JPH06210329A - Roll banding prevention method for rolling roll - Google Patents

Abstract

PURPOSE:To prevent roll banding by binarizing a still picture of the surface of a rolling roll, detecting the stripping degree of a mill scale and controlling the supplied quantity of roll cooling water, steel sheet cooling water and rolling oil, etc., based on the detected results. CONSTITUTION:The surface picture of the rolling roll WR is picked up by the CCD camera of an image pickup unit 2 and the stripping degree of mill scale on the surface of the rolling roll is detected by binarizing the image. The roll cooling water supplying parameters such as quantity and pressure of cooling water nozzles 3 and 3' are controlled based on the detected mill scale stripping degree. The steel sheet cooling water supplying parameters such as quantity and pressure of steel sheet cooling water nozzles 5 and 5', the rolling reduction and the rolling oil supplying parameters such as quanity and pressure of rolling oil nozzles 4 and 4' are also controlled. Thus, bitten flaws of steel sheet are not generated and the quality of steel sheet and production yield are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents roll banding of rolling rolls, which prevents roll banding, which is a rough state of rolling rolls that causes biting scale defects on the surface of hot rolled steel sheet. It is about the method.

[0002]

2. Description of the Related Art As is well known, a finish rolling mill in a hot rolling line for steel sheets usually has 6 to 7 finishing stands. The first stage finishing stand of this finishing mill
In the finishing stand of F1 and subsequent F2 and F3, black skin is generated on the surface of the rolling roll (work roll) with rolling. Then, as the rolling time elapses, the black scale is partially peeled off from the surface of the rolling roll, thereby forming a crater-like recess in a band shape along the roll circumferential direction, and as shown in FIG. 3, roll banding is performed. (Roll Ban
It becomes rough skin called ding). When rolling is performed by the rolling roll in which the roll banding occurs, the portion of the roll surface on which the dent is transferred is pressed by the rolling roll of the post-finishing stand, and bite scale flaws are generated on the surface of the steel sheet.

[0003] Here, although the mechanism by which a black skin, which is a layer of iron oxide, is formed on the surface of the rolling roll has not been clearly clarified, the rolling roll is oxidized by contact with a high heat rolling steel plate at a temperature of about 1000 ° C. It is believed that the iron oxide formed on the surface of the rolled steel sheet adheres to the rolling roll.

Further, the peeling (falling off) of the black skin from the surface of the rolling roll is considered to be caused by the following. On the surface of the rolling roll, as shown in FIG. 4, due to heat crack C1 caused by heat input and heat removal (roll cooling) that cyclically occur due to roll rotation during rolling, contact between the rolling roll and backup roll Rolling fatigue crack C2 occurs due to Hertzian stress. As these cracks C1 and C2 progress, the black skin comes off together with the surface layer of the roll body. By performing rolling with a high rolling load such as rolling of a rolled steel sheet having a large deformation resistance, high reduction rolling, or low temperature rolling, the black scale and the surface layer of the roll body fall off from the rolling roll.

By the way, conventionally, there has been no suitable method for preventing the roll banding which causes the bite scale flaw. Therefore, by rolling the rolls per roll in advance based on past experience, and suppressing the rolls, the rolls can be replaced earlier, or by inspecting the surface of the rolled steel plate after rolling. Means for estimating the degree of roughening of the rolling roll in operation and thereby performing roll replacement is adopted.

[0006]

As described above, conventionally, there is no suitable method for preventing the occurrence of roll banding. Therefore, in the former means, the rolling amount per roll is predetermined and suppressed. However, there is a problem in that the roll replacement frequency increases and the productivity decreases. Further, in the latter means described above, since the degree of roughening of the rolling roll during the rolling operation is estimated by inspecting the surface of the rolled steel sheet, the degree of roughening can be accurately known. However, there is a problem in that the roll replacement time is overlooked, and therefore, a steel plate having a bite scale flaw is produced and the product yield is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for preventing roll banding of a rolling roll, which can prevent roll banding from occurring.

[0008]

In order to achieve the above object, the method for preventing roll banding of a rolling roll according to the present invention has a rough surface of the rolling roll which causes bite scale flaws on the surface of the steel sheet. A method for preventing the occurrence of roll banding, in which a surface image of a rotating rolling roll during rolling is imaged in synchronization with lighting of a strobe illumination light source, and the obtained rolling roll surface still image Detects the degree of peeling of the black scale on the surface of the rolling roll by valuing, and based on the detected degree of peeling of the black scale on the roll surface, roll cooling water such as the amount and pressure of the roll cooling water supplied to the rolling roll. Supply parameters, steel plate cooling water supply parameters such as the supply amount and pressure of the steel plate cooling water supplied to the rolled steel plate, and the reduction amount by the rolling rolls, By controlling the rolling oil supply parameters, such as supply amount and pressure of rolling oil to be supplied to the rolling roll, it is characterized in that so as to prevent the occurrence of roll banding of the rolling rolls.

[0009]

The partial peeling of the black skin formed on the surface of the rolling roll is caused by the above-mentioned and. In order to suppress these, in order to suppress the heat input to the rolling rolls, in order to reduce the heat input to the rolling rolls, the supply amount and pressure of the cooling water for the rolls to be supplied to the rolling rolls are increased, or the cooling water is supplied to the rolled steel sheet. It suffices to increase the supply amount and pressure of the cooling water for the steel plate, and to further reduce the rolling load,
The reduction amount (rolling reaction force) by the rolling rolls may be reduced. Further, in order to reduce the rolling load, the supply amount and pressure of the rolling oil supplied to the rolling rolls may be increased, or the reduction amount by the rolling rolls may be reduced. In the method according to the present invention, by carrying out the above according to the degree of peeling of the surface black scale of the rolling roll that is rotating during rolling, the progress of the peeling of the black scale is prevented and the peeling is performed once. It is possible to regenerate the black skin on the part, and thereby to prevent the occurrence of roll banding of the rolling roll.

[0010]

EXAMPLE An example of the method according to the present invention will be described below. FIG. 1 is a diagram showing the overall configuration of an apparatus for carrying out the method according to the present invention, and FIG. 2 is a diagram showing the configurations of the upper moving device and the upper imaging device shown in FIG.

In FIG. 1, reference numerals WR and WR 'are a pair of rolling rolls (work rolls), which are arranged on a first stage finishing stand of a finishing rolling mill in a hot rolling line for steel plates, and BR and BR. ′ Is the backup roll. On the inlet side of the upper rolling roll WR, the upper rolling roll
On the moving block that is moved along the WR roll axis direction,
An upper moving device 1 including an air cylinder having a rod that moves forward and backward with respect to the rolling roll WR is provided, and the upper image pickup device 2 is provided at the rod tip portion of the air cylinder of the upper moving device 1 described later. Is attached.
This upper imaging device 2 equipped with a CCD camera and a xenon lamp as a strobe illumination light source, which will be described later, captures an image of the surface of the rotating upper rolling roll WR during rolling with a CCD camera in synchronization with lighting of the xenon lamp. However, this is for obtaining the static image of the surface of the rolling roll.

On the inlet side and the outlet side of the upper rolling roll WR, headers extending in the roll axial direction are provided with upper rolling rolls.
An upper roll cooling water jet nozzle device 3 is provided in which a plurality of nozzles for jetting the roll cooling water toward the WR are attached at predetermined intervals. Further, as shown in FIG. 1, the upper rolling roll WR has an inlet side, as shown in FIG.
The rolling oil jet nozzle device 4 and the steel plate cooling water jet nozzle device 5 for the upper side are arranged in order from the side. The upper rolling oil jet nozzle device 4 is configured by mounting a plurality of nozzles for injecting rolling oil toward the upper rolling roll WR at predetermined intervals on a header extending in the roll axial direction. The cooling water jet nozzle device 5 is configured such that a plurality of nozzles for jetting the steel plate cooling water toward the upper surface of the rolled steel plate S are attached to a header extending in the plate width direction at predetermined intervals. 6 is a reduction amount adjusting device.

Reference numeral 7 denotes an upper side image processing apparatus for obtaining rough surface information about the upper side rolling roll WR. The upper image processing device 7 includes a binarization processing unit, a memory, a CPU, and the like, and binarizes the image captured by the CCD camera of the upper imaging device 2 to black the rolling roll surface. Detects the degree of peeling of the skin and compares the detected degree of peeling of the black skin on the surface of the roll with a set value to indicate which level of the degree of rough skin is set in advance in multiple levels. This is a device for converting into a rough skin level signal and outputting this roll rough skin level signal. The roll surface roughness level signal from the upper image processing device 7 is used as the upper roll cooling water control device 8, the upper steel plate cooling water control device 9, the upper rolling oil control device 10,
And the reduction amount control device 11.

The upper roll cooling water control device 8 supplies the roll cooling water supplied to the upper rolling roll WR as a roll cooling water supply parameter in response to the roll surface roughness level signal from the upper image processing device 7. Amount, the collision pressure of the cooling water to the upper rolling roll WR, and the distribution pattern of the cooling water supply amount in the roll axial direction, and each control output signal is given to the two upper roll cooling water jet nozzle devices 3, respectively. Is. Upper steel plate cooling water control device 9
Is a supply amount of the steel plate cooling water supplied to the rolled steel plate S and a collision pressure of the cooling water to the rolled steel plate S as a steel plate cooling water supply parameter in accordance with the roll surface roughness level signal from the upper image processing device 7. , And the distribution pattern of the cooling water supply amount in the plate width direction, and each control output signal for controlling the distribution pattern is supplied to the upper steel plate cooling water jet nozzle device 5.

Further, the upper rolling oil control device 10 responds to the roll surface roughness level signal from the upper image processing device 7, and determines the upper rolling roll WR as a rolling oil supply parameter.
To control the supply amount of rolling oil supplied to the upper rolling roll WR, the collision pressure of the rolling oil to the upper rolling roll WR, and the distribution pattern of the rolling oil supply amount in the roll axis direction. 4 is given. The reduction amount control device 11 controls the reduction amount in accordance with the roll rough surface level signals from the upper image processing device 7 and a lower image processing device 7'described later, and outputs a control output signal for that purpose to the reduction amount adjusting device. 6 is given.

Here, the above-mentioned upper moving device 1 and image pickup device 2 will be described in more detail. The applicant has previously proposed these as a part of an optical surface inspection device for a rolling roll (Japanese Patent Application No. 3-165648).
issue). As shown in FIG. 2, the upper moving device 1 includes a feed screw shaft 101 which is arranged in parallel with an upper rolling roll WR and which is rotated in the forward and reverse directions by a motor (not shown).
The moving block 102 which is moved along the roll axis of the rolling roll WR according to the rotation of the feed screw shaft 101, and the moving block
The air cylinder 103 is fixed to the upper surface of 102. The upper image pickup device 2 is attached to the rod tip of the air cylinder 103. As shown in FIG. 2, the upper imaging device 2 has a box-shaped housing box 20 in which a transparent window glass plate 201 is fitted on the front surface.
Two-dimensionally arranged CCD as an image sensor inside 2
CCD camera 203 using (Charge Coupled Device)
, And an annular xenon lamp 204,
Water column forming nozzle 205 on the front side facing the upper rolling roll WR
Is attached.

As shown in FIG. 2, the water column forming nozzle 205 has a water ejection port communicating with the window glass plate 201 of the housing box 202, and when the pressurized water is supplied, the roll cooling water is supplied. This is for forming a water column between the surface of the upper rolling roll WR that is rotating while being sprinkled with water and the window glass plate 201. As a result, the window glass plate 201 is prevented from being contaminated by the roll cooling water containing dirt, and the static image of the surface of the rolling roll is prevented from becoming unclear. Cylindrical water column forming nozzle 205
Is made of acrylic resin that allows light to pass through and is transparent.When it is attached to the front of the housing box 202, water pressurized from a supply source (not shown) is introduced inside via a pressurized water supply pipe. It is supposed to be done.

The apparatus configuration used to prevent the occurrence of roll banding in the upper rolling roll WR has been described above. As shown in FIG. 1, the apparatus configuration in the lower rolling roll WR 'is substantially the same as that described above. Since it is the same, it is omitted and only the reference numerals are explained. That is, in FIG. 1, 1 '
Is a lower moving device, 2'is a lower imaging device, 3'is a lower roll cooling water jet nozzle device, 4'is a lower rolling oil jet nozzle device, and 5'is a lower steel plate cooling water. A jet nozzle device, 7'is a lower image processing device, 8'is a lower roll cooling water control device, 9'is a lower steel plate cooling water control device, and 10 '.
Shows a lower rolling oil control device, respectively.

Next, the method according to the present invention, which is carried out by using the apparatus having the above-mentioned structure, will be described. An image of the surface of the upper rolling roll WR which is rotating during rolling is picked up by the upper side image pickup device 2 at predetermined time intervals. A still image signal of the surface of the rolling roll is input to the upper image processing device 7. The upper image processing device 7 binarizes the image captured by the upper image capturing device 2 to detect the degree of peeling of the black skin on the surface of the upper rolling roll. In this case, the binarization processing of the image is performed by utilizing the fact that the black skin part is black and the part where the black skin is peeled is silver white, and the black skin peeling degree is binarized in this embodiment. The area ratio of the white part to the black part in the image is calculated. Then, the upper image processing device 7 compares the detected degree of peeling of the black surface of the roll surface with a set value to indicate which level of the rough skin level is set and set in advance in a plurality of stages. It is converted into a roll rough surface level signal and this roll rough surface level signal is output.

The upper roll cooling water control device 8 responds to the roll surface roughness level signal input from the upper image processing device 7, and supplies the amount of roll cooling water supplied to the upper rolling roll WR and the upper rolling roll. The collision pressure of the cooling water on the WR and the distribution pattern of the cooling water supply amount in the roll axis direction are controlled, and respective control output signals for that are given to the upper roll cooling water jet nozzle device 3. As a result, the opening of the roll cooling water flow control valve of each nozzle is automatically adjusted to adjust the roll cooling water supply amount and the cooling water supply amount distribution pattern in the roll axial direction, as well as the header position adjustment cylinder (not shown). The distance between the nozzle and the upper rolling roll is automatically adjusted by advancing and retracting the rod in (1), and the collision pressure of the cooling water on the upper rolling roll WR is adjusted. In this case, as the degree of peeling of the black scale generated on the surface of the upper rolling roll WR is larger, the supply amount of the roll cooling water and the collision pressure of the cooling water to the upper rolling roll WR are increased. Controlled.

The upper-side steel plate cooling water control device 9 responds to the roll surface roughness level signal input from the upper-side image processing device 7, and supplies the steel plate cooling water supplied to the rolled steel plate S to the rolled steel plate S. The collision pressure of the cooling water and the distribution pattern of the cooling water supply amount in the plate width direction are controlled, and respective control output signals therefor are given to the upper steel plate cooling water jet nozzle device 5. Thereby, the opening of the steel plate cooling water flow control valve of each nozzle is automatically adjusted to adjust the supply amount of the steel plate cooling water and the distribution pattern of the cooling water supply amount in the plate width direction, and the header position adjusting cylinder (not shown). The distance between the nozzle and the rolled steel plate is automatically adjusted by advancing and retracting the rod of), and the collision pressure of the cooling water on the upper surface of the rolled steel plate S is adjusted. In this case, the greater the degree of peeling of the black scale generated on the surface of the upper rolling roll WR, the more the supply amount of the steel plate cooling water and the collision pressure of the cooling water to the rolled steel plate S are controlled so that the values increase. To be done. In addition, as a matter of course, the temperature is controlled so as not to fall below the finish delivery side temperature of the rolled steel sheet S.

Further, the upper rolling oil control device 10 responds to the roll surface roughness level signal from the upper image processing device 7, and supplies the amount of rolling oil supplied to the upper rolling roll WR.
The collision pressure of the rolling oil to the upper rolling roll WR and the rolling oil supply amount distribution pattern in the roll axial direction are controlled, and control output signals therefor are output to the upper rolling oil ejection nozzle device 4
Give to. Thereby, the opening of the rolling oil flow control valve of each nozzle is automatically adjusted and the rolling oil supply amount and the rolling oil supply amount distribution pattern in the roll axis direction are adjusted,
By moving the rod of the header position adjusting cylinder (not shown) forward and backward, the distance between the nozzle and the upper rolling roll is automatically adjusted, and the collision pressure of the rolling oil on the upper rolling roll WR is adjusted. In this case, the greater the degree of peeling of the black scale generated on the surface of the upper rolling roll WR, the more the amount of rolling oil supplied and the collision pressure of the rolling oil on the upper rolling roll WR are controlled so that the values increase. To be done.

Further, the reduction amount control device 11 controls the reduction amount in accordance with the roll surface roughness level signal from the upper image processing device 7, and supplies a control output signal therefor to the reduction amount adjusting device 6. Accordingly, the reduction amount is controlled to decrease as the degree of peeling of the black scale generated on the surface of the upper rolling roll WR increases. The lower rolling roll W
The description of R'is substantially the same as that described above, and is omitted here.

As a result of the above, it is possible to prevent the progress of peeling of the black scale on the surface of the rolling roll during the rolling operation, and it is possible to regenerate the black scale on the part which has been once peeled off. Banding can be prevented.

[0025]

As described above, according to the present invention,
Taking an image of the surface of the rolling roll during rotation during rolling,
The obtained static image of the rolling roll surface was binarized to detect the degree of peeling of the black scale on the surface of the rolling roll, and based on the detected degree of peeling of the black scale on the roll surface, the roll cooling water was supplied. Amount, steel plate cooling water supply amount,
Since the amount of rolling oil supplied is controlled, roll banding of the rolling roll can be prevented. Thereby, it is possible to eliminate the occurrence of bite scale flaws of the steel plate due to roll banding of the rolling rolls of the finishing rolling mill in the steel plate hot rolling line, which can contribute to the improvement of the quality of the steel plate and its product yield. .

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an apparatus for carrying out a method according to the present invention.

FIG. 2 is a diagram showing a configuration of an upper moving device and an upper image pickup device shown in FIG.

FIG. 3 is a diagram for explaining how roll banding occurs on the surface of a rolling roll.

FIG. 4 is a diagram for explaining heat cracks and rolling fatigue cracks that occur on the surface of a rolling roll.

[Explanation of symbols]

1 ... Upper moving device 101 ... Feed screw shaft 102 ... Movement block 103 ... Air cylinder 2 ... Upper imaging device 20
1… Window glass plate 202… Housing box 203… CC
D camera 204 ... xenon lamp 205 ... water column forming nozzle 3 ... upper roll cooling water jet nozzle device 4 ... upper rolling oil jet nozzle device 5 ... upper steel plate cooling water jet nozzle device 6 ... rolling reduction device 7 ... upper side Image processing device 8 ... Upper roll cooling water control device 9 ... Upper steel plate cooling water control device 10 ... Upper rolling oil control device 11 ... Rolling amount control device 1 '... Lower moving device 2' ... Lower imaging Device 3 '... Lower roll cooling water jet nozzle device 4'
... Lower rolling oil jet nozzle device 5 '... Lower steel plate cooling water jet nozzle device 7' ... Lower image processing device 8 '... Lower roll cooling water control device 9' ... Lower steel plate cooling water Control device 10 '... Rolling oil control device for lower side WR ... Upper rolling roll WR' ... Lower rolling roll S ... Rolled steel plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuro Dejima 1 Kanazawa-machi, Kakogawa-shi, Hyogo Prefecture Kamido Steel Works Kakogawa Steel Works (72) Makoto Fukuda 1-Kanazawa-machi, Kakogawa-shi, Hyogo Kamido Co., Ltd. Inside the Kakogawa Works

Claims (1)

[Claims] 1. A method for preventing the occurrence of roll banding, which is a rough condition of a rolling roll that causes biting scale flaws on the surface of a steel sheet, and is characterized by strobing a surface image of the rolling roll during rotation. The rolling roll surface still image obtained by imaging in synchronization with the lighting of the illumination light source is binarized to detect the degree of peeling of the black skin on the rolling roll surface, and the detected roll surface black Based on the degree of peeling, roll cooling water supply parameters such as roll cooling water supply amount and pressure supplied to the rolling rolls, and steel plate cooling water supply parameters such as steel plate cooling water supply amount and pressure supplied to the rolled steel plate, and By controlling the reduction amount by the rolling roll and the rolling oil supply parameters such as the amount and pressure of the rolling oil supplied to the rolling roll, A method for preventing roll banding of a rolling roll, characterized in that the roll banding is prevented from occurring.