JPH06258251A - Surface inspection device for rolling roller - Google Patents

Abstract

PURPOSE:To recognize a degree of the surface roughness and a degree of degradation of metal of a rolling roller surface layer part in a rotating rolling roller. CONSTITUTION:An image of an outer peripheral surface of a rotating rolling roller W is picked up by an image pickup device 20, and an obtained still picture of the surface of the rolling roller is displayed on a CRT display 33. On the other hand, by an overcurrent sensor 41, a size difference between crystal particle diameters of metal of a rolling roller surface layer part of the rolling roller W is taken out as an output difference between amplitude components by an impedance change in a detecting coil. Output of the amplitude components of the overcurrent sensor 41 becomes large in proportion to the size of the crystal particle diameter of the metal of the rolling roller surface layer part as degradation of the metal of the roller surface layer part proceeds. A judging processing device 44 compares the output of the amplitude components of the overcurrent sensor 41 with a preset value corresponding to a degradation limit, and judges whether or not the rolling roller W reaches roller replacing time since the degradation proceeds in the metal of the roller surface layer part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection device for a rolling roll, which is applied to the surface inspection of a rolling roll of a hot finish rolling mill in a hot rolling line for steel sheets.

[0002]

2. Description of the Related Art As is well known, a hot finish rolling mill in a steel sheet hot rolling line is usually equipped with 6 to 7 finishing stands. In the first stage finishing stand F1 of this hot finishing rolling mill and the subsequent finishing stands of F2 and F3,
Since a high chrome roll containing a large amount of chromium (Cr) is used, a black scale is formed on the outer peripheral surface of the metal rolling roll (work roll) during rolling. The black skin has turtle shell-like minute cracks that gradually increase in number with the lapse of time due to rolling. Then, depending on the rolling conditions, the outer surface of the rolling roll partially peels off the black skin to form a crater-like recess in a band shape along the circumferential direction, and as shown in FIG. 3, roll banding (Ro
ll Banding), which causes rough skin. When rolling is performed with the rolling roll in which this roll banding occurs,
A portion of the outer circumferential surface of the roll to which the dent is transferred is pressed by the rolling roll of the latter stand, and biting scale flaws are generated in the steel plate.

For this reason, the hot finish rolling mill is appropriately stopped, the rolling roll is pulled out from the stand, and a visual inspection of the roll surface is directly conducted by the operator. I try to exchange it. Such direct visual inspection by workers requires a lot of time and labor to remove and install the rolling rolls at each inspection, and also requires warming up of the rolls when restarting the rolling work. There is a problem in that

Therefore, the present applicant has previously proposed an optical surface inspection device for a rolling roll in order to solve the above-mentioned problems (Japanese Patent Application No. 3-165648). This device, during rolling, obtains a surface still image of the rolling roll that is rotating while the roll cooling water is being sprinkled, and by visually observing the surface image of the rolling roll, it is possible to know the degree of roughening of the rolling roll. It was done like this.

As shown in FIG. 2 which is an explanatory view of the structure of the conventional optical surface inspecting apparatus, the moving apparatus 10 and the outer peripheral surface of the rolling roll W which is rotating while the roll cooling water is being sprinkled during rolling. An image pickup device 20 for picking up an image to obtain a still image of the surface of the rolling roll, a control device 31, a frame memory 32 as an image storage device, and a CRT display 33 as an image display device.

More specifically, the rolling rolls (work rolls) W of the second stage finishing stand F2 and the rolling rolls (not shown) of the next stage finishing stand F3 of the hot finish rolling mill in the steel sheet hot rolling line. A moving device 10 is provided between them. The moving device 10 is provided in parallel with the longitudinal direction (roll axis direction) of the rolling roll W, and has a feed screw shaft 11 that is normally and reversely rotated by a motor (not shown), and the longitudinal direction of the rolling roll W according to the rotation of the feed screw shaft 11. The moving block 12 is moved along the moving block 12, and the air cylinder 13 provided on the upper surface of the moving block 12.

An image pickup device 20 is attached to the tip of the rod of the air cylinder 13. The image pickup device 20 has a transparent window glass plate 21 on the front surface thereof which faces the outer peripheral surface of the rolling roll W.
Inside the box-shaped housing box 21 in which a is fitted, two-dimensionally arranged CCD (Charge Coupled Devic)
e) CCD camera 22 using an image pickup device and rolling roll W
An annular xenon lamp 23 as a strobe irradiation light source for irradiating illumination light is arranged on the outer peripheral surface of the housing, and a water column forming nozzle 24 is attached to the front surface of the housing box 21.

As shown in the figure, the water column forming nozzle 24 has a water ejection port communicating with the window glass plate 21a of the housing box 21, and the window glass plate is supplied when pressurized water is supplied.
It is for forming a water column between 21a and the rolling roll W which is rotating while the roll cooling water is sprinkled. This prevents the window glass plate 21a from being contaminated by the roll cooling water containing dirt and prevents the rolling roll surface static image from becoming unclear. The cylindrical water column forming nozzle 24 is made of an acrylic resin that allows light to pass through and has transparency, and when it is attached to the front surface of the housing box 21, pressurized water from a supply source not shown is It is adapted to be introduced inside through a pressurized water supply pipe 24a.

The control device 31 receives an inspection start signal from the outside and turns on the annular xenon lamp 23 in synchronization with the vertical synchronizing signal of the CCD camera 22 and also frame the roll surface still image signal from the CCD camera 22. Memory 32
It is a device for controlling to take out the roll surface still image signal stored in the frame memory 32 to the CRT display 33 according to the switch operation of the inspector. The control device 31, the frame memory 32, and the CRT display 33 are arranged in the examination room.

To explain the operation, when the image pickup device 20 is positioned at a required inspection position in the longitudinal direction of the rolling roll W, the synchronizing signal of the CCD camera 22 and the lighting of the annular xenon lamp 23 are controlled. It is synchronously controlled by the device 31. The illumination light from the xenon lamp 23 passes through the window glass plate 21a and the water column formed by the water column forming nozzle 24 and is applied to the outer peripheral surface of the rolling roll. CCD camera 22 is a window glass plate
An image of the outer peripheral surface of the rolling roll W which is rotating while the roll cooling water is being sprinkled is taken through the water column 21a and the water column, and the stationary rolling roll surface static image signal is output. This image signal is stored in the frame memory 32. Mobile device
While the imaging device 20 is moved along the longitudinal direction of the rolling roll W by the 10, the above-described operation is sequentially repeated at a predetermined pitch.

After the imaging of the outer surface of the rolling roll is completed, the rolling roll surface still image signal stored (memorized) in the frame memory 32 is sequentially taken out for each screen according to the imaging position by the switch operation of the inspector. And is displayed on the CRT display 33 as a still image. The inspector is configured to inspect the degree of roughening of the rolling roll by visually observing the static image of the rolling roll surface displayed on the monitor. FIG. 4 is a sketch of an example of a static image of the surface of a rolling roll obtained by imaging the outer surface of the rolling roll, showing the appearance of a hexagonal crack (crack) in the black skin of the outer surface of the rolling roll. It is a figure.

[0012]

By the way, in the rolling roll, in addition to the roll banding due to the above-mentioned rough surface, the metal of the surface layer of the rolling roll is deteriorated, and thereby the metal of the surface layer of the rolling roll is partially peeled off or missing. The phenomenon may occur. Deterioration of the surface layer metal of the rolling roll with the passage of time due to this rolling is caused by coarsening of crystal grains at a depth of about 1 mm below the metal surface of the rolling roll.
This is due to the progress of oxidation of the crystal grain boundary portion accompanying this coarsening.

In the conventional optical surface inspection device, the degree of skin roughness can be known by visually observing a rolling roll still image obtained by an image pickup device for a rolling roll that is rotating during rolling. It was not possible to obtain information on the degree of deterioration of the partial metal. In particular, in the case of a recycled roll whose surface has been ground for reuse, information on the degree of deterioration is required. For this reason, there is a demand for a device having a function of automatically detecting that the metal of the surface layer of the rolling roll has deteriorated and the roll replacement time has come.

The present invention has been made in view of the above-mentioned circumstances, and the degree of skin roughness is obtained by visually observing a static image of the surface of a rolling roll obtained by an image pickup device for a rolling roll that is rotating during rolling. It is an object of the present invention to provide a surface inspection device for a rolling roll, which can automatically detect that the deterioration of the metal of the surface layer of the rolling roll has progressed and the roll replacement time has been reached.

[0015]

In order to achieve the above object, the surface inspection device for a rolling roll according to the present invention has a strobe irradiation light source for irradiating the outer peripheral surface of a metal rolling roll with illumination light. An image of the outer peripheral surface of the rotating rolling roll, an image pickup device that picks up an image in synchronization with lighting of the strobe irradiation light source, and an image display device that displays a rolling roll surface still image obtained by the image pickup device, Eddy current that is located close to the outer peripheral surface of the rolling roll, the difference in crystal grain size of the rolling roll surface layer metal of the rolling roll, as an amplitude component output difference due to impedance change of the detection coil Based on the sensor and the amplitude component output of this eddy current sensor, it is detected that the rolling roll has reached the roll replacement time due to the progress of deterioration of the metal of the surface layer of the rolling roll. Characterized by comprising a that determination processor.

[0016]

In the surface inspection device for a rolling roll according to the present invention, the image of the outer peripheral surface of the rotating rolling roll during rolling is picked up by the image pickup device, and the obtained still image of the rolling roll surface is displayed on the image display device. To be done. Thereby, the degree of skin roughening of the rolling roll can be known by visually observing the rolling roll surface static image.

On the other hand, the difference in the crystal grain size of the roll surface layer metal of the rolling roll is taken out by the eddy current sensor as the difference in the amplitude component output due to the impedance change of the detection coil. The amplitude component output of the eddy current sensor is proportional to the crystal grain size of the rolling roll surface layer metal, and the size of the crystal grain size, as described above, depends on the rolling roll surface layer portion over time. It becomes larger as the deterioration of metal progresses. Then, the determination processing device compares the amplitude component output of the eddy current sensor with a preset value corresponding to the amplitude component output of the eddy current sensor at the crystal grain size indicating the limit of deterioration of the surface metal of the rolling roll, for example. By doing so, it is detected that the rolling roll has reached the time of roll replacement due to the deterioration of the metal of the surface layer portion of the rolling roll.

[0018]

Embodiments of the present invention will be described below.
FIG. 1 is a structural explanatory view of a surface inspection device for a rolling roll according to an embodiment of the present invention. Here, in this embodiment, the same parts as those of the conventional apparatus shown in FIG.
The same reference numerals are given to omit the description, and different points will be described.

In FIG. 1, reference numeral 41 is an eddy current sensor.
The eddy current sensor 41 includes an eddy current sensor head 41a and an amplitude component detector 41b. The eddy current sensor 41 determines the difference in the crystal grain size of the surface layer metal of the rolling roll W by the amplitude component due to the impedance change of the detection coil. This is for extracting as a difference in output. As shown in the figure, the eddy current sensor head 41a has a circular cross-sectional front end surface which is predetermined with respect to the outer peripheral surface of the rolling roll W via a supporting arm 42 whose one end side is fixed to the housing box 21 of the imaging device 20. They are arranged so as to be located close to each other with a space.

The eddy current sensor head 41a has a known structure including an AC bridge composed of an excitation coil, a detection coil and a resistor, and an amplifier for amplifying the output of this AC bridge. Amplitude component detector
The reference numeral 41b detects only the amplitude of the output signal of the eddy current sensor head 41a, and as the amplitude component output, the maximum value in a predetermined period can be sequentially output in this embodiment. Since the value of the amplitude component output from the amplitude component detector 41b of the eddy current sensor 41 is proportional to the crystal grain size of the rolling roll surface layer metal, the rolling roll surface layer metal Deterioration progresses, and as a result, the crystal grains become coarser (the crystal grain size becomes larger), and thus become larger. The eddy current sensor head 41a
, Whose oscillating frequency can be variably adjusted within the range of 200 Hz to 10 kHz and whose sensor head diameter is 20 mm.

The amplitude component output from the amplitude component detector 41b is input to the determination processing device 44 via the A / D converter 43 at every predetermined tamming. The determination processing device 44 can be configured by, for example, a microcomputer, and as an input, the amplitude component detector 41b of the eddy current sensor 41.
Amplitude component output from the setter and the deterioration limit set value from the setter 45 are input, and a message indicating that the rolling roll W has reached the roll replacement time is given to the CRT display 33. The deterioration limit set value set in advance by the setter 45 corresponds to the amplitude component output of the eddy current sensor 41 at the crystal grain size that indicates the limit of deterioration of the surface metal of the rolling roll. The amplitude component detector 41b, the A / D converter 43, the determination processing device 44, and the setting device 45 are provided in the examination room.

Next, the operation will be described with reference to FIG.
In the same manner as in the past, the moving device 10 moves the imaging device 20 along the longitudinal direction of the rolling roll W, and the CCD camera 22 of the imaging device 20 rotates the roll cooling water while sprinkling the roll cooling water at a predetermined pitch. An image of the outer peripheral surface of the rolling roll W is taken. The rolling roll surface still image signals from the CCD camera 22 are sequentially stored in the frame memory 32. On the other hand, every time an image is taken by the image pickup device 20 along the roll longitudinal direction at a predetermined pitch, the amplitude component output (signal) from the amplitude component detector 41b of the eddy current sensor 41 becomes A
The data is sequentially stored in the memory of the determination processing device 44 via the / D converter 43.

When the moving device 10 is moved along the lengthwise direction of the roll and the above-described operation is carried out at a predetermined pitch, the inspector operates the switch to switch the rolling roll surface still image signal stored in the frame memory 32. Are sequentially taken out for each one screen according to the image pickup position and displayed as a still image on the CRT display 33. The inspector can know the degree of roughening of the rolling roll by visually observing the static image of the rolling roll surface displayed on the monitor.

On the other hand, the judgment processing device 43 sequentially reads out the amplitude component output of the eddy current sensor 41 detected for each predetermined pitch from the memory, and sets the amplitude component output of the eddy current sensor 41 by the setting device 45. The deterioration limit set value thus obtained is compared. Then, as a result of the comparison, when the amplitude component output of the eddy current sensor 41 is larger than the deterioration limit set value, the determination processing device 43 determines that the rolling roll W has deteriorated in the metal of the surface layer portion of the rolling roll W and the roll is replaced. Judge that the time has arrived and indicate that fact "Replace the roll."
A message such as "" is displayed on the CRT display 33.

As described above, the degree of skin roughness can be known by visually observing a static image of the surface of the rolling roll obtained by the imaging device for the rotating rolling roll during rolling. It is possible to automatically detect that the deterioration has progressed and the roll replacement time has come.

[0026]

As can be understood from the above description, according to the surface inspection device for a rolling roll of the present invention, the rolling roll surface still image obtained by the imaging device is visually observed for the rolling roll which is rotating during rolling. By observing, it is possible to know the degree of skin roughness, and it is possible to automatically detect that the deterioration of the metal of the surface layer of the rolling roll has progressed and the time for roll replacement has been reached. It can contribute to prevent the occurrence of scale scale flaws in the steel sheet due to the rough surface of the roll, and also contribute to the prevention of rolling roll accidents where the metal on the surface of the roll of the rolling roll is partially peeled or missing due to its deterioration. can do.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a surface inspection device for a rolling roll according to an embodiment of the present invention.

FIG. 2 is a structural explanatory view of a conventional optical surface inspection device for a rolling roll.

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

FIG. 4 is a sketch of an example of a rolling roll surface static image obtained by imaging the outer peripheral surface of a rolling roll,
It is a figure which shows the mode of the hexagonal crack (crack) which arose on the black skin of the outer peripheral surface of a rolling roll.

[Explanation of symbols]

10… Movement device 11… Feed screw shaft 12… Movement block 13
… Air cylinder 20… Imaging device 21… Housing box 21a… Window glass plate 22… CCD camera 23… Xenon lamp 24… Water column forming nozzle 31… Controller 32… Frame memory 33… CRT display 41… Eddy current sensor 41a… Eddy current Sensor head 41b ... Amplitude component detector 43 ... A / D
Converter 44 ... Judgment processor 45 ... Setting device W ... Rolling roll

Claims (1)

[Claims] 1. A strobe irradiation light source for irradiating the outer peripheral surface of a metal rolling roll with illumination light, and an image of the outer peripheral surface of the rotating rolling roll is synchronized with lighting of the strobe irradiation light source. An image pickup device for picking up an image, an image display device for displaying a still image of a rolling roll surface obtained by the image pickup device, and a rolling roll surface layer metal crystal of the rolling roll which is positioned close to the outer peripheral surface of the rolling roll. Based on the amplitude component output of the eddy current sensor and the eddy current sensor for extracting the difference in the size of the grain size as the difference in the amplitude component output due to the impedance change of the detection coil, the rolling roll has its surface layer portion. A surface inspection device for a rolling roll, comprising: a determination processing device that detects that the deterioration of metal has progressed and the roll replacement time has come.