An online detection method and system for strip steel folding marks

Abstract

The application discloses an online detection method for a strip steel folding mark, comprising the following steps: (1) collecting current folding mark monitoring parameters of the strip steel; (2) detecting whether the current folding mark monitoring parameters jump, if there are folding mark monitoring parameters jumping, it is determined that there is a folding mark at the corresponding position. The online detection method for the strip steel folding mark can online and real-time reflect the folding condition of the strip steel surface and give a prewarning, thereby reducing secondary hazards caused by the folding. At present, the online process prewarning and closure of the folding mark have been realized in a certain production line, and the outflow rate of the folding mark is reduced by more than 30%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of steel rolling, and more particularly, relates to an online detection method and system for folding marks of a strip steel. BACKGROUND

[0002] In the production process of hot-rolled strip steel, folding marks on the surface of the strip steel are one of the key factors affecting production stability. Folding marks formed during the coiling process of the strip steel not only affect the production stability during secondary processing, but also have adverse effects on the plating process on the surface of the strip steel.

[0003] In the production process of the strip steel, due to the production conditions on site, folding marks generated on the strip steel cannot be effectively and timely discovered and identified online. Instead, they are detected by partially uncoiling the steel coil for sampling inspection. Subsequent inspection cannot be performed on each coil and each uncoiled inspection. There are problems of missed detection of folding marks and low detection efficiency.

[0004] Therefore, how to identify folding marks of the strip steel online is a technical problem that needs to be solved urgently. SUMMARY

[0005] The present application provides an online detection method for folding marks of a strip steel, aiming to improve the above-mentioned problems.

[0006] The present application is implemented as follows. An online detection method for folding marks of a strip steel, the method comprising the following steps:

[0007] (1) Collecting current folding mark monitoring parameters of the strip steel;

[0008] (2) Detecting whether the current folding mark monitoring parameters jump, and if there are folding mark monitoring parameters that jump, it is determined that there are folding marks at the corresponding position.

[0009] Further, if the folding mark monitoring parameters satisfy the following conditions 1 and 2, it is determined that there are jumps at the current position of the strip steel, and the conditions 1 and 2 are as follows:

[0010] Condition 1: The difference between the folding mark monitoring parameters on the left and right sides of the current position is greater than a set threshold value.

[0011] Condition 2: The derivative of the folding mark monitoring parameters at the current position is opposite to the derivative at the previous position.

[0012] Further, the folding mark monitoring parameters include at least one of rolling pressure, rolling pressure deviation, roll gap, and roll gap deviation.

[0013] Further, when there are two folding mark monitoring parameters, one folding mark monitoring parameter is selected from the rolling pressure and the rolling pressure deviation; and one folding mark monitoring parameter is selected from the roll gap and the roll gap deviation.

[0014] Furthermore, if the current rolling pressure is less than the rolling pressure threshold, either the rolling pressure or the rolling pressure deviation can be selected as the folding mark monitoring parameter; if the current rolling pressure is greater than the rolling pressure threshold, the rolling pressure deviation can be selected as the folding mark monitoring parameter.

[0015] Furthermore, if the current strip thickness is less than the thickness threshold, either the roll gap or the roll gap deviation can be selected as the fold mark monitoring parameter; if the current strip thickness is greater than the thickness threshold, the roll gap deviation can be used as the fold mark monitoring parameter.

[0016] Furthermore, after step (2), the following is also included:

[0017] (3) When it is determined that there is a fold mark on the current strip, output the fold mark warning flag.

[0018] This invention is implemented as follows: an online detection system for steel folding marks, the system comprising:

[0019] Reading unit and processor;

[0020] The reading unit reads the current fold mark monitoring parameters of the strip and sends them to the processor. The processor uses the online detection method for strip fold marks to detect whether there are fold marks at the corresponding positions of the strip.

[0021] Furthermore, the system also includes:

[0022] The alert unit, connected to the processor, issues a fold mark warning when a fold mark is detected on the strip.

[0023] The online detection method for strip fold marks provided by this invention can detect the folding status of the strip surface online and in real time, and provide early warnings, thereby reducing secondary hazards caused by folding. Currently, a certain production line has implemented online early warning and closure of fold mark processes, reducing the fold mark outflow rate by more than 30%. Attached Figure Description

[0024] Figure 1 This is a flowchart of an online detection method for steel strip fold marks provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the online detection system for steel strip fold marks provided in an embodiment of the present invention;

[0026] Figure 3 This is an example diagram of leveling data provided in an embodiment of the present invention.

[0027] Figure 4 Provided for embodiments of the present invention Figure 3 A magnified view of point A in the middle;

[0028] Figure 5 This is an example diagram showing the deviation of the pinch roll rolling pressure at different times provided in an embodiment of the present invention;

[0029] Figure 6 This is an example diagram of folded print information provided in an embodiment of the present invention. Detailed Implementation

[0030] 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.

[0031] When strip folding is detected during strip rolling, the rolling pressure (FORCE), rolling pressure deviation (DIFF-FORCE), roll gap (GAP), and roll gap deviation (LEVELING) will change abruptly. The rolling pressure deviation is the difference in rolling pressure between the two sides of the roll (operating side and drive side), and the rolling pressure is the total rolling pressure formed based on the rolling pressures on both sides of the roll, generally the average of the two. The roll gap deviation is the difference in roll gap between the two sides of the roll (operating side and drive side), and the roll gap is the total roll gap formed based on the roll gaps on both sides of the roll, generally the average of the two or using a center roll gap.

[0032] By monitoring the above parameters, online detection of steel strip fold marks can be achieved. Figure 1 The flowchart below shows an online detection method for steel strip fold marks provided in an embodiment of the present invention. The method includes the following steps:

[0033] (1) Real-time acquisition of folding mark monitoring parameters, including at least one of rolling pressure, rolling pressure deviation, roll gap and roll gap deviation;

[0034] (2) Detect whether the currently collected folded print monitoring parameters have changed. If there are folded print monitoring parameters that have changed, it is determined that there is a folded print at the corresponding position and the folded print warning flag is output. If none of the folded print monitoring parameters have changed, it is determined that there is no folded print at the corresponding position.

[0035] In this embodiment of the invention, if the fold mark monitoring parameters meet the following conditions 1 and 2, it is determined that there is a jump in the current position of the strip. The specific conditions are as follows:

[0036] Condition 1: The difference J between the monitoring parameters of the fold marks on the left and right sides under the current intercept. max If it exceeds the set threshold, the specific calculation formula is as follows:

[0037] J max =abs((y R -y L)·Δp)

[0038] Among them, y R y L The monitoring parameter values ​​of the fold mark at the right and left endpoints of the current intercept Δp are respectively.

[0039] Condition 2: The derivative of the fold mark detection parameter at the current position is in the opposite direction to the derivative at the previous position.

[0040] In this embodiment of the invention, the fold mark monitoring parameter can be any one of rolling pressure, rolling pressure deviation, roll gap and roll gap deviation. Assuming that rolling pressure is selected, the rolling pressure at different positions of the strip is collected periodically or according to the set step size. The rolling pressure difference between the left and right sides of the current position is calculated, and the derivative of the rolling pressure at the current position is calculated. If the rolling pressure difference is greater than the set difference threshold, and the derivative of the rolling pressure at the current position is opposite to the derivative of the previous position, then it is determined that there is a fold mark at the current position.

[0041] The opposite of the derivative value at the current position to the derivative value at the previous position means that if the derivative value at the current position is positive, then the derivative value at the previous position is negative, and vice versa.

[0042] In this embodiment of the invention, the fold mark monitoring parameters can be any two of rolling pressure, rolling pressure deviation, roll gap, and roll gap deviation. Since rolling pressure and rolling pressure deviation are one set of related parameters, and roll gap and roll gap deviation are another set of related parameters, the evaluation dimensions of the two sets of related parameters are different. In this case, it is best to select one of the two sets of related parameters. For example, if rolling pressure and roll gap are used as fold mark monitoring parameters, the rolling pressure and roll gap at different positions of the strip are periodically collected or collected according to the set step size. The difference between the rolling pressure and roll gap on the left and right sides of the current position is calculated. At the same time, the derivative values ​​of rolling pressure and roll gap at the current position are calculated. If the difference in rolling pressure is greater than the set difference threshold, and the derivative value of rolling pressure at the current position is opposite to the derivative value at the previous position, or if the difference in roll gap is greater than the set difference threshold, and the derivative value of roll gap at the current position is opposite to the derivative value at the previous position, then it is determined that there is a fold mark at the current position.

[0043] In this embodiment of the invention, if the current rolling pressure is too low, i.e., less than the rolling pressure threshold (e.g., 25000kN), then either the rolling pressure or the rolling pressure deviation can be selected as the fold mark monitoring parameter. If the current rolling pressure is greater than the rolling pressure threshold, then the rolling pressure deviation is selected as the fold mark monitoring parameter. If the current strip thickness is too low, i.e., less than the thickness threshold (e.g., 2.5mm), then either the roll gap or the roll gap deviation can be selected as the fold mark monitoring parameter. If the current strip thickness is greater than the thickness threshold, then the roll gap deviation is selected as the fold mark monitoring parameter.

[0044] Of course, the fold mark monitoring parameters can be any three of the following: rolling pressure, rolling pressure deviation, roll gap and roll gap deviation, or all four of the above parameters. That is, three or four fold mark monitoring parameters can be monitored at the same time. As long as there is a jump in the fold mark monitoring parameter, the corresponding position is identified as having a fold mark.

[0045] Figure 2 This is a schematic diagram of the online detection system for steel strip fold marks provided in an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown. The system includes:

[0046] The reading unit reads the current fold mark monitoring parameters of the strip and sends them to the processor. The processor detects whether there is a fold mark at the corresponding position of the strip based on the above-mentioned online detection method for strip fold marks.

[0047] In this embodiment of the invention, the system further includes: a prompting unit connected to the processor; when a fold mark is detected on the strip, the prompting unit issues a fold mark warning.

[0048] Taking roll gap deviation (LEVELING) data as an example, its data conditions Figure 3 As shown, taking point A as an example, zooming in yields... Figure 4 The difference in roll gap at point A is J. max The derivative to the left of point A is D1, and the derivative to the right is D2. If J max If the value is greater than or equal to the threshold and the directions of D1 and D2 are opposite, then point A is determined to have a fold mark, and the fold mark warning flag ERR is output.

[0049] Taking a steel mill producing 2.5mm thick steel as an example, the configuration parameters of finishing mill F1-F7, pressure roll DR, and pinch roll PR are as follows:

[0050]

[0051] Figure 5 The deviation of the pinch roll rolling pressure at different times is represented by J at the position of 01:09:15. max=6.19567 - 0.770193 = 5.425477 kN, which is greater than the given threshold of 4 kN. The left derivative at this position is opposite to the right derivative, indicating that a fold mark has appeared at this position. Specific information is as follows... Figure 6 Show.

[0052] 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. An online detection method for steel strip fold marks, characterized in that, The method includes the following steps: (1) Collect the current fold mark monitoring parameters of the strip steel; (2) Detect whether the current fold mark monitoring parameter has changed. If there is a fold mark monitoring parameter that has changed, then it is determined that there is a fold mark at the corresponding position. If the monitoring parameters of the fold mark meet the following conditions 1 and 2, then it is determined that there is a jump in the current position of the strip. Conditions 1 and 2 are as follows: Condition 1: The difference in monitoring parameters of the fold marks on the left and right sides under the current intercept. Greater than the set threshold; Condition 2: The derivative of the fold mark detection parameter at the current position is in the opposite direction to the derivative at the previous position; The derivative value at the current position is opposite to the derivative value at the previous position, meaning that if the derivative value at the current position is positive, then the derivative value at the previous position is negative, and vice versa. The monitoring parameters for folding printing include: rolling pressure, rolling pressure deviation, roll gap, and at least one of the following: roll gap pressure, roll pressure deviation, roll gap gap, and roll gap deviation. Rolling pressure deviation is the difference in rolling pressure between the two sides of the roll, and rolling pressure is the total rolling pressure formed based on the rolling pressure between the two sides of the roll; roll gap deviation is the difference in roll gap between the two sides of the roll, and roll gap is the total roll gap formed based on the roll gap between the two sides of the roll.

2. The online detection method for steel strip fold marks as described in claim 1, characterized in that, When there are two fold mark monitoring parameters, select one fold mark monitoring parameter from rolling pressure and rolling pressure deviation; select one fold mark monitoring parameter from roll gap and roll gap deviation.

3. The online detection method for steel strip fold marks as described in claim 2, characterized in that, If the current rolling pressure is less than the rolling pressure threshold, either the rolling pressure or the rolling pressure deviation can be selected as the folding mark monitoring parameter. If the current rolling pressure is greater than the rolling pressure threshold, the rolling pressure deviation can be selected as the folding mark monitoring parameter.

4. The online detection method for steel strip fold marks as described in claim 2, characterized in that, If the current strip thickness is less than the thickness threshold, either the roll gap or the roll gap deviation can be selected as the fold mark monitoring parameter. If the current strip thickness is greater than the thickness threshold, the roll gap deviation will be used as the fold mark monitoring parameter.

5. The online detection method for steel strip fold marks as described in claim 1, characterized in that, The process after step (2) also includes: (3) When it is determined that there is a fold mark on the current strip, output the fold mark warning flag.

6. An online detection system for steel folding marks, characterized in that, The system includes: Reading unit and processor; The reading unit reads the current fold mark monitoring parameters of the strip steel and sends them to the processor. The processor detects whether there is a fold mark at the corresponding position of the strip steel based on the online detection method of strip steel fold mark according to any one of claims 1 to 5.

7. The online detection system for steel strip folding marks as described in claim 6, characterized in that, The system also includes: The prompting unit is connected to the processor; When a fold mark is detected on the strip, a fold mark warning is issued through the prompting unit.

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