KR20130099336A - Apparatus for flattening steel plate and method thereof - Google Patents

Abstract

PURPOSE: A steel sheet correction device and a steel sheet correction method are provided to provide an optimized correction environment for an initial bending phenomenon of the front end portion of steel sheet, thereby previously preventing a back-bending phenomenon. CONSTITUTION: A steel sheet correction device includes a plurality of lower and upper correction rollers (110, 120), lower and upper lifting rollers (130, 140), and a lifting motor (200). The upper correction roller is arranged on the upper part of the lower correction roller. The upper and lower correction rollers are separately arranged and partially overlapped in a steel sheet moving direction. The extent of the lower and upper correction rollers being press-fitted are linearly reduced from a steel sheet entering direction to a steel sheet discharging direction.

Description

Steel plate straightening device and method of straightening {APPARATUS FOR FLATTENING STEEL PLATE AND METHOD THEREOF}

The present invention relates to a steel sheet straightening device and a calibration method, and more particularly to a steel sheet straightening device and a calibration method that can remove the bending deformation and residual stress of the steel sheet.

In general, in the thick plate production process, the rolled plate is rolled through a rolling mill. The rolled plate is cooled through a cooling device to improve strength, and then passed through a roller straightener to produce a final thick plate.

By the way, in the conventional thick plate rolling process, a problem arises in that bending occurs at the leading end of the rolled plate by asymmetrical rolling factors in the thickness direction of the rolled plate.

For example, as shown in FIG. 1, when up bending occurs in the tip of the rolled plate 10, the phenomenon in which the tip of the rolled plate passed through the rolling mill continues to be bent upward continues, followed by the preceding rolled plate. Due to the weight of the roller table (roller table) descends to the height and at the same time proceeds in the rolling direction, in order to prevent this further pass pass rolling to extend the bending of the top end of the rolling plate before going to the cooling process dummy pass rolling was required.

In addition, when downward bending occurs at the tip of the rolled plate 10, the end of the rolled plate which has passed through the rolling mill is bent downward, and then the end of the rolled plate is rolled while causing a collision with the roller of the roller table. In this case, slip and bending occur between the work roll and the rolled plate, and there are temperature irregularities and residual stresses inside the rolled plate due to the difference in the injection distance during the subsequent accelerated cooling. As a result, even after passing through the hot calibrator, the flatness of the tip portion remains.

In order to solve this problem, conventionally, "thick plate straightening rolling mill and its control method (Patent Publication, 10-2004-0056056)" is known.

However, in the prior art, the roller of the roller straightener consists of an upper straightening roller group and a lower straightening roller group in which the rollers are asymmetrically staggered, so that the upper roller is pushed down when the steel sheet tip is bending upward, and the lower roller serves as a supporting point. When the tip is downward bending, the lower roller is pushed down and the upper roller serves as a supporting point. At this time, the tip of the steel plate does not contact the roller, so it is a free end condition. There was no correction.

In particular, if the shape of the tip of the steel sheet before the straightening is in the state of upward or downward bending deformation, bending (reverse bending) in the opposite direction to the existing bending occurs during the calibration, which causes a problem of worsening the flatness of the steel sheet. .

Accordingly, there is a demand for a technology capable of effectively removing the reverse bending of the steel sheet by providing an optimum calibration environment for the initial bending phenomenon of the steel sheet tip during the hot steel sheet rolling process.

Patent Publication 10-2004-0056056 (2004.6.30)

An object of the present invention for solving this problem is to provide a steel sheet straightening device and a calibration method that can effectively remove the reverse bending phenomenon for the steel sheet front end by optimally correcting the initial bending phenomenon of the steel sheet end.

In order to achieve the above object, the steel sheet straightening device according to the present invention is a steel sheet straightening device which is a rolling operation and a straightening operation while the steel sheet is moved, including a lower straightening roller and an upper straightening roller, the lower straightening roller is part of the steel sheet moving direction Is made up of a plurality of spaced apart overlapping, the upper straightening roller is located on the upper side of the plurality of lower straightening rollers, and consists of a plurality of spaced apart so that some overlap in the moving direction of the steel sheet.

Preferably, the steel sheet straightening device is a lower lifting roller which is arranged to move up and down at one end of the plurality of lower straightening rollers, and the upper lifting roller is arranged to be movable up and down at the other end side of the plurality of upper calibration rollers And, the lower lifting roller may further include a lifting motor which is driven to the upper lifting roller.

Preferably, the plurality of upper straightening rollers and the lower straightening rollers may include a plurality of first straightening rollers which are dividedly disposed to be spaced apart in the longitudinal direction, and at least a portion thereof in a space between the plurality of first straightening rollers. And a plurality of second straightening rollers which are divided and arranged to be spaced apart from each other, wherein the plurality of first straightening rollers and the second straightening rollers are continuously disposed in the moving direction of the steel sheet.

Preferably, the indentation amounts of the plurality of lower and upper calibration rollers are linearly decreased from the inlet side into which the steel sheet enters to the outlet side from which the steel sheet is discharged.

Preferably, the steel sheet straightening device further includes a control unit for selectively controlling the vertical movement of the lower lifting roller and the upper lifting roller in accordance with the bending shape of the steel sheet leading end, the control unit is a steel plate with the front end bent downward correction When the roller enters the roller, an operation signal for moving the upper lifting roller upward is applied to the operating motor, and when the steel sheet having a tip bent upward enters the calibration roller, the lower lifting roller moves downward. The operation signal is applied to the operation motor.

Steel sheet calibration method according to the present invention, the step of detecting the bending shape of the steel plate front end to enter between the plurality of upper, lower rollers, the number of the plurality of upper and lower rollers in contact with the steel sheet according to the detected bending shape of the steel sheet front end And adjusting the linearly reduced indentation amount of the upper and side rollers toward the exit side from which the steel sheet is discharged.

Preferably, the step of adjusting the number of the upper, lower rollers, when the steel sheet is bent the lower end is entered into the upper, lower rollers of the upper roller which is in contact with the steel sheet by moving the position of the upper roller located in the mouth in the upward direction When the number of steel sheets, which are bent upwards, enters the upper and lower rollers, the number of lower rollers contacting the steel sheets is reduced by moving the position of the lower rollers located at the mouth side downward.

Preferably, the indentation amount is set by the following equation 1 so that the plastic strain (YR) is 80% or more in the thickness direction of the steel sheet,

[Formula 1]

Where δ: indentation amount, L: roll pitch, YS: yield strength, E: elastic modulus, t: steel sheet thickness, and YR: plastic strain.

According to the present invention, the following remarkable effects can be realized.

First, the present invention has an advantage that the reverse bending phenomenon generated in the front end portion of the steel sheet can be prevented in advance by configuring a part of the straightening roller in the steel plate moving direction to minimize the roll pitch.

Second, the present invention has the advantage of maximizing the calibration effect while maintaining the same number of the upper and lower rollers by varying the number of upper and lower rollers according to the bending shape of the front end of the steel plate while maintaining the number of the entire roller constant.

Third, since the present invention can use a roll having a larger diameter than the roll pitch, it is possible to obtain a large load necessary for the correction of the steel sheet and to provide a sufficient rolling force to the steel sheet.

1 is a perspective view showing an example of bending occurring in the tip portion of a conventional steel sheet.
Figure 2 is a block diagram showing a steel sheet straightening apparatus according to the present invention.
Figure 3a is a perspective view showing the upper and lower calibration rollers of the steel sheet straightening apparatus according to an embodiment of the present invention.
Figure 3b is a perspective view of the upper and lower calibration rollers of the steel sheet straightening apparatus according to a modification of the present invention.
4a to 4b is a configuration diagram showing the operating state of the calibration roller according to the bending shape of the steel sheet in the steel sheet straightening apparatus according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a view showing a steel sheet straightening apparatus according to the present invention, Figure 3a is a view showing a perspective view of the upper and lower calibration rollers of the steel sheet straightening apparatus according to an embodiment of the present invention, Figure 3b is a modification of the present invention Figure is a view showing a perspective view of the upper and lower calibration rollers of the steel sheet straightening device.

As shown in Figure 2 to 3a, the steel sheet straightening apparatus according to the present invention, the lower straightening roller 110, the upper straightening roller 120, the lower lifting roller 130, the upper lifting roller 140, the lifting It comprises a motor 200 and a control unit (not shown).

Specifically, the lower straightening roller 110 is composed of a plurality of straightening rollers arranged side by side in the advancing direction of the steel sheet (S) is located on the lower side of the steel sheet straightening device, the steel sheet straightening device via the lower support block 121 It is rotatably mounted on the lower side of the.

The lower straightening roller 110 is disposed to be spaced apart so that the roll pitch is minimized in the moving direction of the steel sheet (S), for this purpose, the lower straightening roller 110 is divided into a plurality of straightening rollers spaced apart to overlap each other Is done.

For example, the lower straightening roller 110 includes a first straightening roller 101 and a second straightening roller 102 which are continuously disposed in the moving direction of the steel sheet S under the steel sheet straightening apparatus. Here, the first straightening roller 101 is composed of a plurality of straightening rollers are divided and arranged to be spaced apart in the longitudinal direction, the second straightening roller 102 is at least a part of the space between the plurality of first straightening rollers 101 It consists of a plurality of calibration rollers are divided and arranged spaced apart in the longitudinal direction so as to be located in.

The upper straightening roller 120 is composed of a plurality of straightening rollers arranged side by side in the advancing direction of the steel sheet (S), is positioned inclined toward the upper side of the steel sheet straightening device, for example, the plurality of lower straightening rollers 110, Preferably, it is disposed to face the space between the plurality of lower straightening rollers 110, and is rotatably mounted on the upper side of the steel sheet straightening device via the upper support block 111.

Accordingly, when the steel sheet (S) enters the steel sheet straightening device, the steel sheet (S) is moved to the space between the plurality of lower calibration roller 110 and the upper calibration roller 120 described above to the indentation amount applied in the thickness direction. Calibration can be done by this.

The upper straightening rollers 120 are arranged to be spaced apart so that the roll pitch is minimized in the steel sheet (S) moving direction, for this purpose, the upper straightening rollers 120 are divided into a plurality of straightening rollers spaced apart to overlap each other Is done. For example, the upper straightening roller 120 is longitudinally spaced such that a plurality of first straightening rollers 101 are dividedly arranged to be spaced apart in the longitudinal direction, and a part thereof is located in a space between the plurality of first straightening rollers 101. It consists of a second straightening roller 102 is divided into spaced apart, these first straightening roller 101 and the second straightening roller 102 are continuously disposed in the direction of moving the steel sheet (S) from the upper side of the steel sheet straightening device. .

As such, the lower calibration roller 110 and the upper calibration roller 120 are disposed to overlap each other along the corresponding longitudinal direction, thereby reducing the roll pitch of the calibration roller while maintaining the diameter of the calibration roller as the conventional calibration roller. Can be implemented. This is because the reverse bending of the front end of the steel sheet S has a correlation with the length of the roll pitch, and the longer the roll pitch, the greater the reverse bending, and thus, the roll pitch must be minimized to eliminate the reverse bending.

For reference, in order to minimize the roll pitch, the diameter of the straightening roller should also be small, and as the diameter of the straightening roller becomes smaller, the contact area between the straightening roller and the steel sheet S becomes small, so that the press-fitting load of the thick steel plate S is increased. As the area becomes larger and the load is narrower, bending does not occur, and thus, indentation occurs, and eventually, steel plate S is impossible to calibrate. Accordingly, in the present invention, by partially overlapping the straightening roller in the moving direction of the steel sheet S so as to minimize the roll pitch, it is possible to effectively prevent the reverse bending phenomenon generated in the front end portion of the steel sheet S.

The lower lifting roller 130 is disposed at one end side of the plurality of lower straightening rollers 110 and is installed to be movable upward and downward through the lower lifting block 131. In the present embodiment, the lower lifting roller 130 is disposed on one end side of the plurality of lower straightening rollers 110, but the lower lifting roller 130 has one end side of the plurality of lower straightening rollers 110. Of course, it can be disposed in, of the plurality of lower calibration rollers 110 may be disposed on both sides.

4a to 4b is a view showing the operating state of the calibration roller according to the bending shape of the steel sheet in the steel sheet straightening apparatus according to the present invention.

In particular, as shown in Figure 4a, the lower lifting roller 130 is a downward direction by the operation of the lifting motor 200 according to the operating signal of the control unit when the steel sheet (S) is bent upwardly the front end is entered By moving to, the number of rollers located at the top of the steel sheet straightening device is arranged to be larger than the number of rollers located at the bottom of the steel sheet straightening device.

The upper lifting roller 140 is disposed at one end side of the plurality of upper straightening rollers 120, and is installed to be movable upward and downward through the upper lifting block 141. In this embodiment, the upper lifting roller 140 is disposed on one end side of the plurality of upper straightening rollers 120, but the upper lifting roller 140 is one end of the plurality of upper straightening rollers 120. It may be disposed in, or may be disposed on both sides of the plurality of upper calibration roller 120.

And, as shown in Figure 4b, when the upper lifting roller 140 enters the steel plate (S) is bent the front end downward, by the operation of the lifting motor 200 according to the operation signal of the control unit By moving in the direction, the number of rollers located at the bottom of the steel sheet straightening device is arranged to be larger than the number of rollers located at the top of the steel sheet straightening device.

Through this, the tip of the downwardly bent steel sheet (S) can be supported in contact with the lower lifting roller 130, and eventually, to implement the three-point bending deformation of the steel sheet (S) to implement an effective correction of the steel sheet (S) Can be.

For example, when the material is subjected to bending deformation by the straightening roll, the basic mechanism is a three-point bending deformation. When the upward bending is performed, the upper roller is pushed down and the lower roller serves as a supporting point. The roller serves as a support point, in order for the bending deformation to be made correctly, the support must be made at two points, and the desired bending deformation is indicated by inserting the steel sheet S at least by a distance between the two points. However, in the case of the conventional straightening rollers, since the lower rollers are arranged in a larger number than the upper rollers, the ends of the upwardly bent steel sheet S do not come into contact with the rollers. As a result, three-point bending does not occur, and thus, only the up and down bending is repeated at a specific point, so that an effective calibration is not performed.

Therefore, in the present invention, by varying the number of upper and lower rollers according to the bending shape of the front end portion of the steel sheet (S) while maintaining the number of the entire roller constant, it is possible to maximize the calibration effect while equalizing the calibration load.

The control unit selectively controls the vertical movement of the lower elevating roller 130 and the upper elevating roller 140 in accordance with the bending shape of the front end of the steel sheet (S), when the lower end of the bent steel sheet (S) enters the calibration roller Applying the upper operation signal to the operation motor to move the lifting roller upwards, and when the upwardly bent end of the steel sheet (S) enters the calibration roller by applying the operation signal to the operation motor to lower the lower lifting roller 130 Move to.

In particular, the control unit linearly decreases the press-in amounts of the plurality of lower and upper straight rollers 110 and 120, from the entrance to which the steel sheet S enters toward the exit side where the steel sheet S is discharged. To control.

For example, when the lower straightening roller 110 is aligned so that the pass line of the steel sheet S and the upper surface of the roller are parallel, the distance between the lower straightening roller 120 and the lower surface of the upper straightening roller 120 may be defined as the indentation amount. The indentation amount of the upper correction roller 120 may decrease linearly from the inlet side to the outlet side, and the indentation amount of the inlet side may be 80% or more in the plastic strain in the thickness direction of the steel sheet S. Set it like this:

[Formula 1]

Where δ: indentation amount, L: roll pitch, YS: yield strength, E: elastic modulus, t: steel sheet (S) thickness, and YR: plastic strain. In addition, the indentation amount is set to be linearly small while going to the exit side, and the indentation amount is set to zero in the exit calibration roller.

For example, when entering the front end of the bent steel sheet (S), when the upper lifting roller 140 is moved upward, four rollers are arranged on the upper side and five rollers are arranged on the lower side, the entry side of the upper straightening roller 120 When the indentation amount is set to 3 mm, the indentation amounts to the second, third, and fourth are set to 2, 1, 0 mm, respectively. And when entering the upper bent end of the steel sheet (S), the lower lifting roller 130 is moved downwards, when five rollers are arranged on the upper side and four rollers are arranged on the lower side, the indentation of the upper correction roller 120 In order to set the amount to 3 mm, the actual indentation amount is set to 3.5, 2.5, 1.5, 0.5, -0.5 mm from the entrance side, respectively.

On the other hand, the steel sheet calibration method according to the present invention includes the step of detecting the bending shape of the front end of the steel sheet (S), adjusting the number of upper and lower rollers, and adjusting the indentation amount to be linearly reduced .

First, the step of detecting the bending shape of the front end of the steel sheet (S), when the steel sheet (S) enters between the upper and lower rollers of the steel sheet (S) correction apparatus, detects the bending shape of the front end of the steel sheet (S) entering. At this time, a separate sensor may be used to detect the upward bending or downward bending shape of the front end of the steel sheet (S).

The adjusting of the number of upper and lower rollers is performed by adjusting the number of upper and lower rollers contacting the steel sheet S according to the detected bending shape of the front end portion of the steel sheet S. When the steel sheet (S) enters a portion of the upper roller is moved upwards to increase the number of the lower rollers in contact with the steel sheet (S), and when the steel sheet (S) is bent in the front end portion of the lower rollers It moves downward and the number of the upper rollers which contact the steel plate S is increased.

The step of adjusting the indentation amount to linearly decreases the indentation amount of the upper and side rollers from the inlet side into which the steel sheet S enters to the outlet side from which the steel sheet S is discharged. The amount is set through the above formula 1 so that the plastic strain (YR) is 80% or more in the thickness direction of the steel sheet (S).

As described above, the present invention is configured by overlapping a part of the straightening roller in the steel plate moving direction to minimize the roll pitch to prevent the reverse bending phenomenon occurring in the front end of the steel sheet in advance, while maintaining the number of the entire roller constant Depending on the bending shape of the front end of the roller, the number of upper and lower rollers can be changed to maximize the calibration effect while maximizing the calibration load. It is possible to provide sufficient rolling force to the steel sheet.

Although the present invention has been described in detail using the preferred embodiments, the scope of the present invention is not limited to the specific embodiments, and should be interpreted by the appended claims. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the present invention.

101: first calibration roller 102: second calibration roller
110: lower calibration roller 120: upper calibration roller
130: lower lifting roller 140: upper lifting roller
200: lifting motor

Claims (8)

As the steel sheet is moved, the steel sheet straightening device that the rolling and correction work,
A plurality of lower straightening rollers spaced apart from each other in the steel plate moving direction; And
Located in the upper side of the plurality of lower straightening rollers, the steel sheet straightening device including a plurality of upper straightening rollers spaced apart so as to overlap a portion in the steel plate moving direction.
The method according to claim 1,
A lower elevating roller arranged to be movable up and down at one end of the plurality of lower calibration rollers;
An upper elevating roller disposed to be movable up and down at the other end side of the plurality of upper calibration rollers;
And a lifting motor driven and connected to the lower lifting roller and the upper lifting roller.
The method according to claim 1,
The plurality of upper straightening rollers and the lower straightening rollers may be spaced apart in the longitudinal direction such that the plurality of first straightening rollers are divided and disposed to be spaced apart in the longitudinal direction, and at least a part thereof is located in a space between the plurality of first straightening rollers. A plurality of second straightening rollers that are divided and disposed;
And the plurality of first straightening rollers and the second straightening rollers are continuously disposed in the steel plate moving direction.
The method according to claim 1,
The press-fitting amount of the plurality of lower straightening rollers and the upper straightening rollers, the steel sheet straightening device, characterized in that linearly decreases toward the exit side from which the steel sheet is discharged from the entrance side entering the steel sheet.
The method according to claim 2,
Further comprising a control unit for selectively controlling the vertical movement of the lower lifting roller and the upper lifting roller in accordance with the bending shape of the steel sheet tip,
The control unit applies an operation signal for moving the upper lifting roller upward to the operation motor when the steel sheet bent downwardly enters the calibration roller, and the steel plate whose tip is upwardly bent enters the calibration roller. In this case, the steel sheet correction apparatus, characterized in that for applying the operation signal for moving the lower lifting roller to the operation motor.
Detecting a bending shape of a steel sheet leading end portion between the plurality of upper and lower rollers;
Adjusting the number of upper and lower rollers in contact with the steel sheet according to the detected bending shape of the front end portion of the steel sheet; And
Steel plate calibration method comprising the step of adjusting the indentation amount of the upper and side rollers linearly toward the exit side from which the steel sheet enters the discharge side.
The method of claim 6,
In the adjusting of the number of upper and lower rollers, when the steel sheet having the front end bent downward enters the upper and lower rollers, the upper rollers located in the mouth are moved upward to reduce the number of upper rollers contacting the steel sheets. The steel sheet straightening method, characterized in that when the steel sheet is bent upwardly enters the upper and lower rollers, the position of the lower roller located in the mouth side is moved downward to reduce the number of lower rollers in contact with the steel sheet.
The method of claim 6,
The indentation amount is set by Equation 1 below so that the plastic strain (YR) is 80% or more in the thickness direction of the steel sheet,
[Formula 1]

Wherein δ: indentation amount, L: roll pitch, YS: yield strength, E: elastic modulus, t: steel sheet thickness, and YR: plastic strain.

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