A method for quickly obtaining and correcting strip thickness compensation coefficient

Abstract

The present application relates to the field of electric power and metallurgy, and relates to a method for quickly obtaining and correcting a strip thickness compensation coefficient, which comprises two aspects: 1. quickly obtaining the compensation coefficient; and 2. correcting the compensation coefficient.The present application has the following beneficial effects: 1. The method meets the measurement accuracy requirements and conforms to the process requirements, thereby providing strong technical support for the production of continuous rolling silicon steel.2. The method adopts a low-cost design scheme, has high running stability, and is accurate in measurement. If the method is widely used, a large amount of equipment cost can be saved for the users, the principle of reducing cost and increasing efficiency is met, and the method has great popularization value.

Description

Technical Field

[0001] This invention relates to the fields of electric power and metallurgy, and in particular to a method for rapidly obtaining and correcting the strip thickness compensation coefficient. Background Technology

[0002] In the metallurgical industry, online thickness gauges are mainly used for real-time continuous measurement and control of the thickness of materials such as steel plates and strips on rolling production lines. With computer automatic control as its core, it measures the thickness of steel plates and strips online in real time. Through a series of monitoring circuits, the measurement results are fed back to the pressing control system, which then changes the pressing position, tension, and rolling speed to achieve automatic control of the thickness of steel plates and strips.

[0003] Four thickness gauges and one edge drop gauge are used in the pickling continuous rolling mill to measure the thickness of the steel strip, calculate the thickness deviation and edge drop, and participate in closed-loop control to achieve the purpose of thickness control and edge drop control.

[0004] The main principle of a thickness gauge is that steel plates of different thicknesses and materials absorb different amounts of X-rays. The purpose of recalibrating a thickness gauge is to calculate a new compensation coefficient by measuring a standard plate.

[0005] The method for calculating and rapidly correcting the strip thickness compensation coefficient of this invention is mainly used in the development of new steel grades. It requires calculating the thickness compensation coefficient for the new steel grade and then inputting the compensation coefficient into the thickness measuring equipment system to ensure that the finished product thickness rolled by the steel grade is basically consistent with the planned finished product thickness, as well as to continuously correct the thickness compliance rate of the original steel grade.

[0006] Since the invention was put into use, the thickness measurement system has been operating stably, and the thickness deviation is within the allowable range of the process. At the same time, in terms of correction and compensation coefficient, it has achieved the effect of fast correction and accurate accuracy. Summary of the Invention

[0007] The purpose of this invention is to address the above-mentioned problems by providing a method for rapidly obtaining and correcting the strip thickness compensation coefficient.

[0008] The purpose of this invention is achieved as follows: a method for rapidly obtaining and correcting the thickness compensation coefficient of strip steel, comprising two aspects: 1. Rapid acquisition of compensation coefficient: (1) Simplify the calibration process and establish a data statistics table: adopt a thickness gauge that only calibrates the thickness of the finished product at the mill exit. The first column of the table contains the thicknesses A1, B1, C1, D1... measured by placing samples of different thicknesses on the thickness gauge; the second column contains the compensation coefficient of the steel strip in the current stand; the third column contains the values ​​in the first column divided by the data in the second column to obtain A2, B2, C2, D2...; the fourth column contains the standard thickness data A, B, C, D... divided by the data in the third column to obtain A3, B3, C3, D3...; The data in the fifth column is the average of the data in the fourth column to obtain E; the data in the sixth column is the data in the fifth column E rounded to obtain E1; (2) The obtained thickness compensation coefficient E1 is entered into the steel rolling model. When the rolling mill rolls a new steel grade, the rolling parameters are sent to the first-level system, and the thickness compensation coefficient is also sent to the thickness measurement system accordingly; II. Correction of compensation coefficient: The specific algorithm is as follows: Assuming the target thickness of the steel coil is H (unit: mm), the thickness compensation value before correction is A, and the next process feedback is that the thickness is thicker by X (unit: μm), then the corrected thickness compensation value A1 = A + X / H; if the next process feedback is that the thickness is thinner by X (unit: μm), then the corrected thickness compensation value A1 = AX / H.

[0009] It takes 20-40 minutes to obtain the thickness compensation coefficient.

[0010] The beneficial effects of this invention are: 1. It meets the requirements for measurement accuracy and process requirements, providing strong technical support for the production of silicon steel in continuous rolling mills.

[0011] 2. This method adopts a low-cost design scheme, has high operational stability, and accurate measurement. If it is widely used, it will save users a lot of equipment costs, which is in line with the principle of cost reduction and efficiency improvement, and has great promotional value. Implementation

[0012] Current situation: According to the known thickness calibration methods, a standard thickness plate of the same type and material as the steel plate being measured should be selected. The measurement uncertainty of its thickness should not exceed 1 / 2 to 1 / 3 of the basic error limit of the thickness gauge being calibrated. The thickness of the standard plate should be roughly uniformly distributed within the thickness range of the products on the production line. The thickness of the thickest and thinnest sample should be as close as possible to the upper and lower limits of this range. The thickness should be uniform, and the surface should be free of deformation, scratches, rust, or other defects that affect the measurement results, and it should be metrologically confirmed to be qualified.

[0013] Calibration must be performed after the production line has stopped and the thickness gauge is offline. The thickness gauge should generally be warmed up for at least 1 hour, and calibration can only begin after there are no fault alarms on the control interface.

[0014] Clean the oil and dust off the surface of the standard thickness plate, place it on the support, align the axis with the radiation source, and ensure that the height of the support is at the same level as the rolling line position.

[0015] Indication error: According to the actual application of the thickness gauge, select 3 to 5 standard thickness plates within its actual measurement range, measure each standard thickness plate 3 times and record the thickness gauge readings, calculate the arithmetic mean as the measurement result of that point, and the difference between the arithmetic mean of each point and the actual value Hi of the standard thickness plate is the indication error δi of that point, calculated according to formula (1).

[0016]

[0017] Where: Δi: the average value of the instrument reading at the i-th measuring point, mm; Hi: the standard value of the corresponding standard thickness plate, mm.

[0018] Within the actual measuring range of the thickness gauge, select a standard thickness plate whose thickness value should be approximately at half the range. Repeat the measurement of this standard thickness plate 10 times and record the thickness gauge readings. h i Calculate the standard deviation of a single experiment according to formula (2). s As a result of repeatability measurement.

[0019]

[0020] In the formula: h i : The instrument reading of the i-th measurement, in mm; : n The arithmetic mean of the measurements, in mm; n Number of measurements n =10.

[0021] Problems: 1. Existing calibration methods involve numerous procedures, are cumbersome to operate, and are labor-intensive. Under normal circumstances, it takes at least 3-4 hours to complete calibration when the operator is proficient. 2. The pickling and rolling mill currently has 4 thickness gauges and 1 edge drop gauge. Is it necessary to recalibrate all equipment every time? Or is it possible to calibrate only the finished product thickness gauge? 3. Poor adaptability to unforeseen circumstances. For example, if the mill is temporarily scheduled to roll a new steel grade, the existing thickness compensation coefficients are not applicable. Using the existing calibration method would cause prolonged mill downtime, affecting the smooth completion of production tasks. 4. During production, feedback from downstream processes frequently indicates large thickness deviations in the rolled steel coils, such as being several μm thicker or thinner. Timely adjustments to the thickness compensation coefficients are required. Using the existing calibration method would require a lengthy calibration correction process.

[0022] The above are some of the situations that have occurred during the operation of the unit in recent years, which are mainly reflected in the fact that the existing thickness measurement device calibration methods are cumbersome and time-consuming. Therefore, we need to consider whether we can invent a method that is both convenient and fast, and also meets the required accuracy.

[0023] Through long-term statistical analysis of calibration data and continuous testing of new methods, a method for quickly obtaining and correcting the strip thickness compensation coefficient has been summarized.

[0024] This includes the following two aspects.

[0025] I. Quickly Obtaining the Compensation Coefficient (1) Simplify the calibration process and independently develop data statistics tables.

[0026] Currently, there are 4 thickness gauges and 1 edge drop meter in use for pickling and rolling. Considering that these 5 devices are from the same manufacturer and have basically the same function, we will only calibrate the RM051 thickness gauge that measures the thickness of the finished product at the mill exit. This will save time and meet the accuracy requirements.

[0027]

[0028] Explanation: XX-1,2,3,4… represent sample pieces of different thicknesses for a new steel grade, and it is generally advisable to take 4 pieces; A, B, C, D… represent standard thicknesses (these thicknesses are precise data obtained by the automation company using precision instruments), and the thicknesses are concentrated around the finished product thickness. For the current continuous rolling mill, the finished product thickness is basically 0.3MM, 0.35MM and 0.5MM; RM051 is a thickness gauge for measuring the finished product thickness.

[0029] The first column contains the thicknesses of samples of different thicknesses measured on the RM051 thickness gauge: A1, B1, C1, D1, etc.

[0030] The second column of data indicates that the steel strip in the current frame is carbon steel (Q235A). In this case, the compensation coefficient is 1.01. It should be noted that during calibration, it is best to use Q235A steel strip in the frame, which will facilitate data processing later.

[0031] The data in the third column is obtained by dividing the value in the first column by the data in the second column (usually 1.01), resulting in A2, B2, C2, D2, etc.

[0032] The data in the fourth column is A, B, C, D... (standard thickness. The standard data here refers to the thickness measured by professionals at Taiyuan Iron & Steel Automation Co., Ltd. using specialized instruments after we send samples cut from different finished product thicknesses to them. This is called standard thickness data, or more accurately, standard version thickness data.) Dividing this by the data in the third column gives A3, B3, C3, D3...

[0033] The data in the fifth column is E, which is obtained by averaging the data in the fourth column.

[0034] The data in the sixth column is E1, which is obtained by rounding the data in the fifth column, E.

[0035] (2) Inform the second-level technicians of the obtained thickness compensation coefficient E1. The second-level technicians will enter the corresponding thickness compensation coefficient into the new steel rolling model. When the rolling mill rolls the new steel, the rolling parameters will be sent to the first-level system and the thickness compensation coefficient will also be sent to the thickness measurement system.

[0036] (3) The above method of obtaining the thickness compensation coefficient only takes half an hour, which is far less than the 3 hours required by the existing calibration method.

[0037] II. Correction of Compensation Coefficient During the production process, we encounter situations where the thickness compensation coefficient obtained by calibrating the thickness gauge, regardless of the method used, always has varying degrees of error. This error may be caused by the testing instrument or by environmental factors. Consequently, feedback from the next process in the rolling mill indicates that the strip thickness is a few μm thicker or thinner than the target value. In such cases, we need to correct the thickness compensation coefficient. Recalibrating the gauge is obviously very time-consuming. If we statistically analyze the thickness deviation data from the next process, can we obtain a reasonably accurate correction value? Therefore, we have summarized a basic, reliable, and scientifically feasible correction method.

[0038] The specific algorithm is as follows: Assuming the target thickness of the steel coil is H (unit: mm), the thickness compensation value before correction is A, and the next process reports that the thickness is too thick by X (unit: μm), then the corrected thickness compensation value A1 = A + X / H; if the next process reports that the thickness is too thin by X (unit: μm), then the corrected thickness compensation value A1 = AX / H.

[0039] Practical Application Example 1

[0040] After a series of measurements and calculations, the required thickness compensation coefficient for rolling DG40 steel was determined to be 1.0230. This compensation coefficient is input into the rolling system. After rolling one batch of steel coils, the next finishing process will sample and re-measure the thickness. If the next process reports that the target thickness is 0.5 mm, but the actual thickness is 4 μm thinner, it indicates that the thickness compensation coefficient we provided was too high and needs to be reduced. 4 μm / 0.5 mm = 0.008, 1.0230 - 0.008 = 1.0150. The corrected thickness compensation value should be 1.0150. Practical Application Example 2

[0041] After a series of measurements and calculations, the required thickness compensation coefficient for rolling DW130 steel was determined to be 1.0023. This compensation coefficient is input into the rolling system. After rolling a batch of steel coils, the next finishing process will sample and re-measure the thickness. If the next process reports that the target thickness is 0.35 mm, but the actual thickness is 6 μm thicker, it indicates that the thickness compensation coefficient we provided was too small and needs to be increased. 6 μm / 0.35 mm = 0.017, 1.0023 + 0.017 = 1.0193. The corrected thickness compensation value should be 1.0193. Since the invention was put into use, the effects have been very obvious. It can not only meet the accuracy requirements of thickness measurement, but also greatly save calibration time, reduce labor intensity and maintenance difficulty. 1) The calibration time has been reduced from the original 3 hours to the current 30 minutes; 2) Value creation: Based on a profit of 800 yuan / ton, 10 minutes to produce one coil, and 20 tons of steel coil, one calibration can create a profit of 800*(3*60-30) / 10*20=240,000 yuan.

[0042] The calculation and rapid correction method for strip thickness compensation coefficient is mainly used in the development of new steel grades. It is necessary to calculate the thickness compensation coefficient for the new steel grade and then input the compensation coefficient into the thickness measurement equipment system to ensure that the finished thickness of the rolled steel grade is basically consistent with the planned finished thickness, and to continuously correct the thickness compliance rate of the original steel grade. Since the invention was put into use, the thickness measurement system has been operating stably, and the thickness deviation is within the allowable range of the process. At the same time, it has achieved the effect of rapid and accurate correction of the compensation coefficient.

[0043] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for rapidly obtaining and correcting the strip thickness compensation coefficient, characterized in that: It includes two aspects: I. Quick acquisition of compensation coefficient: (1) Simplify the calibration process and establish a data statistics table: Adopt only the thickness gauge that measures the thickness of the finished product at the mill exit. The first column of the table is the thickness A1, B1, C1, D1... measured by placing samples of different thicknesses on the thickness gauge; the second column is the compensation coefficient of the steel strip in the current stand; the third column is the value of the first column divided by the data of the second column to obtain A2, B2, C2, D2...; the fourth column is the standard thickness data A, B, C, D... divided by the data of the third column to obtain A3, B3, C3, D3...; the fifth column is the average value of the data of the fourth column to obtain E; the sixth column is the data of the fifth column E rounded to make the final value retain four decimal places to obtain E1; (2) Enter the obtained thickness compensation coefficient E1 into the steel rolling model. When the mill rolls a new steel grade, the rolling parameters are sent to the first-level system, and the thickness compensation coefficient is also sent to the thickness measurement system accordingly; II. Correction of the compensation coefficient: The specific algorithm is as follows: Assuming the target thickness of the steel coil is H (unit: mm), the thickness compensation coefficient before correction is E1, and the next process reports that the thickness is X (unit: μm) thicker, then the corrected thickness compensation coefficient E2 = E1 + X / H; if the next process reports that the thickness is X (unit: μm) thinner, then the corrected thickness compensation coefficient E2 = E1 - X / H.

2. The method for rapidly obtaining and correcting the strip thickness compensation coefficient according to claim 1, characterized in that: It takes 20-40 minutes to obtain the thickness compensation coefficient.

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