JP2023036413A - Scale removing equipment and scale removing method - Google Patents

Abstract

To provide a scale removing equipment and a scale removing method which can provide a predetermined scale remaining amount with a high production efficiency.SOLUTION: A scale removing equipment for removing scale on the surface of a steel plate on a pickling line includes a scale removing implement for removing scale on the surface of the steel plate, a scale photographing part which photographs residual scale on the surface of the steel plate after scale removal treatment is performed by the scale removing implement and a control part which adjusts a position and/or a movement of the scale removing implement in accordance with the residual scale amount which is determined on the basis of the residual scale photographed by the scale photographing part.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to scale removal equipment and a scale removal method in a steel plate pickling line. INDUSTRIAL APPLICABILITY The scale removing equipment of the present invention can be suitably used as a scale removing equipment in a pickling line for hot rolled steel sheets.

In recent years, the strength of steel sheets has been increasing in order to reduce the weight of automobiles and improve collision safety. is being done. On the other hand, while moldability is also required, there are cases where a higher coiling temperature is desired in order to achieve high strength and high workability. On the other hand, as the coiling temperature rises, the scale of the hot-rolled steel sheet increases. Especially in the steel sheet with increased Si content and Mn content in the steel, the scale of the hot-rolled steel sheet increases due to the high coiling temperature. I have a problem that happens a lot. Methods for removing scale from hot-rolled steel sheets have been proposed so far.

For example, Patent Document 1 relates to a pickling method for a high Si high Mn content hot-rolled steel sheet. It is proposed to apply physical force with at least one of the abrasive brushes.

In Patent Document 2, a plurality of shape straighteners and scale grinding units (brush rolls) are arranged in a pickling line that mechanically and chemically removes scale adhering to the surface of a steel plate such as stainless steel. A stainless steel plate that uniformly suppresses scales and flaws on the surface of the steel plate in the width direction by grinding the flaws on the surface of the steel plate after correcting the shape of the steel plate with a shape straightening machine based on the detection signal from the shape sensor. We are proposing pickling equipment.

JP 2016-194153 A JP-A-8-188892

For example, when a brush roll is used as a descaling jig, in a continuous pickling line for removing scales from hot-rolled steel sheets, physical washing equipment such as a chemical washing equipment using acid and a brush roll equipment are generally used. have

In the brush roll equipment described above, scales on the surface of the steel sheet are cleaned by rotating the brush roll, which is generally arranged with the roll axis orthogonal to the advancing direction of the steel sheet, at a constant number of revolutions and pressing the brush roll against the sheet. The closer the rotating shaft of the brush roll is to the steel plate, the greater the frictional force acting between the brush and the steel plate, so the scale cleaning effect increases, but the motor current value required to maintain the brush roll rotation speed increases. , the amount of wear of the bristles of the brush roll also increases. In other words, a decrease in production efficiency is caused.

Conventionally, in a continuous pickling line for removing scales from hot-rolled steel sheets, the ease of removing scale from steel sheets varies depending on the steel type of the target steel sheet and the degree of scale formation in the hot rolling process. Depending on the target steel sheet, set the target values for the rotation speed of the motor that rotates the roll and the load current at preset values (constant values). It is used in the method of adjusting the distance of the steel plate. However, the amount of scale and the ease of descaling of hot-rolled steel sheets generally vary from one steel product to another or even within the same steel product. Therefore, if brush roll equipment is used at a constant rotation speed and load current, depending on the steel plate to be cleaned, the cleaning load may be insufficient and scale may remain, or the cleaning load may be excessive, resulting in power consumption and brush bristle material consumption. The problem was that unnecessary costs were generated in terms of wear and tear. One of the problems is that if the bristles of the brush are severely worn, the frequency of replacement of the roll increases, resulting in a decrease in productivity.

Patent Document 1 proposes a pickling method for high-Si-high-Mn-containing hot-rolled steel sheets that are prone to scale formation. There are many problems in terms of manufacturing costs, such as excessive wear of the bristles of the brush roll.

Patent Document 2 proposes a method of uniformly improving the surface of the steel sheet in the product by using a sheet shape straightening machine, but it is not possible to change the scale removal method according to the amount of residual scale. Not proposed.

SUMMARY OF THE INVENTION The present invention has been developed in view of such circumstances, and an object of the present invention is to provide a scale removal facility and a scale removal method capable of achieving a predetermined residual scale amount with high production efficiency.

The present invention can use, for example, a brush roll as a descaling jig for a pickling line. Furthermore, in the process after the scale removal process, the number of scales present on the surface of the steel sheet is measured using, for example, a camera capable of continuously photographing. By increasing or decreasing the current target value of the rotation motor of the brush roll, it is possible to optimize the power consumption and brush roll bristle consumption due to cleaning. Reducing the consumption of brush roll bristles can reduce the frequency of replacement of brush rolls, leading to improved productivity.
In order to achieve the above-described problems, the present inventors have made intensive studies and found the following.
[1] A scale removal facility for removing scale on the steel plate surface in a pickling line,
a scale removing jig for removing scale on the surface of the steel plate;
a scale photographing unit for photographing residual scale on the surface of the steel sheet after the scale removal process has been performed by the scale removal jig;
and a control unit that adjusts the position and/or movement of the scale removal jig according to the amount of residual scale obtained based on the residual scale photographed by the scale photographing unit.
[2] A scale removal method for removing scale on the surface of a steel sheet in a pickling line,
A scale removing step for removing scale on the surface of the steel plate;
a scale photographing step of photographing the residual scale on the surface of the steel plate after the scale removal treatment in the scale removing step;
and an adjustment step of adjusting a scale removal amount according to a residual scale amount obtained based on the residual scale photographed in the scale photographing step.

ADVANTAGE OF THE INVENTION According to this invention, the descaling equipment and descaling method which can achieve the predetermined|prescribed amount of residual scales with high production efficiency can be provided.

According to the descaling equipment and descaling method of the present invention, even if the amount of scale on a hot-rolled steel sheet and the easiness of descaling vary from one steel plate product to another, or within the same steel plate product, a predetermined residual scale can be obtained. Quantity can be achieved with high production efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram for demonstrating the whole structure of the scale removal equipment of this invention. It is a figure for demonstrating the structure (Type1) of a brush roll. It is a figure for demonstrating the structure (Type2) of a brush roll. FIG. 10 is a diagram for explaining a change in remaining scale amount with respect to elapsed time; FIG. 10 is a diagram for explaining a change in brush roll rotation motor current value with respect to elapsed time; It is a flow figure for explaining a scale removal method of a steel plate.

MODE FOR CARRYING OUT THE INVENTION Hereinafter, a scale removal facility and a scale removal method according to embodiments of the present invention will be described with reference to the drawings.

<Scale removal equipment>
FIG. 1 is a conceptual diagram for explaining the overall configuration of the scale removing equipment of the present invention.
The scale removing equipment of the present invention is a scale removing equipment for removing scale on the surface of a steel plate in a pickling line, and includes a scale removing jig for removing scale on the steel plate surface and the scale removing jig described above. The position and/or movement of the scale removal jig according to the amount of residual scale obtained based on the scale photographing unit that photographs the residual scale on the surface of the steel plate after the treatment, and the residual scale photographed by the scale photographing unit. and a control unit that adjusts the scale removal equipment.

The scale removal equipment 1 of FIG. 1 is equipment used when removing the scale of a steel plate.
In the acid scale cleaning apparatus 2 of FIG. 1, hydrochloric acid is mainly used as the acid. The acid washing device 3 mainly uses water. The device 4 having a brush roll in FIG. 1 is a device used for physically removing scale.
The step of physically removing scales using a brush roll includes the step of physically removing scales using a brush roll after the step of washing the acid with water as shown in FIG. 1, and the step of using the brush roll while washing the acid. There is a process to remove the scale by using the process, and each is used properly. Incidentally, in the present embodiment, the brush roll described above corresponds to a scale removing jig. Then, after the step of removing scales, the front and back surfaces of the steel plate surface are photographed using the device 5 for photographing the surface of the steel plate. The device 5 for photographing the steel plate surface corresponds to the scale photographing unit described above. A CCD (Charge Coupled Devices) camera, for example, can be used as a device for photographing the steel plate surface. Using the steel sheet feed length measuring device 6, the threaded length of the steel sheet can be obtained from the rotation speed of the roll in contact with the steel sheet and the circumference of the roll. The remaining scale amount computing device 7 counts the number of areas determined to be remaining scale from the image captured by the above-described device 5 for capturing the steel plate surface, and obtains the number from the steel plate feeding length measuring device 6. The amount of remaining scale (pieces/m) is obtained by dividing by the strip threading length. A region having a darker color tone than the steel plate substrate, an aspect ratio of 2 or less, and a size of 10 mm×10 mm or less was determined to be residual scale. From the viewpoint of improving the yield of cold-rolled steel sheets, the amount of residual scale is preferably 0.025 (pieces/m) or less.

FIG. 2 is a diagram for explaining the structure (Type 1) of the brush roll. FIG. 3 is a diagram for explaining the structure (Type 2) of the brush roll. The brush roll has a columnar shape and is arranged so that the rotation axis of the roll is perpendicular to the direction in which the steel sheet advances, and the brush roll rotates as the steel sheet advances. In addition, bristles are formed on the entire surface of the brush roll for removing residual scale, and although the material of the bristles is not particularly limited, it is preferably nylon containing abrasive grains.
Brush rolls are often used with Type 1 and Type 2 structures. The first is a structure of the type shown in FIG. A backup roll 103 is installed on the back side of the brush roll. The second is a structure of the type shown in FIG. A backup roll 103 is placed in contact with the contact surface, and a brush roll is placed in contact with the other surface. For steel sheets that tend to warp in the width direction of the steel sheet due to unevenness in the structure of the hot-rolled steel sheet due to temperature unevenness in the width direction and thickness direction during hot rolling, the structure shown in Fig. 3 is used. By using it, board warpage can be greatly reduced. In particular, for steel sheets in which sheet warpage does not pose a problem, the type shown in FIG. 2, which is inexpensive, is used.

The control unit 13 shown in FIG. 1 adjusts the position and/or movement of the scale removing jig according to the amount of residual scale photographed by the scale photographing unit described above. The control unit 13 may have the remaining scale amount computing device 7, the brush roll rotating motor current target value computing device 8, the brush roll facility control device 9, and the host process computer 12 shown in FIG. The brush roll rotation motor current target value calculation device 8, the brush roll facility control device 9, the brush roll rotation motor 10, the brush roll reduction motor 11, and the host process computer 12 will be described with reference to FIGS. 4 and 5. FIG.

Adjusting the position of the descaling jig according to the amount of residual scale described above means that if the amount of residual scale is large, a high load is applied to the brush roll reduction motor, and the axial position of the brush roll is shifted to the steel sheet side. to increase the pressing pressure of the brush roll to enhance the effect of removing scales. It means to keep away from the steel plate side to reduce the pressing pressure of the brush roll and reduce the amount of scale removal. Further, adjusting the movement of the descaling jig according to the amount of residual scale described above means that when the amount of residual scale is large, a high load is applied to the brush roll reduction motor, and the rotation speed of the brush roll is is increased to increase the effect of removing scale, and on the other hand, when the amount of remaining scale is small, the load on the brush roll reduction motor is reduced, the rotation speed of the brush roll is reduced, and the amount of scale removal is reduced. means By implementing the contents shown above, a predetermined remaining scale amount can be achieved with high production efficiency by optimizing power consumption and brush roll bristle consumption.

FIG. 4 is a diagram for explaining changes in the remaining scale amount with respect to elapsed time. The target data for the residual scale amount differs depending on the end use and the presence or absence of plating, and the host process computer 12 stores manufacturing conditions as preset values for achieving the target residual scale amount according to each steel type and product. there is The amount of residual scale is continuously obtained using the residual scale amount calculating device 7, and the actual value of the residual scale amount and the residual scale obtained from the host process computer 12 are obtained in the brush roll rotating motor current target value calculating device 8. A current target correction amount is calculated by multiplying the difference between the target amounts by a constant gain, and is added to the current target preset value obtained from the host process computer 12 to create the current target value. FIG. 5 is a diagram for explaining the change in the current value of the rotary motor of the brush roll with respect to elapsed time. As shown in Fig. 5, the above target current values are created with restrictions so that they do not exceed the upper limit value and lower limit value set according to the strength of the brush roll equipment and the rated current of the motor. there is

The brush roll equipment control device 9 is a control device for the brush roll equipment, and is composed of a calculator and a drive device. The current target value created by the brush roll rotating motor current target value computing device 8 is acquired, and the brush roll reduction motor is operated so that the current actual value of the brush roll rotating motor shown in the brush roll rotating motor 10 and the current target value match. It controls a screw down motor that adjusts the axial position of the brush roll shown at 11 . Specifically, when the current value 115 of the brush roll rotation motor in FIG. 5 is higher than the preset current setting value 113, a high load is applied to the brush roll reduction motor, and as a result, the axial position of the brush roll is shifted toward the steel sheet. As it gets closer, the pressing pressure of the brush roll increases, and the effect of removing scale increases. Conversely, when the current value 115 of the brush roll rotation motor is lower than the preset current setting value 113, the load on the brush roll reduction motor becomes small, the axial position of the brush roll moves away from the steel plate side, and the pressing pressure of the brush roll becomes small. Become.
Also, the movement of the removal jig described above can be adjusted by controlling the number of rotations of the brush roll, for example. Specifically, when the brush roll rotation motor current value 115 in FIG. 5 is higher than the preset current setting value 113, a high load is applied to the brush roll reduction motor, and as a result, the rotation speed of the brush rolls increases. , the effect of removing scale is higher. Conversely, when the brush roll rotation motor current value 115 is lower than the preset current setting value 113, the brush roll rotation speed is reduced.

By adjusting the position and/or the number of revolutions of the brush roll in this way, it is possible to suppress the application of excessive current to the brush roll rotating motor, and further to suppress the amount of wear of the bristles existing on the surface of the brush roll. is possible, and high production efficiency can be achieved. In addition, it is possible to keep the remaining scale amount below a predetermined value at any product position.
<Scale removal method>
The scale removal method of the present invention is a scale removal method for removing scale on the surface of a steel sheet in a pickling line. Scale including a scale photographing step of photographing the residual scale on the steel plate surface after the scale is removed, and an adjustment step of adjusting the scale removal amount according to the residual scale amount obtained based on the residual scale photographed in the scale photographing step. removal method.

FIG. 6 is a flowchart for explaining a method for removing scale from a steel plate. As shown in FIG. 6, when removing scales, first, an acid washing step S1, an acid washing step S2, and a brush roll removing step S3 are performed.
Thereafter, in step S4 of continuously photographing the surface of the steel sheet, the surface of the steel sheet after removing the scale is photographed using the apparatus 5 for photographing the surface of the steel sheet in FIG. Further, after that, in the step S5 of determining the remaining scale amount, the remaining scale amount is determined based on the image taken as described above. After that, in the calculation step S6 for determining the brush roll rotation motor current target value, the current target value that maximizes the production efficiency is determined according to the remaining scale amount obtained above. In the calculation step S7 of determining the load of the screw roll motor for adjusting the axial position and/or movement of the brush roll, the load value of the screw roll motor that provides the highest production efficiency is determined. By doing so, it is possible to ensure a predetermined steel sheet surface condition (remaining scale amount) without impairing productivity. The adjustment step of adjusting the amount of descaling described above is determined based on the value calculated in the calculation step S7 for determining the load of the screw-down motor for adjusting the axial position and/or movement of the brush roll. It is a step of adjusting the amount of scale removal by adjusting the position and/or movement of the scale removal jig according to the amount of residual scale.
Further, the step S2 of washing with acid and the step S3 of removing scales with a brush roll can be performed simultaneously, that is, a step of removing scales with a brush roll while washing with acid.

The scale removal equipment and scale removal method of the present invention have been described above. If such equipment and methods are used, even if the steel sheet is of any kind, and even if the degree of scale formation in the hot rolling process is different and the amount of residual scale varies within the same product, In addition, it is possible to suppress the amount of wear of the bristles existing on the surface of the brush roll, thereby improving the production efficiency. Also, the remaining scale amount can be suppressed below a predetermined value at any product position.

REFERENCE SIGNS LIST 1 scale removal equipment 2 scale washing equipment with acid 3 equipment for washing with acid 4 equipment with brush roll 5 equipment for photographing steel plate surface 6 equipment for measuring steel plate feed length 7 equipment for calculating the amount of residual scale 8 brush roll rotating motor current target value Arithmetic device 9 Brush roll equipment control device 10 Brush roll rotation motor 11 Brush roll reduction (axis position adjustment) motor 12 Host process computer 13 Control unit 101 Steel plate 102 Brush roll 103 Backup roll 104 Direction of movement of steel plate 110 Amount of residual scale 111 Residual scale Quantity target 112 Upper limit value 113 Preset current setting value 114 Lower limit value 115 Current value of rotary motor of brush roll S1 Scale cleaning process with acid S2 Acid washing process S3 Scale removal process with brush roll S4 Continuous photographing of steel plate surface step S5 of determining the amount of residual scale step S6 calculating a brush roll rotary motor current target value S7 calculating a load on the screw down motor for adjusting the shaft position and/or movement of the brush roll

Claims (2)

A scale removal facility for removing scale on the steel plate surface in a pickling line,
a scale removing jig for removing scale on the surface of the steel plate;
a scale photographing unit for photographing residual scale on the surface of the steel sheet after the scale removal process has been performed by the scale removal jig;
and a control unit that adjusts the position and/or movement of the scale removal jig according to the amount of residual scale obtained based on the residual scale photographed by the scale photographing unit. A scale removal method for removing scale on a steel plate surface in a pickling line,
A scale removing step for removing scale on the surface of the steel plate;
a scale photographing step of photographing the residual scale on the surface of the steel plate after the scale removal treatment in the scale removing step;
and an adjustment step of adjusting a scale removal amount according to a residual scale amount obtained based on the residual scale photographed in the scale photographing step.

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