A method for improving the setting accuracy of front slip in hot rolling finishing

Abstract

The present invention provides a method for improving the setting accuracy of the front slip of hot rolling finishing, and belongs to the technical field of hot rolling automatic control. The method comprises: installing a loop encoder on the loop roller, and when the downstream frame bites the steel during steel rolling, the speed of the loop roller during the strip threading is detected by the installed loop encoder; wherein, the detected loop roller speed is used as the strip speed; it is judged whether the detected loop roller speed is valid, and if it is valid, the front slip self-learning is started, and the front slip correction coefficient is periodically calculated according to the strip speed; when the front slip of the next piece of steel is set, the theoretical calculated front slip value is corrected by using the final front slip correction coefficient obtained after the front slip self-learning correction, and the corrected front slip setting value is obtained and sent to the basic automation, and the basic automation calculates the strip speed by the roller speed * the corrected front slip setting value as the benchmark for finishing rolling and coiling speed control and tracking. The present invention can improve the calculation accuracy of the front slip of the rolling mill, thereby improving the rolling stability.

Description

Technical Field

[0001] The invention relates to the technical field of hot rolling automatic control, in particular to a method for improving the setting accuracy of pre-slip of hot rolling finishing. Background Art

[0002] In the hot strip rolling production line, the head threading is often unstable during the strip threading process during rolling, which is particularly serious for thin specifications. In addition to the finishing rolling threading plate type, the main influencing factor is the inaccurate calculation of the second flow rate between the finishing rolling stands. When threading, the finishing rolling looper is affected by the second flow rate between the stands, and the starting or starting phenomenon occurs to ensure the stability of the threading, resulting in the problem of product narrowing and over-rolling. The roll speed is usually considered in model calculation and the roll speed is detectable, but the actual speed of the strip is decisive in the actual production process. During the rolling process, the strip is affected by rolling deformation, and forward and backward flow will occur within the range of contact between the metal and the roll, that is, the front and rear slip zone. The speed of the strip is expressed by the roll line speed * (1 + front slip value). Therefore, the accuracy of the front slip value calculation determines the accuracy of the strip speed prediction, and ultimately determines the matching degree of the second flow rate between the stands, thereby determining the stability of the head during the threading process.

[0003] In response to this situation, some newly built production lines are equipped with laser speed meters after finishing rolling or use instrument detection to obtain the actual strip speed at the finishing exit, and finally convert the second flow rate between stands in the finishing area according to the principle of constant second flow rate. However, since the finishing rolling unit is composed of multiple stands, the thickness at the exit of each stand is different from the result calculated by the non-model due to control reasons such as temperature and thickness. When the actual thickness changes, the second flow rate of each rolling mill is different. Therefore, how to know the strip speed between stands and reversely calculate the forward slip value through the actual strip speed is an improvement plan that is born, which ultimately alleviates the occurrence of unstable threading of thin and ultra-thin specifications. Summary of the invention

[0004] The embodiment of the present invention provides a method for improving the setting accuracy of the front slip of hot rolling finishing, which can improve the calculation accuracy of the front slip of the rolling mill, thereby improving the rolling stability. The method includes:

[0005] The looper roller is equipped with a looper encoder. When the downstream frame bites the steel during steel rolling, the installed looper encoder detects the speed of the looper roller during strip threading. The detected looper roller speed is used as the strip speed.

[0006] Determine whether the detected looper roller speed is valid. If it is valid, start the forward slip self-learning and periodically calculate the forward slip correction coefficient according to the strip speed;

[0007] When setting the forward slip of the next piece of steel, the theoretically calculated forward slip value is corrected using the final forward slip correction coefficient obtained after the forward slip self-learning correction, and the corrected forward slip setting value is obtained and sent to the basic automation. The basic automation calculates the strip speed by the roll speed * the corrected forward slip setting value as the benchmark for finishing rolling and coiling speed control and tracking.

[0008] Furthermore, the looper roller is equipped with a looper encoder. When the downstream frame bites the steel during steel rolling, the speed of the looper roller during the belt threading is detected by the installed looper encoder, including:

[0009] The loop roller is equipped with a loop encoder. During steel rolling, the loop roller speed is continuously collected through the installed loop encoder within 0.5-2s after the downstream frame bites the steel. The collection cycle is 100ms.

[0010] Further, the step of judging whether the detected looper roller speed is valid, and if valid, starting the forward sliding self-learning includes:

[0011] Determine whether the detected looper roller speed is 0 or a null value. If the detected looper roller speed is not 0 and is not a null value, start the forward sliding self-learning.

[0012] Furthermore, the method further comprises:

[0013] If the detected looper roller speed is invalid, the forward sliding self-learning will not be started.

[0014] Further, the periodic calculation of the forward slip correction coefficient according to the strip speed includes:

[0015] The collected looper roller speed is divided into multiple sections, and the current steel forward slip correction coefficient fs is calculated for each section corr :

[0016] fs corr =(v s / v R -1)*fs

[0017] Among them, v s is the speed of the looper roller; v R is the roller linear speed; fs is the theoretical forward slip value;

[0018] The forward slip correction coefficients calculated in multiple sections are averaged to obtain the average forward slip correction coefficient fs avecorr ;

[0019] The forward slip correction factor fs is preset by the upper coil oldcorr The average forward slip correction factor fs of the current steel avecorr Calculate the final forward slip correction factor fs newcorr :

[0020] fs newcorr =fs oldcorr +v L *(fs avecorr -fs oldcorr )

[0021] Among them, v L Learning speed.

[0022] Furthermore, the corrected forward slip setting value fs is obtained new It is expressed as:

[0023] fs new =fs newcorr *fs

[0024] Among them, fs newcorr is the final forward slip correction coefficient; fs is the theoretically calculated forward slip value.

[0025] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0026] In the embodiment of the present invention, a looper encoder is installed on the looper roller. When the downstream frame bites the steel during steel rolling, the installed looper encoder is used to detect the speed of the looper roller during strip threading. The detected looper roller speed is used as the strip speed. It is determined whether the detected looper roller speed is valid. If it is valid, the forward slip self-learning is started, and the forward slip correction coefficient is periodically calculated according to the strip speed. When the forward slip of the next piece of steel is set, the theoretically calculated forward slip value is corrected by the final forward slip correction coefficient obtained after the forward slip self-learning correction, and the corrected forward slip setting value is obtained and sent to the basic automation. The basic automation calculates the strip speed by the roll speed * the corrected forward slip setting value as the benchmark for finishing rolling and coiling speed control and tracking. In this way, the forward slip self-learning corrects the subsequent strip forward slip setting value by the actual strip speed during strip threading, which improves the calculation accuracy of the rolling mill forward slip and improves the rolling stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic flow chart of a method for improving the setting accuracy of pre-slipping in hot rolling finishing provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of data before and after improvement of scrap steel analyzed by quarter provided by an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram comparing the effects of the set forward slide and the actual forward slide during the strap threading process provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, an embodiment of the present invention provides a method for improving the setting accuracy of the front slip of hot rolling finishing rolling, comprising:

[0033] S101, loop roller speed collection: a loop encoder is installed on the loop roller. When the downstream stand bites the steel during steel rolling, the installed loop encoder is used to detect the loop roller speed during strip threading. The detected loop roller speed is used as the strip speed.

[0034] In this embodiment, a loop encoder is installed on the loop roller. During steel rolling, the loop encoder continuously collects the speed of the loop roller within 0.5-2s after the downstream frame bites the steel, and the collection period is 100ms.

[0035] In this embodiment, the basic automation sends the collected loop roller speed to the process control system during strip threading, so that the process control system can calculate the forward slip correction coefficient periodically according to the strip speed through the newly added forward slip self-learning function.

[0036] In this embodiment, basic automation belongs to an automation system, which is a system connected to the method for improving the setting accuracy of the front slip of hot rolling finishing described in this embodiment.

[0037] S102, judging whether the detected looper roller speed is valid, if valid, starting the forward slip self-learning, and periodically calculating the forward slip correction coefficient according to the strip speed;

[0038] In this embodiment, it is determined whether the detected loop roller speed is 0 or a null value. If the detected loop roller speed is not 0 and is not a null value, the forward slip self-learning is started; otherwise, it is determined that the detected loop roller speed is invalid (the loop roller speed is 0 or a null value), and the forward slip self-learning is not started, that is, the theoretically calculated forward slip value is not corrected, wherein the theoretically calculated forward slip value is specifically the forward slip value calculated by the theoretical model.

[0039] In this embodiment, the looper roller speed data verification and forward slip self-learning function are added. The forward slip self-learning function is a newly added calculation function in the existing model system, with the purpose of improving the model accuracy.

[0040] In this embodiment, the periodic calculation of the forward slip correction coefficient according to the strip speed (i.e., the forward slip self-learning function) may specifically include the following steps:

[0041] A1, because the collected effective looper roller speed data lasts for a certain period, it can be divided into multiple sections for learning. Specifically: the collected effective looper roller speed is divided into multiple sections, and the current steel forward slip correction coefficient fs is calculated for each section. corr :

[0042] fs corr =(v s / v R -1)*fs

[0043] Among them, v s is the speed of the looper roller; v R is the roller linear speed; fs is the theoretical forward slip value;

[0044] In this embodiment, considering that the sampling point abnormality and the unstable state of the head will affect the forward slip self-learning correction result, the head data collection period is set to 0.5-2s, the collection period is 100ms, and the collected effective looper roller speed is divided into 2-3 sections according to the actual speed. The forward slip self-learning correction coefficient in the early debugging period is set to the number of collection points and / the number of collection points. After the later stabilization, the forward slip self-learning correction coefficient of each point is weighted to calculate the current steel forward slip correction coefficient fs corr .

[0045] A2, average the forward slip correction coefficients calculated in multiple sections to obtain the average forward slip correction coefficient fs avecorr， To ensure the reliability of the correction results; among them, fs avecorr It is the average forward slip correction coefficient within 0.5-2s;

[0046] A3, forward slip correction factor fs set by upper coil oldcorr The average forward slip correction factor fs of the current steel avecorr Calculate the final forward slip correction factor fs newcorr :

[0047] fs newcorr =fs oldcorr +v L *(fs avecorr -fs oldcorr )

[0048] Among them, v L Learning speed.

[0049] S103, forward slip calculation value correction: when setting the forward slip of the next steel piece, the theoretically calculated forward slip value is corrected by using the final forward slip correction coefficient obtained after the forward slip self-learning correction to obtain a corrected forward slip setting value to improve the forward slip calculation accuracy. The corrected forward slip setting value is sent to the basic automation, and the basic automation calculates the strip speed by the roll speed * the corrected forward slip setting value as the benchmark for finishing rolling and coiling speed control and tracking; wherein the corrected forward slip setting value fs is obtained. new It is expressed as:

[0050] fs new =fs newcorr *fs

[0051] Among them, fs newcorr is the final forward slip correction coefficient; fs is the theoretically calculated forward slip value.

[0052] In this embodiment, the theoretical calculated forward slip value fs before correction and the corrected forward slip setting value fs new Send it to the basic automation synchronously. During debugging, the weight coefficient can be increased according to the actual situation. After the system is stable, the converted weight coefficient can be gradually increased. It can be debugged step by step according to the actual application situation until all fs are adopted. new Values ​​such as:

[0053] fs=fs*0.4+fs new *0.6

[0054] In this embodiment, the forward sliding self-learning is divided into a short-term mode and a long-term mode; wherein,

[0055] In the short-term mode, it is learned block by block, inherited and applied, and stored in the database after being processed by the exponential smoothing algorithm. The adoption of the long-term and short-term modes is synchronized with the rolling specification change logic. Specifically: the short-term mode adopts a separate learning of each roll of strip steel and applies it to the subsequent strip steel of this mode. In this embodiment, the forward slip correction coefficient is processed by the exponential smoothing method, and the smoothed forward slip correction coefficient and the process and equipment parameters affecting the forward slip calculation (including: composition, roller diameter, measured thickness of rough rolling, calculated thickness between each frame of finishing rolling, measured thickness of finishing rolling, target thickness of finishing rolling, target width of finishing rolling, pressure reduction of each frame, front and rear tension, rolling lubrication, etc.)) are stored in the database for similar search in the long-term mode. Among them, the forward slip short-term correction coefficient is processed by the exponential smoothing algorithm and stored:

[0056] α new =β·α * +(1-β)·α old

[0057] Among them, α new is the short-term correction coefficient of the smoothed forward slip, which is stored in the database; α* Equal to fs newcorr is the forward slip correction coefficient calculated by forward slip self-learning; α old Equal to fs oldcorr is the forward slip correction coefficient preset for the coil; β is the learning speed factor, 0≤β≤1;

[0058] The long-term mode is self-learning between batches, that is, the long-term self-learning coefficient is divided into grades according to steel type, finished product thickness and finished product width. The long-term mode can use similar data search method, take out multiple data under the most similar conditions, use smoothing algorithm for processing, and apply it to the first volume of steel in the long-term mode.

[0059] In order to verify the effectiveness of the method for improving the setting accuracy of the pre-slip of hot rolling finishing rolling described in the embodiment of the present invention, it was applied to a domestic hot rolling strip production line, and the scrap steel data before and after finishing rolling were used. Figure 2 The matching between the set forward slide and the actual forward slide is shown as follows Figure 3 The actual application results on site show that the forward slip value calculated by the traditional mechanism model has deviations. After learning and correction through the actual speed, the calculation accuracy of the forward slip of the rolling mill can be effectively improved, and the threading stability during thin-gauge production can be greatly improved.

[0060] The method for improving the setting accuracy of the front slip of hot rolling finishing described in the embodiment of the present invention is that the looper roller is installed with a looper encoder, and when the downstream frame bites the steel during steel rolling, the looper roller speed during the strip threading is detected by the installed looper encoder; wherein, the detected looper roller speed is used as the strip speed; it is determined whether the detected looper roller speed is valid, if it is valid, the front slip self-learning is started, and the front slip correction coefficient is periodically calculated according to the strip speed; when the front slip of the next piece of steel is set, the theoretical calculated front slip value is corrected by the final front slip correction coefficient obtained after the front slip self-learning correction, and the corrected front slip setting value is obtained and sent to the basic automation, and the basic automation calculates the strip speed by the roller speed * the corrected front slip setting value as the benchmark for finishing rolling and coiling speed control and tracking. In this way, the front slip self-learning corrects the subsequent strip front slip setting value by the actual strip speed during the strip threading, thereby improving the calculation accuracy of the rolling mill front slip and improving the rolling stability.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the setting accuracy of the pre-slip of hot rolling finishing, characterized in that: include: The looper roller is equipped with a looper encoder. When the downstream frame bites the steel during steel rolling, the installed looper encoder detects the speed of the looper roller during strip threading. The detected looper roller speed is used as the strip speed. Determine whether the detected looper roller speed is valid. If it is valid, start the forward slip self-learning and periodically calculate the forward slip correction coefficient according to the strip speed; When setting the forward slip of the next piece of steel, the theoretically calculated forward slip value is corrected using the final forward slip correction coefficient obtained after the forward slip self-learning correction, and the corrected forward slip setting value is obtained, which is sent to the basic automation. The basic automation calculates the strip speed by the roller line speed * the corrected forward slip setting value as the benchmark for finishing rolling and coiling speed control and tracking; Wherein, the looper roller is equipped with a looper encoder. When the downstream frame bites the steel during steel rolling, the looper roller speed during the belt threading is detected by the installed looper encoder, including: The looper roller is equipped with a looper encoder. During steel rolling, the looper roller speed is continuously collected through the installed looper encoder within 0.5-2s after the downstream frame bites the steel. The collection cycle is 100ms. The step of judging whether the detected looper roller speed is valid, and if so, starting the forward sliding self-learning includes: Determine whether the detected looper roller speed is 0 or a null value. If the detected looper roller speed is not 0 and not a null value, start the forward sliding self-learning; Wherein, the periodic calculation of the forward slip correction coefficient according to the strip speed includes: The collected looper roller speed is divided into multiple sections, and the current steel forward slip correction coefficient fs is calculated for each section corr : fs corr =(v s / v R -1)*fs Among them, v s is the speed of the looper roller; v R is the roller linear speed; fs is the theoretical forward slip value; The forward slip correction coefficients calculated in multiple sections are averaged to obtain the average forward slip correction coefficient fs avecorr ; The forward slip correction factor fs is preset by the upper coil oldcorr The average forward slip correction factor fs of the current steel avecorr Calculate the final forward slip correction factor fs newcorr : fs newcorr =fs oldcorr +v L *(fs avecorr -fs oldcorr ) Among them, v L Learning speed; Among them, the corrected forward slip setting value fs is obtained new It is expressed as: fs new =fs newcorr *fs Among them, fs newcorr is the final forward slip correction coefficient; fs is the theoretically calculated forward slip value.

2. The method for improving the setting accuracy of the pre-slip during hot rolling finishing according to claim 1, characterized in that: The method further comprises: If the detected looper roller speed is invalid, the forward sliding self-learning will not be started.

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