Method and system for measuring MgO interlayer gap distribution quality of oriented silicon steel

Abstract

The invention belongs to the technical field of thickness detection, and particularly relates to a method and system for measuring MgO interlayer gap distribution quality of oriented silicon steel. The measuring method comprises the following steps: acquiring the strip steel thickness of oriented silicon steel; the outer diameters of the same position or different positions in the width direction in the oriented silicon steel winding process are detected in real time; calculating an interlayer gap value according to a difference value between the characteristic points with the outer diameters periodically changed at the same position and the thickness of the strip steel; and comparing the interlayer gap values at different positions and / or at different times to obtain the MgO interlayer gap distribution quality information of the oriented silicon steel. According to the invention, the change of the interlayer gap in the steel coil coiling process can be measured in real time, the interlayer gap of each layer can be detected in real time, and the transverse, local longitudinal and overall longitudinal interlayer gap distribution quality of the steel coil can be detected; content needing to be adjusted of the unit is judged according to distribution quality, so that production units are fed back in real time and adjusted in time, and product quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of thickness detection technology, specifically relating to a method and system for measuring the quality of the interlayer gap distribution in oriented silicon steel MgO. Background Technology

[0002] Before high-temperature annealing, a layer of magnesium oxide release agent is generally coated on the surface of the oriented silicon steel coil. Its main purpose is to prevent the strip from sticking during high-temperature annealing and to form a magnesium silicate underlayer during high-temperature annealing, which promotes desulfurization and denitrification reactions during purification annealing.

[0003] Due to the presence of magnesium oxide as a release agent, an interlayer gap containing magnesium oxide is formed between the strip layers after coiling. This gap serves as a channel for the discharge of moisture, sulfur-containing gases, and nitrogen-containing gases from within the coil during subsequent high-temperature annealing. The size of the interlayer gap is affected by various factors, including the properties of magnesium oxide itself, the coating amount, the coiling tension, and the coiling tension gradient. An excessively large interlayer gap during coiling can easily cause coil collapse, while an excessively small gap can hinder moisture and air discharge, increasing the risk of coil adhesion. Uneven interlayer gaps can obstruct the venting channels, resulting in watermarks that affect surface quality, or even, in severe cases, poor product shape and performance.

[0004] After magnesium oxide coating is completed, it needs to be dried. The dried magnesium oxide is in a powdery state on the steel strip surface, making it difficult to directly measure the thickness of the magnesium oxide layer. The traditional method involves sampling after winding, scraping off the magnesium oxide from the sample surface, weighing it, and calculating the coating amount. This method requires precise sampling and measurement, cannot be measured in real-time, and has poor timeliness. Monitoring deviations in coating amount during winding is time-consuming, making it difficult to detect problems promptly. Anomalies such as localized missed coatings or thickening are often discovered through periodic inspections during strip steel production, by which time the anomalies have often persisted for a considerable period. Therefore, the traditional method has significant timeliness limitations in measuring interlayer gap distribution and detecting anomalies.

[0005] Furthermore, different specifications of steel coils typically employ different winding tension processes during the winding process, which can be constant tension or gradient tension. When the magnesium oxide coating is wound into the steel coil along with the strip, the powdered magnesium oxide is compressed to a certain volume due to the winding tension. The amount of compression varies under different tension conditions and also differs under different coil diameters. Therefore, the coating amount data in traditional measurement methods cannot reflect the size and variation of the interlayer gap.

[0006] In the prior art, patent CN110319795A provides a method for measuring coating thickness, which is also applicable to the measurement of interlayer gaps in oriented silicon steel coils. This patent proposes measuring the coil length L, outer diameter R, inner diameter R0, and strip thickness T, and then substituting these values ​​into a formula: T 涂层 =(π / 4 (R 2 -R0 2 ))⁄LT 带钢 The coating thickness of the steel coil can be calculated. This method requires measuring length data. The difficulty lies in accurately and synchronously matching the strip length with the coil diameter during the calculation. Furthermore, it cannot detect defects such as local missed coating or thickening during the coil winding process, nor can it measure the uniformity of the interlayer gap in the width direction of the steel coil. Summary of the Invention

[0007] The present invention aims to solve the problems of large measurement and calculation errors in the prior art, and the inability to measure the uniformity of interlayer gaps in the longitudinal and transverse directions of steel strips in real time, and provides a method and system for measuring the quality of interlayer gap distribution in oriented silicon steel MgO.

[0008] According to the technical solution of the present invention, the method for measuring the interlayer gap distribution quality of the MgO in the oriented silicon steel includes the following steps: S1: Obtain the strip thickness of grain-oriented silicon steel; S2: Real-time detection of the outer diameter at the same or different positions in the width direction during the winding process of grain-oriented silicon steel; S3: Calculate the interlayer gap value based on the difference between characteristic points where the outer diameter changes periodically at the same location and the strip thickness; S4: By comparing the interlayer gap values ​​at different locations and / or at different times, the quality information of the interlayer gap distribution of MgO in oriented silicon steel is obtained.

[0009] Furthermore, in step S2, the standard for real-time detection is: for every one turn of the oriented silicon steel coil, the number of detections is no less than 12.

[0010] Furthermore, in step S3, the periodic change in outer diameter refers to the change in outer diameter when the steel coil is wound up once, and the characteristic point is the point where the trend of outer diameter change changes.

[0011] Furthermore, step S4 includes: By comparing the interlayer gap values ​​at different locations in the same time and width direction, the quality information of the transverse MgO interlayer gap distribution in oriented silicon steel is obtained. By comparing the interlayer gap values ​​at the same location but at different times, the quality information of the longitudinal MgO interlayer gap distribution in oriented silicon steel is obtained.

[0012] Furthermore, the specific operation of step S4 is as follows: calculate the deviation value of the interlayer gap value, and determine whether the interlayer gap distribution of the oriented silicon steel MgO conforms to the standard according to the preset deviation standard.

[0013] Furthermore, after step S4, the method further includes a step of determining the adjustment information required for the MgO coating unit based on the quality of the MgO interlayer gap distribution in the oriented silicon steel.

[0014] Another aspect of the present invention provides a measurement system for the distribution quality of MgO interlayer gaps in oriented silicon steel, comprising: The data acquisition unit includes a thickness gauge and several precision displacement sensors. The thickness gauge is positioned before the oriented silicon steel strip is coated with magnesium oxide and is used to detect the thickness of the oriented silicon steel strip. There are one or more precision displacement sensors used to detect the distance between the outer surface of the oriented silicon steel coil and the precision displacement sensor in real time. When there are multiple precision displacement sensors, they are arranged parallel to the winding axis of the oriented silicon steel coil. The data processing unit is used to receive and process the detection data from the thickness gauge and the precision displacement sensor, and to determine the distribution quality of the interlayer gap of the MgO in the oriented silicon steel according to preset information.

[0015] Furthermore, the measurement accuracy of the precision displacement sensor is higher than that of the grain-oriented silicon steel strip.

[0016] Furthermore, the centerline of the precision displacement sensor that measures the displacement intersects perpendicularly with the winding axis of the oriented silicon steel coil.

[0017] Compared with the prior art, the technical solution of the present invention has the following advantages: The present invention can measure the change of interlayer gap during the coil winding process in real time, detect the interlayer gap of each layer in real time, and detect the distribution quality of interlayer gap in the transverse direction, local longitudinal direction, and overall longitudinal direction of the coil; based on the distribution quality, it can determine the adjustments that the unit needs to make, thereby providing real-time feedback to the production unit for timely adjustments and improving product quality. Attached Figure Description

[0018] Figure 1 It refers to the outer circumference shape of the steel coil.

[0019] Figure 2 This is a schematic diagram for feature point recognition.

[0020] Figure 3 This is a schematic diagram of the interlayer air gap.

[0021] Figure 4 This is a schematic diagram of the test system of the present invention.

[0022] Figure 5 This is a graph of interlayer gap data in Example 3 (blue represents fitted data, green represents actual measurement data).

[0023] Explanation of reference numerals in the attached drawings: 1-Precision displacement sensor, 2-Oriented silicon steel coil, 3-Data processing unit, 4-Thickness gauge, 5-Oriented silicon steel strip, 6-Coating roller. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0025] During the winding process of grain-oriented silicon steel, the steel strip needs to be wound onto a spool. For example... Figure 1 As shown, the outer circumferential cross-section of the steel coil (oriented silicon steel coil 2) has a certain degree of non-circularity, and is an irregular near-circular shape. Through actual measurement, this invention found that the non-circularity of the steel coil is generally greater than the measurement accuracy of the high-precision displacement sensor, and this non-circularity exists on the outer surface of the steel coil from the beginning to the end of winding.

[0026] Based on this, the present invention provides a method for measuring the interlayer gap distribution quality of MgO in oriented silicon steel, comprising the following steps: S1: Obtain the strip thickness of grain-oriented silicon steel; S2: Real-time detection of the outer diameter at the same or different positions in the width direction during the winding process of grain-oriented silicon steel; S3: Calculate the interlayer gap value based on the difference between characteristic points where the outer diameter changes periodically at the same location and the strip thickness. S4: By comparing the interlayer gap values ​​at different locations and / or at different times, the quality information of the interlayer gap distribution of MgO in oriented silicon steel is obtained.

[0027] Specifically, in step S1, the thickness of the grain-oriented silicon steel strip is the thickness without coating. It can be measured before the steel strip is coated with MgO (coating roller 6), or the thickness data measured during cold rolling (the process before coating with MgO) or rewinding can be used.

[0028] In step S2, a precision displacement sensor 1 can be installed on the outside of the grain-oriented silicon steel coil 2 to detect the distance from the outer surface of the grain-oriented silicon steel coil 2 to the precision displacement sensor 1, which is then converted into the outer diameter of the grain-oriented silicon steel coil 2. Since data from different positions in the width direction needs to be detected, multiple precision displacement sensors 1 are used, distributed along the same line parallel to the winding axis of the grain-oriented silicon steel coil 2. It is conceivable that, since the positions of the precision displacement sensors 1 remain unchanged, the detected distance data does not need to be converted; instead, the conversion is performed later when calculating the difference between feature points.

[0029] Because the outer surface of the grain-oriented silicon steel coil 2 has a certain degree of non-circularity, the distance between it and the high-precision displacement sensor 1 varies at different positions along the circumference. During the winding process, this difference in distance can be detected by the high-precision displacement sensor, particularly the changes in the position of feature points. The identification of its outer circumference shape and feature points is as follows: Figure 2 As shown. To ensure that the precision displacement sensor 1 can detect the non-roundness of the oriented silicon steel coil 2, its measurement accuracy should be higher than the strip thickness (0.1-0.3mm). For example, a laser displacement sensor, ultrasonic displacement sensor, or other forms of high-precision displacement sensor can be used. Simultaneously, to accurately capture the position of feature points and achieve real-time detection, the data detection / recording frequency must meet certain requirements. Through repeated testing, this invention found that the number of records should be no less than 12 times per revolution of the oriented silicon steel coil 2.

[0030] The feature points in this invention are points where the trend of outer diameter change changes. For example, it can be a point where the outer diameter value changes from increasing to decreasing, with the maximum outer diameter being a typical feature point; or a point where the outer diameter value changes from decreasing to increasing, with the minimum outer diameter being a typical feature point; or other points where the rate of increase of the outer diameter value changes.

[0031] The periodic change in outer diameter in step S3 refers to the change in outer diameter after one coil rotation. By measuring the distance data (which can be converted to outer diameter) and identifying feature points, the change in outer diameter Δh after one rotation of the oriented silicon steel is obtained; subtracting the strip thickness t yields the interlayer gap size. Figure 3 As shown.

[0032] Based on the interlayer gap obtained in step S3, a series of processes can be performed to obtain the interlayer gap distribution quality of MgO in oriented silicon steel. For example, by comparing the interlayer gap values ​​at different locations in the width direction at the same time, the quality information of the transverse MgO interlayer gap distribution (interlayer gap uniformity) of the oriented silicon steel can be obtained; by comparing the interlayer gap values ​​at the same location at different times, the quality information of the longitudinal MgO interlayer gap distribution of the oriented silicon steel can be obtained. The specific operation is as follows: calculate the deviation value of the interlayer gap value, and determine whether the MgO interlayer gap distribution of the oriented silicon steel meets the standard according to the preset deviation standard.

[0033] Following step S4, the process also includes determining the necessary adjustments to the MgO coating unit based on the quality of the MgO interlayer gap distribution in the oriented silicon steel. These adjustments include adjusting the coating roller pressure, changing the coating roller, and ensuring the coating solution is mixed evenly.

[0034] Specifically, when multiple interlayer gap values ​​in the transverse (width direction) deviate and exceed the set deviation (transverse interlayer gap distribution quality does not meet the standard), the deviation category is classified to indicate potential problems with the MgO coating unit. For example: if the transverse interlayer gap shows an increasing or decreasing deviation exceeding 10%, it indicates that the pressure on one side of the coating roller needs to be adjusted; if the transverse interlayer gap shows a deviation of thicker at both sides and thinner in the middle exceeding the set deviation by 10%, it indicates that the pressure on both sides of the coating roller needs to be adjusted; if the transverse interlayer gap shows a deviation of thinner at both sides and thicker in the middle exceeding the set deviation by 10%, it is necessary to check the condition of the coating roller, check for defects such as no lines, and adjust or replace the coating roller in a timely manner.

[0035] The longitudinal interlayer gap distribution refers to the deviation in the interlayer gap value at the same location but at different times (different winding turns). If it is less than the set deviation, it indicates that the coating thickness is uniform within the two turns being compared. If the actual curve shows anomalies and the deviation is greater than the set deviation, the deviation category is classified to indicate potential problems with the unit. For example, if the set deviation is 10%, and the abnormal decrease in deviation exceeds 10% of the set deviation, it indicates possible defects such as missed coating or an excessively thin coating; if the abnormal increase in deviation exceeds 10% of the set deviation, it indicates localized thickening defects such as lines or lumps.

[0036] When comparing the distribution of longitudinal interlayer gaps, a fitting comparison method can also be used: based on the displacement distance curve of each rotation of the steel coil, the displacement distance curve within each rotation is fitted, and the obtained displacement curve data is used to predict the displacement distance data for the next rotation. The predicted curve is then compared with the actual curve.

[0037] For the entire winding process, measurements can be taken of steel coils of different specifications under different winding tensions to establish a database of interlayer gaps under different winding tensions. The interlayer gap data under each winding tension can be calculated to form an interlayer gap distribution curve. A curve function with coil diameter as the independent variable and interlayer gap as the dependent variable is then fitted and input into a storage device. During the winding process, the real-time detected interlayer gap is compared with this curve. If the measured interlayer gap is too high or too low, the anomaly must be addressed promptly.

[0038] Specifically: The actual curve under a specific winding tension during the winding process of each steel coil is compared with the interlayer gap distribution curve stored in the storage device. This determines whether the actual interlayer gap of each layer is the same as the interlayer gap distribution curve under that tension condition. If the deviation is within the allowable set deviation range, it indicates that the coating thickness along the length of the steel coil is uniform. If the actual curve shows abnormal points and the deviation exceeds the set deviation, the deviation category is classified to indicate potential problems with the unit. Taking a set deviation of 5% as an example, if the abnormal decrease in deviation exceeds 5%, it indicates that the pressure on both sides of the coating roller needs to be reduced promptly; if the abnormal increase in deviation exceeds 5%, it indicates that the pressure on both sides of the coating roller needs to be increased promptly.

[0039] The detection method of this invention is based on a measurement system, such as... Figure 4 As shown, the measurement system includes a data acquisition unit and a data processing unit 3.

[0040] The data acquisition unit includes a thickness gauge 4 and a precision displacement sensor 1. The thickness gauge 4 is positioned before the magnesium oxide coating on the grain-oriented silicon steel strip 5 and is used to detect the thickness of the grain-oriented silicon steel strip. One or more precision displacement sensors 1 are used to detect the distance between the outer surface of the grain-oriented silicon steel coil 2 and the precision displacement sensor 1 in real time. When multiple precision displacement sensors 1 are used, they are positioned parallel to the winding axis of the grain-oriented silicon steel coil 2. The centerline of the displacement measurement by the precision displacement sensor 1 intersects perpendicularly with the winding axis of the grain-oriented silicon steel coil 2, resulting in more accurate and convenient data conversion.

[0041] The data processing unit 3 receives and processes the detection data from the thickness gauge 4 and the precision displacement sensor 1, and determines the distribution quality of the MgO interlayer gap in the oriented silicon steel based on preset information. Specifically, it can be equipped with a computer, a microcontroller, a PLC (programmable logic controller), or other similar devices. The preset information refers to the preset deviation standard, which can be set to 5%, 10%, or other suitable standards, depending on the production process requirements.

[0042] The data acquisition unit may also include a storage mechanism, such as a hard disk, and the data processing unit 3 may retrieve data from the storage mechanism; the data processing unit 3 may also include an information output mechanism, such as a display screen.

[0043] When data processing unit 3 performs data processing, one typical algorithm is to use the farthest distance (corresponding to the smallest outer diameter) as a feature point for identification, h maxi =max(h i-n ,h i-n+1 …h i h i+1 ,h i+2 …h i+n ), h i h is the current measurement point. maxiThe feature point value is the farthest point within the current i-th layer period. The value of n can range from x to 2x (where x is the number of data points recorded in the current period, e.g., x points measured per week). Artificial intelligence can also be integrated to train the feature point value, thereby more accurately identifying and calculating the feature points. This invention can also use other peak detection methods such as curve fitting and wavelet transform. These algorithms can automatically calculate the measured distance and displacement data and identify the feature point location through programmed execution.

[0044] Subtracting the data from the (i+1)th layer and the data from the ith layer, and then subtracting the strip thickness t, yields the interlayer gap value for the ith layer: Ci = h maxi -h maxi+1 -t.

[0045] In some preferred embodiments, feature point data can be used for multi-layer calculations, combined with the i-th layer distance data h. maxi Distance data h between the s-th layer and the s-th layer maxi+s And the corresponding number of layers s, which are then divided equally using the following formula, Ci av =(h maxi -h maxi+s By calculating (s-1)-t, the average interlayer gap within a certain thickness range can be obtained, further improving the accuracy of the test and reducing measurement errors.

[0046] Example 1: Detection of the quality of transverse interlayer gap distribution in steel coils During strip coiling, the surface displacement of the strip is measured. The coil width is 1250 mm, the strip thickness is 0.23 mm, the coiling tension is specific to the process, and the coiling tension coefficient is 6 kg / mm. 2 The winding machine rotates at 0.5 r / s. Five high-precision displacement sensors are positioned at 100 mm, 300 mm, 500 mm, 700 mm, 900 mm, and 1100 mm along the width of the steel coil. The high-precision displacement sensors have a measurement accuracy of 0.2 mm, and the data acquisition frequency is 100 ms. Data on the five interlayer gaps (corresponding to the five high-precision displacement sensors) along the width direction at four time points during the winding process are processed, and the interlayer gap deviation is calculated. This deviation is compared with the set deviation and verified in conjunction with the actual sheet surface conditions. The results are shown in Table 1.

[0047] Table 1

[0048]

[0049] The results show that the method of the present invention, by measuring multiple interlayer gap data in the width direction of the steel coil in real time, can promptly detect abnormalities in the interlayer gap in the width direction of the plate, and defects that are not visible to the naked eye can also be identified quantitatively. Defects that are visible to the naked eye can also be detected in a timely manner, and the two can be correlated well.

[0050] Example 2: Detection of local longitudinal interlayer gap distribution quality The winding parameters are the same as in Example 1. One high-precision displacement sensor is used, positioned 600mm across the width of the steel coil, with the same detection parameters as in Example 1. The distance data measured by the high-precision displacement sensor allows for the generation of the displacement distance curve for each revolution of the steel coil. The algorithm described above accurately identifies feature points in the displacement distance curve for each revolution during the coil winding process. The measured displacement data is then segmented and calculated based on these feature points. The displacement distance curve for each revolution is fitted, and the obtained displacement curve data is used to predict the displacement distance data for the next revolution. The predicted curve is compared with the actual curve, and the results are shown in Table 2.

[0051] Table 2

[0052] The results show that the method of the present invention can accurately identify the characteristic points in the displacement distance curve of each rotation of the steel coil by measuring the displacement distance curve in real time during the coil winding process. The measured displacement data is then segmented and calculated based on the characteristic points. By comparing the displacement distance curves within each rotation, defects such as localized missing coating and clumping in the longitudinal direction of the steel coil can be detected.

[0053] Example 3: Method for measuring the longitudinal interlayer gap distribution quality of an entire roll The winding parameters and high-precision displacement sensor settings are the same as in Example 2. By measuring the winding of steel coils of the same specification under a specific winding tension, a database of interlayer gaps under that tension is established. The interlayer gap data under that winding tension is used to calculate the interlayer gap distribution curve, and a curve function with coil diameter as the independent variable and interlayer gap as the dependent variable is fitted and input into a storage device. During the winding process, the interlayer gap detected in real time is compared with this curve, and the results are shown in Table 3. Figure 5 As shown.

[0054] Table 3

[0055] With a set deviation value of 5%, the results showed that at a roll diameter of 1000, the interlayer gap deviated from the standard curve by 7.06%, indicating that the coating roller pressure might be too low. The unit adjusted the interlayer gap in a timely manner based on the measured abnormal interlayer gap information, and the subsequent interlayer gap basically conformed to the trend of the standard curve.

[0056] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for measuring the quality of MgO interlayer gap distribution in oriented silicon steel, characterized in that, Includes the following steps: S1: Obtain the strip thickness of grain-oriented silicon steel; S2: Real-time detection of the outer diameter at the same or different positions in the width direction during the winding process of grain-oriented silicon steel; S3: Calculate the interlayer gap value based on the difference between characteristic points where the outer diameter changes periodically at the same location and the strip thickness; S4: By comparing the interlayer gap values ​​at different locations and / or at different times, the quality information of the interlayer gap distribution of MgO in oriented silicon steel is obtained.

2. The measurement method as described in claim 1, characterized in that, In step S3, the standard for real-time detection is: for every one turn of the oriented silicon steel coil, the number of detections is no less than 12.

3. The measurement method as described in claim 1, characterized in that, In step S3, the periodic change in outer diameter refers to the change in outer diameter when the steel coil is wound up once, and the characteristic point is the point where the trend of outer diameter change changes.

4. The measurement method as described in claim 1, characterized in that, Step S4 includes: By comparing the interlayer gap values ​​at different locations in the same time and width direction, the quality information of the transverse MgO interlayer gap distribution in oriented silicon steel is obtained. By comparing the interlayer gap values ​​at the same location but at different times, the quality information of the longitudinal MgO interlayer gap distribution in oriented silicon steel is obtained.

5. The measurement method as described in claim 1 or 4, characterized in that, The specific operation of step S4 is as follows: calculate the deviation value of the interlayer gap value, and judge the quality of the interlayer gap distribution of the oriented silicon steel MgO according to the preset deviation standard.

6. The measurement method as described in claim 5, characterized in that, Step S4 is followed by a step of determining the adjustment information required for the MgO coating unit based on the quality of the MgO interlayer gap distribution in the oriented silicon steel.

7. A system for measuring the quality of MgO interlayer gap distribution in oriented silicon steel, characterized in that, include: The data acquisition unit includes a thickness gauge (4) and a precision displacement sensor (1); the thickness gauge (4) is set at the position before the oriented silicon steel strip (5) is coated with magnesium oxide, and is used to detect the thickness of the oriented silicon steel strip; there are one or more precision displacement sensors (1), which are used to detect the distance between the outer surface of the oriented silicon steel coil (2) and the precision displacement sensor (1) in real time. When there are multiple precision displacement sensors (1), they are set parallel to the winding axis of the oriented silicon steel coil (2); The data processing unit (3) is used to receive and process the detection data of the thickness gauge (4) and the precision displacement sensor (1), and to determine the distribution quality of the MgO interlayer gap of the oriented silicon steel according to the preset information.

8. The measurement system as described in claim 7, characterized in that, The precision displacement sensor (1) has a higher measurement accuracy than the thickness of the grain-oriented silicon steel strip.

9. The measurement system as described in claim 7 or 8, characterized in that, The centerline of the precision displacement sensor (1) measures the displacement and intersects perpendicularly with the winding axis of the oriented silicon steel coil (2).

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