Serpentine control device for continuous rolling mill

Abstract

The present invention provides a meandering control device for a continuous rolling mill, which can maintain the center line of a material to be rolled on the center line of the continuous rolling mill without deteriorating the shape and flatness of the material to be rolled in a stable rolling state. A common meandering information estimation section estimates a common meandering information indicating the meandering tendency of the entire material to be rolled in the continuous rolling mill based on a meandering amount. A reduction level correction amount calculation section calculates a reduction level correction amount for all rolling stands based on the common meandering information. A reduction level control section applies an i-th reduction level correction amount to an i-th rolling stand when a rolling position on the material to be rolled rolled by a first rolling stand to which a first reduction level correction amount is applied reaches the i-th rolling stand (2 ≤ i ≤ N) in the stable rolling state.

Description

TECHNICAL FIELD

[0001] The present application relates to a snake control device for a continuous rolling mill. BACKGROUND

[0002] A continuous rolling mill composed of a plurality of rolling stands such as a hot finishing mill is known. In the case where a material to be rolled is rolled by the continuous rolling mill, a phenomenon in which a center position in a width direction of the material to be rolled is deviated from a center position in the width direction of a roll and moved to one of a work side and a drive side is called "snake". In the following description, in most cases, the work side (WS) and the drive side (DS) are simply expressed as "left and right". Further, in the present specification, a line connecting center points in a length direction of the material to be rolled is called "a center line of the material to be rolled". A line connecting center points in the width direction of the rolls of the respective rolling stands of the continuous rolling mill is called "a center line of the continuous rolling mill".

[0003] The snake can occur in a tail end portion of the material to be rolled as well as in a stable portion.

[0004] Regarding the snake occurring in the tail end portion of the material to be rolled, when the tail end of the material to be rolled is separated from the rolling stand on the upstream side and the constraint based on the rear tension disappears, a difference in the left and right stretches due to the rolling appears as a bend of the material to be rolled into the rolling stand on the downstream side. When the bent material to be rolled enters the rolling stand on the downstream side, a position of the material to be rolled directly below the roll is moved toward the roll end portion. The load on the side where the material to be rolled is moved increases due to this movement, and thus a difference in the rolling stretches on the left and right of the rolling mill becomes large. As a result, the difference in the left and right stretches of the material to be rolled further expands. It is known that in the tail end portion of the material to be rolled, this phenomenon repeatedly occurs in a short time, and thus the snake rapidly develops.

[0005] Sometimes the tail end portion in which the snake has thus developed collides with a side guide provided on the rolling stand entry side, and the material to be rolled in a state of being partially bent enters the rolling stand. This case is called "pull-in". When the pull-in occurs, the roll is damaged, and the productivity decreases due to the replacement work of the roll and the like.

[0006] During the rolling of the stable portion of the material to be rolled, the material to be rolled is constrained by the rolling stands on the front and rear sides, and thus the material to be rolled does not rapidly snake. However, in the case where a thickness wedge, a difference in the left and right temperatures, or the like exists in the material to be rolled on the rolling entry side, or in the case where the entire material to be rolled becomes a shape curved in the width direction (hereinafter, referred to as an arc shape), the center line of the material to be rolled in the rolling mill sometimes gradually deviates from the center line of the continuous rolling mill.

[0007] In order to suppress the snake in the rolling mill, it is common to adjust the opening between the upper and lower rolls by the screwdown leveling device. When the center position of the material to be rolled deviates from the center position of the width of the rolls and moves toward the end of the rolls, the load applied to the end of the roll in the direction in which the material to be rolled moves becomes large. This case is detected as the difference in the rolling load (the difference between the rolling load on the working side and the driving side).

[0008] The difference in the rolling load varies in accordance with the change in the position of the material to be rolled in the rolling mill, and therefore, in particular in a continuous rolling mill, a snake control method based on the difference in the rolling load to adjust the screwdown leveling has been proposed. However, the detected value of the difference in the rolling load also includes the difference in the deformation resistance due to the temperature difference between the left and right of the material to be rolled and the amount of change in the rolling load due to the difference in the screwdown amount between the left and right, and therefore, in the case where these influences are large, in the snake control method based on the above-described difference in the rolling load, the snake suppressing ability cannot be sufficiently exerted.

[0009] In recent years, in a continuous rolling mill, in order to directly measure the position of the material to be rolled, a snake detection camera is provided between the stands of the rolling mill, and the screwdown leveling is automatically adjusted based on the detected amount of snake, and thereby a control technique for preventing the snake has been put into practical use.

[0010] Patent Document 1 discloses a method of inferring the amount of snake at a prescribed position on the downstream side from the amount of snake detected by one snake amount detection device provided between the stands of the rolling mill, and operating the screwdown leveling of the most upstream stand among the stands of the rolling mill on the downstream side from the snake amount detection device based on the inferred amount of snake. Further, Patent Document 1 proposes a method of operating the screwdown leveling of the stands on the downstream side from the stand in which the screwdown leveling is operated in such a manner that the wedge rates on the entry side and the exit side of the stands do not change.

[0011] Patent Document 2 discloses a method of simultaneously using the amount of snake detected between the stands, the difference in the rolling load, and the load distribution acting on the loop, inferring the angle of the steel sheet toward the entry side of the rolls, and operating the screwdown leveling amount of each stand.

[0012] Patent Document 3 discloses a method of providing a snake amount detection device between the entry side of the most upstream stand and the intermediate stands and between the exit side of the most downstream stand, determining the range in which the snake is generated from the amount of deviation of the snake between the adjacent snake amount detection devices, and sequentially operating the screwdown leveling from the stand on the upstream side of the determined range.

[0013] Prior Art Documents

[0014] Patent Documents

[0015] Patent Document 1: Japanese Patent No. 4016761

[0016] Patent Document 2: Japanese Patent No. 6323384

[0017] Patent Document 3: Japanese Patent Application Publication No. 8-318304 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] Reference Figure 10 Explanation of the relationship between the tail end and the stabilizing part of the rolled material 2 and the i-th mill stand F i The different actions taken when adjusting the pressure level. Figure 10 (A) indicates that the tail end of the rolled material 2 is produced by the i-th mill stand F. i A diagram showing the rolling process. The material being rolled, 2, was not processed by the (i-1)th mill stand F. i-1 constraint. Figure 10 (B) indicates that the stable part of the rolled material 2 is formed by the i-th mill stand F. i A diagram showing the rolling process. The material being rolled is processed by the (i-1)th mill stand F. i-1 constraint.

[0020] like Figure 10 As shown in (A), in the case of serpentine control with the tail end of the rolled material 2 as the object, when the rolled material 2 leaves the (i-1)th mill stand F i-1 Subsequently, the i-th mill stand F was appropriately modified. i When the leveling device is applied, the rolled material 2 on the unconstrained inlet side rotates, which can suppress the rotation of the material through the i-th mill stand F. i The serpentine movement of the rolled material 2 at that time.

[0021] On the other hand, such as Figure 10 As shown in (B), during the rolling of the stable portion of the rolled material 2 (during stable rolling), even if the i-th mill stand F is changed... i The pressure reduction and leveling, due to the i-th mill stand F i The rolled material 2 on both the inlet and outlet sides is constrained by two adjacent mill stands, so the rolled material 2 does not rotate and its position in the width direction does not change.

[0022] like Figure 10 As shown in (B), the rolled material 2 is rolled by the (i-1)th mill stand F i-1 Under constrained conditions, in order to change the position of the rolled material 2 in the width direction, a large reduction leveling correction is required, such that a force in the width direction above the frictional force between the rolled material 2 and the roll acts on the left and right tension difference of the rolled material 2.

[0023] However, in the state where the rolled material is restrained by a plurality of rolling stands as in the stable rolling, when the roll gap adjustment of a specific rolling stand is operated largely, the shape and flatness of the rolled material between the rolling stands can deteriorate.

[0024] In the method described in Patent Document 1, the roll gap adjustment is operated only in the rolling stand on the downstream side of the snake amount detection device provided between the rolling stands, and therefore it is difficult to suppress the snake in the stable rolling for the above reason.

[0025] In Patent Document 2, a method of operating the roll gap adjustment of all the rolling stands is proposed, but the entry angle of the rolled material and the roll gap adjustment correction amount are calculated separately for each rolling stand. Therefore, the direction and size of the operation of the roll gap adjustment are different for each rolling stand, and the operation becomes non-uniform between the rolling stands. As a result, the suppression effect of the snake in the stable rolling is small, and in addition, the shape and flatness of the rolled material between the rolling stands can deteriorate.

[0026] In the method described in Patent Document 3, since the roll gap adjustment is corrected sequentially from the upstream side rolling stand, the snake amount of the rolled material can be changed even in the stable rolling. However, in the case where the snake is performed with the same degree of eccentricity from the upstream side rolling stand to the downstream side, the snake amount deviation becomes zero, and the roll gap adjustment is not corrected and the snake cannot be suppressed.

[0027] The present application is made to solve the above problem, and aims to provide a snake control device for a continuous rolling mill, which does not promote the deterioration of the shape and flatness of the rolled material and can maintain the center line of the rolled material on the center line of the continuous rolling mill in the stable rolling state of the continuous rolling mill for the rolled material.

[0028] Means for solving the problem

[0029] To achieve the above object, the snake control device for a continuous rolling mill of the present application is constituted as follows.

[0030] The continuous rolling mill has N rolling stands (N≥2) from the 1st rolling stand to the Nth rolling stand.

[0031] The snake control device has a snake amount detection device, a common snake information estimation section, a roll gap adjustment correction amount operation section, and a roll gap adjustment control section.

[0032] The snake amount detection device is provided on the exit side of at least one of the N rolling stands, and detects the snake amount of the rolled material in the stable rolling state in which all the N rolling stands are rolling the rolled material.

[0033] A common snake information estimation unit estimates a common snake information indicating a snake tendency of the entire rolled material in the continuous rolling mill, based on the snake amount.

[0034] A reduction level correction amount operation unit calculates each of the reduction level correction amounts from the first reduction level correction amount of the first rolling stand to the Nth reduction level correction amount of the Nth rolling stand, based on the common snake information, so as to make the snake amount small.

[0035] A reduction level control unit applies the i-th reduction level correction amount to the i-th rolling stand when the rolled part of the rolled material rolled by the first rolling stand to which the first reduction level correction amount is applied reaches the i-th rolling stand (2≤i≤N) in the stable rolling state.

[0036] Preferably, the common snake information is not recalculated until the rolling control in which the Nth reduction level correction amount is applied to the Nth rolling stand is completed, and is recalculated after the rolling control is completed.

[0037] Effects of the Invention

[0038] The snake control device of the continuous rolling mill according to the present application can determine the reduction level correction amounts of all the rolling stands based on a common snake information common to all the rolling stands, and reflect the reduction level correction amounts to all the rolling stands at appropriate timings. Therefore, the snake control device does not exacerbate the shape and flatness of the rolled material in the stable rolling state of the continuous rolling mill, and can maintain the center line of the rolled material to the center line of the continuous rolling mill. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a diagram showing a configuration example of a continuous rolling mill to which the snake control device of the present application is applied.

[0040] Figure 2 is a block diagram showing a configuration of the snake control device of Embodiment 1 of the present application.

[0041] Figure 3 is a diagram for explaining the snake estimation unit of Embodiment 1 of the present application.

[0042] Figure 4 is a diagram for explaining the effects of the snake control device of Embodiment 1 of the present application.

[0043] Figure 5 is a block diagram showing a configuration of the snake control device of Embodiment 2 of the present application.

[0044] Figure 6 is a diagram for explaining the snake estimation unit of Embodiment 2 of the present application.

[0045] Figure 7 This is a diagram illustrating the effect of the snake control device according to Embodiment 2 of the present invention.

[0046] Figure 8 This is a block diagram illustrating the configuration of the snake control device according to Embodiment 3 of the present invention.

[0047] Figure 9 This is a conceptual diagram illustrating an example of the hardware configuration of the processing circuitry in a snake control device.

[0048] Figure 10 This is a diagram used to illustrate the rotation of the rolled material on the inlet side during the correction of the rolling pressure. Detailed Implementation

[0049] Hereinafter, embodiments of the serpentine control device for a continuous rolling mill according to the present invention will be described in detail with reference to the accompanying drawings and numerical formulas. Furthermore, common elements are labeled with the same symbols in the various figures, and repeated descriptions are omitted.

[0050] Implementation method 1.

[0051] 1. Continuous rolling mill

[0052] Figure 1 This is a diagram illustrating an example configuration of a continuous rolling mill to which the serpentine control device of the present invention is applied. The continuous rolling mill 1 includes first rolling mill stands F1 to Nth rolling mill stands F1 arranged in close proximity. N There are N rolling mill stands (N is a natural number greater than 2). A continuous rolling mill 1 is a tandem mill that continuously rolls one piece of workpiece 2. The workpiece 2 starts from... Figure 1 The plates are conveyed from left to right in continuous rolling mill 1 and rolled to the specified thickness. Each mill stand F... i (1≤i≤N) It ​​has two working rollers and two support rollers, and the gap between the upper and lower working rollers can be adjusted by various pressing devices set on the working side and the driving side of the support rollers.

[0053] Each pressure leveling device V i (1≤i≤N) The parallelism of the working side and drive side of the upper and lower work rollers is adjusted by the pressing device, thereby changing the difference in the roller gap between the working side and drive side. Additionally, the pressing leveling device V... i The zero reference is the position where the load detected by the load sensors on the working side and the driving side is approximately equal when the upper and lower working rollers are in contact and the pressing devices on the working side and the driving side are tightened by a certain amount.

[0054] Each snake movement detection device D i (1≤i≤N) in the i-th mill stand F idownstream side exit distance L DI The amount of meandering is detected by the meandering amount detection device D i The meandering amount detection device D i The meandering amount detection device D i The meandering amount detection device D i detects the left and right end positions of the rolled material, and outputs the deviation of the center position of the rolled material 2 from the center position of the continuous rolling mill 1, which is determined based on the left and right end positions of the rolled material 2, as the amount of meandering.

[0055] The adjustment device 10 calculates various adjustment values required by the meandering control device 20, specifically, the plate thickness of the rolled material 2 in each rolling stand, the influence coefficient, the reference roll gap adjustment amount, and the like, and outputs them to the meandering control device 20 before the rolling of the rolled material 2 is started.

[0056] The meandering control device 20 calculates the roll gap adjustment correction amount of each rolling stand based on the adjustment values obtained from the adjustment device 10 and the amount of meandering obtained from the meandering amount detection device D i The meandering control device 20 uses the final roll gap adjustment amount obtained by correcting the reference roll gap adjustment amount with the roll gap adjustment correction amount, and operates the roll gap adjustment device V i .

[0057] 2. Causes of meandering

[0058] Next, two causes of meandering of the rolled material 2 in a stable rolling state in which all of the N rolling stands are rolling the rolled material 2 will be described.

[0059] The first cause of meandering of the rolled material 2 in the stable rolling state is that the plate thickness wedge ratio of the entry side and the exit side of the rolling stand changes due to a poor setting of the roll gap adjustment device when the leading end of the rolled material 2 passes through each rolling stand. The plate thickness wedge ratio is a value obtained by dividing the plate thickness difference (plate thickness wedge) of both ends in the width direction of the rolled material 2 by the plate thickness at the center in the width direction. When the plate thickness wedge ratio of the entry side and the exit side of the i-th rolling stand F i differs, the amount of stretching of the left and right of the rolled material 2 at the exit side of the i-th rolling stand F i differs. As a result, the rolled material 2 at the exit side of the i-th rolling stand F i enters the (i+1)-th rolling stand F i+1 bent toward the side with less stretching. Then, the rolled material 2 is rolled at a position deviated from the center position in the width direction just below the roll of the (i+1)-th rolling stand F i+1 . As long as the roll gap adjustment amount of the i-th rolling stand F i , the (i-1)-th rolling stand F i-1The snake state is maintained if the width direction position of the rolled material 2 in the above condition does not change in the following rolling.

[0060] A second reason for the snake of the rolled material 2 in the stable rolling state is that the rolling stock has a left-right temperature difference, a plate thickness wedge, or a curved shape in the width direction (hereinafter, referred to as an arc shape) that varies in the length direction. When the left-right temperature difference or the plate thickness wedge of the rolled material 2 entering the first rolling stand Fl changes, a rotation of the rolled material 2 with the width direction center point of the rolled material 2 directly below the roll as a reference point is generated in the rolled material 2 on the entry side of the first rolling stand Fl, and the position of the rolled material 2 passing through each rolling stand gradually moves toward the roll end portion. In addition, when the rolling stock has an arc shape, the position of the rolled material 2 passing through each rolling stand also gradually snakes in the direction in which the rolling stock is curved.

[0061] As described above, the rolled material 2 snakes in the stable rolling state due to two reasons.

[0062] 3. Method of snake control

[0063] Figure 2 is a block diagram showing the configuration of the snake control device 20 of Embodiment 1. The control period of the snake control device 20 is from when the leading end of the rolled material 2 passes through the Nth rolling stand F N or the Nth rolling stand F N The snake amount detection device D N functions until the trailing end of the rolled material 2 passes through the first rolling stand Fl.

[0064] The snake control device 20 of Embodiment 1 includes a common snake information estimation section 30a, a reduction level correction amount calculation section 40a, and a reduction level control section 50.

[0065] As shown in Figure 3 , the common snake information estimation section 30a acquires the snake amounts of the rolled material 2 detected at the same time by at least one snake amount detection device D i . The common snake information estimation section 30a estimates one common snake information indicating the snake tendency of the entire rolled material 2 in the continuous rolling mill 1 from the detected snake amounts. In Embodiment 1, the common snake information is the average snake amount of the rolled material 2 in the continuous rolling mill 1.

[0066] The reduction level correction amount calculation section 40a calculates the first reduction level correction amount of the first rolling stand Fl to the Nth reduction level correction amount of the Nth rolling stand F Nthe i-th rolling mill stand based on the i-1-th screw-down level correction amount of the i-1-th rolling mill stand, so that the snake amount becomes small.

[0067] The screw-down level correction amount operation section 40a calculates the first screw-down level correction amount of the first rolling mill stand F1 at the most upstream so that the average snake amount becomes small. The screw-down level correction amount of the first rolling mill stand F1 can be calculated, for example, by a PID controller shown in Expression (1) or the like.

[0068] [Expression 1]

[0069]

[0070] ΔS LV,F1 : Screw-down level correction amount

[0071] ΔY OC : Snake amount

[0072] K p ,K D ,K I : Control gain

[0073] s: Laplace operator

[0074] Next, the screw-down level correction amount operation section 40a calculates each of the screw-down level correction amounts from the second screw-down level correction amount to the N-th screw-down level correction amount so that the thickness wedge rate change amounts at the exit side of the first rolling mill stand Fl and the exit side of the i-th rolling mill stand Fi i (2≤i≤N) become the same. In addition, the thickness wedge rate change amount is the difference between the exit side thickness wedge rate in the case where the j-th rolling mill stand Fj j (1≤j≤N) has rolled the rolled material 2 without using the j-th screw-down level correction amount and the exit side thickness wedge rate in the case where the j-th rolling mill stand Fj j has rolled the rolled material 2 using the j-th screw-down level correction amount. The exit side thickness wedge rate is a value obtained by dividing the thickness difference (thickness wedge) at both ends in the width direction of the rolled material 2 by the thickness at the center in the width direction.

[0075] Here, the relationship between the screw-down level correction amount and the change amount of the thickness wedge can be expressed as shown in Expression (2).

[0076] [Expression 2]

[0077]

[0078] Δh DF,i : Change amount of exit side thickness wedge

[0079] ΔH DF,i : Change amount of entry side thickness wedge

[0080] ΔS LV,i : correction amount of the roll gap adjustment

[0081] influence coefficient

[0082] genetic coefficient

[0083] in order to make the plate thickness wedge rate of the entry side and the exit side of the i-th roll stand F i not change, it is only necessary to determine the correction amount of the roll gap adjustment of the roll stand in a manner satisfying equation (3). Here, the entry side of the i-th roll stand F i is the exit side of the (i-1)-th roll stand.

[0084] [Equation 3]

[0085]

[0086] Thus, as shown in equation (4), the correction amount of the roll gap adjustment of each roll stand after the 2nd roll stand F2 can be calculated using the correction amount of the roll gap adjustment of the roll stand immediately upstream.

[0087] [Equation 4]

[0088]

[0089] The influence coefficient and the plate thickness used in equation (4) are provided by the adjustment device 10.

[0090] The roll gap adjustment control section 50 is such that, in a stable rolling state, when the rolling position on the rolled material rolled by the 1st roll stand Fl to which the 1st correction amount of the roll gap adjustment has been applied reaches the i-th roll stand F i (2≤i≤N), the i-th roll stand F i is applied with the above-mentioned i-th correction amount of the roll gap adjustment. The i-th roll stand F i is controlled with a roll gap adjustment amount obtained by adding the i-th correction amount of the roll gap adjustment to the i-th reference roll gap adjustment amount. When the operation of the correction amount of the roll gap adjustment operation section 40a ends, first, the 1st roll gap adjustment device Vl of the 1st roll stand Fl is immediately operated. Each roll gap adjustment device from the 1st roll gap adjustment device Vl of the most upstream to the Nth roll gap adjustment device V N of the most downstream is operated in order.

[0091] The press-down level control section 50 has a tracking unit that calculates the conveyance distance of the rolled material 2 on the exit side of each rolling stand using the roll rotational speed of each rolling stand, for each calculation cycle. Based on the conveyance distance of the rolled material 2 calculated by the tracking unit, the second press-down level control device V2 is operated when the position of the rolled material 2 after operation by the first press-down level control device Vl of the first rolling stand Fl reaches the second rolling stand F2. The same applies to the subsequent rolling stands, and when the position of the rolled material 2 after operation by the press-down level control device reaches the next rolling stand, the press-down level control device of the next rolling stand is operated based on the press-down level correction amount.

[0092] In the case where the operation of the Nth press-down level control device V N of the Nth rolling stand F N is completed, the processing of the common snake information estimation section 30a is returned to, and the processing in the next control time is executed. That is, the common snake information is not recalculated until the rolling control of the Nth rolling stand F N to which the Nth rolling control correction amount has been applied is completed, and is recalculated after the rolling control is completed.

[0093] In addition, in the case where the snake amount detection device D N exists on the exit side of the Nth rolling stand F N , the common snake information is recalculated after the position of the rolled material 2 rolled by the Nth rolling stand F N to which the Nth rolling control correction amount has been applied reaches the snake amount detection device D N .

[0094] As described above, the snake control device 20 according to Embodiment 1 is able to control the position of the rolled material 2 so that the average snake amount at the time of stable rolling becomes small, as shown in (A) of FIG. 10. When the center line of the rolled material 2 is shifted in parallel with respect to the center line of the continuous rolling mill 1 (the center line of the rolling line) and snakes before the control is started (A), the press-down level (B) is corrected in a manner that rotates in a direction in which the snake amount of the rolled material 2 toward the entry side of the first rolling stand Fl decreases, and the snake amount is gradually reduced up to the downstream stand (C). Figure 4 Figure 4 Figure 4 Figure 4

[0095] ​​​​According to the snake control device 20 of Embodiment 1, the press-down leveling correction amount of all the rolling stands is determined based on one common snake information common to all the rolling stands, and the press-down leveling correction amount is reflected to all the rolling stands at an appropriate timing. Therefore, the snake control device 20 is capable of maintaining the center line of the material to be rolled 2 at the center line of the continuous rolling mill 1 in a stable rolling state of the continuous rolling mill 1 for the material to be rolled 2. By making the center line of the material to be rolled 2 approach the center line of the continuous rolling mill 1 from the time of stable rolling, even when a sharp snake occurs at the tail end of the material to be rolled 2, it is possible to minimize the possibility of developing into a rolling accident such as a deep draw. Further, the snake control device 20 is capable of determining the press-down leveling correction amount of each rolling stand based on the press-down leveling correction amount of the upstream rolling stand, so that each press-down leveling correction amount does not change extremely, and since each press-down leveling correction amount is applied to the same position on the material to be rolled 2, it is possible to avoid deterioration of the shape and flatness of the material to be rolled 2.

[0096] Embodiment 2.

[0097] Next, the snake control device 20 of Embodiment 2 will be described with reference to Figures 5-7 The snake control device 20 of Embodiment 2 will be described. Figure 5 is a block diagram showing the configuration of the snake control device 20 of Embodiment 2. The snake control device 20 of Embodiment 2 is the same as Embodiment 1 except that the common snake information estimation section 30a of Embodiment 1 is replaced by a common snake information estimation section 30b, and the press-down leveling correction amount calculation section 40a is replaced by a press-down leveling correction amount calculation section 40b. Hereinafter, the description of the processing contents common to Embodiment 1 will be omitted or simplified. Figure 2

[0098] According to the snake control device 20 of Embodiment 1 described above, in the case where the center line of the material to be rolled 2 snakes in parallel with respect to the center line of the continuous rolling mill 1, the average snake amount can be used as the common snake information, and the center line of the material to be rolled 2 is made to coincide with the center line of the continuous rolling mill 1. However, there are also cases where the center line of the material to be rolled 2 snakes obliquely with respect to the center line of the continuous rolling mill 1. In the snake control device 20 of Embodiment 2, in this case, the snake angle is used as the common snake information, and the center line of the material to be rolled 2 is made to coincide with the center line of the continuous rolling mill 1.

[0099] As shown in Figure 6 , the common snake information estimation section 30b acquires the snake amounts of the material to be rolled 2 detected by at least two snake amount detection devices D i at the same timing in a stable rolling state. The common snake information estimation section 30b estimates the obliquity of the center line of the material to be rolled 2 with respect to the center line of the continuous rolling mill 1, that is, the snake angle, as the common snake information, based on the detected snake amounts. ​

[0100] Specifically, the common snake information estimation section 30b obtains a linear approximation formula (y = a - x + b) that sets the position of each snake amount detection device as the X axis and sets the detected snake amount as the Y axis. Here, the position of the first roll stand F is defined as the origin of the X axis, and the advancing direction of the rolled material 2 is defined as the positive direction of the X axis coordinate. Each coefficient of the linear approximation formula of the snake amount is expressed by the least square method as the following formula. i

[0101] [Formula 5]

[0102]

[0103]

[0104] y D,i : detected snake amount

[0105] x D,i : position of snake amount detection device

[0106] average value of detected snake amount

[0107] average value of position of snake amount detection device

[0108] According to the coefficient a of the above linear approximation formula, the inclination θ (snake angle) of the rolled material 2 with respect to the center line of the continuous mill 1 can be estimated by Formula (6).

[0109] [Formula 6]

[0110] θ OC = tan (a) (6)

[0111] The press-down leveling correction amount operation section 40b calculates each press-down leveling correction amount from the first press-down leveling correction amount to the Nth press-down leveling correction amount based on the snake angle so that the center line of the rolled material 2 approaches parallel to the center line of the continuous mill 1 (the snake angle becomes smaller).

[0112] It is generally known that the angular velocity of the rolled material 2 on the entry side or the exit side of the roll stand is proportional to the press-down leveling. The influence coefficient of the press-down leveling correction amount on the angular velocity of the rolled material 2 is calculated by the adjustment device 10. Thus, the press-down leveling correction amount operation section 40b calculates the press-down leveling correction amount of each roll stand based on the snake angle estimated by the common snake information estimation section 30b by Formula (7). For example, the inter-roll stand conveying speed is faster in the roll stand on the more downstream side, and thus each press-down leveling correction amount is set to a smaller value in the roll stand on the more downstream side.

[0113] [Formula 7]​

[0114]

[0115] Δt T,i : rolling mill interstand delivery speed

[0116] influence coefficient

[0117] The screwdown level control section 50 operates the screwdown level devices V of each rolling mill stand in accordance with the screwdown level correction amount, as in Embodiment 1 i .

[0118] As explained above, the snake control device 20 according to Embodiment 2, as shown in Figure 7 , is able to control the position of the material to be rolled 2 so as to make the snake angle at the time of stable rolling smaller. When the center line of the material to be rolled 2 before the start of control is inclinedly snaking with respect to the center line of the continuous rolling mill 1 (center line of the rolling line) (A of Figure 7 , the screwdown level is corrected so as to make the center line of the material to be rolled 2 on the entry side of the 1st rolling mill stand close to parallel to the center line of the continuous rolling mill 1, and the amount of snake is gradually reduced up to the downstream stand.

[0119] Embodiment 3.

[0120] Next, Embodiment 3 of the present application will be explained with reference to Figure 8 . Figure 8 is a block diagram showing the configuration of the snake control device 20 of Embodiment 3. The snake control device 20 of Embodiment 3 is the same as Embodiments 1 and 2 except that the common snake information estimation section 30a of the above-mentioned Figure 2 and the common snake information estimation section 30b of the above-mentioned Figure 5 are replaced by the common snake information estimation section 30c, and the screwdown level correction amount operation section 40a and the screwdown level correction amount operation section 40b are replaced by the screwdown level correction amount operation section 40c. Hereinafter, the explanation of the processing contents which are the same as Embodiments 1 and 2 will be omitted or simplified.

[0121] In the above-mentioned Embodiment 1, the snake control in the case where the center line of the material to be rolled 2 is snaking in parallel with respect to the center line of the continuous rolling mill 1 was explained. In Embodiment 2, the snake control in the case where the center line of the material to be rolled 2 is snaking in inclined with respect to the center line of the continuous rolling mill 1 was explained. In Embodiment 3, the snake control which combines them is explained.

[0122] The common snake information estimation section 30c acquires the at least two snake amount detection devices D iThe amount of meandering of the rolled material 2 detected at the same time. The common meandering information estimation section 30c estimates the average meandering amount and the inclination of the center line of the rolled material 2 with respect to the center line of the continuous rolling mill 1, i.e., the meandering angle, as the common meandering information, based on the detected amount of meandering.

[0123] The press-down level correction amount calculation section 40c calculates the first press-down level correction amount of the first rolling stand Fl at the most upstream side so as to make the average meandering amount smaller, like the press-down level correction amount calculation section 40a. Further, the press-down level correction amount calculation section 40c calculates each of the second to Nth press-down level correction amounts so as to make the thickness wedge rate change amount at the exit side of the first rolling stand Fl and the exit side of the i-th rolling stand Fi (2≤i≤N) the same (Equation (4)). i

[0124] Next, the press-down level correction amount calculation section 40c calculates the press-down level correction amount of the j-th rolling stand (1≤j≤N) having the relevant j-th meandering angle correction amount so as to make the center line of the rolled material 2 and the center line of the continuous rolling mill 1 nearly parallel, based on the meandering angle for all of the N rolling stands (Equation (7)), like the press-down level correction amount calculation section 40b.

[0125] Next, the press-down level correction amount calculation section 40c calculates a new j-th press-down level correction amount obtained by adding the j-th press-down level correction amount to the j-th meandering angle correction amount.

[0126] The press-down level control section 50 applies the new first press-down level correction amount to the first rolling stand Fl at the most upstream side when the rolling position on the rolled material 2 reaches the first rolling stand Fl at the most upstream side in the stable rolling state. i i The press-down level control section 50 applies the new i-th press-down level correction amount to the i-th rolling stand Fi when the rolling position on the rolled material 2 reaches the i-th rolling stand Fi (2≤i≤N) in the stable rolling state. i The press-down level control section 50 operates the press-down level device of each rolling stand based on the new press-down level correction amount, like the press-down level control section 50 of Embodiment 1.

[0127] As described above, the meandering control device 20 according to Embodiment 2 can obtain the effects of Embodiments 1 and 2. The meandering control is repeatedly performed based on the common meandering information that is repeatedly recalculated, whereby the average meandering amount and the meandering angle gradually decrease.

[0128] (Hardware Configuration Example)

[0129] Figure 9 is a conceptual diagram showing a hardware configuration example of the processing circuit of the above-described meandering control device 20. Figure 2 Figure 5 and Figure 8 ​​​The functions of the respective sections in the snake control device 20 are realized by the processing circuit. As one mode, the processing circuit includes at least one processor 91 and at least one memory 92. As another mode, the processing circuit includes at least one dedicated hardware 93.

[0130] In the case where the processing circuit includes the processor 91 and the memory 92, the functions are realized by software, firmware, or a combination of software and firmware. At least one of the software and the firmware is described as a program. At least one of the software and the firmware is stored in the memory 92. The processor 91 realizes the functions by reading out the program stored in the memory 92 and executing it.

[0131] In the case where the processing circuit includes the dedicated hardware 93, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, or a combination thereof. The functions are realized by the processing circuit.

[0132] The above describes the embodiments of the present application, but the present application is not limited to the above-described embodiments, and can be implemented in various modifications without departing from the spirit of the present application.

[0133] Explanation of Symbols

[0134] 1: continuous rolling mill; 2: material to be rolled; 10: adjusting device; 20: snake control device; 30a, 30b, 30c: common snake information estimation section; 40a, 40b, 40c: reduction level correction amount calculation section; 50: reduction level control section; 91: processor; 92: memory; 93: hardware; D i : i-th snake amount detection device; F i : i-th rolling stand; V i : i-th reduction level device.

Claims

1. A snake control device of a continuous rolling mill, provided with N rolling stands from a first rolling stand to an Nth rolling stand, where N≥2, characterized in that, Possessing: a snake amount detecting device, provided at the exit side of at least one of the N rolling stands, detecting a snake amount of the rolled material in a stable rolling state in which all of the N rolling stands are rolling the rolled material; a common snake information estimating section, estimating one common snake information indicating a snake tendency of the rolled material as a whole in the continuous rolling mill, based on the snake amount; a reduction level correction amount calculating section, calculating each of the reduction level correction amounts from the first reduction level correction amount of the first rolling stand to the Nth reduction level correction amount of the Nth rolling stand based on the common snake information, so as to make the snake amount smaller; and a reduction level control section, applying the i-th reduction level correction amount calculated by the reduction level correction amount calculating section to the i-th rolling stand when the rolled material rolled by the i-1th rolling stand to which the i-1th reduction level correction amount calculated by the reduction level correction amount calculating section is applied reaches the i-th rolling stand, in the stable rolling state, wherein 2 ≤ i ≤ N.

2. The snake control device for a continuous rolling mill according to claim 1, wherein the common snake information is not recalculated until the rolling control applying the Nth reduction level correction amount calculated by the reduction level correction amount calculating section to the Nth rolling stand is completed, and is recalculated after the rolling control is completed.

3. The snake control device for a continuous rolling mill according to claim 1 or 2, wherein the common snake information is an average snake amount of the rolled material in the continuous rolling mill, the reduction level correction amount calculating section is the first reduction level correction amount is calculated so as to make the average snake amount smaller, each of the reduction level correction amounts from the second reduction level correction amount of the second rolling stand to the Nth reduction level correction amount is calculated so as to make the plate thickness wedge rate change amount at the exit side of the first rolling stand and the exit side of the i-th rolling stand the same, the plate thickness wedge rate change amount is a difference between the exit side plate thickness wedge rate when the j-th rolling stand rolls the rolled material without applying the j-th reduction level correction amount calculated by the reduction level correction amount calculating section to the j-th rolling stand and the exit side plate thickness wedge rate when the j-th rolling stand rolls the rolled material applying the j-th reduction level correction amount calculated by the reduction level correction amount calculating section to the j-th rolling stand, wherein 1 ≤ j ≤ N.

4. The snake control device for a continuous rolling mill according to claim 1 or 2, wherein the common snake information is a snake angle which is an inclination of a center line of the rolled material with respect to a center line of the continuous rolling mill, the reduction level correction amount calculating section calculates each of the reduction level correction amounts from the first reduction level correction amount to the Nth reduction level correction amount based on the snake angle, so as to make the center line of the rolled material and the center line of the continuous rolling mill close to parallel.

5. The snake control device for a continuous rolling mill according to claim 3, wherein The common snake information includes the average snake amount and a snake angle that is an inclination of the center line of the rolled material with respect to the center line of the continuous rolling mill, The reduction level correction amount calculation section is configured to calculate a new i-th reduction level correction amount by adding the i-th reduction level correction amount to the i-th snake angle correction amount, Based on the snake angle, the i-th snake angle correction amount is calculated for the j-th rolling stand, where 1≤j≤N, so that the center line of the rolled material and the center line of the continuous rolling mill are close to parallel, A new i-th reduction level correction amount is calculated by adding the i-th reduction level correction amount to the i-th snake angle correction amount, The reduction level control section is configured to apply the new i-th reduction level correction amount calculated by the reduction level correction amount calculation section to the i-th rolling stand when a rolling position of the rolled material rolled by the i-1-th rolling stand to which the new i-1-th reduction level correction amount calculated by the reduction level correction amount calculation section is applied reaches the i-th rolling stand in the stable rolling state, where 2≤i≤N.

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