JPH09111431A - Top roll mending device for hot dip metal coating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start a polishing means in an adequate period without the worry about a reading error by constituting this device in such a manner that the size of flaws is not directly observed but the stains as a sign thereof are observed. SOLUTION: This top roll mending device consists of the polishing means 10 of a top roll 2, an illuminating means 3, a photographing means 4 for photographing the specified area of the surface of the top roll 2, an image recording section 5 for periodically recording the photographed image as a static image, a luminescent point area judging section 6 for discriminating whether or not the ratio at which the area of the luminescent point of the specified or higher luminance in the recorded image occupies the entire area exceeds the specified value and a polishing control section 7 for having the top roll polished by starting this polishing means 10 in accordance with the information that this luminescent point area exceeds the specified value. As a result, the intricate means, such as illuminated traveling means and polygonal mirrors, are not required and, therefore, the trouble rate of the device is low and the maintenance and inspection thereof are easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a top roll care device for hot dip galvanizing equipment.

[0002]

2. Description of the Related Art FIG. 8 is a layout diagram of a typical molten metal plating equipment. The molten metal plating equipment 100 includes a molten metal bath 101, a heating zone 102, a heat retaining zone 103, and a cooling zone 1.
04, a seal roll 105 and a top roll 106, and a steel strip 109 that has been annealed by heating in a continuous annealing furnace 108.
Then, the molten metal is applied in the molten metal bath 101, the molten metal is heated in the heating zone 102, and the temperature is kept in the heat retaining zone 103,
By cooling in the cooling zone 104, the alloying treatment of iron and molten metal (for example, zinc) is performed. After the above-described alloying treatment is applied to the steel strip 109 which moves vertically and from the bottom to the top, the steel strip 109 is bent 90 ° by the top roll 106 and turned horizontally.

In the case of hot dip galvanizing, the top roll 10
The temperature of the plated steel strip 109 in No. 6 is 150 to 350 ° C.
The hardness of the plated film is still small. Therefore, by bending with the top roll 106 and then returning it, cracks may occur in the plating film and the plating film may peel off in the form of fine powder. This powder adheres to the top roll 106 and forms a scratch or a recess on the subsequent steel strip 109. Since the scratches and the recesses are likely to be the starting points of the strength reduction and significantly impair the commercial property, it is necessary to observe the surface of the top roll 106 and polish it appropriately.

Conventionally, the top roll 106 is polished with a grindstone or sandpaper based on the visual confirmation and the judgment of the observer. With this, individual difference error occurs,
Since the burden on the observer is heavy, it is necessary to automate the observation, judgment and polishing.

The applicant of the present invention previously detected a flaw in mm unit by detecting flaws with a light emitter and a light receiver which scan the roll surface in the roll axial direction in the "Roll inspection device" of Japanese Utility Model Laid-Open No. 4-1436. We proposed a device that wipes the surface with a wiping device.

[0006]

However, although the above-mentioned apparatus is suitable for slowly inspecting and re-grinding rolls in a roll shop or the like, it has the following problems when applied to inspection of top rolls. Since it is a scanning type inspection device, the state of the portion other than the scanning line (and the length of 1/2 or less of the roll length) is unknown at that time. If the roll is stopped, there is no problem, but since the top roll 106 is rotating, the surface of the roll is inspected in a spiral shape, which makes signal processing difficult. The projector is configured to be movable in the roll axis direction, a polygon mirror (polyhedral mirror) is built in the receiver, and this polygon mirror must be rotated accurately at high speed, which makes the apparatus expensive.

[0007]

Therefore, studies were started for the purpose of establishing a technique more suitable for automatic observation and polishing of the top roll than the above-mentioned conventional technique. First, the inventors of the present invention carefully observed the surface of the top roll in use, found that the surface of the top roll became dirty over time, and found that the brightness was increased as a whole. Further, it has been found that the stain element of the top roll is a powder separated from the plating film and this powder is extremely fine.

Therefore, the following process was assumed. Start of powder adhesion → the next powder newly adheres to the non-adhered surface and the next powder adheres to the previous powder → In the former case, the powder adhesion area ratio on the roll surface increases with time. In the latter case, the powder will become large particles over time, and the steel strip will be damaged in mm units. Obviously, the former and the latter were observed to proceed simultaneously. Therefore, the present inventors have established a technique of polishing a roll before inconvenience such as scratching occurs by observing stains quantitatively instead of directly detecting grains and scratches.

Specifically, the top roll care device of claim 1 comprises a polishing means for polishing the surface of the top roll,
Illuminating means for brightening the portion of the top roll that is not in contact with the plated steel strip, photographing means for receiving the reflected light of the light emitted from this illuminating means and photographing a certain area of the surface of the top roll, and the photographed image An image recording unit that periodically records as a still image, and a bright spot area determination unit that determines whether or not the ratio of the area of the bright spots of a certain brightness or more in the recorded image to the total area exceeds a certain value. And a polishing controller for starting the polishing means and polishing the top roll based on the information that the bright spot area exceeds a certain value.

According to another aspect of the present invention, there is provided a top roll care device, a polishing means for polishing the surface of the top roll, an illumination means for illuminating a portion of the top roll which is not in contact with the plated steel strip, and a light emitted from the illumination means. An imaging means for receiving the reflected light of and capturing a certain area of the surface of the top roll,
An image recording unit that periodically records the captured image as a still image, a maximum brightness determination unit that determines whether or not the brightness of the brightest bright spot among the bright spots in the recorded image exceeds a predetermined value, and And a polishing controller that starts the polishing means and polishes the top roll based on the information that the maximum brightness exceeds a predetermined value.

Since the stain as a precursor thereof is observed not by directly looking at the size of the scratch, there is no fear of a reading error and the polishing means can be started at a suitable time. Further, since it is not a scanning type, complicated means such as an illumination traveling means and a polygon mirror are not required, so that the failure rate of the device is small and maintenance and inspection is easy.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a principle view of a top roll care device for a top roll according to the present invention. The top roll care device 1 comprises a polishing means 1 for polishing the surface of the top roll 2.
0, an illumination unit 3 that brightens a portion of the top roll 2 that is not in contact with the plated steel strip W, and a reflected light of the light emitted from the illumination unit 3 is received to photograph a certain area of the surface of the top roll 2. The image capturing unit 4, the image recording unit 5 that periodically records the captured image as a still image, and whether or not the ratio of the area of the bright spots having a certain brightness or more to the entire area in the recorded image exceeds a certain value. Bright spot area determination unit 6 for determining
And a polishing controller 7 for starting the polishing means 10 to polish the top roll based on the information that the bright spot area exceeds a certain value. It does not matter that the image recording unit 5, the bright spot area determination unit 6, and the polishing control unit 7 are integrated into one control unit.

The illuminating means 3 is, for example, a 500 W halogen lamp and has an angle of 45 ° to measure the scattered reflected light.
Aim at the center of the field of view of the camera. It should be noted that the axis of the camera and the axis of the illumination means 3 may be coaxial and only specularly reflected light may be used. The photographing means 4 is a two-dimensional CCD (solid-state image pickup device) camera housed in a heatproof case, and this camera has a measurement field of view of about 300 mm × 300 mm.
The resolution is about 0.5 mm, and a still image with an exposure time of 1/1000 seconds can be captured with an electronic shutter.

FIG. 2 is a front view of the polishing means according to the present invention. The polishing means 10 includes a base frame 11 and a rail 1.
Slide base 1 that moves above 2 and 12 in the front and back direction of the drawing
3 and the slanted base 14 provided on the slide base 13
A slider 16 that slides on the inclined base 14 via a rail 15, a motor 17 and a polishing roll 18 attached to the slider 16, a cylinder 19, and elements described in the next figure. If the cylinder 19 is advanced,
The polishing roll 18 can be brought into contact with a top roll (not shown).

FIG. 3 is a plan view of the polishing means according to the present invention. The polishing rolls 18, 18 are provided with abrasives such as sandpaper on their peripheral surfaces and are attached to a shaft 22 horizontally supported by bearings 21 and 21. This shaft 22 has a belt 23
It is rotated by a motor 17 via. Also, tilt base 1
4 is reciprocated along the rails 12 and 12 by the action of the motor 25 with a speed reducer and the feed screw 26.

The operation of the above-mentioned top roll care device will be described below. FIG. 4 is an operation flow chart according to the first embodiment of the present invention, in which STXX indicates a step number. ST01: Still image information obtained by the photographing means 4 in FIG. For example, it is assumed that the image A is bright in the lower right and becomes darker toward the upper left because of the illumination. The ripple line schematically shows the lightness distribution.

Further, in this embodiment, black WC-12Co (tungsten carbide containing 12% cobalt) was sprayed on the surface of the top roll 2. When white gray zinc adheres to such a top roll 2, this zinc becomes a bright spot. For example, it is assumed that bright points P1 to P4 are present in the image A.

ST02: The image A is recorded by the image recording means 5 of FIG. 1 and divided into 480 × 480 pixels. This is shown in picture B. ST03: Shading the image B. This shading is a process performed for the purpose of eliminating the influence of uneven illumination of the illumination means 4. Specifically, in the normal illumination means 4, the brightness is not uniform from one end to the other within the illumination range, and furthermore, the sensitivity of each pixel of the camera varies. Further, when the F-number of the camera becomes smaller, the amount of incident light from the edge becomes smaller than that at the center of the visual field.
The unevenness caused by such a cause is called shading, and the correction for eliminating this effect is the shading correction. In the present embodiment, shading correction is performed on the original image by 3 ×.
Image processing for averaging 3 pixels is performed 50 times.
Since the averaging process is repeated, the bright spots disappear and only the background remains. This is shown in picture C.

ST04: Subtract the image C from the image B. Then, as shown in the image D, only the bright points P1 to P4 remain. The bright points P1 to P4 have a brightness of any of 0 to 100. Therefore, the bright points P1 to P4 shine on the screen according to the respective brightness. However, since it is not easy to identify this, the following threshold processing is performed. ST05: For example, the threshold value is set to 30 (brightness), pixels exceeding the threshold value are given the brightness index 255, and pixels below the threshold value are given the brightness index 0. A general-purpose display can display brightness in 256 levels from 0 to 255. Therefore, 255 and 0 are given, and actually 255 is a bright point and 0 is a dark point (not visible). If 255 are given to the bright points P1 and P4 and 0 is given to the bright points P2 and P3, the bright points P1 and P4 are displayed on a black background as shown in the image E. With this, you can easily confirm the position of the problematic zinc deposits simply by looking at the display.

ST06: Count the number of pixels exceeding the threshold value. ST07: All pixels of the total number of this pixel (480 × 480)
When the ratio occupying the ratio exceeds α (for example, 0.05 = 5%), the process proceeds to ST08. ST08: Start the polishing means to polish the surface of the top roll. The method described above is to check the ratio of the pixels of the brightness index 255 to the whole, and is synonymous with checking the area ratio. Therefore, this method is called "area method".

Next, a second embodiment of the present invention will be described. In a device therefor, the bright spot area discriminating unit 6 in FIG. 1 is changed to a maximum bright spot discriminating unit 8. That is, the top roll care device 1A for the second embodiment includes a polishing means 10 for polishing the surface of the top roll 2 and an illuminating means 3 for illuminating a portion of the top roll 2 which is not in contact with the plated steel strip. An image capturing unit 4 that receives reflected light of the light emitted from the illumination unit 3 and captures a fixed area on the surface of the top roll 2, an image recording unit 5 that periodically records the captured image as a still image, and recording A maximum brightness determining unit 8 that determines whether or not the brightness of the brightest spot (the maximum brightness) among the bright spots in the image exceeds a predetermined value, and information that this maximum brightness exceeds the predetermined value. And a polishing controller 7 for starting the polishing means 10 to polish the top roll based on the above.

FIG. 5 is an operation flow chart according to the second embodiment of the present invention. In order to distinguish it from the first embodiment, STxx is given a number of 11 or more. Note that ST11 to ST14 are the same as ST01 to ST04, but will be described again.

ST11: Still image information obtained by the photographing means 4 in FIG. The ripple line schematically shows the lightness distribution. For example, it is assumed that bright points P1 to P4 are present in the image A.

ST12: The image A is recorded by the image recording means 5 of FIG. 1 and is divided into 480 × 480 pixels. This is shown in picture B. ST13: The image B is shaded. In the present embodiment, the shading correction is performed by performing image processing for averaging the original image with 3 × 3 pixels 50 times. Since the averaging process is repeated, the bright spots disappear and only the background remains. This is shown in picture C.

ST14: Subtract the image C from the image B. Then, as shown in the image D, only the bright points P1 to P4 remain. The bright points P1 to P4 have a brightness of any of 0 to 100. Therefore, the bright points P1 to P4 shine on the screen according to the respective brightness. However, since it is not easy to identify this, the following processing is performed. ST15: The brightest one is searched from the bright points P1 to P4. For example, the bright spot P4 has the highest brightness,
It is assumed that the brightness is 55. ST16: The maximum brightness is a threshold value (for example, brightness 5
0) Check if it is greater than or equal to. If it is not less than the threshold value, the process proceeds to ST17. ST17: Start the polishing means to polish the surface of the top roll. Since the method described above is to check the maximum brightness,
This method will be called the "maximum brightness method".

[0026]

Embodiments of the present invention will be described below. Various conditions according to the example are as follows. Top roll size: Outer diameter 1200 mm, body length 2100 mm Surface treatment of top roll: WC-12Co Type of galvanized steel sheet: Alloyed hot-dip galvanized steel sheet Thickness of galvanized steel sheet: 0.35-2.3 mm Width of galvanized steel sheet: 600 to 1880 mm Temperature of plated steel sheet: 150 to 350 ° C. Threshold in area method: 5%

FIG. 6 is an example graph when the top roll is polished by the area method of the present invention, the horizontal axis is time,
The vertical axis is the area ratio (%). In the figure, the present invention is applied from point B. At this point, the area ratio is 15% or more, which exceeds the threshold value of 5%, and therefore the polishing means is activated by ST07 and ST08 in FIG. 4 to polish the surface of the roll. Then, the area ratio becomes almost 0 as shown at the point C. That is, the surface of the top roll is clean. This state continues for about 20 minutes, and then the area ratio starts to increase. Since the threshold value is exceeded at point D, after inertia delay, E
At that point, the polishing means is reactivated. ▽ indicates the start timing of the polishing means. Hereinafter, the same cycle is repeated. The above control is basically performed automatically, but in the case of the area method,
Since the sticking point of zinc appears clearly on the display,
Easy to visually identify.

FIG. 7 is an example graph when the top roll is polished by the maximum brightness method of the present invention. The horizontal axis represents time and the vertical axis represents maximum brightness. Regarding brightness, the following data are known. Range that does not cause a problem in product quality: Brightness less than 30 Severe automotive exterior steel plate: Brightness 40 or less Range in which surface transfer is a problem with general steel plate: Brightness 60 or higher Upper limit brightness: Brightness 70 About the maximum brightness method Sets the threshold to 50. The present invention is applied from the point G in the figure. At this point, the maximum brightness is 70, which exceeds the threshold value of 50.
The polishing means is operated by ST16 and ST17 of FIG. 5 to polish the surface of the roll. Then, as shown at the point H, the maximum brightness drops to about 20. Since the maximum brightness exceeds the threshold value in about 45 minutes, re-polishing is performed at this point. Hereinafter, this cycle is repeated. Since the maximum brightness method needs to monitor only one point, the processing load on the control unit is lighter than that of the area method, and the processing time is short. Therefore, there is a feature that the control unit can be configured by a relatively low-priced inexpensive device.

The threshold value may be appropriately changed according to the characteristics of the target product and operating conditions. Further, it is no problem to use the area method and the maximum brightness method together.

[0030]

The present invention has the following effects due to the above configuration. According to a first aspect of the present invention, there is provided a top roll care device, a top roll polishing means, an illumination means for illuminating the top roll,
A photographing means for photographing a certain area of the surface of the top roll,
An image recording unit that records the captured image as a still image,
In the recorded image, a bright spot area determination unit that determines whether or not the ratio of the area of bright spots with a certain brightness or more to the total area exceeds a certain value, and information that this bright spot area exceeds a certain value. Based on the polishing control unit that starts the polishing means based on this and polishes the top roll, and instead of directly observing the size of the scratch, the stain as the precursor of the scratch is observed, so there is no concern about a read error. Therefore, the polishing means can be started at a suitable time. Further, since it is not a scanning type, complicated means such as an illumination traveling means and a polygon mirror are not required, so that the failure rate of the device is small and maintenance and inspection is easy. Further, since the position and area of the problematic zinc adhesion can be easily confirmed only by looking at the display, the burden on the operator of the apparatus is lightened.

A second aspect of the present invention is to provide a top roll care device,
A polishing means for polishing the top roll, an illuminating means for illuminating the top roll, a photographing means for photographing a certain area of the surface of the top roll, an image recording section for periodically recording the photographed image as a still image, and recording A maximum brightness determination unit that determines whether or not the brightness of the brightest bright point among the bright points in the image exceeds a predetermined value, and starts the polishing means based on information that this maximum brightness exceeds a predetermined value. Since it is composed of a polishing control unit that polishes the top roll by observing stains as a precursor to the size of scratches, instead of directly looking at the size of scratches, there is no concern about reading errors, and at a suitable time. The polishing means can be activated. Further, since it is not a scanning type, complicated means such as an illumination traveling means and a polygon mirror are not required, so that the failure rate of the device is small and maintenance and inspection is easy. Furthermore, since only one point of maximum brightness needs to be monitored, the processing load on the control unit is lighter than in claim 1, and the processing time is short. Therefore, the control unit can be configured with a relatively low-priced inexpensive device.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a top roll care device for a top roll according to the present invention.

FIG. 2 is a front view of a polishing means according to the present invention.

FIG. 3 is a plan view of a polishing means according to the present invention.

FIG. 4 is an operation flow chart according to the first embodiment of the present invention.

FIG. 5 is an operation flow chart according to a second embodiment of the present invention.

FIG. 6 is an example graph when a top roll is polished by the area method of the present invention.

FIG. 7 is an example graph when a top roll is polished by the maximum brightness method of the present invention.

[Figure 8] Layout diagram of typical hot-dip galvanizing equipment

[Explanation of symbols]

1, 1A ... Top roll care device, 2 ... Top roll, 3 ... Illumination means, 4 ... Imaging means, 5 ... Image recording section, 6
... bright spot area determination unit, 7 ... polishing control unit, 8 ... highest brightness determination unit, 10 ... polishing means, 18 ... polishing roll, 101 ... molten metal bath, W ... plated steel strip.

Claims (2)

[Claims] 1. A maintenance device for a top roll for transporting a plated steel strip immediately after solidification of molten metal, which is in a high temperature state after passing through a molten metal bath, and which polishes the surface of the top roll. Polishing means, illuminating means for illuminating a portion of the top roll that is not in contact with the plated steel strip, and photographing means for receiving reflected light of the light emitted from the illuminating means and photographing a certain area of the surface of the top roll. , An image recording unit that periodically records a captured image as a still image, and a bright spot area that determines whether or not the ratio of the area of bright spots with a certain brightness or more to the total area in the recorded image exceeds a certain value. Molten metal characterized by comprising a judging section and a polishing control section for starting the polishing means and polishing the top roll based on the information that the bright spot area exceeds a certain value. Top roll cleaning device in the Kki equipment. 2. A top roll care device for transporting a plated steel strip immediately after solidification of a molten metal, which is in a high temperature state after passing through a molten metal bath. The top roll care device polishes the surface of the top roll. Polishing means, illuminating means for illuminating a portion of the top roll that is not in contact with the plated steel strip, and photographing means for receiving reflected light of the light emitted from the illuminating means and photographing a certain area of the surface of the top roll. An image recording unit that periodically records the captured image as a still image, and a highest brightness determination unit that determines whether or not the brightness of the brightest bright point among the bright points in the recorded image exceeds a predetermined value, In a hot-dip galvanizing facility characterized by comprising a polishing control unit for starting the polishing means and polishing the top roll based on the information that the maximum brightness exceeds a predetermined value. Top roll care unit.