A method for controlling the thickness of a cold-rolled steel strip

Abstract

Embodiments of the present application provide a cold rolling strip thickness control method, which is applied to a cold rolling and pickling tandem mill, the cold rolling and pickling tandem mill comprising a plurality of stands, the method comprising: obtaining a strip thickness deviation of a strip within a preset strip head length during rolling; for each stand, determining an adjustment ratio corresponding to the each stand according to the strip thickness deviation, the adjustment ratio being positively correlated with an absolute value of the strip thickness deviation; adjusting an initial stand lift speed compensation gain of the each stand according to the adjustment ratio to obtain a target stand lift speed compensation gain of the each stand; and controlling the each stand to operate according to the target stand lift speed compensation gain. The technical solution provided by the embodiments of the present application can reduce the strip thickness fluctuation caused by the cold rolling and pickling tandem mill.

Description

Technical Field

[0001] This application relates to the field of steel rolling process control technology, and more specifically, to a method for controlling the thickness of cold-rolled strip steel. Background Technology

[0002] The types of steel rolled by cold continuous rolling and pickling mills are very diverse. However, regardless of the type of steel rolled, it is necessary to ensure the rolling quality of that type of steel. At present, during the rolling process of cold continuous rolling and pickling mills, there are often many influencing factors that cause thickness fluctuations in the rolled strip, such as the speed of the mill, the start-up and shutdown of the mill, etc. If the strip thickness wavelength is large, the part exceeding the upper and lower limits needs to be re-rolled and cut off. Understandably, if the strip thickness fluctuations generated during the rolling process are large, it will greatly reduce the rolling efficiency of the cold continuous rolling and pickling mill. Therefore, how to reduce the strip thickness fluctuations caused by cold continuous rolling and pickling mills is an urgent technical problem to be solved. Summary of the Invention

[0003] The embodiments of this application provide a method for controlling the thickness of cold-rolled strip steel, which can control the strip steel thickness fluctuation caused by the cold continuous rolling pickling and rolling mill based on the technical solution provided in this application.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] An embodiment of this application provides a method for controlling the thickness of cold-rolled strip. The method is applied to a cold-rolled pickling and tempering continuous rolling mill, which includes multiple stands. The method includes: during the rolling process, acquiring the strip thickness deviation within a preset strip head length; for each stand, determining an adjustment ratio corresponding to each stand based on the strip thickness deviation, wherein the adjustment ratio is positively correlated with the absolute value of the strip thickness deviation; adjusting the initial stand acceleration / deceleration compensation gain of each stand according to the adjustment ratio to obtain a target stand acceleration / deceleration compensation gain for each stand; and controlling each stand to operate according to the target stand acceleration / deceleration compensation gain.

[0006] In some embodiments of this application, based on the foregoing scheme, the method further includes: setting a transverse air purging device at the mill inlet of the cold continuous rolling pickling mill, the transverse air purging device being used to prevent the emulsion from interfering with the thickness gauge.

[0007] In some embodiments of this application, based on the foregoing scheme, the plurality of racks includes five racks, and the method further includes: setting water curtains of a set size at the entrance of the second rack and the entrance of the fifth rack among the five racks, the water curtains being used to prevent the emulsion from interfering with the thickness gauge, wherein the fifth rack is the rack through which the strip head last passes.

[0008] In some embodiments of this application, based on the foregoing scheme, the set dimensions include a height of 1.5m and a length of 2m.

[0009] In some embodiments of this application, based on the foregoing scheme, the plurality of stands includes five stands, and the method further includes: adjusting the deceleration point of the cold continuous rolling pickling mill from the initial position to the target position, wherein the distance between the initial position and the first stand is greater than the distance between the target position and the first stand, the first stand belongs to the five stands, and the first stand is the stand through which the strip head first passes.

[0010] In some embodiments of this application, based on the foregoing scheme, the distance between the target location and the first rack is less than or equal to 1m.

[0011] In some embodiments of this application, based on the foregoing scheme, the method further includes: during the rolling process, obtaining the looper quantity of the cold continuous rolling and pickling mill; if it is determined that the looper quantity is lower than a first set value, reducing the shearing speed of the cold continuous rolling and pickling mill to a preset shearing speed; if it is determined that the looper quantity is lower than a second set value, reducing the threading speed of the cold continuous rolling and pickling mill to a preset threading speed, wherein the second set value is less than the first set value.

[0012] In some embodiments of this application, based on the aforementioned scheme, the preset shearing speed is 200 mpm and the preset threading speed is 65 mpm.

[0013] In some embodiments of this application, based on the foregoing scheme, the cold continuous rolling and pickling mill further includes a coiler, and the method further includes: when it is detected that the strip of the target steel coil is being sheared by a flying shear, obtaining a target coiling speed corresponding to the target steel coil, the target coiling speed being used to prevent the coiling weight of the coiler from exceeding a preset weight threshold, the preset weight threshold being the coiling weight at which the coiler triggers the cold continuous rolling and pickling mill to stop; controlling the coiler to coil the strip of the target steel coil according to the target coiling speed; and after it is detected that the coiler has completed coiling the target steel coil, adjusting the coiling speed of the coiler to the coiling speed corresponding to the next coil.

[0014] In some embodiments of this application, based on the foregoing scheme, the method further includes: obtaining a preset time pre-calibrated for the coiler, the preset time being the coiling time required from the time the strip of a steel coil is sheared by a flying shear until the coiler completes coiling of the steel coil; obtaining the thickness, width, and density of the target steel coil strip; using the ratio of the preset weight threshold to the target value as the initial coiling speed; and adjusting the initial coiling speed according to a preset adjustment ratio to obtain the target coiling speed.

[0015] The technical solution of this application adds a step of adjusting the stand lifting compensation gain of each stand based on the strip thickness deviation when the cold continuous rolling pickling mill dynamically changes its specifications. If the absolute value of the strip thickness deviation is larger, the degree of adjustment of the stand lifting compensation gain of the corresponding stand will be greater. This can reduce the loss of thickness control when the cold continuous rolling pickling mill dynamically changes its specifications, thereby reducing the thickness fluctuation of the strip head, reducing the strip thickness fluctuation caused by the cold continuous rolling pickling mill, and improving the rolling quality of the cold continuous rolling pickling mill in the process of rolling strip.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0018] Figure 1 A schematic flowchart of a method for controlling the thickness of cold-rolled strip steel according to an embodiment of this application is shown;

[0019] Figure 2 A schematic diagram of the architecture of a cold continuous rolling and pickling mill unit according to an embodiment of this application is shown;

[0020] Figure 3 A schematic flowchart illustrating the control of the winding speed of a winding machine according to an embodiment of this application is shown. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that "multiple" in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0024] The following detailed description of some embodiments of this application will be provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] It should be noted that the technical solution of this application is applied to a cold continuous rolling and pickling mill, which includes multiple stands.

[0026] Typically, a cold continuous rolling and pickling mill consists of five stands. Specifically, these five stands include the first stand, the second stand, the third stand, the fourth stand, and the fifth stand. The strip head will pass through the first stand, the second stand, the third stand, the fourth stand, and the fifth stand in sequence. That is to say, the first stand is the first stand that the strip head passes through, and the fifth stand is the last stand that the strip head passes through.

[0027] See Figure 1 The diagram illustrates a flow chart of a cold-rolled strip thickness control method according to an embodiment of this application, specifically including the following steps 110 to 140:

[0028] Step 110: During the rolling process, obtain the strip thickness deviation within the preset strip length.

[0029] In some implementations, the preset belt length can be set to 15m, 10mm, 28m, etc., but this application does not limit the specific value of the preset belt length.

[0030] In some implementations, the thickness deviation of the strip within a preset strip length can be obtained using a thickness gauge.

[0031] Step 120: For each frame, determine the adjustment ratio corresponding to each frame based on the strip thickness deviation, wherein the adjustment ratio is positively correlated with the absolute value of the strip thickness deviation.

[0032] It should be noted that if the absolute value of the strip thickness deviation corresponding to each frame is larger, then the adjustment ratio corresponding to each frame is larger.

[0033] In some implementations, the adjustment ratio is greater than or equal to 1.

[0034] In some implementations, adjustment rules corresponding to each rack can be pre-established. For example, for the first rack, if the strip thickness deviation is greater than 35, then 1.8 is set as the corresponding adjustment ratio; if the strip thickness deviation is greater than 20 and less than 35, then 1.5 is set as the corresponding adjustment ratio; if the strip thickness deviation is greater than 0 and less than 20, then 1.2 is set as the corresponding adjustment ratio; and if the strip thickness deviation is 0, then 1 is set as the corresponding adjustment ratio.

[0035] Step 130: Adjust the initial rack lift-rise compensation gain of each rack according to the adjustment ratio to obtain the target rack lift-rise compensation gain of each rack.

[0036] In step 130, a specific implementation method may be to multiply the adjustment ratio and the initial rack lift-up speed compensation gain of each rack, and use the result of the multiplication as the target rack lift-up speed compensation gain.

[0037] Step 140: Control each rack to operate according to the target rack's acceleration / deceleration compensation gain.

[0038] It should be noted that at present, when the specifications of the cold continuous rolling and pickling continuous rolling mill are dynamically changed, the stand lifting and lowering speed compensation gain for a stand is fixed. Under this method, if the strip thickness deviation corresponding to the stand is large, adjusting the lifting and lowering of the stand according to the fixed stand lifting and lowering speed compensation gain will reduce the rate of thickness fluctuation control, which may lead to uncontrolled strip thickness and cause large thickness fluctuations.

[0039] Therefore, in this application, an appropriate adjustment ratio is determined based on the strip thickness deviation, so that the initial lifting and lowering speed compensation gain of each stand is not always fixed. The stand lifting and lowering speed of each stand can be adjusted, thereby improving the efficiency of thickness fluctuation control and reducing strip thickness fluctuation caused by cold continuous rolling pickling continuous rolling mill.

[0040] In this application, in order to further reduce the strip thickness fluctuation caused by the cold continuous rolling pickling mill, the following can also be implemented: a transverse air purging device is installed at the mill inlet of the cold continuous rolling pickling mill, the transverse air purging device being used to prevent the emulsion from interfering with the thickness gauge.

[0041] The following is combined with Figure 2 This embodiment will be described in detail.

[0042] See Figure 2 The diagram shows a schematic architecture of a cold continuous rolling and pickling mill unit according to an embodiment of this application.

[0043] exist Figure 2 The machine includes a first frame 11, a second frame 12, a third frame 13, a fourth frame 14, a fifth frame 15, a thickness gauge 10, and a winding machine 16.

[0044] In this embodiment, a transverse air purging device can be installed in front of the first stand 11 to prevent the backflow of emulsion from interfering with the thickness gauge installed in front of the first stand 11 when the cold continuous rolling pickling mill is running at low speed. It is understood that if the thickness gauge is interfered with by the emulsion, the thickness of the strip measured by the thickness gauge will be inaccurate, which will affect the control accuracy of the mill's AGC thickness control system.

[0045] In this embodiment, the transverse blowing device consists of multiple transversely arranged blowing nozzles, wherein the spacing between each blowing nozzle can be set to 4cm, and the length formed by each nozzle can be set to 2.8m. This can effectively prevent the emulsion from flowing back into the thickness gauge when the cold continuous rolling pickling mill is running at low speed, thereby improving the measurement accuracy of the thickness gauge on the strip thickness, and thus improving the control accuracy of the mill AGC thickness control system, and reducing the strip thickness fluctuation caused by the cold continuous rolling pickling mill.

[0046] In this application, in order to further reduce the strip thickness fluctuation caused by the cold continuous rolling pickling continuous rolling mill, the following can also be implemented: water curtains of a set size are respectively installed at the entrance of the second stand of the five stands and at the entrance of the fifth stand of the five stands. The water curtains are used to prevent the emulsion from interfering with the thickness gauge. The fifth stand is the stand through which the strip head last passes.

[0047] Specifically, it can be found in, for example Figure 2Water curtains of a set size are installed at the entrance of the second rack 12 and the entrance of the fifth rack 15.

[0048] In some implementations, the dimensions of the water curtain include a height of 1.5m and a length of 2m.

[0049] When the cold continuous rolling and pickling mill is running at low speed, the emulsion will splash everywhere, which may land on the thickness gauges located between the first and second stands, as well as at the exit of the fifth stand. Therefore, if a water curtain with a set size is added, it can effectively prevent the emulsion from flowing into the thickness gauges when the cold continuous rolling and pickling mill is running at low speed. This can improve the measurement accuracy of the thickness gauges on the strip thickness, thereby improving the control accuracy of the mill's AGC thickness control system and reducing the strip thickness fluctuations caused by the cold continuous rolling and pickling mill.

[0050] In this application, in order to further reduce the strip thickness fluctuation caused by the cold continuous rolling pickling mill, the following can also be performed: the deceleration point of the cold continuous rolling pickling mill passing the weld seam is adjusted from the initial position to the target position, the distance between the initial position and the first stand is greater than the distance between the target position and the first stand, the first stand belongs to the five stands, and the first stand is the stand through which the strip head first passes.

[0051] In some implementations, the distance between the target location and the first rack is less than or equal to 1m.

[0052] In some implementations, the distance between the target location and the first rack is equal to 1.

[0053] Normally, after detecting that the weld has passed the deceleration point, the cold continuous rolling pickling mill will decelerate. However, under the condition of low-speed operation, the thickness of the rolled strip fluctuates greatly. At present, the initial position of the deceleration point of the mill passing the weld is usually 3m away from the first mill. Therefore, in this application, the initial position is adjusted, that is, the deceleration point of the mill passing the weld is moved backward and changed to the target position, and the distance between the target position and the first mill is set to 1m or less. This can shorten the duration of low-speed operation of the mill and reduce the strip thickness fluctuation caused by the mill.

[0054] In this application, in order to further reduce the strip thickness fluctuation caused by the cold continuous rolling and pickling mill, the following can also be performed: during the rolling process, the looper quantity of the cold continuous rolling and pickling mill is obtained; if it is determined that the looper quantity is lower than a first set value, the shearing speed of the cold continuous rolling and pickling mill is reduced to a preset shearing speed; if it is determined that the looper quantity is lower than a second set value, the strip threading speed of the cold continuous rolling and pickling mill is reduced to a preset strip threading speed, wherein the second set value is less than the first set value.

[0055] In some implementations, the first set value can be 30%.

[0056] In some implementations, the second setting value can be 20%.

[0057] In some embodiments, the preset shearing speed is 200 mpm and the preset threading speed is 65 mpm.

[0058] It should be noted that if the looper quantity of the cold continuous rolling and pickling mill is lower than a certain value, it will cause the cold continuous rolling and pickling mill to stop without looper quantity. When the cold continuous rolling and pickling mill restarts after stopping, it will cause significant thickness fluctuations in the rolled strip. Therefore, in this application, if the looper quantity is detected to be lower than the first set value, the mill can be prevented from stopping without looper quantity by reducing the mill's shearing speed. If the looper quantity is detected to be lower than the second set value, the mill can be prevented from stopping without looper quantity by reducing the mill's threading speed, thereby avoiding strip thickness fluctuations caused by the mill's stop-and-start operation.

[0059] In this application, as Figure 2 As shown, the cold continuous rolling and pickling mill also includes a coiler 16. To further reduce the strip thickness fluctuations caused by the cold continuous rolling and pickling mill, it can also perform actions such as... Figure 3 The steps shown are as follows:

[0060] See Figure 3 , Figure 3 A flowchart illustrating the control of the winding speed of a winding machine according to an embodiment of this application is shown, specifically including the following steps 310 to 330:

[0061] Step 310: When it is detected that the strip of the target steel coil is being sheared by the flying shear, the target coiling speed corresponding to the target steel coil is obtained. The target coiling speed is used to prevent the coiling weight of the coiler from exceeding a preset weight threshold. The preset weight threshold is the coiling weight that triggers the shutdown of the cold continuous rolling pickling continuous rolling mill unit.

[0062] It should be noted that, in order to avoid a large drop due to gravity when the coiler is rotating, the rolling mill will be stopped when the coiled weight exceeds a preset weight threshold (e.g., 12t). Therefore, if the rolling mill is stopped and then restarted, it will inevitably cause thickness fluctuations in the rolled strip.

[0063] In this embodiment, if it is detected that the strip of the target steel coil is being sheared by the flying shear, the winding speed of the coiler is adjusted to the target winding speed. In this way, during the winding process of the coiler completing the winding of the target steel coil, the winding weight of the coiler will not exceed the preset weight threshold, thereby avoiding the mill stopping and avoiding the strip thickness fluctuation caused by the start-up of the mill.

[0064] In some implementations, the target winding speed in step 310 is associated with the physical parameters of the target steel coil and the type of winding machine. The specific determination of the target winding speed can be performed according to steps 311 to 315 as follows:

[0065] Step 311: Obtain the preset time for the coiler, which is the winding time required from the time the strip of a steel coil is cut by the flying shear until the coiler completes winding the steel coil.

[0066] It should be noted that this setting time is related to the type of winding machine; for example, the setting time may be 90 seconds.

[0067] In step 311, after the strip of a steel coil is cut by the flying shear, the coiler completes the winding of the steel coil, which means that after the strip of the coil is cut by the flying shear, the external support of the coiler is in place.

[0068] Step 312: Obtain the thickness, width, and density of the target steel coil / strip.

[0069] Step 313: Calculate the product of the thickness, the width, the density, and the set time to obtain the target value.

[0070] Step 314: Use the ratio of the preset weight threshold to the target value as the initial winding speed;

[0071] Step 315: Adjust the initial winding speed according to the set adjustment ratio to obtain the target winding speed.

[0072] In some implementations, the adjustment ratio is less than or equal to 1, for example, it can be 0.95.

[0073] Specifically, the target scrolling speed can be determined using the following formula 1:

[0074] V = K * T / (S * W * P * t) Formula 1

[0075] Wherein, V represents the target winding speed; K represents the set adjustment ratio; S represents the thickness of the target steel coil; W represents the width of the target steel coil; P represents the density of the target steel coil; and t represents the set time.

[0076] See also Figure 3 Step 320: Control the coiler to coil the strip of the target steel coil at the target coiling speed.

[0077] Understandably, if the winding machine is controlled to run at the target winding speed, problems such as overload stoppage and low speed efficiency caused by manual control can be avoided.

[0078] See also Figure 3 Step 330: After detecting that the coiler has completed winding the target steel coil, the winding speed of the coiler is adjusted to the winding speed corresponding to the next steel coil.

[0079] In step 330, the winding speed corresponding to the next coil can be the highest speed set at level two.

[0080] In summary, this application achieves the following results by adjusting the stand speed compensation gain based on strip thickness deviation, adding a transverse air purging device, adding a water curtain of a set size, adding a speed reduction interlock for the front looper of the rolling mill, moving the speed reduction point of the rolling mill past the weld seam backward, and controlling the coiling speed of the coiler: These measures reduce strip thickness fluctuations and reduce strip breakage and scrap. Calculations show the following effects can be achieved:

[0081] 1. Reducing thickness fluctuations and tape breakage waste by approximately 120 tons per month. Based on an economic benefit of 0.1 million per ton, the increased benefit is 120 tons * 0.1 million * = 120,000 per month.

[0082] 2. The developed automatic speed-up after shearing of the rolling mill and the optimal speed control of the coiler rotation enable the rolling mill speed to achieve maximum efficiency, creating approximately 10 hours of additional production time per month, with an average hourly output of 330 tons. Based on the production cost impact of 120 yuan / ton, the increased production and improved benefits amount to 400,000 yuan / month.

[0083] Total annual benefit = (12 + 40) * 12 months = 6.24 million / year

[0084] In some embodiments of the technical solutions provided in this application, during the rolling process, the strip thickness deviation within a preset strip length is obtained; for each stand, an adjustment ratio corresponding to each stand is determined based on the strip thickness deviation, the adjustment ratio being positively correlated with the absolute value of the strip thickness deviation; according to the adjustment ratio, the initial stand acceleration / deceleration compensation gain of each stand is adjusted to obtain the target stand acceleration / deceleration compensation gain of each stand; and each stand is controlled to operate according to the target stand acceleration / deceleration compensation gain.

[0085] In this application, when the cold continuous rolling and pickling mill dynamically changes its specifications, a step is added to adjust the stand lifting compensation gain of each stand based on the strip thickness deviation. If the absolute value of the strip thickness deviation is larger, the degree of adjustment of the stand lifting compensation gain of the corresponding stand is greater, which can reduce the loss of thickness control when the cold continuous rolling and pickling mill dynamically changes its specifications, thereby reducing the thickness fluctuation of the strip head, reducing the strip thickness fluctuation caused by the cold continuous rolling and pickling mill, and improving the rolling quality of the cold continuous rolling and pickling mill in the process of rolling strip.

[0086] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for controlling the thickness of cold-rolled strip steel, characterized in that, The method is applied to a cold continuous rolling and pickling mill, which includes multiple stands and a coiler. The method includes: During the rolling process, the strip thickness deviation within the preset strip length is obtained; For each frame, an adjustment ratio corresponding to each frame is determined based on the strip thickness deviation, and the adjustment ratio is positively correlated with the absolute value of the strip thickness deviation; According to the adjustment ratio, the initial rack lift-rise compensation gain of each rack is adjusted to obtain the target rack lift-rise compensation gain of each rack. Control each rack to operate according to the target rack's acceleration / deceleration speed compensation gain; When it is detected that the strip of the target steel coil is cut by the flying shear, a preset time is obtained for the coiler. The preset time is the coiling time required from the time the strip of a steel coil is cut by the flying shear until the coiler completes the coiling of the steel coil. Obtain the thickness, width, and density of the target steel coil / strip; The target value is obtained by multiplying the thickness, width, density, and set time. The ratio of the preset weight threshold to the target value is used as the initial roll-up speed; The initial winding speed is adjusted according to the set adjustment ratio to obtain the target winding speed; The target winding speed is used to prevent the winding weight of the winding machine from exceeding the preset weight threshold, which is the winding weight that triggers the shutdown of the cold continuous rolling pickling continuous rolling mill. The coiler is controlled to coil the strip steel of the target steel coil at the target coiling speed; After detecting that the coiler has completed winding the target steel coil, the winding speed of the coiler is adjusted to the winding speed corresponding to the next steel coil.

2. The method according to claim 1, characterized in that, The method further includes: A transverse air purging device is installed at the mill inlet of the cold continuous rolling pickling mill unit. The transverse air purging device is used to prevent the emulsion from interfering with the thickness gauge.

3. The method according to claim 1, characterized in that, The plurality of racks includes five racks, and the method further includes: Water curtains of a set size are installed at the entrance of the second frame and the entrance of the fifth frame among the five frames. The water curtains are used to prevent the emulsion from interfering with the thickness gauge. The fifth frame is the last frame through which the strip head passes.

4. The method according to claim 3, characterized in that, The specified dimensions include a height of 1.5m and a length of 2m.

5. The method according to claim 1, characterized in that, The plurality of racks includes five racks, and the method further includes: The deceleration point of the cold continuous rolling pickling mill is adjusted from the initial position to the target position. The distance between the initial position and the first stand is greater than the distance between the target position and the first stand. The first stand belongs to the five stands and is the stand through which the strip head first passes.

6. The method according to claim 5, characterized in that, The distance between the target location and the first rack is less than or equal to 1m.

7. The method according to claim 1, characterized in that, The method further includes: During the rolling process, the looper quantity of the cold continuous rolling and pickling continuous rolling mill is obtained; If it is determined that the looper quantity is lower than the first set value, the shearing speed of the cold continuous rolling pickling continuous rolling mill is reduced to the preset shearing speed. If it is determined that the looper quantity is lower than the second set value, the threading speed of the cold continuous rolling pickling continuous rolling mill is reduced to the preset threading speed, where the second set value is less than the first set value.

8. The method according to claim 7, characterized in that, The preset shearing speed is 200 mpm, and the preset threading speed is 65 mpm.

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