Method for controlling head stability of strip steel in hot rolling process

Abstract

The invention discloses a method for controlling the head stability of strip steel in the hot rolling process. The method comprises the steps that S1, real-time monitoring and data collection are conducted; s2, data analysis and deviation trend prediction; and S3, adjusting parameters. The invention belongs to the technical field of hot-rolled strip steel production, and particularly relates to a method for controlling the head stability of strip steel in the hot rolling process.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-rolled strip steel production, and specifically refers to a method for controlling the stability of a strip steel head during the hot rolling process. Background Art

[0002] Hot rolling of strip steel using a finishing mill is a complex process. Due to the limitations of the current process technologies (including heating, descaling, and side-shooting), there is no such thing as a rolled piece with an absolutely straight head. During the rolling process, even if the rolled strip steel is of exactly the same type and specification, there will inevitably be some differences in some aspects.

[0003] The width and thickness of the strip head play a key role in the hot rolling process. On the one hand, the width stability of the strip head directly affects the smooth progress of subsequent processing procedures. If the width of the strip head fluctuates greatly, it may cause dimensional deviations in shearing, welding and other links, affecting the assembly accuracy and performance of the product. In addition, unstable width may also cause the strip to deviate during transportation, affecting the continuity of production and even causing equipment failure; on the other hand, the thickness control of the strip head is also crucial. Excessive thickness deviation will affect the mechanical properties of the strip, such as strength and toughness. If the strip head is too thick, it may increase the difficulty in the subsequent cold processing process and even cause damage to the processing equipment; if the strip head is too thin, it may not meet the strength requirements of the product and reduce the service life of the product.

[0004] At present, in the production process of hot-rolled strip, due to the influence of various factors, the stability of the strip head is difficult to be effectively controlled. In order to solve these problems, some traditional control methods are usually used, such as manual adjustment of process parameters, regular inspection of equipment, etc. However, these methods have great limitations. Manual adjustment of process parameters often depends on the experience and skills of the operator, and it is difficult to achieve precise control; regular inspection of equipment can only find problems when the equipment has obvious faults, and it is impossible to prevent the instability of the strip head in time. Moreover, these methods can usually only adjust the stability of the strip head after the fact, and cannot achieve real-time control, which is difficult to meet the requirements of modern industry for high-quality and high-efficiency production. Summary of the invention

[0005] In order to solve the above-mentioned problems, the present invention provides a method that can combine the differentiation factors in the hot rolling process of the strip to accurately and flexibly control the stability of the strip head during the hot rolling process.

[0006] In order to achieve the above functions, the technical solution adopted by the present invention is as follows: A method for controlling the shape of a hot-rolled coil comprises the following steps: S1. Real-time monitoring and data acquisition: When the strip runs to the finishing mill, the thickness and width of the strip head are collected in real time using high-precision thickness and width sensors. Width sensors are installed on both sides of the strip to directly measure the actual width of the strip, monitor the width change of the strip during the rolling process in real time, and provide accurate width data for the control system. A thickness sensor is installed at the roller entrance of the finishing mill to measure the thickness of the strip before it enters the roller. The thickness information of the strip can be obtained in advance, providing more time for the control system to adjust the process parameters to ensure that the strip can be accurately rolled after entering the roller. S2. Data analysis and deviation trend prediction: Analyze the collected strip head thickness and width data, calculate the thickness deviation and width deviation, determine the allowable range of thickness deviation and width deviation based on historical data and experience, and if the deviation exceeds the allowable range, judge that there is an instability risk in the strip head, establish a mathematical model to predict the deviation trend of the strip head, and calculate the stability index; Define the stability index S, S = g (H, W, ΔH, ΔW, P, T, V), where H is the actual thickness of the strip head, W is the actual width of the strip head, ΔH is the thickness deviation, ΔW is the width deviation, P is the rolling force, T is the tension, and V is the speed; Through a large number of experiments and data analysis, the specific form of the function g is determined, and methods such as multivariate regression analysis can be used to establish the mathematical relationship between the stability index S and various parameters; When S is less than or greater than the preset stability threshold, corresponding adjustment measures are taken to improve the stability of the strip head; S3. Adjust parameters: According to the stability index, the hot rolling process parameters such as rolling force, tension, speed, etc. are quickly adjusted through the control system to correct the deviation of the strip head in time to improve the stability of the strip head.

[0007] Preferably, the control system comprises The central processing unit analyzes and processes the collected data, calculates the process parameters that need to be adjusted according to the preset algorithm, and issues control instructions; Data transmission module, which can quickly and accurately transmit the data collected by the sensor to the central processor; The execution module receives the control instructions from the central processing unit and controls the actions of the execution mechanisms such as the rolling force adjustment mechanism, the tension adjustment mechanism and the speed adjustment mechanism.

[0008] Preferably, the rolling force adjustment mechanism adopts a hydraulic system or an electric mechanical device to change the thickness of the strip by adjusting the pressure of the rolling roller; the tension adjustment mechanism uses tension rollers, tension motors and other equipment to control the width of the strip by adjusting the tension of the strip; the speed adjustment mechanism changes the operating speed of the hot rolling equipment by adjusting the speed of the motor or the output frequency of the inverter.

[0009] The present invention adopts the above structure to achieve the following beneficial effects: By continuously monitoring the thickness and width changes of the strip head and adjusting the process parameters in real time, it is possible to ensure that the dimensional accuracy of the strip head meets the requirements, which helps to reduce product quality problems caused by thickness and width deviations. Stable strip head size can also improve product consistency and reliability. Real-time control of the stability of the strip head can make the production process smoother and improve equipment utilization and production efficiency. In addition, a stable production process can also reduce the generation of waste and defective products, further improving production efficiency.

[0010] An unstable strip head may cause serious damage to the equipment during hot rolling. For example, excessive thickness deviation may cause roll overload, damage the roll bearings and transmission system; width deviation may cause the strip to deviate and hit the equipment frame or other components. By controlling the stability of the strip head in real time, these unexpected situations can be reduced, the service life of the equipment can be extended, and the equipment maintenance cost can be reduced. DETAILED DESCRIPTION

[0011] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] A method for controlling hot rolled coil shape according to the present invention comprises the following steps: S1. Real-time monitoring and data collection: When the strip runs to the middle rack of the finishing mill, the thickness and width of the strip head are collected in real time using high-precision thickness and width sensors; S2. Data analysis and deviation trend prediction: Analyze the collected strip head thickness and width data, calculate the thickness deviation and width deviation, determine the allowable range of thickness deviation and width deviation based on historical data and experience, and if the deviation exceeds the allowable range, judge that there is an instability risk in the strip head, establish a mathematical model to predict the deviation trend of the strip head, and calculate the stability index; Define the stability index S, S = g (H, W, ΔH, ΔW, P, T, V), where H is the actual thickness of the strip head, W is the actual width of the strip head, ΔH is the thickness deviation, ΔW is the width deviation, P is the rolling force, T is the tension, and V is the speed; Through a large number of experiments and data analysis, the specific form of the function g is determined, and methods such as multivariate regression analysis can be used to establish the mathematical relationship between the stability index S and various parameters; When S is less than or greater than the preset stability threshold, corresponding adjustment measures are taken to improve the stability of the strip head; S3. Adjust parameters: According to the stability index, the hot rolling process parameters such as rolling force, tension, speed, etc. are quickly adjusted through the control system to correct the deviation of the strip head in time to improve the stability of the strip head.

[0013] Example 1: The strip head is too thick and the width is too wide When the actual thickness H of the strip head is 2mm larger than the target thickness and the width is 15mm larger than the target width, the following adjustment measures are taken according to the stability index formula: For rolling force P: Since the thickness deviation is positive and large, it is decided to increase the rolling force. According to experience, the rolling force is increased by 10% for every 1mm thickness deviation, so the rolling force is increased by 20% here to compress the strip more strongly to reduce the thickness.

[0014] For tension T: Because the width deviation is positive and large, the tension is appropriately increased. For every 10mm width deviation, the tension is increased by 5%, and here the tension is increased by 7.5%, so that the strip is subjected to contraction force in the width direction and the width deviation is reduced.

[0015] For speed V: Keep the current speed unchanged and observe the reaction of the strip after adjusting the rolling force and tension. If there is no obvious problem with the stability of the strip, consider whether to adjust the speed according to the production efficiency requirements.

[0016] After adjustment, the thickness and width of the strip head were measured again, and it was found that the thickness and width deviations were reduced and the stability of the strip head was improved.

[0017] Example 2: The strip head is too thin and the width is too narrow When the actual thickness of the strip head is 1.5mm smaller than the target thickness, the width is 12mm smaller than the target width.

[0018] For rolling force P: if the thickness deviation is negative and large, reduce the rolling force. For every 1mm thickness deviation, reduce the rolling force by 8%, here reduce the rolling force by 12% to prevent the strip from becoming thinner.

[0019] For tension T: if the width deviation is negative and large, reduce the tension. For every 10mm width deviation, reduce the tension by 4%, here reduce the tension by 4.8%, reduce the stretching of the strip and avoid the strip becoming narrower.

[0020] For speed V: reduce the speed appropriately, for example, by 10%, so that the strip has more time to adjust and stabilize during the hot rolling process, reducing the unstable factors caused by excessive speed.

[0021] After adjustment, the thickness and width of the strip head gradually approached the target values, and the stability was improved.

[0022] Example 3: The strip head has poor stability and obvious deviation For rolling force P: check the thickness deviation of the strip. If the thickness deviation is not large, keep the rolling force unchanged or make a small adjustment to avoid new problems caused by excessive changes in rolling force.

[0023] For tension T: adjust the tension appropriately, observe the edge status of the strip, and ensure that the tension adjustment will not cause edge cracks and other problems. If there is no abnormality on the edge of the strip, you can try to increase or decrease the tension by a certain percentage to see if the deviation can be improved.

[0024] For speed V: immediately reduce the speed by 15% to 20%. After reducing the speed, the strip has more time to adjust during the hot rolling process, and the deviation phenomenon may be alleviated. At the same time, closely observe the changes in the strip. Once the deviation is improved, gradually adjust the speed and other process parameters according to the actual situation.

[0025] The present invention and its embodiments are described above, and such description is not restrictive. What is shown in the embodiment is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A method for controlling the stability of a strip head during hot rolling, characterized in that: The steps include: S1. Real-time monitoring and data acquisition: When the strip runs to the finishing mill, the thickness and width of the strip head are collected in real time using high-precision thickness and width sensors. Width sensors are installed on both sides of the strip to directly measure the actual width of the strip, monitor the width change of the strip during the rolling process in real time, and provide accurate width data for the control system. A thickness sensor is installed at the roller entrance of the finishing mill to measure the thickness of the strip before it enters the roller. The thickness information of the strip can be obtained in advance, providing more time for the control system to adjust the process parameters to ensure that the strip can be accurately rolled after entering the roller. S2. Data analysis and deviation trend prediction: Analyze the collected strip head thickness and width data, calculate the thickness deviation and width deviation, determine the allowable range of thickness deviation and width deviation based on historical data and experience, and if the deviation exceeds the allowable range, judge that there is an instability risk in the strip head, establish a mathematical model to predict the deviation trend of the strip head, and calculate the stability index; S3. Adjust parameters: According to the stability index, the hot rolling process parameters such as rolling force, tension, speed, etc. are quickly adjusted through the control system to correct the deviation of the strip head in time to improve the stability of the strip head.

2. A method for controlling the stability of a strip head during hot rolling according to claim 1, characterized in that: The stability index in step S2 is defined as S, S = g (H, W, ΔH, ΔW, P, T, V), where H is the actual thickness of the strip head, W is the actual width of the strip head, ΔH is the thickness deviation, ΔW is the width deviation, P is the rolling force, T is the tension, and V is the speed.

3. A method for controlling the stability of a strip head during hot rolling according to claim 2, characterized in that: The function g is established by using a multivariate regression analysis method. When S is less than or greater than a preset stability threshold, corresponding adjustment measures are taken to improve the stability of the strip head.

4. A method for controlling the stability of a strip head during hot rolling according to claim 1, characterized in that: The control system includes The central processing unit analyzes and processes the collected data, calculates the process parameters that need to be adjusted according to the preset algorithm, and issues control instructions; Data transmission module, which can quickly and accurately transmit the data collected by the sensor to the central processor; The execution module receives the control instructions from the central processing unit and controls the actions of the execution mechanisms such as the rolling force adjustment mechanism, the tension adjustment mechanism and the speed adjustment mechanism.

5. A method for controlling the stability of a strip head during hot rolling according to claim 4, characterized in that: The rolling force adjustment mechanism adopts a hydraulic system or an electric mechanical device to change the thickness of the strip by adjusting the pressure of the rolling roller; the tension adjustment mechanism uses tension rollers, tension motors and other equipment to control the width of the strip by adjusting the tension of the strip; the speed adjustment mechanism changes the operating speed of the hot rolling equipment by adjusting the speed of the motor or the output frequency of the inverter.