KR101428150B1 - Rolling mill and control method thereof - Google Patents

Abstract

The present invention discloses a mill and a mill control method. A rolling mill according to the present invention is a mill rolling mill in which a widthwise shape is varied by an applied bending force to produce a rolled thin sheet by applying a rolling load to the thinned sheet and a rolling mill work roll having a ratio between the rolling load and the bender strength And then adjusting the bender force according to the rolling load by using the ratio.

Description

[0002] Rolling mill and control method [0003]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill and a control method for the rolling mill. More particularly, the present invention relates to a rolling mill for rolling a thin plate produced in a casting machine of a twin roll type thin plate manufacturing process and a control method of the rolling mill.

The twin roll thin plate manufacturing process is a process for manufacturing a thin plate by rolling a thin plate manufactured in a casting machine through a rolling mill. At this time, molten steel is supplied to the casting machine, and the molten steel is supplied in ladle units. However, the molten steel contained in the ladle differs in component and temperature in ladle units. Therefore, the speed of the casting machine in the twin roll thin sheet manufacturing process also changes accordingly. In addition, as the speed of the casting machine is changed, the speed of the rolling mill is changed in units of ladle, and the temperature of the cast thin plate supplied to the rolling mill is also changed in ladle units. As a result, the rolling load also varies as the speed of the mill and the temperature of the cast thin sheet supplied to the mill change. The variable rolling load changes the widthwise shape of the rolling roll, and a wave defect is generated in the thin plate passing through the rolling roll whose width direction is variable, due to the change in the width reduction state of the thin plate. Therefore, it is necessary to control the rolling mill so that the widthwise shape of the rolling roll of the rolling mill is constant.

There are a number of prior arts about apparatus and methods for controlling the shape of a roll in a sheet manufacturing process. For example, application numbers 10-2009-0028682, 10-2006-0133062, and 10-2006-0132006 filed by the present applicant. However, most of these conventional techniques control the widthwise shape of the rolling roll by a method of measuring the shape of the roll or the thin plate to reduce the shape error. Therefore, a special measuring device for measuring the shape of the roll or the thin plate is required, and the control method thereof is also complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rolling mill capable of simply and efficiently preventing occurrence of wave defects in a rolled thin plate due to irregular shape of a rolling roll.

Another object of the present invention is to provide a mill control method for achieving the above object.

In order to achieve the above object, a rolling mill of the present invention is a rolling mill work roll in which a width direction shape is varied by an applied bending force to produce a rolled thin sheet by applying a rolling load to a cast thin sheet, And adjusting the bender force according to the rolling load by using the ratio.

In order to accomplish the above object, the control unit of the rolling mill of the present invention is characterized in that the rolling load measured during the operation of the molten steel supplied from the first ladle, the rolling load applied to the molten steel supplied from the first ladle, And the bender force may be adjusted according to the rolling load by using the correlation during the operation of the molten steel supplied from the second or subsequent ladle.

To achieve the above object, the mill work roll of the mill of the present invention may comprise a top mill work roll disposed on top of the thin sheet to be rolled and a bottom mill work roll disposed below the thin sheet to be rolled, A lower mill back-up roll disposed at the bottom of the lower mill work roll, an upper mill back-up roll disposed at the lower end of the upper mill work roll, , A rolling mill main hydraulic cylinder for applying a force to the shaft of the upper mill backup roll, and a load cell for measuring the rolling load, which is disposed under the shaft of the lower mill backup roll, for measuring the rolling load As shown in FIG.

In order to achieve the above object, the control unit of the rolling mill of the present invention receives the rolling load measured from the load cell for measuring the rolling load, and controls the rolling mill bender hydraulic cylinder and the rolling mill main hydraulic cylinder.

According to another aspect of the present invention, there is provided a method of controlling a rolling mill including a rolling mill work roll having a widthwise shape varied by an applied bending force to produce a rolled thin sheet by applying a rolling load to the thinned sheet, The method comprising: setting a ratio between the rolling load and the bender force; and adjusting the bender force according to the rolling load using the set ratio.

The setting step of the rolling mill control method of the present invention for achieving the other object is performed during the operation progress of the molten steel supplied in the first ladle, and the adjusting step is performed for the molten steel supplied in the second and subsequent ladle And can be performed at the time of operation.

In order to accomplish the above object, the setting of the rolling mill control method of the present invention is characterized in that the rolling load measured in the finishing step for the molten steel supplied from the first ladle and the operation for the molten steel supplied from the first ladle The ratio can be set using the bender force applied in the finishing step of FIG.

The setting of the rolling mill control method of the present invention for achieving the above other object may be performed in response to a signal applied by an operator.

According to another aspect of the present invention, there is provided a method of controlling a rolling mill, comprising the steps of: providing information on a vendor force to be adjusted to an operator; and adjusting the vendor force in response to a signal input by the operator The method comprising the steps of:

Therefore, according to the rolling mill and rolling mill control method of the present invention, it is possible to simply and efficiently prevent the occurrence of wave defects in the rolled thin plate by adjusting the bender force using the correlation between the rolling load and the bender force.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view schematically showing an apparatus for producing a thin plate in a twin roll thin plate manufacturing process. FIG.
Fig. 2 shows an embodiment of the rolling mill shown in Fig. 1, which shows a case where a wave defect occurs in the central part of the thin plate due to the unevenness in the width direction of the rolling roll.
Fig. 3 shows an embodiment of the rolling mill shown in Fig. 1, which shows a case where a wave defect occurs in the edge portion of the thin plate due to the shape irregularity in the width direction of the rolling roll.
4 is a flow chart for explaining a rolling mill control method of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

In addition, when a part is referred to as being "comprising" an element, it is understood that other elements may be included in the element, not the other element.

1 is a schematic view of an apparatus for manufacturing a thin plate in a twin roll type thin plate manufacturing process. The apparatus comprises a casting machine 1, a pinch roll 3 for a side drawing, a rolling machine 4, a pinch roll 6 ), A cutter 7, and a coiler 8. In Fig. 1, reference numeral 2 denotes a thin plate cast through the casting machine 1, and 5 denotes a rolled thin plate. Although not shown in Fig. 1, the apparatus for manufacturing a thin plate includes a casting machine 1, a pinch roll 3 for drawing on the side, a rolling machine 4, a pinch roll 6 for drawing out, a cutter 7, And a control unit for controlling the display unit 8.

Referring to FIG. 1, the twin roll thin plate manufacturing process will be schematically described as follows.

A casting machine (1) supplies molten steel to produce a thin sheet (2) cast. At this time, the molten steel is supplied in units of ladle (not shown), and the components and the temperature of molten steel may be different in ladle units.

The pinch roll 3 for drawing-in side feeds the cast thin sheet 2 to the rolling mill 4.

The rolling mill 4 rolls the cast thin plate 2 to produce the rolled thin plate 5. [ At this time, each part constituting the rolling mill 4 can be controlled by a control unit (not shown). That is, the rolling mill 4 manufactures the rolled thin plate 5 by applying an appropriate force (i.e., a rolling load) to the thin plate 2 cast under the control of a control unit (not shown).

The exit pinch roll 6 feeds the rolled thin plate 5 to the coil 8.

The coiler 8 winds the rolled thin plate 5 fed through the exit pinch roll 6.

The cutter 7 cuts the rolled sheet according to plan.

The operation of the casting machine 1, the pinch roll 3 for the side drawing, the rolling machine 4, the pinch roll 6 for drawing out, the cutter 7 and the coiler 8 is controlled by a control unit (not shown) Lt; / RTI >

Figures 2 and 3 illustrate an embodiment of the rolling mill 4 shown in Figure 1 wherein the mill 4 includes a mill backup roll 9, a mill work roll 10, a mill backup roll axis 11, A roll axis 12, a rolling mill main hydraulic cylinder 13, a rolling mill bender force hydraulic cylinder 14, and a load cell 15 for rolling load measurement. 2 is a view showing a case 16 in which a wave defect occurs in the central part of the thin plate due to the widthwise unevenness of the rolling mill work roll 10 and Fig. 3 is a cross- (17) in which a wave defect occurs in the edge portion of the thin plate due to the wave.

The operation of each component in the rolling mill 4 will be described with reference to FIGS. 2 and 3. FIG.

The rolling mill 4 shown in Fig. 1 is composed of two rolling mill work rolls 10 arranged on the upper and lower sides of a thin sheet to be rolled and two roll mill rolls 10 And a four-stage rolling mill having two rolling mill backup rolls (9).

The rolling mill main hydraulic cylinder 13 is constructed so as to push the rolling mill backup roll axis 11 in a direction perpendicular to the width direction of the rolling mill backup roll 9 and to generate a force for rolling the cast thin plate 2 Rolling load) is applied to the mill work roll 10 via the mill back-up roll 9. A lower mill work roll located at the top of the thin mill to be rolled, a lower mill work roll located at the bottom of the thin mill to be rolled, a top mill back-up roll disposed at the top of the upper mill work roll, If a lower mill backup roll disposed at the bottom of the work roll is provided, the mill main hydraulic cylinder 13 may apply a force to the shaft of the upper mill backup roll.

Roller Bender The hydraulic cylinder 14 is configured to allow the mill work roll axis 12 to be pushed in a direction perpendicular to the width direction of the mill work roll 10 and to change the shape of the mill work roll 10 (I.e., the bender force) to adjust the roll 10 to the desired level. Roller Bender The hydraulic cylinder 14 is also used to replace the mill rolls (i.e., the mill backup roll 9 and the mill roll 10).

The magnitude of the force applied through the rolling mill main hydraulic cylinder 13 and the rolling mill bender hydraulic cylinder 14 can be determined by a control unit (not shown). That is, the control unit (not shown) can control the roll main hydraulic cylinder 13 and the rolling mill bender hydraulic cylinder 14 so as to control the rolling load and also control the shape of the rolling mill work roll 10 .

 The load cell 15 for measuring the rolling load is disposed adjacent to the rolling mill backup roll axis 11 and measures the rolling load. As described above, when the rolling mill backup roll 9 is constituted by an upper mill backup roll and a lower mill backup roll, the load cell 15 for rolling load measurement can be disposed adjacent to the axis of the lower mill backup roll. The measured rolling load may be output to a control unit (not shown).

When the force (i.e., bender force) applied through the rolling machine bender hydraulic cylinder 14 is large, as shown in Fig. 2, the mill work roll located at the upper portion of the thin plate is bent in a downward direction , The rolling mill work roll located at the bottom of the thin plate is bent in the direction in which the center portion is moved upward. Therefore, more force is applied to the central portion of the rolled thin plate 5, and a wave defect occurs in the central portion of the thin plate 5. [

When the force (i.e., bender force) applied through the rolling machine bender force hydraulic cylinder 14 is small, the rolling mill work roll located at the upper portion of the thin plate as shown in Fig. 3 bends in the upward direction of the center portion, The work roll of the rolling mill located at the lower part of the roll is warped to the downward direction. Therefore, more force is applied to the edge portion of the rolled thin plate 5, so that a wave defect occurs at the edge portion of the thin plate 5. [

4 is a flow chart for explaining a rolling mill control method of the present invention. The control method shown in Fig. 4 can be performed by a control unit (not shown).

The rolling control method of the present invention will be described with reference to FIG.

First, the ratio between the rolling load measured by the load cell 15 for measuring the rolling load and the force (that is, the bender force) applied through the rolling mill bender hydraulic cylinder 14 when there is no wave defect in the thin plate is calculated Step S100). Step S100 may be performed when the operation for the molten steel supplied by the first ladle is in progress. In particular, step S100 may be performed at the time when the operation for the molten steel supplied by the first ladle is completed. Also, the step S100 may be performed in response to the instruction inputted by the operator. That is, at the time when the operation of the molten steel supplied by the first ladle is completed, the ladle becomes an appropriate state in which the wave defect does not occur in the thin plate through the operation process. For example, by adjusting the bender force by feeding back the state of the thin plate while operating, it is possible to obtain an appropriate state in which no wave defect occurs in the thin plate. At this point, the control unit (not shown) calculates the ratio between the rolling load measured by the load cell 15 for measuring the rolling load and the force (i.e., the bender force) applied through the rolling mill bender hydraulic cylinder 14. At this time, the control unit (not shown) can calculate the average value of the rolling load during the predetermined time and the average value of the bending force during the predetermined time, and calculate the ratio of the average value of the rolling load and the average value of the bender force.

Next, the rolling load is measured using the load cell 15 for measuring the rolling load (step S200). Step S200 may be performed when the operation for the molten steel supplied by the second and subsequent ladle is in progress. In particular, step S200 may be performed at the time when the operation of the molten steel supplied by each ladle is started. As described above, the molten steel supplied by the ladle may have different components and temperatures, etc., depending on the respective ladle, and thus the rolling load may be varied. Accordingly, in the present invention, at the time when the operation of the molten steel supplied by each ladle is started (for example, at a time point when a predetermined time has elapsed since the start of the supply of molten steel from the second or subsequent ladle to the casting machine 1) , And the rolling load can be measured using the load cell 15 for measuring the rolling load.

Next, the control unit (not shown) calculates the bender force using the rolling load measured in step S200 and the ratio calculated in step S100, and calculates the bender force to be applied to the rolling mill work roll axis 12 So as to control the rolling machine bender force hydraulic cylinder 14. At this time, the control unit (not shown) provides the vendor to be adjusted to the operator, and may control the rolling machine bender hydraulic cylinder 14 in response to input of a signal to be applied by the vendor to be adjusted.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (9)

A mill work roll for producing a rolled thin sheet by applying a rolling load to a cast thin plate, the widthwise shape of which is changed by a bender force applied in a direction perpendicular to the width direction; And
And a controller for setting the ratio between the rolling load and the bender force and then adjusting the bender force according to the rolling load using the ratio,
The control unit
The ratio is set from the rolling load measured during the operation of the molten steel supplied from the first ladle and the bender force applied when the molten steel supplied from the first ladle is operated,
And the bender force is adjusted according to the rolling load by using the ratio when the molten steel supplied in the second and subsequent ladle is operated. delete The method of claim 1, wherein the mill work roll
An upper mill work roll disposed on top of the thin sheet to be rolled and a lower mill work roll disposed below the thin sheet to be rolled,
The rolling mill
A top mill back-up roll disposed on top of the top mill work roll;
A lower mill backup roll disposed below the lower mill work roll;
A rolling mill bender hydraulic cylinder for applying the bender force to an axis of the upper mill work roll and an axis of the lower mill work roll;
A mill main hydraulic cylinder for applying a force to an axis of the upper mill backup roll; And
Further comprising a load cell for measuring the rolling load, the load cell being disposed under the shaft of the lower rolling mill backup roll and measuring the rolling load. 4. The apparatus of claim 3, wherein the control unit
And receives the rolling load measured from the load cell for measuring the rolling load, and controls the rolling mill bender force hydraulic cylinder and the rolling mill main hydraulic cylinder. A mill control method for a rolling mill comprising a rolling mill work roll for producing a rolled thin sheet by applying a rolling load to a cast thin plate, the widthwise shape of which is varied by a bender force applied in a direction perpendicular to the width direction As a result,
Setting a ratio between the rolling load and the bender force;
And adjusting the bender force according to the rolling load using the set ratio,
Wherein the setting is performed during operation of the molten steel supplied in the first ladle,
Wherein the adjusting step is performed at the time of operation of the molten steel supplied in the second and subsequent ladle. delete 6. The method of claim 5, wherein the setting comprises:
The ratio is set using the rolling load measured in the finishing step for the molten steel supplied from the first ladle and the bender force applied in the finishing step for the molten steel supplied from the first ladle. / RTI > 6. The method of claim 5, wherein the setting comprises:
And in response to a signal applied by the operator. 6. The method of claim 5, wherein the adjusting
Providing information on the vendor power to be adjusted to the operator; And
And adjusting the bender force in response to a signal input by the operator.

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