Method for controlling tension of hot continuous rolling and finish rolling loop plate head

Abstract

The invention discloses a method for controlling tension of a loop raising plate head of a hot continuous rolling finish rolling loop, which comprises the following steps of: presetting before strip steel threading of a finish rolling unit, and determining loop tension setting data TFXset between racks; according to the set tension TFXset before strip steel threading of the finishing mill group, the plate head set tension TFXhset planned to be used is calculated; after the rack bites steel, the target tension of an outlet loop of the rack is switched from the set tension TFXset before threading to the set tension TFXhset of a planed plate head; after the next rack bites steel, the loop carries out tension closed-loop control with the target tension TFXhset; when the actual tension TFXact of the loop reaches the set tension TFXhset of the plate head, keeping the actual tension TFXact for a certain time TFXht; the target tension TFXhset of the loop is restored to the set tension TFXset before threading at the speed SFXhs, and normal rolling is carried out; the method is beneficial to improving the head threading stability of the strip steel and reducing the deviation risk of the strip steel between the finishing mills, and has positive significance in stabilizing the deviation of the center line of a finish rolling outlet.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical automation control, and in particular relates to a method for controlling the tension of a hot rolling finishing looper plate head. Background Art

[0002] In the field of metal rolling, the looper plays an important role in establishing the strip tension between stands and adjusting the strip flow rate between stands in the hot rolling mill. Generally, after the next stand bites the steel, the current looper controls the tension to start with the tension set before threading the strip, and keeps the tension unchanged during the rolling process.

[0003] At present, there are several existing technologies for hot rolling finishing looper control: 1. (Announcement number: CN116673343A, title: A method for accurately controlling the looper angle of hot-rolled plate), the patent application proposes a control method for calculating the speed intervention amount of the upstream frame of the next strip looper according to the actual angle of the looper after the current strip looper is started, the set angle and other related information. 2. (Announcement number: CN117340020A, title: A method for solving the problem of soft contact between the looper and the strip when the looper is started), the patent application proposes a method for judging the contact timing between the looper and the strip according to the set value and actual value of the strip tension moment and setting the segmentation point of the approach controller, and using the segmented approach control method to control the output of the approach controller, thereby solving the problem of soft contact between the looper and the strip when the looper is started. 3. (Announcement number: CN115245962A, title: Method for controlling the angle of the looper between rolling mill stands), the patent application proposes a method for adjusting or not adjusting the forward sliding speed of the rear stand of the looper when rolling the next strip according to the angle deviation of the looper angle of the previous strip and its corresponding relationship.

[0004] However, due to various reasons, such as: large speed drop of the rolling mill, unreasonable second flow rate setting between stands, etc., the strip has problems such as small instantaneous tension at the head and deviation of the strip head during threading, which makes the strip gradually deviate from the rolling center line during threading, resulting in instability in threading of the finishing mill; In summary, there is currently a lack of control methods for the tension of the loose-loop plate head of the hot rolling finishing mill in the field of metal rolling, which can effectively control the head stability of the strip during threading.

[0005] Therefore, we introduce a method for controlling the tension of the hot rolling finishing looper plate head. Summary of the invention

[0006] The object of the present invention is to provide a method for controlling the tension of a hot rolling finishing looper plate head to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: A method for controlling the tension of a hot rolling finishing looper, comprising: S1, performing presetting before the strip of the finishing mill is threaded, and clarifying the looper tension setting data T between each stand FXset ; S2, according to the finishing mill strip before the set tension T FXset Calculate the board head setting tension T that you plan to use FXhset ; S3. After the frame bites the steel, the target tension of the frame outlet loop is set by the tension T before threading. FXset Switch to the board head tension setting T that you plan to use FXhset ; S4, after the next frame bites the steel, the looper is set at the target tension T FXhset Conduct tension closed-loop control; S5, actual tension of the looper T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht ; S6, set the target tension of the loop to T FXhset At speed S FXhs Restore to the tension T set before threading FXset , and rolled normally.

[0008] Preferably, the S1 includes: Taking the finishing rolling stand 8 as an example, the looper tension setting data T FXset , where X represents the frame code. Before threading, the tension setting data of the 7 loops needs to be clearly set.

[0009] Preferably, S2 includes: Before the strip is threaded through the finishing mill, the set tension T acting on the entire length of the strip is calculated according to the process control model. FXset , calculate the planned board head setting tension T FXhset .

[0010] Preferably, the board head setting tension T is planned to be used FXhset The calculation formula is: T FXhset = T FXset × k FXp Among them, T FXset represents the set tension calculated by the process control model acting on the entire length of the strip, T FXhset Indicates the planned board head setting tension, k FXp Indicates the tension coefficient set for the calculation plate head of each rack loop.

[0011] Preferably, calculate the tension coefficient k of the board head setting to be used FXp It is an empirical value, ranging from 1 to 3.

[0012] Preferably, S3 includes: When this control method is not used, the target control tension of the loop is the preset tension T acting on the full length of the strip. FXset If this control method is used, the loop target control tension needs to be switched to the plate head setting tension T in S2. FXhset .

[0013] Preferably, the step S4 includes: controlling the current of the actuator servo valve used to start the looper, and then FXhset The actual tension T of the looper FXact Calculate the current setting in real time.

[0014] Preferably, the step S5 includes: when the actual tension T of the looper FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht This shows that the control method achieves the expected control effect and makes the tension at the moment of loop establishment more stable.

[0015] Preferably, the stabilization time T FXht It is an empirical value, ranging from 0 to 500, in ms.

[0016] Preferably, in S6, the tension T is set by the plate head. FXhset Restore to the tension T set before threading FXset Speed ​​S FXhs It is a given empirical value, ranging from 50-200, in kN / s.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Through the pre-setting of the strip steel of the finishing mill before threading, the setting data T of the looper tension between each stand is clarified. FXset ; Set the tension T according to the strip tension of the finishing mill before passing the strip through FXset Calculate the board head setting tension T that you plan to use FXhset After the frame bites the steel, the target tension of the frame outlet loop is set by the tension T before threading. FXset Switch to the tension T for the board head you plan to use FXhset ; When the next rack bites the steel, the looper is at the target tension T FXhset Perform tension closed-loop control; wait for the actual tension of the looper to be T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht ; Set the looper target tension T FXhsetAt speed S FXhs Restore to the tension T set before threading FXset , and rolled normally; (2) The control method of the present invention is simple and easy to implement, which is beneficial to improving the threading stability of the strip head and reducing the risk of strip deviation between the finishing mills, and has a positive significance for stabilizing the deviation of the center line of the finishing outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flowchart of the execution of a method for controlling the tension of a hot rolling finishing looper provided in an embodiment of the present invention; Figure 2 A schematic diagram of a plate head tension setting method for controlling the plate head tension of a hot rolling finishing looper provided in an embodiment of the present invention; Figure 3 A schematic diagram of a given plate head tension of a method for controlling the plate head tension of a hot rolling finishing looper provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0020] See also Figure 1-3 The present invention provides a technical solution: a method for controlling the tension of the hot rolling finishing looper, the control effect of the method is as follows: Figure 3 As shown, the strip of the finishing mill is pre-set before threading, and the setting data T of the looper tension between each stand is clarified. FXset ; Set the tension T according to the strip tension of the finishing mill before passing the strip through FXset Calculate the board head setting tension T that you plan to use FXhset After the frame bites the steel, the target tension of the frame outlet loop is set by the tension T before threading. FXset Switch to the tension T for the board head you plan to use FXhset ; When the next rack bites the steel, the looper is at the target tension T FXhset Perform tension closed-loop control; wait for the actual tension of the looper to be T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht ; Set the looper target tension T FXhset At speed S FXhs Restore to the tension T set before threading FXset , and rolled normally.

[0021] Specifically, the execution process of this method is as follows Figure 1 As shown, the following steps are included: S1, pre-set the strip before threading the strip of the finishing mill, and clarify the setting data T of the looper tension between each stand FXset ; S2, according to the strip tension T set before the strip is threaded in the finishing mill FXset Calculate the board head setting tension T that you plan to use FXhset , the formula is: T FXhset = T FXset × k FXp Among them, T FXset represents the set tension calculated by the process control model acting on the entire length of the strip, T FXhset Indicates the planned board head setting tension, k FXp Indicates the tension coefficient set for the calculation plate head of each rack loop.

[0022] Among them, the calculation plan is to use the board head setting tension coefficient k FXp It is an empirical value, and its value range is [1,3].

[0023] S3, after the frame bites the steel, the target tension of the frame outlet loop is set by the tension T before threading. FXset Switch to the tension T for the board head you plan to use FXhset ; S4, after the next rack bites the steel, the looper is set at the target tension T FXhset Conduct tension closed-loop control; S5, waiting for the actual tension of the looper T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht ; Among them, the stabilization time T FXht It is an empirical value, ranging from [0,500], in ms.

[0024] S6, set the looper target tension T FXhset At speed S FXhs Restore to the tension T set before threading FXset , and rolled normally; Among them, the tension T is set by the plate head FXhset Restore to the tension T set before threading FXset Speed ​​S FXhs It is an empirical value, its value range is [50,200], and the unit is kN / s.

[0025] The implementation process of the method of the present invention is described below in conjunction with specific application examples.

[0026] In this application example, taking the number of finishing mill stands as 8 as an example, the operation is performed as follows: (1) The strip of this strip is pre-set before the strip is threaded through the finishing mill, and the setting data of the looper tension between each stand is clarified, as shown in Table 1 below: Table 1 (2) The planned plate head setting tension is calculated based on the setting tension of the strip before threading the finishing mill, where the calculation formula is: T FXhset = T FXset × k FXp Set the tension coefficient k for each rack head FXp And calculate the rear plate head tension, as shown in Table 2 below: Table 2 (3) After the frame bites the steel, the target tension of the frame outlet looper is switched from the tension set before threading to the tension set by the plate head to be used. This step is to switch the target tension of the No. 1 looper from 74kN to 88.8kN after F1 bites the steel, and the same applies to the other frames. (4) When the next frame bites the steel, the looper performs tension closed-loop control at the target tension. This step is that when F2 bites the steel, the No. 1 looper performs tension closed-loop control at 88.8 kN. (5) Wait until the actual tension of the loop reaches the set tension of the plate head and maintains it for a certain period of time. The holding time here is shown in Table 3 below: Table 3 (6) The target tension of the looper is restored to the tension set before threading at a certain speed, and normal rolling is performed. The certain speed here is shown in Table 4 below: Table 4 Through the above application examples, it can be found that the control method of the hot rolling finishing looper plate head tension of the present invention can adaptively control the loopers of different frames in actual production, has greater adjustment flexibility, and can gradually increase the plate head tension during the strip threading process, thereby more accurately realizing the effective control of the hot rolling finishing looper plate head tension, thereby achieving a more stable effect of the strip in the process of strip threading in the finishing mill.

[0027] In summary, the control method of this embodiment calculates the target tension used when the looper is lifted after the next stand bites the steel, and the timing and speed of restoring the plate head set tension to the set tension before the strip is worn, according to the looper set tension before the strip is worn, the plate head set tension coefficient, the time when the actual looper tension reaches the plate head set tension and the speed at which the plate head set tension is restored to the set tension before the strip is worn, thereby realizing the looper lifting control when the strip is worn at the head of the finishing mill. It is beneficial to improve the stability of the strip head wearing, reduce the center line deviation of the strip at the finishing exit, and improve the rolling stability, which has certain positive significance.

[0028] In addition, it should be noted that the present invention can be provided as a method, an apparatus or a computer program product. Therefore, the embodiments of the present invention can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0029] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0030] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, so that a series of operation steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the tension of a hot rolling finishing looper, characterized in that: include: S1. Perform pre-setting before strip threading of the finishing mill, and clarify the setting data of the looper tension between each stand T FXset ; S2, according to the finishing mill strip before the set tension T FXset Calculate the board head setting tension T that you plan to use FXhset ; S3. After the frame bites the steel, the target tension of the frame outlet loop is set by the tension T before threading. FXset Switch to the board head tension setting T that you plan to use FXhset ; S4, after the next frame bites the steel, the looper is set at the target tension T FXhset Conduct tension closed-loop control; S5, actual tension of the looper T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht ; S6, set the target tension of the loop to T FXhset At speed S FXhs Restore to the tension T set before threading FXset , and rolled normally.

2. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 1 is characterized in that: The S1 includes: Taking the finishing rolling stand 8 as an example, the looper tension setting data T FXset , where X represents the frame code. Before threading, the tension setting data of the 7 loops needs to be clearly set.

3. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 1, characterized in that: The S2 includes: Before the strip is threaded through the finishing mill, the set tension T acting on the entire length of the strip is calculated according to the process control model. FXset , calculate the planned board head setting tension T FXhset .

4. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 3 is characterized in that: Planned board head setting tension T FXhset The calculation formula is: T FXhset = T FXset × k FXp Among them, T FXset represents the set tension calculated by the process control model acting on the entire length of the strip, T FXhset Indicates the planned board head setting tension, k FXp Indicates the tension coefficient set for the calculation plate head of each rack loop.

5. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 4, characterized in that: Calculate the tension factor k of the board head setting you plan to use FXp It is an empirical value, ranging from 1 to 3.

6. The method for controlling the tension of the hot rolling finishing looper plate head according to claim 1, characterized in that: In the step S4, the current of the actuator servo valve used to control the looper is given, and the target tension T is set. FXhset The actual tension T of the looper FXact Calculate the current setting in real time.

7. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 1, characterized in that: S5 includes: when the actual tension of the looper T FXact Reach the board head set tension T FXhset And keep it for a certain time T FXht This shows that the control method achieves the expected control effect and makes the tension at the moment of loop establishment more stable.

8. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 7, characterized in that: Stabilization time T FXht It is an empirical value, ranging from 0 to 500, in ms.

9. The method for controlling the tension of the hot rolling finishing looper as claimed in claim 1, characterized in that: In S6, the tension T is set by the plate head. FXhset Restore to the tension T set before threading FXset Speed ​​S FXhs It is a given empirical value, ranging from 50-200, in kN / s.

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