JP2002137012A - Meandering control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a meandering control method which can effectively suppress meandering of steel strip that takes place at a group of rolling machines composed of a plurality of numbers of stands, by which method leveling correction by feedback according to actual meandering and varying set leveling value according to the camber of rough-rolled material are conducted without having both of these correction means interfere with each other. SOLUTION: The relation between each leveling correction amount necessary for suppressing meandering at each stand of a rolling train and the camber value of a material to be rolled is obtained in advance. Leveling correction amount Ai at each stand from the measured value of camber at the entry side of the mill obtained for a material that passed through the hot-rolling mill just before a concerned material and the leveling correction amount Bi at each stand from measured camber value at the entry side of the mill for the next concerned material to be rolled are figured out from the said relation. Then based on the difference of Ai and Bi, a leveling set value at each stand is modified and hot-rolling of the concerned material is processed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing meandering when hot rolling a metal strip such as a steel strip in a rolling mill train comprising a plurality of stands. More specifically, the present invention relates to a meandering suppressing method capable of eliminating or suppressing meandering of a material to be rolled occurring during rolling.

[0002]

2. Description of the Related Art In the rolling of a metal sheet such as a hot-rolled steel strip, for example, it is necessary to perform rolling so that the center line of the material to be rolled coincides with the center of the pass center, that is, so that no meandering occurs. Important from a point of view.

[0003] At the leading end and the trailing end of the material to be rolled, the meandering tends to be larger than at the intermediate portion, which may hinder the passing of the sheet. In particular, when the meandering becomes large at the rear end, an operation trouble is caused in that the material to be rolled is bent and overlapped at the entry side of the rolling mill and rolled. This is generally called “squeezing”, and since flaws remain on the rolling roll, the quality of the product is impaired. Therefore, when the narrowing-down occurs, the rolling roll needs to be replaced, and the production is interrupted.

Factors that cause meandering include lateral bending (camber) of the material to be rolled, uneven wall thickness (wedge) in the sheet width direction of the material to be rolled, temperature difference in the sheet width direction of the material to be rolled, left and right of the rolling mill row. A setting error of the rolling position (leveling), a difference between left and right of the mill stiffness, a left-right asymmetric shape due to abrasion and thermal expansion of a rolling roll, and the like are considered. These factors influence each other and, in the case of the downstream stand, also affect the rolling history in the upstream stand. However, since these factors are difficult to quantitatively evaluate, there are many unclear parts of the mechanism of the meandering itself.

As a countermeasure against meandering, a method of monitoring the meandering state of the material to be rolled and correcting the leveling of each stand so as to reduce the meandering has been performed. However, for example, if the leveling is corrected so as to eliminate the meandering in the intermediate portion of the material to be rolled, a large meandering is induced in the rear end portion, which may cause a narrowing. Further, it is extremely difficult to observe the meandering state of the leading end and the trailing end and perform instantaneous leveling correction, and no automatic control technology has been established. Therefore, in general, the meandering feedback type inter-material leveling correction operation (hereinafter, referred to as “the meandering feedback-type inter-material leveling operation” in which the leveling of the next material to be rolled is corrected by checking the meandering state of the front end and the rear end of the material to be rolled immediately before. (Referred to as leveling meandering feedback correction).

This work is effective as a countermeasure for meandering when a factor of meandering exists in a rolling mill including a roll. However, the factor exists on the material side, that is, the left-right asymmetry of the material, and the left-right asymmetry is determined for each material. Has no effect if changes.

There are cambers, wedges, temperature differences and the like as left-right asymmetry factors of materials, but only a camber has a practical measuring means. In recent years, a method has been proposed in which a camber of a material to be rolled is measured on the entry side of the rolling mill, and the leveling of the rolling mill is controlled based on the measured camber.

Japanese Unexamined Patent Publication (Kokai) No. 63-80908 discloses a method of combining camber measurement at the upstream rolling mill entry side and meandering measurement at the downstream rolling mill entrance side, and adjusting the leveling based on this to control camber and meandering. Are disclosed.

Further, Japanese Patent No. 2526323 discloses that
Detects the amount of lateral bending (camber) on the entry side of the finishing mill of the hot strip mill, and performs leveling correction of the allowable maximum amount from the upstream stand in order from the upstream stand using the relational expression of the leveling correction amount and the horizontal bending correction amount. Discloses a method of correcting the lateral bending generated in the above by a finish rolling mill.

[0010]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. 63-80908, the meandering generated in the material to be rolled is suppressed to a satisfactory level on both the front end side and the rear end side. Is difficult. In addition, this method requires a meandering detection device between almost all stands,
In addition to an increase in equipment costs, a cooling water spray is usually installed at several locations between the stands of the finishing mill, so that a general optical meander cannot be used.

The method disclosed in Japanese Patent No. 2526323 is a feedforward control in accordance with the camber of the material to be rolled on the rolling mill entry side for the purpose of correcting the camber. However, when the camber control by feedforward and the meandering control by feedback according to the meandering amount on the rolling mill exit side are used together, there is a problem that mutual interference does not result in a sufficient meandering control effect.

An object of the present invention is to make a meandering of a steel strip generated in a rolling mill group composed of a plurality of stands, for example, a finishing rolling mill row of a hot rolling equipment for a steel strip, correspond to an actual meandering amount. An object of the present invention is to provide a meandering suppressing method that can effectively suppress the leveling correction by feedback and the change of the leveling set value according to the camber of the rough rolled material without interference between the two. Also,
An object of the present invention is to present a method of suppressing meandering in hot rolling in a case where the need for suppressing meandering at the rear end is greater than that at the front end, and when it is desired to minimize the leveling setting change.

[0013]

SUMMARY OF THE INVENTION In the present situation where most of the causes of meandering cannot be quantified, meandering control has to be mainly performed by automatic or manual meandering feedback leveling correction.

In order to effectively utilize the camber information of the material to be rolled measured at the entry side of the rolling mill and to perform the meandering control using the camber information, it is necessary to roll the material into one of a plurality of materials to be rolled. It is preferable to compare the camber amounts of the material to be rolled and the material to be rolled immediately before, and change the leveling set value by the difference between the camber amounts.

However, even if the camber amount is the same between the material to be rolled and the material to be rolled immediately before, if the basic rolling conditions such as the size and material of the material to be rolled change, the amount of leveling correction changes. It is important that the setting value is not changed by the difference of the camber amount, but by the difference of the leveling correction amount obtained from the camber amount. Since only the difference between the two states is significant, the leveling correction amount may be obtained by assuming a completely symmetrical state in the rolling mill as the reference state, for example.

FIG. 1 is a plan view schematically showing a planar shape of a material 1 to be rolled to be supplied to a rolling mill. FIG. 1 (a) shows cambers in opposite directions on the leading and trailing ends of the material to be rolled. FIG. 12B shows a case where a camber is generated only on the front end side, and FIG. 8C shows a case where a camber is generated in the same direction on the front end side and the rear end side.

According to the investigation by the present inventors, the planar shape of the material to be rolled is not a shape that can be approximated by an arc over the entire length of the material to be rolled as shown in JP-A-63-80908. As shown in FIGS. 1 (a) and 1 (c), the front and rear ends are bent within a range of 10 to 20 m in length from the respective ends, and the other intermediate portions are substantially straight. There were many. Further, the amount of bending is different between the front end side and the rear end side, and the bending direction is sometimes different.

Therefore, it is necessary to handle the camber separately at the front end and the rear end. Except for the special case of ignoring either one, the leveling set value must be changed twice at the front end and the rear end. It turned out that there was.

Further, as a result of studying how to obtain the leveling correction amount according to the camber amount, the following knowledge was obtained. In other words, the camber on the rear end side can be theoretically completely corrected by offsetting the difference between the left and right lengths of the material to be rolled by the difference in left and right elongation during left and right asymmetric rolling by leveling correction. However, the camber on the tip side is bitten at the position where the tip is shifted to the left or right from the center of the rolling mill, and then the tip side rolled toward the center in the opposite direction to the original camber By the way, camber cannot be completely corrected. Therefore, the concept of the leveling operation for correcting the level and the leveling correction amount differ between the front camber and the rear camber. I knew it needed to be sought.

The present invention has been completed based on the above findings.
The gist is as follows. (1) A rolling mill train composed of a plurality of stands
A meandering suppression method when performing hot rolling on a material to be rolled,
Each stand of the rolling mill row by the camber of the material to be rolled
Of each of the stands required to suppress meandering caused by
Predict the relationship between the leveling correction amount and the camber amount of the material to be rolled.
Rolled hot-rolled immediately before one rolled material
The measured value of the camber amount on the entry side of the rolling mill row of the material
Leveling correction amount (A_i)When,
Camber amount of one rolled material on the entry side of the rolling mill row
Leveling correction amount of each stand for the measured value of
(B _i) Is obtained from the above relationship, and the leveling correction amount is obtained.
(A_i) And (B_i), The level of each stand
Change the set value of the ring and perform hot rolling on one rolled material.
A meandering suppression method characterized by the following.

(2) Rolling composed of a plurality of stands
Meandering suppression method when hot rolling multiple rolled materials in a machine train
The rolling mill train by a camber of a material to be rolled.
Required to suppress meandering that occurs at each stand
Leveling correction amount of each stand and camber amount of rolled material
And hot rolling immediately before one rolled material
On the entry side of the rolling mill row on the rear end side of the material to be rolled
Leveling repair of each stand for camber measurement
Positive quantity a_iAnd the rolling of the front end side and the rear end side of one rolled material
Each of the measured values of the camber amount at the entrance of the aircraft
Leveling correction amount b of each stand_i, C_iAnd the above
From the relationship, the leveling correction amount a _i, B_iDifference
(B_i-A_i) Based on the leveling setting of each stand
Start hot rolling of one rolled material by changing the
Then, the leveling correction amount b_i, C _iDifference (c_i-B
_i), Change the leveling setting of each stand.
Hot rolling is performed on the rear end side of the material to be rolled.
Meaning suppression method to do.

(3) Rolling composed of a plurality of stands
Meandering suppression method when hot rolling multiple rolled materials in a machine train
The rolling mill train by a camber of a material to be rolled.
Required to suppress meandering that occurs at each stand
Leveling correction amount of each stand and camber amount of rolled material
And hot rolling immediately before one rolled material
On the entry side of the rolling mill row on the rear end side of the material to be rolled
Leveling repair of each stand for camber measurement
Positive quantity a_iAnd the rolling of the front end side and the rear end side of one rolled material
Each of the measured values of the camber amount at the entrance of the aircraft
Leveling correction amount b of each stand_i, C_iAnd the above
From the relationship, the leveling correction amount a _i, B_iDifference
(B_i-A_iIf the absolute value of) is smaller than the predetermined value,
Leveling correction amount a_i, C_iDifference (c_i-A_i)
Change the leveling setting of each stand based on
Meandering suppression method characterized by subjecting material to be rolled to hot rolling
Law.

In the above items (1) to (3), the subscript i represents the i-th stand.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the present embodiment,
A rolling mill row having a plurality of stands is a finishing rolling mill row of a hot rolling facility composed of a rough rolling mill row and a finishing rolling mill row, and a rough rolled material in which a material to be rolled is rolled in the rough rolling mill row. Is taken as an example. The subscript i represents the i-th stand.

FIG. 2 is a schematic diagram showing a configuration example of the apparatus according to the present embodiment. Reference numeral 1 denotes a rough rolled material, 2 denotes a camber meter, 3 denotes a leveling amount calculation device, 4 denotes a storage device, 5 denotes a leveling amount setting device, and 6 denotes a finishing mill train.

As shown in FIG. 2, the apparatus according to the present embodiment includes a camber meter 2 provided on the entrance side of the finishing mill train 6.
It includes a leveling amount calculation device 3, a storage device 4, and a leveling amount setting device 5.

The camber meter 2 is a row of rough rolling mills (not shown).
And a function for measuring the camber amounts of the front end side and the rear end side of the rough rolled material 1 coarsely rolled in the above. For example, the camber amount can be obtained by photographing the plane shape of the rough rolled material using a camber meter such as a CCD camera and performing image processing on the photographed plane shape.

In the leveling amount calculation device 3, the relationship between the leveling correction amount and the camber amount necessary to suppress the meandering generated at each stand by the camber is determined for each of the leading and trailing ends and for each rolling condition. Stored as a table or as a mathematical expression.

For example, assuming that the camber amounts of the leading end side and the rear end side on the entry side of the rolling mill row are CH and CT, the leading end side of each stand required to suppress meandering generated at each stand by these cambers. And the leveling correction amounts LH and LT on the rear end side are expressed by the following equations.

LH _i = fH _i (CH) LT _i = fT _i (CT) where the function fH and the function fT are the plate thickness, the plate width, the rolling reduction, the yield stress of the material, the roll diameter and the like in each stand. Although rolling conditions are included as parameters, they are omitted here.

The leveling amount calculation device 3 has a function of calculating the leveling correction amount for each of the measured camber amounts on the front and rear ends of the material to be rolled based on the above relationship between the leveling correction amount and the camber amount. The electric signal of the leveling correction amount is output to the storage device 4. The relationship between the leveling correction amount and the camber amount on the front end side and the rear end side can be obtained in advance by a rolling experiment. The storage device 4 has a function of storing the leveling correction amount output from the leveling amount calculation device 3. .

The leveling amount setting device 5 has a function of changing the leveling setting value of each stand based on the leveling correction amount information output from the storage device 4. That is, the leveling correction amount a _{i at} the rear end of the rough-rolled material that has been rolled immediately before rolling of the one rough rolled material, and the leveling correction amount at the leading end and the rear end of the rough-rolled material, respectively. b _i ,
Based on the information with c _i , the difference (b _i
−a _i ) and a difference (c _i −b _i ) of the leveling correction amount, and further, before starting the rolling of one rough rolled material, the difference (b _i −a _i ) based change the leveling setpoint for each stand, before start rolling the rear end side of the one rough rolled material, a function of changing the leveling setpoint for each stand based on the difference (c _i -b _i). When the difference (b _i -a _i ) is smaller than the predetermined value, the leveling of each stand is performed based on the difference (c _i -a _i ) of the leveling correction amounts a _i and c _i before the start of one rough rolling material. A function to change the set value is provided.

The device according to the present embodiment is configured as described above. Next, a meandering suppressing method by the device according to the present embodiment will be described. Hereinafter, the rough rolled material that is one rolled material is also referred to as a succeeding material, and the rough rolled material that is rolled immediately before the one rolled material is also referred to as a preceding material.

In the meandering suppression method of the present invention, when rolling a plurality of rough rolled materials in the finishing mill train, first, in the rolling of the preceding material, the camber amount (hereinafter, referred to as the camber amount) of the rear end portion of the preceding material by the camber meter 2. The rear end of the preceding material is also measured based on the relationship between the camber amount and the leveling correction amount previously stored in the leveling amount calculation device 3. The leveling correction amount ai with respect to the partial camber amount is obtained and stored in the storage device 4.

Next, in the rolling of the succeeding material, the camber amount of each of the leading end and the trailing end of the succeeding material is measured by the camber meter 2, and these are output to the leveling amount calculating device 3 and the same as above. Leveling correction amounts b _i and c for the trailing edge camber amount and trailing edge rear camber amount of the trailing material, respectively.
_i is obtained and stored in the storage device 4.

The leveling amount setting device 5 in the storage device leveling correction amount output from the 4 a _i, b _i, based on the information of c _i, leveling correction amount a _i and b _i of the difference (b _i -
a _i) and the difference between the leveling correction amount b _i and c _i (c _i -
b _i ) is calculated, and then, based on the difference (b _i -a _i ) and the difference (c _i -a _i ), the leveling set value of each stand in the rolling of the succeeding material is changed. That is, before starting rolling of the succeeding material at each stand, the difference (b _i −a
_i) only changes the leveling setpoint for each stand, further, before you start rolling the rear end side of each stand, only the difference (c _i -b _i) changing the leveling setpoint for each stand.

The term "before starting rolling on the rear end side of each stand" means that after the leading end of the rough rolled material has passed through the adjacent stand on the downstream side, or after the pressure extension at the stand has reached a predetermined value or more, and It means before the trailing end of the rough rolled material passes through the upstream adjacent stand or before the unrolled portion of the stand reaches a predetermined length. Here, the predetermined length indicates a distance between stands. Hereinafter, this meandering suppression method will be referred to as a first method.
The method.

The change of the leveling set value according to the present invention is carried out for each stand with reference to the leveling state at that time. Therefore, only the leveling correction corresponding to the change in the camber between the materials or between the front and rear ends of the same material is appropriately performed, and even if the meandering feedback type leveling correction is performed simultaneously, it is possible to avoid mutual interference. .

By the way, depending on the state of the rolling mill, a frequent change operation of the leveling set value may rather increase a leveling error. In addition, when the meandering feedback type leveling correction is performed by visual confirmation and manual operation by an operator, the number of times of changing the leveling set value is preferably as small as possible. Further, during the leveling operation, the control of the thickness in the longitudinal direction must be interrupted, and the change of the leveling set value during rolling may not be preferable in terms of quality.

In such a situation, when the necessity of the leveling correction on the front end side is low, the change of the leveling set value on the front end side is stopped, and the change of the leveling set value on the rear end side is made before starting the rolling. Methods of implementation are also conceivable.

That is, according to another meandering suppressing method of the present invention,
First, in the rolling of the preceding material, the camber total 2
Measure the camber amount at the rear end of the material, and use this as the leveling amount.
Output to the arithmetic unit 3 and stored in the leveling amount arithmetic unit 3 in advance.
Based on the relationship between the leveling correction amount and camber amount
Leveling correction amount a to the rear end camber amount of the preceding material
_iAnd stores it in the storage device 4.

Next, in the rolling of the succeeding material, the camber amount of each of the leading end and the trailing end of the succeeding material is measured by the camber meter 2, and these are output to the leveling amount calculating device 3 and the same as above. Leveling correction amounts b _i and c for the trailing edge camber amount and trailing edge rear camber amount of the trailing material, respectively.
_i is obtained and stored in the storage device 4.

The leveling amount setting device 5 in the storage device leveling correction amount output from the 4 a _i, b _i, based on the information of c _i, leveling correction amount a _i and b _i of the difference (b _i -
a _i) and the difference between the leveling correction amount b _i and c _i (c _i -
b _i ) is calculated. Next, when the difference (b _i −a _i ) is smaller than a predetermined value, the leveling correction amounts c _i and a
calculating a _i of the difference (c _i -a _i), the difference (c _i -a
Based on _i ), change the leveling set value of each stand and roll the succeeding material. That is, before rolling start of the following material, by the difference (c _i -a _i) changing the leveling setpoint for each stand. Here, the predetermined value refers to a difference in the leveling correction amount that does not hinder the threading of the distal end portion without performing the leveling correction of the distal end portion. Hereinafter, this other meandering suppression method is referred to as a second method.

In the second method, if the rough rolled material having the same camber shape is continuous and the leading end camber is in a range where there is no problem on the passing of the finishing mill, the leveling set value need not be changed at all and the meandering feedback is provided. Expression leveling correction can be performed stably.

In the description of the present embodiment, one material to be rolled is any material among a plurality of materials to be rolled.
It is not particularly limited. That is, in the present invention, when rolling the second material to be rolled, it is compared with the first material to be rolled, and when rolling the Nth material to be rolled, the (N-1) th material to be rolled is used. The leveling set values are changed as compared with

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First steel sheet is rolled by a hot rolling facility having a finishing rolling mill train consisting of seven stands (No. 1 to No. 7 from upstream to downstream) having the structure shown in FIG. And the meandering suppression effect by the second method was investigated.

For an average length of the rough rolled material 1 of 60 m, CC
A camber meter 2 of an image processing system equipped with a D-camera is installed at a position 80 m upstream of the finishing rolling mill row 6, and the leading end of the rough rolled material 1 is no. The camber amount on the rear end side of the rough rolled material 1 is measured before being bitten by one stand, and the leveling correction amount can be calculated.

In this test, No. 1 was checked by visual confirmation and manual operation by the operator. No. 4 stand and No. The meandering feedback leveling correction by a meandering meter provided between the five stands was also performed at the same time. For comparison, the first
A test (Comparative Example) in which neither the method nor the second method was performed and only the meandering feedback type leveling correction was performed was also performed. The target rolled material has a finished plate thickness of 1.0 to 6.0 mm and a plate width of 6
It is a general low carbon material of 00 mm to 1600 mm, and the number of rolls is the present invention example by the first method, the present invention example by the second method,
Each of the comparative examples was approximately 5000.

No. The meandering amount at the leading end and the trailing end of the material to be rolled was measured with a meandering meter provided between the four and five stands, and the mean value of the meandering amount was determined for each of the leading end and the trailing end. Table 1
Shows the results. In addition, the meandering amount refers to a distance between the center in the width direction and the center line of the rolling mill at each end surface of the front end portion and the rear end portion.

[0050]

[Table 1] As shown in Table 1, in the comparative example, the meandering amount was 14 mm and 37 mm on average at the leading and trailing ends, respectively, whereas in the present invention example by the first method, the meandering amounts were 9 mm and 24 mm, respectively.
Was suppressed. In addition, in the example of the present invention according to the second method, the tip was 15 mm, which was almost the same as the comparative example.
At the rear end, it was suppressed to 21 mm. In addition, the ratio of occurrence of the narrowing trouble due to the meandering of the rear end was about 0.8% in the comparative example, but was reduced to 0.5% and 0.4% in the example of the present invention according to the first method and the second method, respectively. .

[0051]

According to the present invention, the meandering amount of the steel strip can be effectively suppressed without interfering with the meandering feedback type leveling correction. Therefore, it is possible to reduce the trouble of passing the front and rear ends due to the meandering.
In particular, it is possible to reduce the trouble of narrowing, improve the rolling efficiency, and suppress the product yield loss due to roll flaws.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a planar shape of a material to be rolled to be supplied to a rolling mill, and FIG. 1 (a) shows a case where cambers in opposite directions are formed on the front end side and the rear end side of the material to be rolled. (B) shows a case where camber occurs only on the rear end side, and (c) shows a case where cambers occur in the same direction on the front end side and rear end side.

FIG. 2 is a schematic diagram illustrating a configuration example of an apparatus according to the present embodiment.

[Explanation of symbols]

 1: rough rolled material 2: camber meter 3: leveling amount calculation device 4: storage device 5: leveling amount setting device 6: finish rolling mill train

Claims (3)

[Claims] 1. A meandering suppressing method when hot rolling is performed on a plurality of materials to be rolled by a rolling mill train composed of a plurality of stands, wherein a camber of the rolled material is used to control each stand of the rolling mill train. The relationship between the leveling correction amount of each stand and the camber amount of the material to be rolled required to suppress the meandering that occurs is obtained in advance, and the rolling of the material to be rolled that has been subjected to hot rolling immediately before one material to be rolled is performed. The leveling correction amount (A) of each stand with respect to the measured value of the camber amount on the entrance side of the train
_i ) and the leveling correction amount (B _i ) of each stand with respect to the measured value of the camber amount on the entry side of the rolling mill row of one material to be rolled, are obtained from the relationship, and the leveling correction amount (A _i ) is obtained. A meandering control method, wherein a set value of the leveling of each of the stands is changed based on a difference between the two and (B _i ) to perform hot rolling on one rolled material. 2. A meandering suppressing method when hot rolling is performed on a plurality of materials to be rolled by a rolling mill train including a plurality of stands, wherein a camber of the rolled material is used to control each stand of the rolling mill train. The relationship between the leveling correction amount of each stand and the camber amount of the material to be rolled required to suppress the meandering generated in advance is determined in advance, and the rear end of the material to be hot rolled immediately before one material to be rolled The leveling correction amount a _i of each stand with respect to the measured value of the camber amount on the entrance side of the rolling mill row on the side, and the camber amount on the entrance side of the rolling mill row on the leading end side and the rear end side of one rolled material. The leveling correction amounts b _i , c _i of the respective stands with respect to the measured values are obtained from the relationship, and the difference (b) between the leveling correction amounts a _i , b _i (b
_i -a _i) the basis to change the settings of the leveling of the stand to begin hot rolling of one material to be rolled, then, the leveling correction amount b _i, the difference between c _i (c _i -b _i A meandering suppression method characterized by changing the set value of the leveling of each stand based on the above) and performing hot rolling on the rear end side of one rolled material. 3. A method for suppressing meandering when hot rolling is performed on a plurality of materials to be rolled by a rolling mill train including a plurality of stands, wherein a camber of the rolled material is used to control each stand of the rolling mill train. The relationship between the leveling correction amount of each stand and the camber amount of the material to be rolled required to suppress the meandering generated in advance is determined in advance, and the rear end of the material to be hot rolled immediately before one material to be rolled The leveling correction amount a _i of each stand with respect to the measured value of the camber amount on the entrance side of the rolling mill row on the side, and the camber amount on the entrance side of the rolling mill row on the leading end side and the rear end side of one rolled material. The leveling correction amounts b _i , c _i of the respective stands with respect to the measured values are obtained from the relationship, and the difference (b) between the leveling correction amounts a _i , b _i (b
_When the absolute value of _i− a _i ) is smaller than the predetermined value, the leveling set value of each stand is changed based on the difference (c _i −a _i ) between the leveling correction amounts a _i and c _i , and one target is corrected. A meandering suppressing method, wherein hot rolling is performed on a rolled material.