Dynamic plate thickness changing method

Abstract

Provided is a dynamic plate thickness changing method capable of shortening the nonstandard length of the plate thickness and reducing the variation in tension. A dynamic plate thickness changing method for continuously rolling a material to be rolled (6) in which a preceding material (61) and a following material (62), which are metal plates, are joined by a tandem rolling mill (2), in which a plate thickness is changed between a target stand (e.g., a second stand (2B)), which is a rolling stand for changing the plate thickness, and a preceding stand (e.g., a rolling stand preceding the target stand), which is a preceding stand (e.g., a second stand (2B)), which is a rolling stand preceding the target stand. The plate thickness or the plate speed of the material to be rolled (6) is continuously measured between the target racks of the first rack (2A), and the plate thickness change position in the vicinity of the joint between the preceding material (61) and the following material (62) is detected on the basis of the measurement result of the plate thickness, or the plate thickness change position in the vicinity of the joint between the preceding material (61) and the following material (62) is tracked on the basis of the measurement result of the plate speed, and the plate thickness change position in the vicinity of the joint between the following material (62) and the preceding material (61) is detected on the basis of the measurement result of the plate speed. The roller gap of the target rack is changed when the plate thickness changing position reaches the target rack.

Description

Technical Field

[0001] The invention relates to a dynamic plate thickness changing method. Background Art

[0002] In cold rolling of steel plates, a technology called dynamic gauge change is used to improve efficiency and yield, allowing continuous rolling without stopping the mill as much as possible. Dynamic gauge change involves continuously changing the actuator settings of the preceding coil to those of the succeeding coil when rolling the welded joint of coils of different specifications, allowing continuous rolling without stopping the mill. Changing the actuator settings during dynamic gauge change, especially when the change in the reduction position is large, takes time. This temporarily disrupts the stable state, leading to unstable tension and potentially causing plate breakage.

[0003] In the past, as a method for suppressing tension fluctuations during dynamic plate thickness changes, a method of setting an intermediate plate thickness has been used. For example, Patent Document 1 discloses the following method: as a method for determining an intermediate plate thickness for suppressing tension fluctuations, an evaluation function is created with the plate thickness fluctuation amount as a variable, and the intermediate plate thickness is determined in such a way that the evaluation function converges within a certain threshold. In addition, Patent Document 2 discloses a method for determining the value of tension fluctuations and suppressing tension fluctuations by resetting the dynamic plate thickness change time that changes the set values of the roller gap and the roller peripheral speed from pass schedule A to pass schedule B. In Patent Document 2, the value of tension fluctuations is determined based on the tension fluctuation value predicted by a tension fluctuation learning unit, which is based on a neural network that has learned using the actual tension fluctuations during dynamic plate thickness changes as teacher data.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-12423

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 10-49423

[0006] Recent technological innovations and the expansion of steel plate applications have led to the rolling of a wide variety of steel plates (particularly high-deformation-resistance materials, such as electromagnetic and high-strength materials). This has led to the implementation of dynamic thickness changes at the joints of coils with widely varying specifications (thickness, deformation resistance, etc.). As a result, the tension fluctuations during dynamic thickness changes have increased, a problem addressed using the aforementioned prior art.

[0007] However, the method of Patent Document 1 introduces an intermediate plate thickness, which results in a longer plate length due to non-standard plate thickness. Furthermore, the method of Patent Document 2 determines that tension fluctuations during passage through the joint depend on factors such as the thickness difference between the preceding and succeeding materials, the difference in deformation resistance, and variations in rolling conditions before and after the joint. This prediction model does not necessarily account for these influences. Consequently, the method of Patent Document 2 may result in low tension fluctuation prediction accuracy and, for example, increased tension fluctuations. Summary of the Invention

[0008] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a dynamic plate thickness changing method capable of reducing tension fluctuations.

[0009] (1) According to one embodiment of the present invention, a dynamic plate thickness changing method is provided, which is a dynamic plate thickness changing method for continuously rolling a rolled material formed by joining a preceding material and a succeeding material as metal plates using a tandem rolling mill, wherein the plate thickness or plate speed of the rolled material is continuously measured between a rolling stand where the plate thickness change is performed, i.e., an object stand, and a rolling stand preceding the object stand, i.e., an object stand of the preceding stand, and a plate thickness change position near a joining portion of the preceding material and the succeeding material is detected based on the plate thickness measurement result, or a plate thickness change position near a joining portion of the preceding material and the succeeding material is tracked based on the plate speed measurement result, and the roller gap of the object stand is changed when the plate thickness change position reaches the object stand.

[0010] (2) Based on the structure of (1), the plate speed measured between the target stands is used to calculate the length of the tapered plate thickness portion after rolling in the preceding stand, and the speed of change of the pressing position is calculated by dividing the length of the tapered plate thickness portion by the amount of change in the pressing position in the target stand, and the roller gap of the target stand is changed at the calculated change speed.

[0011] (3) In the structure of (1) or (2) above, the rolled material is a high deformation resistance steel plate.

[0012] According to one aspect of the present invention, a dynamic plate thickness changing method capable of reducing tension fluctuation is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram showing the cold rolling equipment according to the first embodiment of the present invention.

[0014] Figure 2It is an explanatory diagram of the existing dynamic plate thickness change method, (A) shows the state where the plate thickness change position S1 is located upstream of the first frame, (B) shows the state where the plate thickness change position S1 has reached the first frame, (C) shows the state where the joint has reached the first frame, (D) shows the state where the plate thickness change position S1 has reached the second frame, (E) shows the state where the plate thickness change position S2 has reached the second frame, and (F) shows the state where the joint has reached the second frame.

[0015] Figure 3 This is a graph showing changes in the tension between the first stand and the second stand in a conventional dynamic plate thickness changing method.

[0016] Figure 4 These are explanatory diagrams of the dynamic plate thickness changing method involved in the first embodiment, (A) shows a state in which the plate thickness changing position is located upstream of the first frame, (B) shows a state in which the plate thickness changing position has reached the first frame, (C) shows a state in which the joint has reached the first frame, (D) shows a state in which the plate thickness changing position has reached the second frame, and (E) shows a state in which the joint has reached the second frame.

[0017] Figure 5 This is a graph showing changes in the tension between the first stand and the second stand in the dynamic thickness changing method according to the first embodiment.

[0018] Figure 6 It is a schematic diagram showing a cold rolling facility according to a second embodiment of the present invention.

[0019] Figure 7 It is an explanatory diagram of the dynamic plate thickness changing method according to the second embodiment of the present invention, wherein (A) indicates a state in which the plate thickness changing position is located upstream of the first frame, (B) indicates a state in which the plate thickness changing position has reached the first frame, (C) indicates a state in which the joint has reached the first frame, (D) indicates a state in which the joint has passed the first frame and the plate thickness changing position is located upstream of the second frame, (E) indicates a state in which the plate thickness changing position has reached the second frame, and (F) indicates a state in which the joint has reached the second frame.

[0020] Figure 8 This is a flowchart showing a dynamic plate thickness changing method according to a second embodiment of the present invention.

[0021] Figure 9 This is a graph showing changes in the tension between the first stand and the second stand when the dynamic thickness change is completed early. DETAILED DESCRIPTION

[0022] In the following detailed description, embodiments of the present invention are described with reference to the accompanying drawings. In the description of the drawings, the same or similar parts are marked with the same or similar figure marks, and repeated descriptions are omitted. The drawings are schematic and include situations that are different from reality. In addition, the embodiments shown below illustrate the devices and methods for concretizing the technical ideas of the present invention. The technical ideas of the present invention do not specify the materials, structures, configurations, etc. of the constituent parts as follows. The technical ideas of the present invention can be modified in various ways within the technical scope specified by the claims recorded in the claims.

[0023] <First embodiment>

[0024] (Structure of cold tandem rolling mill)

[0025] First, a dynamic plate thickness method according to a first embodiment of the present invention will be described. Figure 1 1 is a schematic structural diagram showing an example of a cold rolling mill 1 according to the first embodiment of the present invention. Figure 1 In the figure, other devices attached to the equipment (for example, the rewinder, welding machine and looper on the inlet side, and the cutting machine and winding machine on the outlet side) are omitted.

[0026] like Figure 1 As shown, the cold rolling mill 1 includes: a tandem rolling mill 2; a plurality of plate thickness measuring devices 3; a rolling control controller (PLC) 4 that controls the tandem rolling mill 2; and a control computer (process computer) 5 that manages the cold rolling mill including the rolling control controller 4.

[0027] The tandem rolling mill 2 is a continuous cold tandem rolling mill including a first stand 2A to a fifth stand 2E in order from the inlet side in the sheet passing direction.

[0028] Each of the first to fifth stands 2A to 2E is provided with work rolls 21 , a roll speed control device 22 which is a motor that changes the roll speed of the work rolls 21 , and a screw-down control device 23 that changes the roll gap between the upper and lower work rolls 21 .

[0029] Multiple plate thickness measuring devices 3 are installed between adjacent stands (between stands) from the first stand 2A to the fifth stand 2E. They continuously measure the thickness of the metal plate, or rolled material 6, passing between the stands. The plate thickness measuring device 3 is not particularly limited to the method used to measure the plate thickness. For example, a device that irradiates the material with gamma rays or X-rays and measures the attenuation of the gamma rays (X-rays) transmitted through the material to be measured, converting the result into thickness, is also conceivable. The plate thickness measurement results from the plate thickness measuring device 3 are transmitted to the control computer 5.

[0030] The control computer 5 sets the roll gap value, roll gap change amount, roll speed, roll speed change amount, etc. for each stand. Furthermore, based on the values acquired from the control computer 5, the rolling control controller 4 performs online calculations and processing for the roll speed control device 22 and the roll screw control device 23 for each stand, controlling each of the first to fifth stands 2A to 2E.

[0031] In this cold rolling mill 1, the rolled material 6 is joined at a joint W between the trailing end of the preceding material 61 and the leading end of the succeeding material 62 by welding or other means using a welding machine (not shown) located at the entrance of the tandem mill 2. The rolled material 6 then passes through the cold rolling mill's first stand 2A to the fifth stand 2E, serving as the final stand, to a predetermined finished thickness. The material 6 is then cut by a dynamic shearing machine at or near the joint W between the preceding and succeeding materials 61 and 62. The cut succeeding material 52 is then wound onto a different tension reel than the preceding material 51.

[0032] Here, when the rolling conditions such as the mother plate thickness, the finishing plate thickness, and the deformation resistance are different in the preceding material 61 and the following material 62, when the preceding material 61 and the following material 62 are continuously rolled using a cold rolling mill, a dynamic plate thickness change is performed to dynamically change the rolling conditions (i.e., the state in which the rolled material 6 is transported in the serial rolling mill 2).

[0033] In a conventional method, based on the tracking of the joint W (based on the joint W), the roll gap setting value is changed when the plate thickness change position set at a predetermined distance from the joint and on the side of the preceding material 61 reaches the frame. Figure 2 (A)~ Figure 2 In the method shown in (F), dynamic plate thickness change is performed. In addition, the tension between the first frame 2A and the second frame 2B at this time changes in Figure 3 In addition, Figure 3 The timings of (a) to (f) are equivalent to Figure 2 The timing of the states (A) to (F).

[0034] First, if Figure 2 As shown in (A), rolling is performed with the roll gap value of each stand set to the value for the preceding material 61. Figure 2 In (A), the position indicated by S1 on the trailing end side of the preceding material 61 is a position where the roll gap setting value is changed in the first stand 2A.

[0035] If rolling is further carried out, Figure 2As shown in (B), the thickness change position S1 of the preceding material 61 reaches the first stand 2A, and the roll gap setting value of the first stand 2A begins to be changed so that the roll gap setting value of the first stand 2A becomes the setting value for the following material 62. The thickness change position S1 is set to a position separated by a predetermined distance from the joint W at the trailing end of the preceding material 61. As described later, the position of the thickness change position S1 is determined based on the time required for the roll gap change, the sheet material throughput speed, and other factors.

[0036] If rolling is further carried out, Figure 2 As shown in (C), the change of the roll gap setting value of the first stand 2A is completed, and the rolling of the subsequent material 62 starts in the first stand 2A. Usually, the plate thickness change position S1 is set so that the change of the roll gap setting value is completed before the joint W reaches the first stand 2A. Figure 2 (B) and Figure 2 By changing the roller gap setting value as shown in (C), the plate thickness changes in a tapered shape from the tail end of the preceding material 61 to the joint W.

[0037] If rolling is further carried out, Figure 2 As shown in (D), the plate thickness change position S1 in the first stand 2A reaches the second stand 2B. As will be described later, the change of the roll gap setting value in the second stand 2B starts when the plate thickness change position S2 reaches the second stand 2B. The plate thickness change position S2 is set to a position separated by a predetermined distance from the joint W on the tail end side of the preceding material 61, similarly to the plate thickness change position S1. In addition, as Figure 2 As shown in (D), the preceding material 61 that has passed through the first stand 2A is rolled and extended in the longitudinal direction, so that the plate thickness changing position S1 of the first stand 2A and the plate thickness changing position S2 of the second stand 2B are different positions.

[0038] exist Figure 2 In the state shown in (D), before the roll gap of the second stand 2B is changed, the tapered thickness portion of the rolled material 6 reaches the second stand 2B. At this time, the roll gap setting value of the second stand 2B becomes the setting value for the preceding material 61, so Figure 3 As shown, the tension between the first frame 2A and the second frame 2B is reduced. Therefore, a large tension fluctuation occurs, and the risk of breakage increases.

[0039] If rolling is further carried out, Figure 2 As shown in (E), the plate thickness changing position S2 reaches the second stand 2B, and the change of the roll gap setting value of the second stand 2B is started so that the roll gap setting value of the second stand 2B becomes the setting value for the succeeding material 62.

[0040] Furthermore, if Figure 2As shown in (F), the change in the roll gap setting value for the second stand 2B is complete, and rolling of the subsequent material 62 begins in the second stand 2B. The roll gap setting value for the third stand 2C and subsequent stands is changed in the same manner as for the second stand 2B, thereby dynamically changing the plate thickness. That is, in the third stand 2C and subsequent stands, the roll gap setting value is changed in each stand at the individually set plate thickness change position S. Furthermore, in each stand, the roll peripheral speed setting is changed synchronously with this roll gap setting change.

[0041] (Dynamic plate thickness change method)

[0042] Figure 4 (A)~ Figure 4 (E) is an explanatory diagram showing the dynamic plate thickness changing method according to the first embodiment. Figure 4 (A)~ Figure 4 (C) shows the change of the roller gap setting value of the first stand 2A, which is achieved by Figure 2 (A)~ Figure 2 (C) The roller gap setting value is changed in the same way. In addition, the tension between the first frame 2A and the second frame 2B at this time changes in Figure 5 In addition, Figure 5 The timings of (a) to (e) correspond to Figure 4 The timing of the states (A) to (E).

[0043] Furthermore, in the first embodiment, a plate thickness measuring device 3 is installed between the first stand 2A and the second stand 2B to continuously measure the thickness of the rolled material 6 passing between the stands. Based on the measurement results of the plate thickness measuring device 3, the control computer 5 detects a plate thickness change position S where the thickness of the rolled material 6 changes. The detected plate thickness change position S is the plate thickness change position S set in the first stand 2A, and is the position where the plate thickness changes in a tapered manner.

[0044] Next, if the plate thickness change position S is detected between the first frame 2A and the second frame 2B, Figure 4 As shown in (D) of FIG. 1 , the control computer 5 changes the roll gap setting value of the second stand 2B when the plate thickness change position S reaches the second stand 2B. At this time, the roll gap setting value of the second stand 2B is changed from the setting value for the preceding material 61 to the setting value for the succeeding material 62. The roll gap setting value of the second stand 2B is changed at the plate thickness change position S, so Figure 5 As shown, even if the tapered plate thickness portion reaches the second stand 2B, the reduction in tension is compensated, and the risk of breakage due to the reduction in tension can be reduced.

[0045] If rolling is further carried out, Figure 4 As shown in (E), the change in the roll gap setting value for the second stand 2B is complete, and rolling of the subsequent material 62 begins in the second stand 2B. The roll gap setting value for the third stand 2C and subsequent stands is changed in the same manner as for the second stand 2B, thereby dynamically changing the plate thickness. Specifically, in the third stand 2C and subsequent stands, the plate thickness change position S is detected based on the measurement results of the plate thickness measuring device 3 installed between the stands, and the roll gap setting value is changed when the plate thickness change position S reaches each stand. Furthermore, in each stand, the roll peripheral speed setting is changed synchronously with this roll gap setting change.

[0046] Furthermore, in the first embodiment, the rolled material 6 is a metal plate, preferably a steel plate, particularly a high-deformation-resistant steel plate. Examples of such high-deformation-resistant steel plates include electromagnetic materials and high-strength materials. Such high-deformation-resistant steel plates experience a significant reduction in thickness during dynamic thickness change, leading to a significant deviation in thickness from the set thickness at the weld front portion of the preceding mill frame, resulting in increased tension fluctuations. Therefore, by applying the dynamic thickness change method of the first embodiment, failures such as breakage can be prevented, enabling stable manufacturing.

[0047] The dynamic plate thickness changing method involved in the first embodiment is a dynamic plate thickness changing method when continuously rolling the rolled material 6 formed by joining the leading material 61 and the trailing material 62 as metal plates using a tandem rolling mill 2. The plate thickness of the rolled material is continuously measured between the target stands, and the plate thickness change position S near the joint W is detected. When the plate thickness change position reaches the target stand, the roller gap of the target stand is changed. In addition, the target stand is a rolling stand that performs plate thickness change, and the preceding stand is a rolling stand arranged adjacent to the target stand on the upstream side of the rolling direction. For example, in Figure 4 In the case where the roller gap of the second stand 2B is changed, the second stand 2B becomes the target stand and the first stand 2A becomes the preceding stand.

[0048] The dynamic plate thickness changing method according to the first embodiment eliminates the need for intermediate plate thicknesses, compared to the method of Patent Document 1, thereby reducing the off-gauge length. Furthermore, the dynamic plate thickness changing method according to the first embodiment uses the plate thickness changing point in the preceding stand as the plate thickness changing point in the succeeding stand to change the roll gap. This allows for suppressing tension fluctuations regardless of the material or specifications of the rolled material 6.

[0049] <Second embodiment>

[0050] (Structure of cold tandem rolling mill)

[0051] Next, first, a dynamic plate thickness method according to a second embodiment of the present invention will be described. Figure 6 1 is a schematic structural diagram showing an example of a cold rolling mill 1 according to a second embodiment of the present invention. Figure 6 In, with Figure 1 Similarly, other devices included in the apparatus are omitted from the illustration.

[0052] like Figure 6 As shown, the cold rolling mill 1 includes: a tandem rolling mill 2; a rolling control controller (PLC) 4 that controls the tandem rolling mill 2; a control computer (process computer) 5 that manages the cold rolling mill including the rolling control controller 4; and a plurality of plate speed meters 7.

[0053] The tandem rolling mill 2 is a continuous cold tandem rolling mill including a first stand 2A to a fifth stand 2E in order from the inlet side in the sheet passing direction.

[0054] Each of the first to fifth stands 2A to 2E is provided with work rolls 21 , a roll speed control device 22 which is a motor that changes the roll speed of the work rolls 21 , and a screw-down control device 23 that changes the roll gap between the upper and lower work rolls 21 .

[0055] The control computer 5 sets the roll gap value, roll gap change amount, roll speed, roll speed change amount, etc. for each stand. Furthermore, based on the values acquired from the control computer 5, the rolling control controller 4 performs online calculations and processing for the roll speed control device 22 and the roll screw control device 23 for each stand, controlling each of the first to fifth stands 2A to 2E.

[0056] Multiple plate speed meters 7 are installed between adjacent stands (between stands) from the first stand 2A to the fifth stand 2E. They continuously measure the speed of the metal plate, or rolled material 6, passing between the stands in the conveying direction, i.e., the plate speed. The plate speed measurement method using the plate speed meters 7 is not particularly limited; for example, a laser Doppler velocimeter can be used. The plate speed measurement results from the plate speed meters 7 are transmitted to the control computer 5.

[0057] Similar to the first embodiment, in the cold rolling mill 1, the rolled material 6 is joined at a joint W by welding or other means using a welding machine (not shown) located on the inlet side of the tandem mill 2. The rolled material 6 is then rolled sequentially from the first stand 2A of the cold rolling mill to the fifth stand 2E, serving as the final stand, to a predetermined finished thickness. The rolled material 6 is then cut by a dynamic cutter at or near the joint W between the leading and trailing materials 61 and 62. The cut trailing material 52 is then wound onto a different tension reel than the leading material 51. Similarly to the first embodiment, dynamic thickness adjustment is performed when rolling conditions such as base plate thickness, finished thickness, and deformation resistance differ between the leading and trailing materials 61 and 62.

[0058] (Dynamic plate thickness change method)

[0059] Figure 7 (A)~ Figure 7 (F) and Figure 8 It is an explanatory diagram showing a dynamic plate thickness changing method according to the second embodiment. Figure 7 (A)~ Figure 7 (C) shows a method for changing the roll gap setting value of the first stand 2A (dynamic thickness changing method), by Figure 2 (A)~ Figure 2 Change the roller gap setting value in the same way as (C).

[0060] In the following description, a method for changing the roll gap setting value of the second stand 2B, that is, a method for changing the dynamic thickness will be described. Figure 8 The processing flow shown is performed. In addition, the second stand 2B and subsequent rolling stands are also subjected to dynamic plate thickness change by the same method as the second stand 2B. Here, as in the first embodiment, the rolling stand subjected to dynamic plate thickness change is also referred to as the target stand, and the rolling stand in the previous stage of the target stand is referred to as the previous stage stand. In addition, Figure 8 The process flow shown in the figure starts with the dynamic thickness change of the preceding rack (first rack 2A), that is, Figure 7 Start from the state (B).

[0061] If the dynamic plate thickness change in the first frame 2A starts, first, the plate speed meter 7 set in the target frame is used to continuously measure the plate speed (100) of the rolled material 6 passing through the target frame. The target frame refers to the space between the target frame and the previous frame. When the target frame is the second frame 2B, it is between the second frame 2B and the first frame 2A. In addition, the plate speed measurement is continuously performed at least before the dynamic plate thickness change in the target frame is performed. That is, when the target frame is the second frame 2B, after Figure 7 After the plate thickness change position S shown in (B) reaches the first stand 2A, Figure 7 The plate speed is measured continuously at least until the plate thickness change position S shown in (E) reaches the second stand 2B. In addition, the control computer 5 tracks the plate thickness change position S of the rolled material 6 based on the plate speed measurement results between the target stands by the plate speed meter 7.

[0062] After step S100, the control computer 5 calculates the length L of the tapered plate thickness portion after rolling in the preceding stand. N-1 (S102). In addition, N represents the number of the target stand (Nth stand). That is, when the target stand is the second stand 2B, the length L1 of the tapered plate thickness portion after rolling in the first stand 2A is calculated. The tapered plate thickness portion is a portion where the plate thickness of the rolled material 6 changes in a tapered shape due to the dynamic plate thickness change of the previous stand. When the target stand is the second stand 2B, the tapered plate thickness portion becomes Figure 7 The portion from the plate thickness change position S to the joint W in (D).

[0063] Length L of the tapered plate thickness N-1 The calculation is performed by accumulating (plate speed of the preceding stage) x (time) until the dynamic plate thickness change in the preceding stage is completed. Specifically, the length L of the tapered plate thickness portion is N-1 The calculation is performed using the following formula (1). In formula (1), the measurement timing of the board speed is set as a time step, and the board speed v in each time step is calculated. N-1(i) and time T i Calculate length L N-1 In addition, regarding the time step number, the measurement timing of the start of the dynamic plate thickness change is 1, and the measurement timing of the end of the dynamic plate thickness change is m. In addition, the time T i Each indicates the elapsed time from a predetermined timing serving as a starting point to each time step.

[0064] [Formula 1]

[0065]

[0066] here,

[0067] T i : time in time step i [s]

[0068] v N-1(i) : The board speed between the target racks in time step i [m / s]

[0069] After step S102, the control computer 5 calculates the time t until the tapered plate thickness portion enters the target frame. N(S104) In step S104, the plate speed between target racks measured by the plate speed meter 7 immediately before the target rack is passed and the length L calculated in step S102 is used. N-1 To calculate the time t N In the second embodiment, time t N It corresponds to the time from when the thickness change position S of the rolled material 6 enters the target stand to when the joint W enters the target stand. N It can be calculated using the following formula (2).

[0070] [Formula 2]

[0071]

[0072] After step S104, the control computer 5 calculates the change amount ΔS of the depressed position in the target frame. N and time t N Calculate the change speed R of the pressing position N (S106). The change amount of the pressing position in the target stand corresponds to the adjustment amount of the roll gap of the target stand, and becomes the movement amount of the upper and lower work rolls 21 in the thickness direction of the rolled material 6 accompanying the change in plate thickness. In addition, the plate thickness change amount is a preset value. The change speed R of the pressing position in the target stand is N It is the moving speed of each work roll 21 when changing the reduction position (that is, when performing dynamic thickness change). Change speed R N It can be calculated using the following formula (3). The processing up to step S104 is performed before the plate thickness change position S reaches the target stand. The processing of steps S102 and S104 is preferably performed just before the tapered plate thickness portion reaches the target stand.

[0073] [Formula 3]

[0074]

[0075] After step S106, when the plate thickness change position S reaches the target rack, the control computer 5 moves the plate thickness change position S at the change speed R calculated in step S106. N and thickness change Δs N The dynamic plate thickness change, i.e. the change of the roller gap setting value (S108) is performed. As described above, the plate thickness change position S is tracked based on the plate speed measurement result, and the control computer 5 detects the plate thickness change position S reaching the target rack based on the tracking result, thereby performing the dynamic plate thickness change. In step S108, by changing the speed R N and thickness change Δs NThe dynamic plate thickness change is performed so that the dynamic plate thickness change is completed when the joint W reaches the target rack. In the case where the target rack is the second rack 2A, Figure 7 As shown in (D), by tracking and detecting the arrival of the plate thickness change position S at the second stand 2A, the roll gap setting value in the second stand 2B is changed. Then, in step S108, by changing the speed R N and thickness change Δs N Dynamic plate thickness change, so as to Figure 7 As shown in (F), the dynamic thickness change is completed when the joint W reaches the second frame 2B.

[0076] Furthermore, as described above, dynamic thickness change is also performed on the third to fifth stands 2C to 2E, similarly to the second stand 2B. In this case, by using the results of measuring the strip speed between the target stands starting from the first stand 2A, the strip thickness change position S can be tracked within the production line of the tandem mill 2.

[0077] Furthermore, in the second embodiment, the rolled material 6 is a metal plate, preferably a steel plate, particularly a high-deformation-resistant steel plate. Examples of such high-deformation-resistant steel plates include electromagnetic materials and high-strength materials. Such high-deformation-resistant steel plates experience a significant reduction in thickness during dynamic thickness change, leading to a significant deviation in thickness from the set thickness at the weld front portion of the preceding mill frame, resulting in increased tension fluctuations. Therefore, by applying the dynamic thickness change method of the second embodiment, failures such as breakage can be prevented, enabling stable manufacturing.

[0078] The dynamic plate thickness change method involved in the second embodiment is a dynamic plate thickness change method when continuously rolling the rolled material 6 formed by joining the leading material 61 and the following material 62 as metal plates using a tandem rolling mill 2. The plate speed of the rolled material is continuously measured between the target stands, and the plate thickness change position S near the joint W is tracked. When the plate thickness change position reaches the target stand, the roller gap of the target stand is changed.

[0079] According to this method, as in the first embodiment, there is no need to set an intermediate plate thickness, thus reducing the plate thickness deviation length. In addition, according to the dynamic plate thickness change method of the second embodiment, the plate thickness change point in the preceding stand is used as the plate thickness change point in the succeeding stand to change the roll gap, thereby suppressing tension fluctuations regardless of the raw material and specifications of the rolled material 6.

[0080] In addition, the dynamic plate thickness changing method according to the second embodiment calculates the length L of the tapered plate thickness portion after rolling in the preceding stand using the plate speed measured between the target stands. N-1 , by using the length L of the tapered plate thicknessN-1 Calculate the change rate R of the depressed position by dividing it by the change amount of the depressed position in the target rack. N , with the calculated change rate R N Change the roller gap of the target stand.

[0081] Here, in Figure 9 The figure shows the change in tension between the first and second stands 2A and 2B when the dynamic thickness change is terminated in the middle of the tapered thickness portion in the second stand 2B, i.e., when the dynamic thickness change is terminated earlier than in the second embodiment. If the dynamic thickness change is terminated too early, Figure 9 As shown near the timing of (f), the change of the roll gap ends in the middle of the tapered plate thickness portion, so there is a case where the tension becomes too large during the subsequent rolling of the tapered plate thickness portion. However, according to the dynamic plate thickness change method involved in the second embodiment, the starting point of the tapered plate thickness portion ( Figure 7 Thickness change position S) and end point ( Figure 7 The timing of the joint W) passing through the target stand is used as the start and end timing of the change in the roll gap. Thus, according to the dynamic plate thickness change method involved in the second embodiment, it is possible to suppress excessive tension.

[0082] Furthermore, the plate thickness in the first embodiment and the plate speed in the second embodiment are collectively referred to as operating data. Specifically, the dynamic plate thickness change method of the present invention detects or tracks the plate thickness change position S based on the operating data of the rolled material 6 measured between the target stands, thereby dynamically changing the plate thickness when the plate thickness change position S reaches the target stand.

[0083] Modifications

[0084] The present invention has been described above with reference to specific embodiments, but it is not intended that these descriptions limit the invention. By referring to the description of the present invention, the disclosed embodiments and other embodiments of the present invention including various modifications will be clear to those skilled in the art. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments that include these modifications described in this specification, either individually or in combination.

[0085] For example, in the first and second embodiments, Figure 1 The tandem rolling mill 2 shown has five stands, but the present invention is not limited to this example. The number of stands in the tandem rolling mill 2 can be two or more, and may be six or more. In a typical tandem rolling mill 2, the upper limit of the number of stands is six.

[0086] In the first and second embodiments, the case where the thickness of the following material 62 of the rolled material 6 is thinner than the thickness of the preceding material 61 is described. However, the present invention is not limited to this example. The thickness of the following material 62 of the rolled material 6 may also be thicker than the thickness of the preceding material 61. In this case, the tension between the stands fluctuates to increase.

[0087] Furthermore, in the first and second embodiments, four plate thickness measuring devices 3 or plate speed meters 7 are provided, and the roll gap setting values in the second to fifth stands 2B to 2E are changed based on the measurement results of the four plate thickness measuring devices 3 or plate speed meters 7, but the present invention is not limited to this example. For example, the roll gap setting value may be changed in the same manner as in the above-mentioned embodiment only for the stands where large tension fluctuations become a problem, and the roll gap setting value may be changed in the other stands using the same control method as in the past. In addition, in this case, the plate thickness measuring device 3 or plate speed meter 7 may be provided only for the required stands. Furthermore, the plate thickness measuring device 3 and plate speed meter 7 may be provided separately between different stands, and dynamic plate thickness changes corresponding to the first or second embodiment may be performed for each target stand based on the plate thickness measuring device 3 or plate speed meter 7 provided between the stands.

[0088] While the second embodiment uses the plate speed meter 7 as a method for measuring the plate speed, the present invention is not limited to this example. For example, the plate speed can also be calculated by calculating the motor rotational speed of each rolling stand measured by a PLG or absolute encoder and the forward slip ratio calculated from operating data. Furthermore, considering measurement accuracy, measurement using the plate speed meter 7 is preferred.

[0089] Description of Reference Numerals

[0090] 1…cold rolling mill equipment; 2…tandem rolling mill; 2A–2E…first to fifth stands; 21…working rolls; 22…roll speed control device; 23…pressdown control device; 3…plate thickness measuring device; 4…rolling control controller; 5…control computer; 6…rolled material; 61…preceding material; 62…following material; 7…plate speed meter.

Claims

1. A method for dynamically changing the plate thickness when continuously rolling a rolled material formed by joining a preceding material and a succeeding material as metal plates using a tandem rolling mill, characterized in that: The thickness or speed of the rolled material is continuously measured between the target stand, which is a rolling stand where the thickness change is performed, and the target stand, which is a rolling stand preceding the target stand. Detecting the thickness change position near the junction of the preceding material and the succeeding material based on the plate thickness measurement result, or tracking the thickness change position near the junction of the preceding material and the succeeding material based on the plate speed measurement result, The roll gap of the target stand is changed at a timing when the plate thickness change position reaches the target stand.

2. The dynamic plate thickness changing method according to claim 1, characterized in that: The length of the tapered plate thickness portion after rolling in the preceding stand is calculated using the plate speed measured between the target stands. The change speed of the depression position is calculated by dividing the length of the tapered plate thickness portion by the change amount of the depression position in the target frame. The roller gap of the target stand is changed at the calculated change speed.

3. The dynamic plate thickness changing method according to claim 1 or 2, characterized in that: The rolled material is a high deformation resistance steel plate.

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