JP2737574B2 - Metal sheet straightening method and roll straightening machine for straightening metal sheets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a roll straightening machine for properly and efficiently straightening a metal plate.

[0002]

2. Description of the Related Art The following method has been used to correct and flatten shape defects such as warpage of a metal plate after rolling. That is, an upper straightening roll of a roll straightening machine provided with a plurality of upper straightening rolls above a metal plate to be straightened, and a plurality of lower straightening rolls below it. The metal plate to be straightened is passed between the lower straightening roll and the lower straightening roll, and the flattened flattening is performed by moving the metal plate while lowering it by a predetermined amount by the upper straightening roll and the lower straightening roll. When straightening a metal plate by such a roll straightening machine, it is important to appropriately control the amount of reduction of the correction roll with respect to the metal plate, and when the amount of reduction of the correction roll is inappropriate,
The metal plate cannot be straightened.

However, when the shape of a metal plate, for example, a strip-shaped steel plate is corrected by a roll straightening machine, it is determined whether or not the amount of reduction of the straightening roll with respect to the steel plate is appropriate.
Means for automatically controlling the amount of reduction of the straightening roll,
There was not before. For this purpose, conventionally, an operator visually inspects the shape of the steel sheet straightened by the roll straightening machine to judge whether or not the steel sheet is acceptable, and in the case of rejection, the steel sheet is straightened again by passing it through the roll straightening machine. Was. Therefore, it was not possible to correct the shape defect of the steel sheet accurately and efficiently. In particular, the warpage called so-called strip camber, which occurs when a large thick steel plate is cut in the longitudinal direction and divided into a plurality of small width thick steel plates, is greatly affected by the residual stress of the steel plate. Therefore, when such a large steel plate is straightened by a roll straightening machine, it cannot be determined whether or not the steel plate has been properly straightened unless the steel plate is actually cut.

[0004] In view of the above, various studies have been made on means for solving the above-mentioned problems, and for example, the following methods are known. In advance, for the metal plate for flattening the metal plate, the amount of reduction of the straightening roll of the roll straightening machine is set, and the straightening load on the metal plate by the straightening roll is measured, and the measured straightening load is measured. In order to correct the elongation of the roll straightening machine, the amount of reduction of the straightening roll is controlled (hereinafter referred to as prior art 1).

A method disclosed in Japanese Patent Application Laid-Open No. 61-262427, comprising: setting a straightening load of a straightening roll on a metal plate for straightening a metal plate in advance, and Measure the straightening load on the metal plate by the straightening roll of the straightening machine, based on the difference between the two,
The amount of reduction of the straightening roll with respect to the metal plate is controlled (hereinafter referred to as prior art 2).

[0006] A method disclosed in Japanese Patent Application Laid-Open No. Sho 60-174214, which comprises the following steps: setting a torque of a straightening roll with respect to a metal plate in advance to straighten the metal plate, and The torque of the roll on the metal plate is measured, and the amount of reduction of the straightening roll on the metal plate is controlled based on the difference between the two (hereinafter referred to as Prior Art 3).

[0007] A method disclosed in Japanese Patent Application Laid-Open No. 61-1418, comprising: measuring the strain on the front and back surfaces of a metal plate passing through a roll straightening machine with a strain gauge attached to the front and back surfaces of the metal plate. , Based on the measured distortion values,
The amount of reduction of the straightening roll with respect to the metal plate is controlled (hereinafter referred to as Prior Art 4).

FIG. 7 is a process chart showing a method of the prior art 1 in which the amount of reduction of the straightening roll is controlled by the straightening load on the metal plate. First, taking into account the load limitation, bite amount limitation and torque limitation of the roll straightening machine to be used, a plastic deformation rate, that is, a curvature, which is determined by the material of the metal plate to be straightened and for straightening the metal plate is set. I do. Next, assuming that the metal plate is deformed (for example, in an arc shape) so as to have the set plastic deformation rate, the amount of reduction of the straightening roll for deforming the metal plate in such a manner is set.

Next, the metal sheet to be straightened is passed through a roll straightening machine, and the metal sheet is reduced by a set roll by a straightening roll. The straightening load applied to the metal plate by such reduction is measured, and the elongation of the roll straightening machine is calculated based on the measured straightening load. Then, based on the obtained elongation of the roll straightening machine, the set reduction amount of the correction roll is corrected and reset, and the metal plate is corrected using the reset reduction amount.

[0010]

In the prior art 1, the amount of reduction of the straightening roll with respect to the metal plate is set on the assumption that the straightening roll deforms the metal plate.
The correct amount of reduction cannot be set. Therefore, according to the prior art 1, the shape of the metal plate cannot be accurately and efficiently corrected.

In the prior art 2, since the sensitivity of the straightening load to the amount of reduction of the straightening roll to be controlled is weak in the plastic region of the metal sheet to be straightened, there are many errors in the control. Depending on the shape of the metal plate,
It cannot be corrected properly and efficiently.

In the prior art 3, the measured torque value of the straightening roll for controlling the amount of reduction of the straightening roll is:
The torque includes the torque generated by the friction between the straightening roll and the metal plate. Therefore, the prior art 3 cannot correct the shape of the metal plate accurately and efficiently.
And

As in the prior art 4, in order to measure the strain on the front and back surfaces of the steel sheet passing through the roll straightener, strain gauges must be attached to the front and back surfaces of the steel sheet.
The work becomes extremely complicated, and it is difficult to implement in practical operation.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a method and a roll straightening machine for properly and efficiently straightening the shape of a metal plate.

[0015]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems. As a result, the curvature of the metal plate bent by the reduction of the straightening roll of the roll straightening machine is measured by a curvature measuring device provided in the roll straightening machine, and based on the obtained curvature measurement value, the straightening roll is measured. It has been found that, by controlling the amount of reduction of, the shape of the metal plate can be accurately and efficiently corrected by the roll straightening machine.

The present invention has been made on the basis of the above findings, and has a plurality of upper straightening rolls above a metal plate to be straightened, and a plurality of upper straightening rolls thereunder. A lower straightening roll is provided with a roll straightening machine, a metal plate is passed between the upper straightening roll and the lower straightening roll, and the metal plate is passed through the upper straightening roll and the lower straightening roll. In the method of straightening the metal plate by moving between the upper straightening roll and the lower straightening roll while rolling down by a predetermined rolling amount, the roll straightening machine has in advance. Considering the load limit, bite amount limit and torque limit, the curvature for flattening the metal plate, which is determined by the material of the metal plate to be corrected, etc., is set. Assuming the deformation of the metal plate, set the amount of reduction of the straightening roll for deforming the metal plate in that way, then pass the metal plate to be straightened through a roll straightening machine, and roll the metal plate with the straightening roll. While reducing by the set reduction amount, the curvature of the metal plate bent by the reduction is measured, and the obtained curvature measurement value is compared with the set curvature value. The metal plate is straightened by the set amount of reduction, and when both are different, the amount of reduction of the straightening roll is reset so that the curvatures of the two are the same, and the straightening of the metal plate is performed by the reset amount of reduction. Is performed.

[0017] The present invention is directed to a plurality of upper straightening rolls provided above a metal plate to be straightened and a plurality of lower straightening rolls provided thereunder. In a roll straightening machine for straightening a metal sheet, at least one curvature measurement for measuring the curvature of the metal sheet bent by the straightening roll on each of the upper straightening roll and the lower straightening roll. It is characterized in that a vessel is provided.

[0018]

The principle of controlling the amount of reduction of the straightening roll by the curvature of the metal plate bent by the straightening roll in the method of the present invention will be described below. Although it is well known, whether or not the metal plate has been properly and flatly corrected by the straightening roll is determined by the degree of plastic bending of the metal plate by the straightening roll,
The plastic deformation rate is used as an index of the degree of the plastic bending of the metal plate.

The plastic deformation rate is obtained by the following equation (1). Where αi: plastic deformation rate Ki: curvature coefficient

The curvature coefficient (Ki) is obtained by the following equation (2). In the above formula (2), κi is the reciprocal of the radius of curvature of the bent metal plate, κe is the curvature of the elastic limit of the bent metal plate, and κe is obtained by the following formula (3) . Where t: thickness E: elastic modulus

FIG. 8 shows the above-mentioned plastic deformation rate (αi).
It is explanatory drawing for Formula (1)-(3), Comprising: The state of the metal plate to which plastic bending was added is shown by the longitudinal cross section of the metal plate. In FIG. 8, a indicates the thickness center line of the metal plate,
b indicates the plastic zone of the metal plate and c indicates the elastic zone of the metal plate. ε _i indicates the amount of strain on the surface of the metal plate subjected to plastic bending, and ε _e indicates the strain in the elastic region of the metal plate subjected to plastic bending. Plastic deformation rate (α
i) is 1 from the surface of the metal plate to the center of the plate thickness.
It is obtained by the above equation (1). The relationship between the strain (ε _i ) on the metal plate surface and the strain (ε _e ) in the elastic region is as shown in the following equation (4). ε _i = Kiε _e ───── (4)

FIG. 9 is a graph showing the relationship between the plastic deformation rate (αi) calculated by the above equation (1) and the curvature coefficient (Ki). In order to accurately and efficiently correct the metal plate, the plastic deformation rate needs to be 50% or more. However, as apparent from FIG. 9, when the plastic deformation rate becomes 50% or more, The change in curvature becomes noticeable. Therefore, it can be seen that if the curvature is used as a control factor, the amount of reduction with respect to the metal plate can be controlled accurately and efficiently.

FIG. 10 is a principle diagram showing correction of warpage of a metal plate. In FIG. 10, the horizontal axis represents the curvature (κ) given to the metal plate by each correction roll, κ ₀ represents the initial curvature of the metal plate, and κ _{1 to} κ ₇ represent the first to seventh. The curvature imparted to the metal plate by each straightening roll is shown, in which κ ₆ is the curvature required to straighten the metal plate in the sixth straightening roll. The vertical axis represents the bending moment of the metal sheet by each straightening roll, and this bending moment changes depending on the characteristics of the metal sheet to be straightened. As can be seen from FIG. 10, the curvature given to the metal plate by each straightening roll gradually decreases, and the curvature (κ ₆ ) of the sixth straightening roll determines the residual curvature of the steel sheet.

FIG. 11 is a graph showing the relationship between the plastic deformation rate applied to the metal plate by the second straightening roll and the effect of correcting the metal plate. In FIG. 11, the horizontal axis is the plastic deformation rate and the vertical axis is the correction effect. The correction effect is as follows
Calculated by equation (5). 1−λφ / λi──── (5) Where, λφ: Index indicating the disorder of the shape on the entry side of the metal plate λi: Index indicating the disorder of the shape on the exit side of the metal plate From FIG. It can be seen that this is an important index of the correction effect of the metal plate.

On the other hand, as shown in the graph of FIG. 12, in the relationship between the plastic deformation rate applied to the metal plate and the correction load, when the plastic deformation rate becomes 50% or more, the correction load becomes 15% of the elastic limit load. %, Which is very small. Therefore, it can be seen that the use of the straightening load as a control factor cannot accurately control the amount of reduction of the straightening roll against the metal plate.

FIG. 1 is a diagram showing a method for controlling a reduction amount of a straightening roll according to the curvature of a metal sheet bent by the straightening roll based on the principle described above. 1 is a schematic front view showing an embodiment of the roll straightening machine of FIG. As shown in FIG. 1, a roll provided with a plurality of upper straightening rolls 2 above a metal plate A to be straightened and a plurality of lower straightening rolls 2 'below the same. Between each of the plurality of upper straightening rolls 2 and between each of the lower straightening rolls 2 ′ of the straightening machine 1, a metal plate A bent by the upper straightening roll 2 and the lower straightening roll 2 ′ is provided. A curvature measuring device 4 for measuring the curvature at the center in the plate width direction is provided in proximity to each of the upper straightening roll 2 and the lower straightening roll 2 ′. 3 is an upper backup roll and 3 'is a lower backup roll.

FIG. 2 is a partial schematic front view showing an embodiment of the curvature measuring device. As shown in FIG.
Is composed of, for example, three non-contact type laser distance meters 4a, 4b, 4c.
The curvature of the metal plate is measured by the method shown in FIG.

That is, by the laser rangefinders 4a, 4b, 4c,
That distance between each position and the metal plate _{A h 1, h 2, h} 3 is measured, and the measured values obtained, the metal plate A, and the distance L between the laser distance meter 4a and 4c Then, the curvature の of the metal plate A is obtained by the following equation (6).

FIG. 4 is a partial schematic front view showing another embodiment of the curvature measuring device. In this embodiment, for example, three laser distance meters 4a, 4b, 4c are provided inside each of the straightening rolls 2, 2 ', and each of such straightening rolls 2, 2' is provided. Built-in laser rangefinder 4a, 4
b, the 4c, as described above, the distance between each position and the metal plate _{A h 1, h 2, h} 3 are measured, on the basis of the measurements obtained by the equation (6) Curvature of metal plate A
Is required.

FIG. 6 is a process diagram showing a method of the present invention for controlling the amount of reduction of the straightening roll by the curvature of the metal plate bent by the reduction of the straightening roll. First of all, considering the load limit, bite amount limit and torque limit of the roll straightener such as the roller beller used,
A plastic deformation rate, that is, a curvature, which is determined by the material of the metal plate to be corrected and the like to flatten the metal plate is set. Next, assuming that the metal plate is deformed (for example, in an arc shape) so as to have the set plastic deformation rate, the amount of reduction of the straightening roll for deforming the metal plate in such a manner is set.

Next, the metal sheet to be straightened is passed through a roll straightening machine, and the metal sheet is reduced by the set roll by the straightening roll. The curvature of the metal plate bent by such reduction is measured by the above-described curvature measuring device 4. Then, the obtained measured value of the curvature is compared with the set curvature value, and if they match, the metal plate is corrected by the set reduction amount. On the other hand, when the curvature measured by the curvature measuring device 4 is different from the set curvature, the reduction amount of the straightening roll is reset so that the two coincide with each other, and the metal plate is set by the reset amount of reduction. To make corrections. Hereinafter, the same procedure is repeated until the measured value of the curvature matches the set value, and the metal plate is corrected by the reduction amount in which the two values match.

As shown in a schematic perspective view in FIG. 5, a plurality of curvature measuring devices 4 may be provided in the width direction of the metal plate A. As described above, if a plurality of the curvature measuring devices 4 are provided in the width direction of the metal plate A, the bending of the correction rolls 2 and 2 ′ is determined based on the measured distribution of the curvature of the metal plate A in the width direction. Thus, the effect of correcting the metal plate A can be further improved.

The curvature measuring device 4 is not limited to the laser distance meter described above, but may be a non-contact type eddy current type distance meter, a contact type differential transformer type displacement meter, or the like.

The roll straightening machine may be a roller leveler or a tension leveler that corrects the shape of a metal plate by applying a tension, and the same effect can be obtained. The curvature measuring device 4 does not have to be provided close to each of the plurality of upper straightening rolls 2 and lower straightening rolls 2 ′ as shown in FIG. 1, as long as at least one is provided. Good.

[0035]

Next, the present invention will be described with reference to examples and comparative examples. (Embodiment 1) Using a laser distance meter as a curvature measuring device 4 by a roll straightener 1 comprising a roller leveler shown in FIGS.
10mm 60K high strength steel plate was straightened.

The specifications of the laser distance meter used, the dimensions of the straightening roll, and the like are shown below. Measurement distance of laser range finder: 400mm Resolution of laser range finder: 50 μm Height of laser range finder: 60mm Width of laser range finder: 28mm Depth of laser range finder: 85mm Diameter of straightening roll: 275mm Work roll diameter: 280mm Distance between centers of straightening rolls: 290mm

The straightening of the steel sheet by the roll straightening machine is performed by a so-called tilting reduction method in which the bite amount (inter mesh) of the steel sheet with respect to each straightening roll decreases at the same rate from the entry side to the exit side of the steel sheet. The exit intermesh was controlled such that the residual curvature in FIG. When passing a steel sheet through a roll straightening machine,
When the load, bite amount and torque are caught by the limitation of the roll straightener, the steel plate is passed through the roll straightener in multiple passes, and the first pass is the limited range of the load, bite amount and torque of the roll straightener. The steel plate was straightened in the inside, and the remaining straightening was performed in the second and subsequent passes.

For comparison, the high-tensile steel sheet was straightened by the method of Prior Art 1 shown in the process diagram of FIG. The diameter of the straightening roll, the diameter of the work roll, and the distance between the centers of the straightening rolls of the roll straightening machine are the same as described above. The straightening of the steel sheet was performed by the above-described tilting pressure reduction method, and the outlet intermesh was set to 0 mm.

Table 1 shows the steepness of the steel sheet corrected by the inventive example 1 and the comparative example.

[0040]

[Table 1]

As is clear from Table 1, in the comparative example, the steepness of the steel sheet was 1.0% even after three passes, whereas in the embodiment of the present invention, the steepness of the steel sheet was two passes. Was reduced to 0.6%, and an excellent straightening effect was exhibited. Further, in the comparative example, a large warp occurred in the longitudinal direction of the steel sheet after two passes, but in the example 1 of the present invention, no warpage occurred.

(Embodiment 2) FIG. 5 is a schematic perspective view of a roll straightening machine 1 shown in FIGS. 1 and 2 in which a curvature measuring device 4 composed of a laser distance meter is provided between each straightening roll. As described above, three curvature measuring devices 4 are provided in the width direction of the metal plate A, respectively, and the curvature distribution in the width direction of the steel plate A is also measured. A 60K high-strength steel sheet with a thickness of 10 mm was straightened.

In the case of the second embodiment, a plurality of backup rolls provided at predetermined intervals in the length direction of the straightening rolls (the width direction of the metal plate) are individually used. Without a mechanism that can control the deformation by pressing the straightening roll, when the curvature in the width direction of the steel sheet measured by a curvature measuring device is different, the plurality of backup rolls so that the curvature is the same Can correct the pressing force on the straightening roll.

Table 2 shows the steepness of the steel sheet corrected by the above-described second embodiment of the present invention in comparison with the steepness of the steel sheet corrected by the above-described comparative example.

[0045]

[Table 2]

As is clear from Table 2, in the comparative example, the steepness of the steel sheet was 1.0% even after 3 passes, whereas in the embodiment of the present invention, the steepness of the steel sheet was 2 passes. Was reduced to 0.2%, and a much better correction effect was exhibited. Further, in the comparative example, a large warp occurred in the longitudinal direction of the steel sheet after two passes, but in the example 2 of the present invention, no warpage occurred.

[0047]

As described above, according to the present invention,
An industrially useful effect is exhibited in which the shape of a metal plate can be accurately and efficiently corrected by a roll straightening machine.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing one embodiment of a roll straightening machine for carrying out a method of the present invention.

FIG. 2 is a partial schematic front view showing an embodiment of a curvature measuring device used in the method and the roll straightening machine of the present invention.

FIG. 3 is an explanatory diagram for measuring a curvature of a metal plate using a laser distance meter as a curvature measuring device by the method and the roll straightening machine of the present invention.

FIG. 4 is a partial schematic front view showing another embodiment of the curvature measuring device used in the method and the roll straightening machine of the present invention.

FIG. 5 is a schematic perspective view showing a state in which the curvature of a metal plate in the width direction is measured by the method and the roll straightener of the present invention.

FIG. 6 is a process diagram showing a method of the present invention for controlling the amount of reduction of a straightening roll by the curvature of a metal plate.

FIG. 7 is a process chart showing a method of Prior Art 1 for controlling the amount of reduction of a straightening roll by a straightening load on a metal plate.

FIG. 8 shows the plastic deformation rate (α) showing the principle of the method of the present invention.
It is explanatory drawing for Formula (1) which calculates | requires i).

FIG. 9 shows the plastic deformation rate (α) showing the principle of the method of the present invention.
It is a graph which shows the relationship between i) and a curvature coefficient (Ki).

FIG. 10 is a principle diagram of straightening of a metal plate.

FIG. 11 is a graph illustrating the principle of the method of the present invention and showing the relationship between the plastic deformation rate given to a metal plate and the straightening effect of the steel plate.

FIG. 12 is a graph showing a relationship between a plastic deformation rate applied to a metal plate and a correction load in a conventional method.

[Explanation of symbols]

 A Metal plate, 1 roll straightener, 2,2 'straightening roll, 3,3' backup roll, 4 curvature measuring device, 4a, 4b, 4c laser distance meter.

Continuation of the front page (72) Inventor Yoneaki Fujita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (56) References JP-A-56-50720 (JP, A) JP-A-59-141319 (JP, A) JP-A-4-138821 (JP, A) JP-A-1-202314 (JP, A)

Claims (9)

(57) [Claims] 1. A roll straightening machine comprising a plurality of upper straightening rolls above a metal plate to be straightened and a plurality of lower straightening rolls below the same. A metal plate is passed between the upper straightening roll and the lower straightening roll, and the upper straightening roll is rolled down by the upper straightening roll and the lower straightening roll by a predetermined amount. In the method of straightening the metal plate by moving between the and the lower straightening roll, in advance, considering the load limit, bite amount limit and torque limit that the roll straightening machine has. , Set a curvature for flattening the metal plate, determined by the material of the metal plate to be corrected, etc., assuming deformation of the metal plate so as to have the set curvature, and deform the metal plate as such Let me Set the reduction amount of straightening rolls, then passed through a metal plate to be the correction to the roll straightening machine,
While reducing the metal plate by the set rolling amount by the straightening roll, the curvature of the metal plate bent by the reduction is measured, and the obtained curvature measurement value is compared with the set curvature value. If it is, the metal plate is straightened by the set amount of reduction, and if both are different, the amount of reduction of the straightening roll is reset so that the curvatures of both are the same, and the reset rolling amount is reset. A method for correcting a metal plate, comprising correcting the metal plate according to the amount. 2. A metal plate comprising a plurality of upper straightening rolls provided above a metal plate to be straightened and a plurality of lower straightening rolls provided therebelow. In a straightening roll straightening machine, each of the upper straightening roll and the lower straightening roll is provided with at least one curvature measuring device for measuring a curvature of the metal plate bent by the straightening roll. A roll straightening machine for straightening a metal plate. 3. The curvature measuring device according to claim 2, wherein the curvature measuring device is a non-contact type or contact type curvature measuring device provided near each of the upper straightening roll and the lower straightening roll. Roll straightening machine. 4. The roll according to claim 2, wherein the curvature measuring device is a non-contact type or contact type curvature measuring device provided inside each of the upper straightening roll and the lower straightening roll. Straightening machine. 5. The non-contact type curvature measuring device is a laser range finder or an eddy current range finder.
The roll straightening machine according to the above. 6. The roll straightening machine according to claim 3, wherein the contact type curvature measuring device is a differential transformer type displacement meter. 7. The roll straightening machine according to claim 2, wherein a plurality of the curvature measuring devices are provided in a width direction of the metal plate. 8. The roll straightener according to claim 2, wherein the roll straightener is a roller leveler. 9. The roll straightening machine according to claim 2, wherein said roll straightening machine is a tension leveler.