Hot rolling layer cooling temperature control method under finish rolling speed regulation condition

Abstract

The invention discloses a method for controlling the cold temperature of a hot rolling layer under the condition of finish rolling speed regulation, which comprises the following steps of: 1) tracking and measuring the temperature data of the ith section of strip steel by a strip steel segmentation tracking model, and forming a measurement array with the temperature data of the n sections of strip steel before measurement; 2) preparing data arrays of the ith section and the first (n-1) th section of strip steel by the strip steel strategy model; 3) calculating a time array of the ith section and the first n sections of strip steel passing through each section of cooling valve through a feed-forward model; (4) dynamically adjusting cooling valve setting, and completing and outputting layer cooling valve array setting of the ith section of strip steel; and 5) updating the new cold valve array of each section layer by the strip steel segmentation tracking model, and executing the valve opening array. The method solves the problem of lower layer cold feedforward setting deviation under the hot rolling finish rolling temperature speed regulation control condition, and the hot rolling coiling temperature control precision is improved.

Description

Technical Field

[0001] The invention relates to steel rolling control technology, and more specifically to a method for controlling the cold temperature of a hot rolling layer under the condition of finishing rolling speed regulation. Background Art

[0002] Hot rolling final rolling temperature control and layer cooling temperature control are both important quality indicators to ensure the quality of hot rolled products. For hot rolling production lines, there are two means of finishing rolling final rolling temperature control: speed regulation and water regulation. Generally speaking, if the performance of the finishing rolling cooling valve is relatively good, finishing rolling will preferably use water regulation for final rolling temperature control; some production lines can only rely on speed regulation for final rolling temperature control due to problems with the cooling valve in the finishing rolling area; in addition, for some products (such as thin plates), the finishing rolling water has been completely closed, and only speed regulation can be used for final rolling temperature control. The dynamic adjustment of the finishing speed is difficult to predict. In this case, the layer cooling strip speed is difficult to calculate accurately, and the time for each section of the layer cooling strip to pass through each cooling valve is difficult to calculate accurately. The layer cooling feedforward setting will inevitably have a large deviation, which will have an adverse effect on the layer cooling temperature control.

[0003] Laminar cooling is the strip cooling area after finishing rolling, which consists of a conveyor roller installed between the finishing mill and the coiler and an upper and lower water spray device. The main function of laminar cooling temperature control is to cool the strip from a certain final rolling temperature to the required coiling temperature by controlling the laminar cooling water spray valve. The coiling temperature has a great influence on the performance of the strip, so the coiling temperature must be controlled within a certain target coiling temperature tolerance range. During the laminar cooling process, the microstructure of the finished strip can be controlled by selecting an appropriate cooling method, ensuring a certain cooling rate, and improving the intermediate temperature and coiling temperature accuracy to achieve the specific performance requirements of the strip.

[0004] like Figure 1 As shown in the figure, the hot rolling laminar cooling zone is divided into the main cooling zone and the fine cooling zone. The main cooling zone includes a dense cooling device and a conventional cooling device for feedforward setting; the fine cooling device in the fine cooling zone is used for feedforward fine adjustment and feedback control. The temperature measurement in the laminar cooling zone mainly includes two measurement positions: the entry measurement EMP (Entry Measure Position) and the measurement before coiling CMP (CoilerMeasure Position). The main core control functions of the laminar cooling model include: cooling strategy and pre-calculation, entry feedforward control, feedback control, strip segment tracking, post-calculation and adaptation, time calculation, temperature calculation model, model layer parameter management and genetic coefficient management.

[0005] At present, the strip temperature feedforward control in the layer cooling control system is controlled according to a fixed length. The main function of the conventional inlet feedforward control program is to set the strip cooling setting for a section based on the actual measured strip temperature at the EMP position and the cooling time of the water spray valve array passing through the laminar cooling zone. This function is started by the strip segment tracking program. The main calculation steps of the conventional layer cooling feedforward setting are as follows:

[0006] (1) The strip segment tracking program tracks the i-th strip segment passing through the EMP temperature measurement point and collects the EMP measurement temperature of the strip segment;

[0007] (2) The strip strategy model prepares the cooling strategy, genetic data, and cooling valve settings of the previous strip segment (segment i-1) of the relevant strip segment;

[0008] (3) Start the feedforward model control calculation function, first complete the time array calculation of the strip passing through each cooling valve;

[0009] (4) Feedforward setting dynamically adjusts the valve setting according to the predicted valve time, strip layer cooling temperature drop, and layer cooling target, and completes and outputs the layer cooling valve array setting for the strip section;

[0010] (5) The strip segment tracking program saves the valve settings of this segment in the valve setting array, taking into account the valve delay and the actual position of the strip, and combines them into a real-time valve opening array setting for execution.

[0011] Temperature calculation is the key in the feedforward setting calculation. The accuracy of temperature calculation is closely related to the model itself and the predicted time for the strip to pass through each valve. The time calculation for each section of the strip to pass through each cooling device during layer cooling is mainly completed by the cooling time calculation model. The model calculates the time for a certain section of the strip to pass through a valve or a valve sequence based on the TVD (time velocity curve data) of the strip, which is used as the time parameter for calculating the cooling temperature drop. The cooling time calculation model mainly creates or corrects the TVD speed operation diagram of the strip based on the speed data and tail correction data transmitted from the finishing rolling; it calculates the time for a certain section of the strip to pass through a valve or a valve sequence based on the section number and the TVD created in advance. The TVD object has "pre-" described the operation information of the entire strip. Generally speaking, the caller needs to return the time for a certain section to pass through each valve. There are many situations in the TVD operation diagram, such as Figure 2 A typical F7 maximum speed deceleration steel throwing operation diagram is shown in the figure (in the figure, v max Indicates the maximum allowable running speed of F7 exit strip, v mout Indicates the maximum allowable throwing speed of F7 exit strip steel, v 0 Indicates the threading speed, v 1 One plus end speed, v 2 Second plus end speed, v 3 Throwing speed,

[0012] t 0 ~t 3 Indicates that for different time points), when the finishing rolling is not speed-regulated, the strip runs regularly, and the cooling time of the strip passing through each valve can be accurately calculated. If the final rolling temperature is speed-regulated, then Figure 2 The regular solid speed line may become Figure 2 As shown by the dotted line in the middle, the dotted line is changing every moment, and this change cannot be accurately predicted. In this case, the traditional feedforward setting will inevitably produce a large error, which will seriously affect the control accuracy of the layer cooling temperature. Summary of the invention

[0013] In view of the defects existing in the prior art, the purpose of the present invention is to provide a hot rolling layer cooling temperature control method under the condition of finishing rolling speed regulation, solve the layer cooling feedforward setting deviation under the condition of hot rolling final rolling temperature speed control, and improve the hot rolling coiling temperature control accuracy.

[0014] To achieve the above object, the present invention adopts the following technical solution:

[0015] A method for controlling the cold temperature of a hot rolling layer under the condition of speed regulation of finishing rolling comprises the following steps:

[0016] 1) The strip segment tracking model tracks and measures the temperature data of the i-th strip segment, and forms a measurement array with the temperature data of the previous n strip segments;

[0017] 2) The strip strategy model prepares the data array of the i-th section and the first n-1 sections of the strip;

[0018] 3) Calculate the time array of the i-th section and the first n sections of the strip passing through each cooling valve through the feedforward model;

[0019] 4) Dynamically adjust the cooling valve settings, complete and output the layer cooling valve array settings for the i-th strip;

[0020] 5) The strip segment tracking model updates the new cooling valve array of each segment layer and executes the valve opening array.

[0021] Preferably, in the step 1), the i-th section of the steel strip passes through the EMP temperature measurement point, and the temperature data of the i-th section of the steel strip is collected.

[0022] Preferably, in step 2), the data array includes the cooling strategy, genetic data and completed cooling valve settings for the i-th section and the first n-1 sections of the strip.

[0023] Preferably, in step 3), the time array of the i-th segment includes what has already occurred and what is predicted.

[0024] Preferably, in step 4), the cooling valve setting is dynamically adjusted according to the predicted valve time, belt layer cooling temperature drop, and layer cooling target.

[0025] The present invention provides a method for controlling the hot rolling layer cooling temperature under the condition of finishing rolling speed regulation, which changes the original single feedforward control into a multi-point feedforward tracking calculation, and combines the actual speed diagram that has occurred with the predicted speed diagram when calculating the passage time under the valve in each section, so as to eliminate the influence of the finishing rolling speed change on the layer cooling as much as possible, thereby significantly reducing the layer cooling feedforward control deviation caused by the finishing rolling speed change, and can significantly improve the layer cooling temperature control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the control principle of the hot rolling layer cooling;

[0027] Figure 2 It is a schematic diagram of the existing F7 rolling mill strip running speed;

[0028] Figure 3 Schematic diagram of the i-th section of the strip steel in the method for controlling the cold temperature of the hot rolling layer under the condition of speed regulation of finishing rolling of the present invention;

[0029] Figure 4 It is a schematic diagram of the running speed of the i-th section of the strip steel in the method for controlling the cold temperature of the hot rolling layer under the condition of finishing rolling speed regulation of the present invention;

[0030] Figure 5 It is a schematic flow chart of a method for controlling the cold temperature of a hot rolling layer under the condition of speed regulation of finishing rolling according to the present invention;

[0031] Figure 6 It is a curve diagram of the actual value of the final rolling temperature of the incoming material in the embodiment of the method for controlling the cold temperature of the hot rolling layer under the condition of finishing rolling speed regulation of the present invention;

[0032] Figure 7 It is a curve diagram of the finishing speed and the pre-calculated speed during the rolling process in the embodiment of the hot rolling layer cold temperature control method under the finishing rolling speed regulation condition of the present invention;

[0033] Figure 8 It is a curve diagram of the actual coiling temperature of the strip production in the embodiment of the hot rolling layer cold temperature control method under the condition of finishing rolling speed regulation of the present invention. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0035] Combination Figures 3 to 5 As shown, the present invention provides a method for controlling the cold temperature of a hot rolling layer under the condition of speed regulation of finishing rolling, comprising the following steps:

[0036] 1) The strip segment tracking model tracks and measures the i-th strip segment passing through the EMP temperature measurement point, collects the temperature data of the i-th strip segment, and forms a measurement array with the temperature data of the previous n strip segments;

[0037] 2) The strip strategy model prepares the cooling strategy, genetic data, and completed cooling valve settings for each section of the strip for the i-th section and the previous n-1 sections. In the data preparation, the cooling valve settings for each section of the strip should be replaced by the time cooling valve. Figure 3 As shown, for example, for the i-th section of strip steel, its valve array includes two parts: the occurred part and the predicted part;

[0038] 3) Start the feedforward model control calculation function to complete the time array calculation of the i-th section and the first n sections of strip steel passing through each cooling valve; in addition to calculating the time array of the first n sections of strip steel, the time array of the i-th section of strip steel includes two parts: the already occurred and the predicted part. Figure 4 As shown in the figure, t i Before time t is the speed diagram of the i-th strip steel time operation, i After the moment is the speed diagram of the predicted time operation of the i-th strip steel. Therefore, the time calculation of the valve array of the i-th strip steel is calculated by combining the speed diagram of the two;

[0039] 4) Feedforward setting: According to the predicted valve time, strip layer cooling temperature drop, and layer cooling target, the cooling valve setting is dynamically adjusted to complete and output the layer cooling valve array setting of the i-th strip steel. The present invention is different from the traditional layer cooling feedforward calculation in two aspects: on the one hand, the feedforward control technology of the present invention is used to set the valves of multiple sections of strip steel; on the other hand, the calculation of the valve setting of each section is divided into two parts, one of which is the temperature calculation of each cooling zone that has passed through, using the actual cooling time and cooling valve calculation;

[0040] 5) The strip segment tracking model updates the new cooling valve array for each segment, taking into account valve delay and actual strip position, and executes the valve opening array.

[0041] Example

[0042] In this embodiment, 48 groups of production line layer cooling valves are configured, of which 1 to 24 groups are flow-adjustable valves, 25 to 48 are switch valves, and 40 to 48 are feedback valves.

[0043] Steel grade: AP1055E5

[0044] Thickness: 4.02mm;

[0045] Coil target temperature: 600℃;

[0046] Final rolling target temperature: 880℃.

[0047] (1) Strip pre-calculation starts and valve settings are calculated:

[0048] 1～13 14 15 16～28 30～36 37 38 39 40 41 42 43 44 45 46 47 48 Upper valve 1 1 0 0 1 0 0 0 0 0 0 0 0 0 1 1 1 Lower valve 1 1 0 0 1 1 1 0 0 0 0 0 0 0 0 0 1

[0049] The strip segment tracking model tracks the i-th strip passing through the EMP temperature measurement point, collects the EMP measurement temperature of the strip, and forms a measurement array with the temperature measurement values ​​of the first n strip segments; Figure 6 The actual value of the final rolling temperature of the incoming material is shown.

[0050] (2) Strip strategy program preparation related data is omitted; the finishing speed and pre-calculated speed during rolling are as follows Figure 7 As shown, the straight line is the pre-calculated speed and the curved line is the actual speed.

[0051] (3) During the rolling process, the system tracks the position of the strip, starts the layer cooling feedforward model control function, and completes the time array calculation of the current section and the first n sections of the strip passing through each cooling valve. The layer cooling feedforward control is controlled at equal distances. Assuming that the production line length is 100m and the layer cooling fixed length is controlled at 0.5m, there are a maximum of 20 sections of strip in production in the layer cooling area. For the example strip, the full length includes 407 sections. For the strip within 20 before the strip head, each feedforward calculation calculates the settings of all sections; for strips with a position greater than 20, the feedforward control calculates the feedforward of sections i to i+20.

[0052] The following table shows the dynamic upper valve settings for strip sections i to i+20 at time i.

[0053]

[0054] (4) The strip segment tracking program updates the new valve setting array for each segment, taking into account valve delay and actual strip position, and combines it into a real-time valve opening array setting execution. That is, the valve opening of the actual valve execution at a certain moment is composed of the feedforward settings of segments i to i+20, such as Figure 7 The strip section indicated by the dashed line is the valve setting executed at the time L1.

[0055] (5) The actual coiling temperature of the strip is as follows: Figure 8 shown.

[0056] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for controlling the cold temperature of a hot rolling layer under speed regulation of finishing rolling, characterized in that: The following steps are involved: 1) The strip segment tracking model tracks and measures the temperature data of the i-th strip segment, and forms a measurement array with the temperature data of the previous n strip segments; 2) The strip strategy model prepares the data array of the i-th section and the first n-1 sections of the strip; 3) Calculate the time array of the i-th section and the first n sections of the strip passing through each cooling valve through the feedforward model; 4) Dynamically adjust the cooling valve settings, complete and output the layer cooling valve array settings for the i-th strip; 5) The strip segment tracking model updates the new cooling valve array of each segment layer and executes the valve opening array.

2. The method for controlling the cold temperature of the hot rolling layer under the condition of speed regulation of finishing rolling according to claim 1, characterized in that: In the step 1), the i-th section of the steel strip passes through the EMP temperature measurement point, and the temperature data of the i-th section of the steel strip is collected.

3. The method for controlling the cold temperature of the hot rolling layer under the condition of speed regulation of finishing rolling according to claim 1, characterized in that: In the step 2), the data array includes the cooling strategy of the i-th section and the first n-1 sections of the strip, the genetic data and the completed cooling valve settings of each section.

4. The method for controlling the cold temperature of the hot rolling layer under the condition of speed regulation of finishing rolling according to claim 1, characterized in that: In step 3), the time array of the i-th segment includes what has happened and what is predicted.

5. The method for controlling the cold temperature of the hot rolling layer under the condition of speed regulation of finishing rolling according to claim 1, characterized in that: In the step 4), the multi-stage cooling valve settings are dynamically adjusted according to the predicted valve time, belt layer cooling temperature drop, and layer cooling target.

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