steel, the rolling pass number, the head bending amount of each pass of the previous piece of steel, and the actual leveling value of the sickle bend of the first pass of the previous piece of steel.

3. A rough rolling sickle bending pass control method according to claim 1, characterized in that: The data preprocessing is to use the Laida criterion to remove abnormal values ​​in the collected data.

4. A rough rolling sickle bending pass control method according to claim 1, characterized in that: The matrix A in step 2 is expressed as: When the total rolling pass number N' of the upper steel piece is 7: A=[a1 a3 a5 a7 ]; When the total rolling pass number N' of the upper steel piece is 5: A=[a1 a3 a5 0]; Among them: a i is the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

5. A rough rolling sickle bending pass control method according to claim 4, characterized in that: The size range of the data in the matrix A is: 0.02≤a1<a3<a5<a7≤0.09; Among them: a i is the influence weight of the i-th bending amount of the previous steel block on the first-pass bending amount of the current steel block, and i is 1, 3, 5, or 7.

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