JP2007007710A - Method for straightening steel sheet having different thickness - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of straightening a steel sheet having different thickness surely and highly precisely without increasing equipment cost when performing the rolling reduction and straightening of the steel sheet having different thickness consisting of a flat portion and a tapered portion by a pair of upper and lower work rolls and backup rolls to support them. <P>SOLUTION: In the method for straightening the steel sheet having different thickness, the steel plate consisting of a flat portion and a tapered portion is subjected to the rolling-reduction and straightened by a straightening machine having a pair of upper and lower work rolls and a plurality of divided backup rolls to support them, backup roll rolling-reduction cylinders for vertically moving each divided backup roll, and a main rolling-reduction cylinder for vertically moving the work rolls and the backup rolls. The flat portion is straightened by adjusting the backup roll rolling-reduction cylinders, and the tapered portion is straightened by synchronously adjusting both the main rolling-reduction cylinder and the backup roll rolling-reduction cylinder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for correcting an abnormal thickness steel sheet in which an abnormal thickness steel sheet including a flat plate portion and a taper portion is pressed down and corrected by a pair of upper and lower work rolls and a backup roll that supports the work roll.

The correction of different thickness steel plates whose shape changes in the plate thickness direction has been corrected with a press device so far.
The reason for this is that, with a roller leveler type straightening machine (hot leveler, cold leveler) used for straightening general materials, different thickness steel sheets whose shape changes in the thickness direction are difficult to flatten after correction.
However, since the press apparatus conventionally used for straightening is an off-line process, only about 40 steel plates can be processed per day, and there is a problem that productivity is very low.

Japanese Patent Laid-Open No. 2000-167604 proposes a solution to this problem. This has a mechanism for supporting a work roll by a divided backup roll divided into three or more in the axial direction, and each divided backup roll is provided with a load detection device, a reduction device and a reduction position detection device independently. It is an intelligent rolling mill.
When this intelligent rolling mill is used as a straightening machine, the position of the work roll is controlled by the main reduction cylinder so that a preset reduction load is applied to the entire steel plate, while each backup roll is positioned by each backup roll reduction cylinder. It controls and correct | amends by giving a bending in the position of the length direction of a work roll.
However, in this method, the thickness change in the flat plate part (this change is caused by roll bending and roll wear of the rolling mill, temperature difference of the steel plate) is several tens μm at most, whereas the thickness in the taper part is If the change is large, it may be about several tens of mm (about 100 times).
For this reason, when cultivating only the cylinder under the roll of the backup roll to cope with the change in thickness of the taper portion, the stroke of each cylinder needs to be about several tens of millimeters so that the thickness change of the taper portion can be covered. When the number of divisions is large, there is a problem that the equipment cost becomes expensive.
JP 2000-167604 A

  Therefore, the present invention solves the problems of the prior art as described above, and when the different thickness steel plate composed of a flat plate portion and a taper portion is squeezed and corrected by a pair of upper and lower work rolls and a backup roll supporting the work roll, It is an object of the present invention to provide a method for straightening different thickness steel sheets that can be accurately and reliably straightened without increasing the cost.

The present invention has been made as a result of intensive studies in order to solve the above problems, and the gist of the present invention is as follows.
(1) A pair of upper and lower work rolls and a plurality of divided backup rolls that support the work rolls, a backup roll pressing cylinder that moves the divided backup rolls up and down, and a main that moves the work rolls and the backup roll up and down. A straightening machine having a reduction cylinder is a method of reducing and correcting a different thickness steel plate comprising a flat plate portion and a taper portion, wherein the flat plate portion is adjusted by adjusting the backup roll reduction cylinder, and the taper portion is A method for correcting an abnormal thickness steel sheet, wherein both the main pressure reduction cylinder and the backup roll reduction cylinder are adjusted and corrected.

  According to the present invention, when a different thickness steel plate comprising a flat plate portion and a taper portion is squeezed and corrected by a pair of upper and lower work rolls and a backup roll that supports the work plate, the flat plate portion is corrected by adjusting the backup roll reduction cylinder. The taper portion is industrially useful, for example, by adjusting both the main pressure reduction cylinder and the backup roll pressure reduction cylinder to correct the accuracy without making the equipment cost expensive. There is a remarkable effect.

The best mode for carrying out the present invention will be described in detail with reference to FIGS.
FIG. 1 is a diagram illustrating a straightening device used in the method for straightening a different thickness steel sheet according to the present invention.
In FIG. 1, PR is a pinch roll, GR is a guide roll, WR is a work roll, and BUR is a backup roll.
1 is transported in the direction indicated by the arrow in FIG. 1, and the different thickness steel plates sandwiched between the pinch roll (PR) and the guide roll (GR) are subjected to a constant load by a pair of upper and lower work rolls (WR). By rolling down and straightening, it is possible to perform on-line correction of deformation of a different thickness steel plate whose shape changes in the thickness direction.
Here, the different thickness steel plate is a steel plate having different thickness portions composed of a flat plate portion and a taper portion, for example, a steel plate composed of a large thickness portion, a small thickness portion, and a taper portion.

FIG. 2 is a diagram exemplifying a backup roll used in the method for straightening different thickness steel sheets according to the present invention.
In the present invention, the structure of the backup roll (BUR) that supports the work roll (WR) is not limited. As shown in FIG. 2, the backup roll (BUR) divided into three or more in the axial direction should be used. Thus, the rolling reduction based on the thickness deviation can be performed in the width direction of the steel plate.
The work roll (WR) may be rectified by the work roll (WR) provided by each of the backup rolls divided into three or more of the above-mentioned backup rolls. By providing the main reduction cylinder provided and performing the reduction correction by properly using these cylinders, the reduction correction accuracy can be performed with high accuracy in the tapered portion as well as the flat plate portion.

FIG. 3 is a view illustrating an embodiment of the method for correcting a different thickness steel plate of the present invention, and is a side view of a work roll and a backup roll.
In FIG. 3, BUR indicates a backup roll and WR indicates a work roll.
The present invention relates to a method for correcting a different thickness steel sheet, wherein the different thickness steel sheet comprising a flat plate portion and a taper portion is reduced by a pair of upper and lower work rolls (WR) and a backup roll (BUR) supporting the same. As shown in Fig. 3, the large-thickness part and the small-thickness part are reduced using a backup roll reduction cylinder arranged for each backup roll (BUR), and the taper part is the main part arranged in common with the backup roll (BUR). Reduction is performed using both a reduction cylinder and a backup roll reduction cylinder arranged for each backup roll.

Since there is no change in the plate thickness of the large and small thickness portions that are flat plates, the backup roll (BUR) is moved up and down using the backup roll reduction cylinder arranged for each backup roll (BUR), and each backup is performed. The shape of the steel sheet can be made flat by correcting the rolling so that the load in the sheet width direction of the roll (BUR) is constant.
However, since the thickness of the taper section changes, if the roll reduction is performed using only the backup roll reduction cylinders arranged for each backup roll (BUR), the backup roll reduction cylinders are adjusted according to the taper of the thick steel plate. It has been found that a large expansion / contraction stroke is required due to the necessity of expansion / contraction.
Therefore, in the present invention, by performing the taper portion with the main reduction cylinder and the backup roll reduction cylinder, all the backup rolls in the plate width direction can be adjusted by one cylinder to move up and down simultaneously by the same distance. The equipment cost is low, and the controllability can be improved by dividing the control function.
The different thickness and small thickness parts are reduced using a backup roll reduction cylinder arranged for each backup roll (BUR), and the tapered part is a main reduction cylinder arranged in common with the backup roll (BUR). By rolling down using both the backup roll reduction cylinders arranged for each backup roll, the backup roll reduction cylinders mainly take control of the load in the plate width direction, and the main reduction cylinders mainly load in the longitudinal direction. By performing the role assignment of giving constant control, the confusion of the reduction control can be eliminated and the reduction accuracy can be improved.

Table 1 and FIG. 4 show examples in which the straightening method for different thickness steel sheets according to the present invention is carried out under the following conditions.
<Conditions for implementation>
・ Target material Thickness: 12mm / 16mm / 12mm Dissimilar thickness steel plate changed in the longitudinal direction. Plate width: 3000mm
Length: 28m
-The length of each part of the deformed steel sheet is previously grasped from the information during hot rolling.
-Reduction rate during correction: 0.3%
・ Acceleration / deceleration rate of straightening machine: 80mpm / s2 (accelerates 0 to 120mpm in 2 seconds)
-Lifting speed under main pressure: 8mm / s
The large thickness part L3 and the small thickness parts L1, L5 of the material to be corrected shown in FIG. 4 are reduced using a work roll reduction cylinder arranged for each backup roll, and the taper parts L2, L4 are backup rolls. When both the work roll reduction cylinders arranged for each and the main reduction cylinder common to the backup rolls are used for reduction, the plate thickness accuracy after correction by the method of the present invention is about twice as large as before. It was possible to improve.

It is a figure which illustrates the straightening apparatus used for the straightening method of the different thickness steel plate of this invention. It is a figure which illustrates the backup roll used for the straightening method of the different thickness steel plate of this invention. It is a figure which illustrates embodiment of the correction method of the different thickness steel plate of this invention. It is a figure which shows the Example of the correction method of the thickness steel plate of this invention.

Explanation of symbols

PR pinch roll
GR guide roll
WR work roll
BUR backup roll

Claims (1)

A pair of upper and lower work rolls and a plurality of divided backup rolls supporting the work rolls, a backup roll lowering cylinder for moving each of the divided backup rolls up and down, and a main pressure lowering cylinder for moving the work rolls and the backup roll up and down The flat plate portion is adjusted by adjusting the back-up roll reduction cylinder, and the taper portion is reduced by the main reduction. A straightening method for different thickness steel plates, characterized by adjusting and straightening both the cylinder and the cylinder under the backup roll.

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