Leveling control method for reducing plate shape defect cutting loss

Abstract

The invention provides a flatness control method for reducing strip shape defect cutting loss, and relates to the technical field of hot-rolled strip steel flatness control, and the method comprises the following steps: intercepting a steel coil with serious strip shape defects according to a hot-rolled outlet strip shape curve, and remarking specific information of the strip shape defects of the steel coil; the corresponding condition of the operation side / transmission side of the leveling line and the operation side / transmission side of the hot rolling main line is determined; flattening the steel coil with serious plate shape defects, reducing the flattening speed in advance according to the position condition of the plate shape defects, and adjusting flattening parameters; and 4, after flattening of the strip shape defect position is finished, the flattening parameters are adjusted back to the normal level. According to the method, the steel coil with serious plate shape defects is accurately leveled, plate shape defect cutting damage is avoided, and the plate shape defect leveling yield of the hot rolled steel coil is increased.

Description

Technical Field

[0001] The present application relates to the technical field of flatness control of hot-rolled strip steel, and in particular to a flatness control method for reducing cutting losses caused by plate shape defects. Background Art

[0002] Plate quality is one of the important quality indicators of hot-rolled strip products and the focus of hot-rolled strip production control. One of the manifestations of plate quality defects is wave shape, which will directly affect the use efficiency of downstream uses. In severe cases, it must be cut off and scrapped. In order to avoid affecting customer use, hot-rolled steel coils with large wave defects need to be leveled to improve the strip shape quality. At present, leveling machines do not have raw material plate shape detection equipment, and cannot perform feedforward control on the strip according to the raw material plate shape. This causes the steel coils with excessive wave defects to deviate from the roll gap and break during leveling. At this time, the broken strip must be cut off, causing unnecessary leveling cutting losses, affecting the comprehensive leveling yield of the steel coil. While the strip is broken, it will also cause damage to the surface of the leveling work roll, resulting in a waste of unplanned roll change time and an increase in the number of working roll grindings, which seriously affects the leveling production efficiency and the leveling work roll consumption.

[0003] In the existing technology, the deviation problem of strip steel is mostly corrected by adjusting the roll gap and roll shape of the rolling mill, such as using positive and negative roll bending technology to eliminate the waves on both sides and in the middle, ensuring that the strip steel remains on the center line during the rolling process. However, frequent adjustment of the roll gap and roll shape may increase equipment wear and maintenance costs, affecting production efficiency. Summary of the invention

[0004] The present application is made in view of the above-mentioned problems, and its purpose is to provide a leveling control method for reducing cutting losses due to plate shape defects. After intercepting the steel coil with serious plate shape defects, the starting position, ending position and side position of the plate shape defect are noted, and the position of the defect on the strip is quickly and accurately found during the leveling process. Then, according to the position of the plate shape defect, the leveling speed is reduced in advance, the leveling parameters are adjusted, and the steel coil with serious plate shape defects is accurately leveled to avoid cutting losses due to plate shape defects and improve the leveling yield rate of hot-rolled steel coils with plate shape defects.

[0005] Specifically, the first aspect of the present application provides a flatness control method for reducing plate shape defect cutting loss, comprising the following steps:

[0006] Step 1: According to the hot-rolled export flatness curve, intercept the steel coils with serious flatness defects and note the specific information of the steel coil flatness defects;

[0007] Step 2: Determine the correspondence between the operation side / transmission side of the leveling line and the operation side / transmission side of the hot rolling main line;

[0008] Step 3: Level the steel coil with serious plate shape defects. According to the location of the plate shape defects, reduce the leveling speed in advance and adjust the leveling parameters. The leveling parameters of the defective part are set as follows:

[0009] The leveling speed is 0.1 to 0.2 times that of the normal area of ​​the plate shape, the unwinding tension is 30kN to 140kN, and the rolling force deviation is 2 to 4 times that of the normal area of ​​the plate shape;

[0010] Step 4: After the plate shape defect position is leveled, adjust the leveling parameters to normal levels.

[0011] The adjustment of leveling parameters is specifically to adjust the parameters of the leveling machine. The leveling machine is particularly suitable for strip leveling machines and cold rolling skin pass machines. After recrystallization annealing and galvanizing, the strip often needs to be leveled so that the strip obtains the necessary performance and surface quality to meet the requirements of the subsequent processing. In the leveling machine on the continuous hot-dip galvanizing unit, leveling is essentially a rolling deformation with a small reduction.

[0012] The leveling speed usually refers to the speed of the leveling machine when leveling the plate. The uncoiling tension refers to the tension between the uncoiler and the leveling working roller. Its main purpose is to prevent the strip from loosening or sliding between layers when uncoiling, thereby avoiding scratches or other defects on the strip surface. The rolling force deviation refers to the difference in rolling force applied to the operating side and the transmission side of the leveling machine during the leveling process. The more serious the plate shape defect, the greater the required rolling force deviation.

[0013] Furthermore, the hot rolling exit plate shape curve is a curve characterizing the edge waves or middle waves of the hot-rolled strip measured at the hot rolling exit by a multifunctional instrument or a flatness meter.

[0014] Multi-function instrument: Multi-function instrument is usually installed at the exit of the finishing mill, which can instantly and continuously measure the centerline thickness, cross-sectional thickness, temperature, convexity, width, edge drop and plate shape. These measurement data help operators optimize operations and improve production efficiency and product quality.

[0015] Straightness meter: Straightness meter is mainly used to measure the straightness of strip steel to ensure that the shape of the strip steel meets the requirements during the production process. Straightness meter usually adopts non-contact measurement technology, such as laser triangulation or optical measurement technology, which can detect and feedback straightness data in real time on high-speed production lines.

[0016] In the present invention, the multifunctional instrument and the straightness meter are used to measure the plate shape of the steel coil, that is, the straightness of the steel coil, and can detect the change of the wave value on the strip with the length of the strip. The wave value is the unevenness of the strip, which is convenient for marking areas with serious defects.

[0017] Furthermore, the serious flatness defect refers to a flatness curve value exceeding a set threshold.

[0018] The threshold value for setting the severe plate shape defect of plate shape unevenness is determined by the specific production situation. The present invention determines it based on statistical analysis of historical production data and actual measurement data during the rolling process.

[0019] Furthermore, the specific information of the steel coil shape defect includes the starting position, the ending position, and whether the defect is close to the operating side or far away from the operating side.

[0020] Furthermore, the step 2 specifically includes: determining whether the corresponding relationship between the operating side position of the hot rolling main line and the defect position of the steel coil is consistent with the operating side of the leveling line or the transmission side of the leveling line.

[0021] Determining the correspondence between the operating sides on the hot rolling main line and the leveling line is to quickly locate the position of the wave-shaped defects in the plate. Adjusting the unilateral wave-shaped defects requires increasing or decreasing the rolling force at one end. Only by knowing which side the wave is on can we know whether to increase or decrease the rolling force, and which side needs to be operated.

[0022] The specific adjustment conditions are: if the defect curve is negative and the defect is on the operating side, the transmission side must be pressed down more, that is, the rolling force on the transmission side must be increased; if the defect curve is negative and the defect is on the transmission side, the operating side must be pressed down more, that is, the rolling force on the operating side must be increased; if the defect curve is positive and the defect is on the operating side, the operating side must be pressed down less, that is, the rolling force on the operating side must be reduced; if the defect curve is positive and the defect is on the transmission side, the transmission side must be pressed down less, that is, the rolling force on the transmission side must be reduced.

[0023] Furthermore, the said reducing the leveling speed in advance specifically requires reducing the leveling speed at least 20 m in advance.

[0024] In the second aspect, the present application also 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 function can be implemented by hardware, or by executing the corresponding software implementation 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 function 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.

[0025] In the third aspect, the present application also 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.

[0026] In a fourth aspect, the present application also 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.

[0027] In a fifth aspect, the present application also 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.

[0028] In a sixth aspect, the present application also provides a computing chip, which is connected to a memory, and the chip 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 implementation methods of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 is a flow chart of the steps of the present invention;

[0031] Figure 2 It is a curve diagram of the finishing exit plate type of an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the relative positions of the operating tables and production lines of the hot rolling production line and the flattening line according to an embodiment of the present invention;

[0033] Figure 4 This is a diagram of the real-time adjustment of the leveling parameters in an embodiment of the present invention.

[0034] 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

[0035] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application 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 application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0036] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application 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 in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0037] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0038] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0039] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0040] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0041] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0042] In order to better understand the solutions of the embodiments of the present application, some relevant terms and concepts that may be involved in the embodiments of the present application are first introduced below.

[0043] (1) Hot rolling is a metalworking process mainly used in the production of steel materials. During the hot rolling process, the steel billet is heated to a high temperature (usually over 926°C) and then compressed into the desired shape and size through a series of rollers. This process can improve the mechanical properties of the steel, such as refining the grain and eliminating casting defects, but it also has some disadvantages, such as rough surface, poor toughness and flatness.

[0044] (2) Leveling machine, especially suitable for strip leveling machine and cold rolling skin pass machine. After recrystallization annealing and galvanizing, the strip often needs to be leveled so that the strip can obtain the necessary performance and surface quality to meet the requirements of subsequent processing. In the leveling machine on the continuous hot-dip galvanizing unit, leveling is essentially a rolling deformation with a small reduction.

[0045] In this embodiment, Figure 1 As shown, a flatness control method for reducing plate shape defect cutting loss comprises the following steps:

[0046] Step 1: According to the hot-rolled export flatness curve, intercept the steel coils with serious flatness defects and note the specific information of the steel coil flatness defects;

[0047] Step 2: Determine the correspondence between the operation side / transmission side of the leveling line and the operation side / transmission side of the hot rolling main line;

[0048] Step 3: Level the steel coil with serious plate shape defects. According to the location of the plate shape defects, reduce the leveling speed in advance and adjust the leveling parameters. The leveling parameters of the defective part are set as follows:

[0049] The flattening speed is 0.1 times of the flattening speed in the normal area of ​​the plate shape, the uncoiling tension is 50kN~100kN, and the rolling force deviation is 3 times of the rolling force deviation in the normal area of ​​the plate shape;

[0050] Step 4: After the plate shape defect position is leveled, adjust the leveling parameters to normal levels.

[0051] The adjustment of leveling parameters is specifically to adjust the parameters of the leveling machine. The leveling machine is particularly suitable for strip leveling machines and cold rolling skin pass machines. After recrystallization annealing and galvanizing, the strip often needs to be leveled so that the strip obtains the necessary performance and surface quality to meet the requirements of the subsequent processing. In the leveling machine on the continuous hot-dip galvanizing unit, leveling is essentially a rolling deformation with a small reduction.

[0052] The leveling speed usually refers to the speed at which the leveling machine levels the plate. The uncoiling tension refers to the tension between the uncoiler and the leveling working roll. Its main purpose is to prevent the strip from loosening or sliding between layers when uncoiling, thereby avoiding scratches or other defects on the strip surface. The rolling force deviation refers to the difference in rolling force applied to the operating side and the transmission side of the leveling machine during the leveling process. The more serious the plate defect on one side, the greater the required rolling force deviation.

[0053] Further, the hot rolling outlet plate shape curve is a curve characterizing the edge wave or middle wave of the hot rolled strip measured by a multifunctional instrument or a flatness meter at the hot rolling outlet. In this embodiment, the finishing rolling outlet plate shape curve measured by the flatness meter is as shown in FIG. Figure 2 shown.

[0054] Multi-function instrument: Multi-function instrument is usually installed at the exit of the finishing mill, which can instantly and continuously measure the centerline thickness, cross-sectional thickness, temperature, convexity, width, edge drop and plate shape. These measurement data help operators optimize operations and improve production efficiency and product quality.

[0055] Straightness meter: Straightness meter is mainly used to measure the straightness of strip steel to ensure that the shape of the strip steel meets the requirements during the production process. Straightness meter usually adopts non-contact measurement technology, such as laser triangulation or optical measurement technology, which can detect and feedback straightness data in real time on high-speed production lines.

[0056] In the present invention, the multifunctional instrument and the straightness meter are used to measure the plate shape of the steel coil, that is, the straightness of the steel coil, and can detect the change of the wave value on the strip with the length of the strip. The wave value is the unevenness of the strip, which is convenient for marking areas with serious defects.

[0057] Furthermore, a serious flatness defect means that the flatness curve value exceeds a set threshold.

[0058] The threshold value for setting the severe plate shape defect of plate shape unevenness is determined by the specific production situation. The present invention determines it based on statistical analysis of historical production data and actual measurement data during the rolling process.

[0059] Furthermore, the specific information of the steel coil shape defect includes the starting position, the ending position, and whether the defect is close to the operating side or far away from the operating side.

[0060] Further, step 2 specifically includes: determining whether the corresponding relationship between the operating side position of the hot rolling main line and the defect position of the steel coil is consistent with the operating side of the flattening line or the transmission side of the flattening line. In this embodiment, the relative position of the operating table and the production line of the hot rolling production line and the flattening line is shown in the figure. Figure 3 shown.

[0061] Determining the correspondence between the operating sides on the hot rolling main line and the leveling line is to quickly locate the position of the wave-shaped defects in the plate. Adjusting the unilateral wave-shaped defects requires increasing or decreasing the rolling force at one end. Only by knowing which side the wave is on can we know whether to increase or decrease the rolling force, and which side needs to be operated.

[0062] The specific adjustment conditions are: if the defect curve is negative and the defect is on the operating side, the transmission side must be pressed down more, that is, the rolling force on the transmission side must be increased; if the defect curve is negative and the defect is on the transmission side, the operating side must be pressed down more, that is, the rolling force on the operating side must be increased; if the defect curve is positive and the defect is on the operating side, the operating side must be pressed down less, that is, the rolling force on the operating side must be reduced; if the defect curve is positive and the defect is on the transmission side, the transmission side must be pressed down less, that is, the rolling force on the transmission side must be reduced.

[0063] Furthermore, the leveling speed is reduced in advance, specifically, the leveling speed needs to be reduced at least 20 m in advance.

[0064] In this embodiment, the set threshold of the flatness curve is plus or minus 200 IU, where IU is the unit of unevenness. Figure 2 It can be seen that the peak value of the steel coil shape value is less than -450IU, which exceeds the interception standard. The system determines that plate defect interception is required. The plate defect area of ​​the steel coil is 0~100m. The following detailed repair information is noted: "The single-sided wave on the operating side of the hot-rolled head 0~100m area is eliminated by leveling. Pay attention to adjusting the leveling parameters."

[0065] During the production process, the steel coil is coiled up in the hot rolling production line and uncoiled in the flattening line. Figure 3 When the steel coil produced by the hot rolling production line 1 shown is lifted to the flattening line, the north-south direction of the steel coil must be reversed to achieve the upper uncoiling state. Since the operating sides of the hot rolling production line 1 and the flattening line are in opposite relative positions to the production lines, when the steel coil of the hot rolling production line 1 is uncoiled on the flattening line, the directions of the operating side and the transmission side are not reversed, that is, the operating side of the hot rolling production line 1 is the operating side of the flattening line; similarly, when the steel coil produced by the hot rolling production line 2 is lifted to the flattening line, the north-south direction of the steel coil is reversed. At the same time, since the operating sides of the hot rolling production line 2 and the flattening line are in the same relative position to the production lines, the operating side of the hot rolling production line 2 is the transmission side of the flattening line.

[0066] The steel coil in this embodiment is produced by hot rolling production line 2, and its operating side corresponds to the transmission side of the flat line. Combined with the length and position description of the hot rolling exit plate shape defect, the position of the plate shape defect on the flat line can be accurately located, that is, on the flat line, there is a single-sided wave on the transmission side of the inner ring of the incoming steel coil at 0 to 100m.

[0067] In this embodiment, the operator reduces the speed 20m in advance based on the noted plate defect length information; in this embodiment, the leveling reduction is extremely small, so the leveling speed is consistent with the uncoiler speed, the leveling speed in the normal plate shape area is 300m / min, and the leveling speed in the plate shape defect area is 30m / min. The uncoiler tension is the tension between the uncoiler and the leveling work roll, the uncoiler tension in the normal plate shape area is 0kN, and the uncoiler tension in the plate shape defect area is 50-100kN, which is adjusted according to the unevenness value of the current steel coil leveling position; the rolling force deviation is the difference between the rolling force value on the operating side and the rolling force value on the transmission side. The rolling force deviation in the normal plate shape area is 20kN, and the rolling force deviation in the plate shape defect area is 60kN. The real-time adjustment of the leveling parameters in the embodiment of the present invention is shown in the figure Figure 4 shown.

[0068] It should be noted that the present application 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 application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, 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 application.

Claims

1. A flatness control method for reducing plate shape defect cutting loss, characterized in that: The following steps are involved: Step 1: According to the hot-rolled export flatness curve, intercept the steel coils with serious flatness defects and note the specific information of the steel coil flatness defects; Step 2: Determine the correspondence between the operation side / transmission side of the leveling line and the operation side / transmission side of the hot rolling main line; Step 3: Level the steel coil with serious plate shape defects. According to the location of the plate shape defects, reduce the leveling speed in advance and adjust the leveling parameters. The leveling parameters of the defective part are set as follows: The leveling speed is 0.1 to 0.2 times that of the normal area of ​​the plate shape, the unwinding tension is 30kN to 140kN, and the rolling force deviation is 2 to 4 times that of the normal area of ​​the plate shape; Step 4: After the plate shape defect position is leveled, adjust the leveling parameters to normal levels.

2. A flattening control method for reducing plate shape defect cutting loss according to claim 1, characterized in that: The hot rolling exit flatness curve is a curve characterizing the edge waves or middle waves of the hot-rolled strip measured at the hot rolling exit by a multifunctional instrument or a flatness meter.

3. A flattening control method for reducing plate shape defect cutting loss according to claim 1, characterized in that: The serious flatness defect refers to a flatness curve value exceeding a set threshold.

4. A flattening control method for reducing plate shape defect cutting loss according to claim 1, characterized in that: The specific information of the steel coil shape defect includes the starting position, the ending position of the steel coil shape defect, and whether the defect is close to the operating side or far away from the operating side.

5. A flattening control method for reducing plate shape defect cutting loss according to claim 1, characterized in that: The step 2 specifically includes: determining whether the corresponding relationship between the operating side position of the hot rolling main line and the defect position of the steel coil is consistent with the operating side of the leveling line or the transmission side of the leveling line.

6. A flattening control method for reducing plate shape defect cutting loss according to claim 1, characterized in that: The said reducing the leveling speed in advance specifically requires reducing the leveling speed at least 20m in advance.

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