JP2006208347A - Surface defect detector, grinding device, surface defect detection method and surface defect detection program for reduction roll, and reduction roll grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect detection method and detector capable of detecting, for example, microdefects caused on a reduction roll circumferential surface in inspection, so that a steel sheet (rolled material) of good surface quality can be produced, and to provide a grinding device and grinding method for achieving this method. <P>SOLUTION: This detector comprises a laser beam source 6 for irradiating the circumferential surface of the reduction roll 10, a defect detecting object, with laser beam; a light-receiving means 7 receiving the reflected light of laser beam from the circumferential surface and converting it into a signal showing the light intensity; and a signal processing means 8 detecting defects on the circumferential surface, based on the signal from the light-receiving means 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for detecting surface defects of a roll for rolling. In particular, it is possible to detect fine surface defects that could not be performed by conventional methods. Furthermore, the present invention relates to a rolling roll grinding method using a surface defect detection result.

  A rolling roll (hereinafter referred to as a rolling roll) used for rolling may have fine cracks or missing portions on the surface layer due to wear, seizure, rolling fatigue, or the like during use. If the surface layer is referred to as the surface for convenience, these surface defects generated on the surface of the rolling roll cause a reduction in the surface quality of the rolled material and a new cause of seizure. Therefore, the surface of the rolling roll is periodically ground. And after grinding, the rolling roll surface is inspected. As this inspection method, an eddy current flaw detection method (for example, see Patent Document 1), an ultrasonic flaw detection method using a surface wave (for example, see Patent Document 2), and the like are widely used.

Japanese Patent Publication No.58-11571 JP 2001-13113 A

  According to the eddy current flaw detection method, defects in the surface portion of the rolling roll can be detected relatively easily by the skin effect in which the penetration depth of the eddy current decreases as the excitation frequency for generating eddy current on the surface of the rolling roll increases. It is possible. Nevertheless, when the eddy current flaw detection method is used for flaw detection on the surface of the rolling roll, the depth of flaw detection is up to about 0.2 mm. This is because in the case of a rolling roll, the permeability change due to residual stress is large, and when the excitation frequency is increased, the sensitivity is increased, but the influence due to the permeability change is increased.

  In the ultrasonic flaw detection method using surface waves, the surface wave is propagated while the surface wave probe is in contact with the surface of the rotating cylinder (roll) through the film of the contact medium, and the reflected wave is received. The presence or absence of a defective portion is determined from the frequency and amplitude of the reflected wave. However, in such a method, it is necessary to form a certain gap between the surface wave probe and the rolling roll via a contact medium film. Therefore, when the gap changes due to eccentricity of the rolling roll, local wear, roll crown, etc., the ultrasonic transmission efficiency from the probe to the rolling roll also changes. In accordance with the change, the frequency and amplitude of the reflected wave from the defective portion also change. In particular, when detecting a fine surface defect having a wrinkle depth of 0.05 mm or less, it is difficult to distinguish a noise component due to a gap change and a defective portion.

  On the other hand, the control standards for the surface quality of rolling rolls are becoming more and more strict due to stricter product surface quality requirements of users and the increase of thin rolled materials. Especially for rolling rolls used for mirror rolling (bright materials) of cold rolling and temper rolling of tin (ultra-thin) materials, even with defects of 0.05 mm (50 μm) or less in depth close to the surface roughness level of the rolling rolls. When it is transferred to the surface of the steel plate (rolled material) by rolling, it may be recognized as a defect on the surface of the steel plate. Therefore, it is necessary to accurately detect fine defects on the surface of the ground rolling roll. However, in the two flaw detection methods described above, in order to detect defects having the same level as the finish roughness of the rolling roll surface, such as the dimension (depth) of the defective part of the rolling roll being several to several hundred μm, The ability was insufficient.

  The present invention has been made to solve the above-described problems. For example, in order to be able to manufacture a steel sheet (rolled material) that can withstand more stringent surface quality requirements, An object of the present invention is to obtain a rolling roll grinding apparatus and method equipped with a rolling roll surface defect detection method and apparatus capable of detecting fine defects generated on the surface and means capable of realizing the method.

  The surface defect detection device for a rolling roll according to the present invention includes a laser light source that irradiates laser light onto the outer peripheral surface of the rolling roll, and a signal that indicates the light intensity by receiving the reflected light from the laser light from the outer peripheral surface. And a processing means for determining the presence or absence of a defect on the outer peripheral surface based on a signal from the light receiving means.

  Further, the processing means of the surface defect detection device for a rolling roll according to the present invention detects the presence or absence of a defect by judging the difference in intensity of reflected light between the normal part and the defective part based on the signal.

  Further, the optical axes of the laser light source and the light receiving means of the surface defect detection apparatus according to the present invention are arranged in a certain plane including the rolling roll axis, and are changed to the irradiation angle by the laser light source or the light receiving angle of the light receiving means. Can do.

  Further, the surface defect detection device according to the present invention is based on the finish roughness of the target rolling roll so that the difference in the intensity of reflected light between the normal part and the defect part of the outer peripheral surface is a certain level or more. Set the irradiation angle and / or the receiving angle.

  Moreover, the surface defect detection apparatus according to the present invention includes a first lens having a focal length f for condensing reflected light between the outer peripheral surface and the light receiving means, and reflected light collected by the first lens. And a second lens having the same focal length f as the first lens, along the optical path of the reflected light, the outer peripheral surface, the first lens, the masking slit, and the second lens. In this order, the lens and the light receiving means are arranged at equal intervals of the focal length f.

  In the surface defect detection device according to the present invention, the width of the masking slit can be made variable.

  The rolling roll grinding apparatus according to the present invention includes a driving body that rotates the rolling roll around the rolling roll axis, and a base that supports the rolling roll, and an outer periphery of the rotating rolling roll. A grinding means for grinding the surface; a laser light source for irradiating the outer peripheral surface with laser light; a light receiving means for receiving reflected light from the laser light from the outer peripheral surface and converting it into a signal representing the intensity of the light; a grinding means; And a moving body that moves the laser light source and the light receiving means in the rolling roll axial direction.

  Further, the surface defect detection method for a rolling roll according to the present invention is the intensity of the reflected light of the laser beam irradiated toward the outer peripheral surface of the rolling roll received in a certain plane including the rolling roll axis. Based on the above, the presence or absence of a defect on the outer peripheral surface of the rolling roll is detected based on the difference in intensity of reflected light between the normal part and the defective part.

  Further, the surface defect detection method for a rolling roll according to the present invention includes a rolling roll at an angle within a range determined in advance based on the finishing roughness of the target rolling roll before irradiating the laser beam. Adjusting the irradiation angle of the laser light source that irradiates the laser beam toward the outer peripheral surface of the laser and / or the receiving angle of the light receiving means that receives the reflected light from the laser beam from the outer peripheral surface and converts it into a signal representing the intensity of the light Keep it.

  The rolling roll surface defect detection method according to the present invention includes a first lens having a focal length f, a masking slit, and a second lens having a focal length f on an outer peripheral surface along an optical path of reflected light. The first lens, the masking slit, the second lens, and the light receiving means for receiving the reflected light from the laser light and converting it into a signal representing the intensity of the light are arranged at equal intervals of the focal length f, and the masking slit. Thus, the specific frequency component of the reflected light is blocked.

  The rolling roll surface defect detection program according to the present invention is the intensity of the reflected light of the laser beam irradiated toward the outer peripheral surface of the rolling roll received in a certain plane including the rolling roll axis. Based on the comparison of this data and a predetermined threshold value, the presence or absence of defects on the outer peripheral surface of the rolling roll is detected by a computer.

  The rolling roll grinding method according to the present invention is a rolling roll grinding method in which a grinding device is controlled by a control means to grind the outer peripheral surface of a rolling roll, and rough grinding is performed with a predetermined number of passes and conditions. Then, after the final pass of finish grinding or after finish grinding, surface defects are detected by the surface defect detection method described above, and it is determined from the surface defect detection results that there are surface defects to be removed. Then, based on a predetermined relationship with respect to the surface defect, the conditions relating to the cutting depth, the feed amount of the grinding wheel in the axial direction of the rolling roll per rotation of the rolling roll, the rotational speed of the grinding wheel, or the rotational speed of the rolling roll Among these, finish grinding is performed by changing one or more conditions, and surface defect detection and finish grinding are performed until it is determined that there is no surface defect to be removed.

  The rolling roll grinding method according to the present invention is a rolling roll grinding method in which a grinding device is controlled by a control means to grind the outer peripheral surface of a rolling roll, and rough grinding is performed with a predetermined number of passes and conditions. Then, after the final pass of finish grinding or after finish grinding, surface defects are detected by the surface defect detection method described above, and it is determined from the surface defect detection results that there are surface defects to be removed. Then, based on the relationship determined in advance for the surface defects, among the conditions of the cutting depth, the feed amount of the grinding wheel in the axial direction of the rolling roll per rotation of the rolling roll, the rotational speed of the grinding wheel, or the rotational speed of the rolling roll Determine the number of passes for finish grinding by changing one or more conditions, perform finish grinding with the number of passes, and determine that there are no surface defects to be removed Until performs again fine grinding by the number of passes for finish grinding which has been surface defect detection and determination.

  In the roll grinding method for rolling according to the present invention, the grindstone used for finish grinding after it is determined that there are surface defects to be removed is changed to a high-grain grindstone.

  According to the present invention, the intensity of the reflected light of the laser light irradiated from the laser light source to the outer peripheral surface of the rolling roll is converted into a signal representing the light intensity by the light receiving means, and the outer peripheral surface is converted based on the signal. Since the processing means determines whether or not there is a defect, it is possible to detect a defect on the outer peripheral surface of a very fine rolling roll, which could not be detected in the past, in a non-contact manner. And by detecting a fine defect, since various measures can be taken with respect to the rolling roll as described later, the surface quality of the steel sheet or the like can be improved. At this time, the fact that the intensity of reflected light is different between the normal part and the defective part is used. However, in order to use the action caused by interference of the reflected light caused by grinding marks during rolling roll grinding, the laser light source and the light receiving means By placing the optical axis in a certain plane including the rolling roll axis, and adjusting the irradiation angle of the laser light source and the receiving angle of the light receiving means based on the finishing roughness of the target rolling roll, Since the difference in the intensity of reflected light between the portion and the defective portion is set to a certain level or more, more accurate detection can be performed. In addition, a laser light source and a light receiving means are provided in the rolling roll grinding device so that the rolling roll can be moved in the axial direction of the rolling roll together with the grinding means, so that surface defects can be detected in parallel with grinding. The time required for detection can be shortened.

  Further, the first lens having the focal length f, the masking slit, and the second lens having the focal length f are arranged along the optical path of the reflected light along the outer peripheral surface, the first lens, the masking slit, the second lens, By arranging the light receiving means at equal intervals of the focal length f and blocking the specific frequency component of the reflected light by the masking slit, the finishing roughness of the outer peripheral surface of the rolling roll is large, and the variation in the width of the grinding mark is large. Even if it is difficult to weaken the reflected light intensity from all grinding marks only by setting the incident angle and reflection angle, it can receive light after blocking the frequency component corresponding to the normal part, The light receiving means can receive only the reflected light from the defective portion.

  Further, according to the present invention, when a surface defect is detected, after changing one or a plurality of conditions among the conditions related to the cutting depth, the feed amount, the grindstone rotation speed, or the rolling roll rotation speed, Surface pass or next pass or subsequent grinding, or change conditions to determine the number of passes to be ground, finish grinding with that number of passes, and surface defects until it is determined that there are no surface defects to be removed Since detection and finish grinding are performed, automatic grinding by a rolling roll grinding apparatus can be performed until the surface defects are eliminated based on the surface defect detection result. At that time, if a grindstone having a high particle size is used for the next finish grinding, finer grinding can be performed.

First embodiment.
FIG. 1 is a diagram schematically showing the surface of a rolled roll after grinding. First, the principle of detecting surface defects (fats) based on the present invention will be described here. The present invention intends to detect surface defects based on the width of the ridges. The rolling roll is ground at a certain depth from the rolling roll surface for the purpose of removing surface defects and surface fatigue layers. At this time, depending on the finishing roughness of the target rolling roll, the grindstone to be used, grinding conditions, etc. are selected.For the rolled roll after grinding, as shown in FIG. A feature is that a grinding mark 1 having a certain width and depth is formed. Strictly speaking, the width and depth of each grinding mark 1 are not constant, but may be regarded as almost constant as compared with the surface defect 2 described below. On the other hand, surface defects (疵) 2 occur when large cracks that existed before grinding cannot be removed, or when the grindstone or abrasive grains fall off during the grinding and get caught. Although the depth is very small, it is larger than the grinding mark 1. And most of the generated wrinkles become deeper as the wrinkle width increases.

  Laser light 3 having the same wavelength and phase is incident on the outer peripheral surface of such a rolling roll, and interference is caused between the reflected lights reflected on the surface of the rolling roll. The reason for using laser light is that it is difficult to perform detection using the interference phenomenon unless it is coherent light having the same wavelength and phase. Accordingly, there is no particular limitation on the type of device (light source) that enters the laser beam (for example, a solid-state laser, a semiconductor laser, a gas laser, or the like) as long as it has the same wavelength and phase and can cause interference. For example, the selection can be made on the basis of the level of the surface finish roughness of the rolling roll that is the defect detection target, the wavelength, waveform, output, etc. of the laser light according to the width, depth, etc. of the defect to be detected.

Here, if the incident angle of the laser beam is θ _in , the reflection angle is θ _out , and the width of the grinding mark 1 is d, an optical path difference is generated between the optical path 4 and the optical path 5 by ab as shown in FIG. become. Due to this optical path difference, a phase difference α of light expressed by the following equation (1) is generated. And the intensity A of the reflected light at this time is represented by following Formula (2).

That is, the intensity of the reflected light observed at a certain reflection angle (a certain position) is determined by the wavelength λ of the laser light, the incident angle θ _in , the reflection angle θ _out , and the width d of the grinding mark 1. Compared with the width d of the grinding mark 1, the width of the surface defect 2 is greatly different. Therefore, when the laser light source enters laser light at the same irradiation angle (incident angle) and the light receiving element (means) receives reflected light at the same light receiving angle (reflection angle), the grinding has a substantially constant width and depth. The interference of the reflected light of the normal part due to the mark is different from the interference of the reflected light of the defective part. For this reason, the intensity of the light received by the reflected light is also different. Therefore, by appropriately selecting the irradiation angle of the laser light source (incident angle of the laser light) and the light receiving angle of the reflected light by the light receiving element (the reflection angle of the laser light), the reflected light of the normal part is weakened by interference, It becomes possible to enhance the contrast (difference in the intensity of reflected light between the normal part and the defective part) by increasing the reflected light of the defective part (conversely, the normal part can be strengthened and the defective part can be weakened) Is). In order to perform detection more accurately, it is preferable to adjust the range of the irradiation angle and the light receiving angle so that a certain contrast or more can be obtained. Therefore, by irradiating laser light from the laser light source and determining whether there is a locally strong portion of the reflected light based on the intensity of the reflected light received using the light receiving element, the presence or absence of the defective portion is determined. It can be easily determined and detected. Of course, the position of the defect in the rolling roll can also be detected.

  According to this method, since the defect part is detected in a non-contact manner using an optical method, there are no problems such as the influence of the residual stress in the conventional eddy current flaw detection, the noise component in the gap change in the ultrasonic flaw detection, In addition, even a minute part having a defect size such as depth and width of several to several tens of micrometers can be detected.

  FIG. 2 is a diagram showing a surface defect detection apparatus according to an embodiment of the present invention. In FIG. 2, a laser light source 6 is means for irradiating the outer peripheral surface of a rolling roll as a detection target with laser light. The reflected light from the outer peripheral surface of the rolling roll of the laser light emitted from the laser light source 6 is received by the light receiving means 7 having one or a plurality of light receiving elements such as a CCD camera, and the intensity of the light is converted into an electric signal, for example. Convert. Here, the optical axes B and C of the laser light source 6 and the light receiving means 7 are arranged in a plane including a rolling roll axis (a plane perpendicular to a tangential line on the outer circumferential surface of the rolling roll). preferable. This considers the grinding direction by the grindstone of the rolling roll grinding apparatus mentioned later. Grinding marks remaining on the entire rolling roll are formed with a substantially uniform width in the outer circumferential direction of the rolling roll. For this reason, the interference phenomenon can be generated more satisfactorily by causing the laser beam to enter and reflect within the plane including the rolling roll axis.

  Further, with respect to the laser light source 6 and the light receiving means 7, by changing the angle of the beam supporting each, the irradiation angle by the laser light source 6 (laser light incident angle) and the light receiving angle of the light receiving means 7 (rolling roll) The structure is such that the reflection angle of the laser beam from the surface is appropriately set and the position can be changed. The reason why the irradiation angle of the laser light source 6 and the light receiving angle of the light receiving means 7 are made variable is that the width d of the grinding mark varies depending on the finishing roughness of the rolling roll, and the optimum irradiation angle and light reception depending on the finishing roughness. This is because the corners are different. Therefore, it is preferable to be able to adjust to the optimum angle (position) according to the finishing roughness of the target roll. Further, the above-mentioned position is meant to include not only the angle but also the position in the optical axis direction, and it is preferable that the position of the laser light source 6 and / or the light receiving means 7 can be adjusted in the optical axis direction.

  The signal processing means 8 further includes an AD conversion unit 8A, a data processing unit 8B, a display unit 8C, a data storage unit 8D, and the like. The AD conversion unit 8A is digital data that can be processed by the data processing unit 8B (hereinafter referred to as light intensity data (hereinafter referred to as light intensity) that can be processed by the data processing unit 8B. Strength data)). The data processing unit 8B determines the presence or absence of a defective portion based on the light intensity data. The position of the defective part can also be determined. Specifically, for example, a certain threshold value is set in advance, and a portion that is determined to have been received by the light receiving means 7 with a light intensity greater than or equal to the threshold value is determined to be a defective portion. Further, each part of the signal processing means 8 is also controlled. The signal processing unit 8 (particularly the data processing unit 8B) can be configured only by hardware, but the data processing unit 8B is configured by an arithmetic control unit (computer) such as a CPU (Central Processing Unit), for example. On the other hand, since it is also preferable to program the processing procedure in advance and configure it with software, firmware, etc., this is the case in this embodiment. Then, the arithmetic control means executes the program, and processes based on the program are performed in each part in the signal processing means 8.

  The display unit 8C performs display based on a display signal from the data processing unit 8B (for example, display of an image or the like processed by the data processing unit 8 based on the determination result, the intensity of light received by the light receiving unit 7). The data storage unit 8D stores, for example, data of light intensity for processing by the data processing unit 8B temporarily or for a long time. Here, if the data storage unit 8D has a sufficient storage capacity capable of storing light intensity data, not only real-time processing but also batch processing after storing light intensity data of the entire rolling roll 10 is performed. It can also be done.

  FIG. 3 is a diagram showing a configuration of a rolling roll grinding apparatus including the surface defect detection unit 9. Among the surface defect detection devices described above, the laser light source 6 and the light receiving means 7 are provided in the surface defect detection unit 9 of the rolling roll grinding device. The signal processing means 8 may be housed in the surface defect detection unit 9 or may be provided outside the surface defect detection unit 9 (rolling roll grinding device).

  A rolling roll 10 that is to be ground (defect detection target) is supported by a platform 11 having a first drive source 12. The first drive source 12 rotates the rolling roll 10. Further, the base 11 is provided with a first moving body 13. The first moving body 13 can reciprocate in the axial direction D of the rolling roll 10. On the other hand, the second moving body 14 provided on the first moving body 13 can reciprocate in a direction perpendicular to the axial direction of the rolling roll 10. Therefore, the rotating grindstone 15 and the second drive source 16 on the second moving body 14 can be moved close to and away from the rolling roll 10. After the rotating grindstone 15 is in contact with the rolling roll 10, the second driving source 16 rotates the rotating grindstone 15 so that the rotating grindstone 15 as a grinding means grinds the outer peripheral surface of the rolling roll 10.

  Moreover, the support | pillar 17 is provided on the 1st mobile body 13, The surface defect detection part 9 mentioned above is provided in the upper part. Therefore, the surface defect detection unit 9 can also reciprocate in the axial direction D of the rolling roll 10. Since the surface defect detection unit 9 can be moved by the first moving body 13, the surface defect detection unit 9 can detect the surface defect of the surface of the rolling roll 10 immediately after grinding by following the rotating grindstone 15. Is possible. Therefore, it is possible to detect surface defects in parallel with grinding, which leads to shortening of the time required for detecting surface defects.

  As described above, according to the first embodiment, the light receiving means 7 converts the intensity of the reflected light of the laser light irradiated from the laser light source 6 onto the outer peripheral surface of the rolling roll 10 into a signal, and the signal processing means 8 Based on the signal, the presence / absence of a defect is determined based on the difference in intensity of reflected light due to the difference in width between the grinding mark (normal part) and the flaw (defect part). It is possible to detect even very fine defects. As described later, various countermeasures can be taken against such fine defects, so that the surface quality of a steel sheet or the like rolled by a rolling roll inspected by the method and apparatus of this embodiment is improved. Will be able to.

  In addition, since the irradiation angle of the laser light source 6 and the light reception angle of the light receiving means 7 are appropriately set and the position can be changed, the irradiation angle and the light reception angle are changed according to the finishing roughness of the target rolling roll. can do. Therefore, more accurate defect detection can be performed by setting the contrast of the reflected light of the normal part and the defective part to a certain level or more according to the target finishing roughness of the rolling roll. The rolling roll grinding apparatus is provided with a surface defect detection unit 9 for detecting surface defects based on data from the laser light source 6 and the light receiving means 7, and a rolling roll axis together with a rotating grindstone 15 for grinding the outer peripheral surface of the rolling roll 10. Since it can be moved in the direction, surface defect detection can be performed in parallel with grinding, and the time required for surface defect detection can be shortened. Further, since grinding is performed along the outer peripheral direction of the rolling roll 10 and the grinding mark can be formed with a substantially constant width and depth, the optical axes B and C of the laser light source 6 and the light receiving means 7 include the rolling roll axis. By installing it in a plane, it is possible to effectively exhibit the effect of interference between reflected light from grinding marks on laser light having the same phase and wavelength, and to detect surface defects more accurately. .

Second embodiment.
In addition to the above-described embodiment, the first lens having the focal length f, the masking slit, and the second lens having the focal length f are arranged along the optical path of the reflected light along the outer peripheral surface, the first lens, and the masking. The slit, the second lens, and the light receiving means may be arranged in this order at equal intervals of the focal length f, and the specific frequency component of the reflected light may be blocked by the masking slit.

  In the above-described embodiment, when the finish roughness of the outer peripheral surface of the rolling roll to be detected is small and the width of the grinding mark that is a normal portion is substantially uniform, the detection accuracy becomes very high. However, when the finishing roughness is large, the variation in the grinding mark width is large, and it becomes difficult to weaken the reflected light intensity from all the grinding marks only by setting the incident angle and the reflection angle. For this reason, a grinding mark having a large deviation from the average width of the grinding mark of the normal part is recognized as a defect even though it is not a defect, and there is a possibility that the defect is excessively detected.

  FIG. 4 is a diagram showing a defect profile on an actual rolling roll surface, and is a result of detecting surface defects on two types of roll surfaces having different finishing roughnesses using a stylus type surface roughness meter. Here, the average roughness Ra = 0.55 μm and Ra = 0.15 μm (mirror finish roll level) specified by JIS-B0601 are shown. In the rolling roll with a small finishing roughness Ra = 0.15 μm, the width of the grinding traces other than the defective portion is almost uniform, whereas in the rolling roll with a large finishing roughness Ra = 0.55 μm, the grinding traces It can be seen that the width varies.

  Thus, in order to prevent overdetection of defects even on the outer peripheral surface of a rolling roll having a large finishing roughness, optical Fourier transform is used in the second embodiment. The optical Fourier transform irradiates the object plane P1 with coherent light in an optical system as shown in FIG. Then, the reflected light emitted from the object plane P1 passes through the first lens having the focal length f, is condensed by the condensing point P2, and is further converted into parallel light by the second lens L2 having the focal length f, and output. An image is formed on the plane P3. Here, if the object plane P1, the first lens L1, the condensing point P2, the second lens L2, and the output surface P3 are arranged in this order at the focal distance f, the surface of the condensing point P2 is arranged. Shows a spatial (two-dimensional) Fourier transform image of the image of the object plane P1. That is, the image of the object plane P1 is decomposed into frequency components, and distributed according to the frequency components on the focal point P2. Usually, the center part on the surface of the condensing point P2 becomes a low frequency component, and the higher the frequency component is, the farther from the center part. When the image at the condensing point P2 is formed again on the output surface P3 through the second lens L2 having the same focal length f, an inverse Fourier transform occurs, and the original image is restored. Here, when a specific frequency component is blocked by applying a mask on the surface of the condensing point P2, an image not including the frequency component is obtained on the output surface P3.

  Here, in the second embodiment, the object plane P1 is the outer peripheral surface of the rolling roll, and the first lens L1, the masking means, and the second lens L2 are equidistant from the outer peripheral surface of the rolling roll at the focal length f of the lens. The light receiving means are arranged in order. That is, by arranging the masking means at the position of the condensing point P2 and arranging the light receiving means at the position of the output surface P3, optical Fourier transform of the reflected light from the surface of the rolling roll is possible. Usually, the width of the grinding mark in the normal part is smaller than that in the defective part, so it has a high frequency component, and the masking means has a certain width so as to block the frequency component corresponding to the width of the grinding mark in the normal part. It is possible to filter the reflected light from the normal part, which is a high frequency component away from the central part of the condensing point, by emphasizing the reflected light only from the defective part. Can do. In this method, since the primary filtering of the reflected light from the normal part is performed using the interference phenomenon, the secondary filtering can be performed by the optical Fourier transform. By changing, it becomes possible to filter the reflection component from a wider range of grinding marks, and only the reflected light from the defective part is extracted even in a roll with a large finishing roughness with a large variation in the grinding marks as the background. Is possible.

  FIG. 6 shows a surface defect detection apparatus according to the second embodiment. In FIG. 6, a laser light source 6 is means for irradiating the outer peripheral surface of a rolling roll as a detection target with laser light. The reflected light from the outer peripheral surface of the rolling roll by the laser light source 6 is condensed by the first lens L1 installed at the position of the focal length f from the outer peripheral surface of the rolling roll. A masking slit 20 is installed at a position away from the first lens L1 by the focal length f to block the reflected light component from the grinding mark, which is a normal part, from the Fourier transform image collected by the first lens L1. ing. Further, a second lens L2 is installed at a position away from the masking slit 20 by the focal length f. A light receiving means 7 similar to that in the first embodiment is disposed at a position away from the second lens L2 by the focal length f, and is reflected from the outer peripheral surface of the rolling roll subjected to inverse Fourier transform by the second lens L2. For light, the intensity of the light is converted into an electric signal, for example.

  Here, the laser light source 6, the first lens L 1, the masking slit 20, the second lens L 2, and the light receiving means 7 are arranged in a plane including the rolling roll axis (a plane perpendicular to the tangent to the rolling roll outer peripheral surface). It is preferable to do so. This considers the grinding direction by the grindstone of the rolling roll grinding apparatus mentioned later. Grinding marks that remain on the entire roll and serve as a background are formed with a substantially uniform width in the circumferential direction. Therefore, when the laser beam is incident and reflected in a plane including the rolling roll axis, the interference phenomenon can be most effectively generated.

  Similarly to the first embodiment, with respect to the laser light source 6 and the light receiving means 7, the irradiation angle (laser light incident angle) by the laser light source 6 is changed by changing the angles of the beams supporting the laser light source 6 and the light receiving means 7, respectively. The structure is such that the light receiving angle of the light receiving means 7 (reflection angle of the laser light from the surface of the rolling roll) is appropriately set and the position can be changed. Furthermore, in the second embodiment, the first lens L1, the masking slit 20, and the second lens L2 are integrated with the light receiving means 7, and follow the change in the light receiving angle of the light receiving means 7. ing.

  Moreover, it is preferable that the width of the masking slit 20 is also variable, and it is preferable that the frequency component to be cut off can be appropriately selected according to the finishing roughness of the rolling roll. The signal processing unit 8 includes an AD conversion unit 8A, a data processing unit 8B, a display unit 8C, a data storage unit 8D, and the like as in the first embodiment described above. Since the operation of the signal processing means 8 is the same as that of the first embodiment described above, description thereof is omitted individually.

  As described above, according to the second embodiment described above, since the frequency component corresponding to the grinding mark can be received after being blocked by the masking slit 20, even if the finishing roughness is large, the defect can be accurately detected. It is possible to detect well.

Third embodiment.
In the above embodiment, the light receiving means 7 is a CCD camera, but the present invention is not limited to this. For example, light reception may be performed using a photodiode array. Further, in the above-described embodiment, one laser light source 6 and one light receiving means 7 are provided, respectively, but in order to shorten the time required for detecting surface defects of the rolling roll by expanding the irradiation range and the light receiving range, respectively. A plurality of means may be provided. However, in order to sufficiently ensure the contrast between the normal part and the defective part due to interference, it is preferable that the relationship between the irradiation angle and the light receiving angle is not disturbed as much as possible.

Fourth embodiment.
FIG. 7 is a diagram showing a configuration including an apparatus for controlling a rolling roll grinding apparatus according to the fourth embodiment of the present invention. In the figure, since the same reference numerals as those in FIG. 3 are the same as those described in the first embodiment, description thereof is omitted. In the present embodiment, the signal processing means 8 constituting the surface defect detection apparatus in the first embodiment is provided as an independent means called the data processing apparatus 18. The data processing device 18 and the NC grinder control device 19 can exchange necessary data with each other by transmitting and receiving signals. For example, the storage means of the NC grinder control device 19 stores data on the rotation angle of the first drive source 12 and the position (coordinates) of the first moving body. By transmitting a signal including these data to the data processing device 18 and processing the data in the data processing device 18, the outer peripheral surface of the rolling roll 10 is taken as a coordinate, and the position of the surface defect is specified by the coordinate. Can do.

  The NC grinder control device 19 is a device (control means) for controlling grinding by a rolling roll grinding device. The storage means included in the NC grinder control device 19 includes a program relating to a procedure for performing rough grinding and first finish grinding (surface defect detection of the rolling roll according to the first embodiment or the second embodiment or Others embodying others) and data are stored. The NC grinder controller 19 controls the rotation and movement of the rolling roll 10 by the first driving source 12 and the first moving body 13 and the second driving source 14 and the second moving body 16 by performing control based on the program and data. It is possible to perform grinding automatically by performing rotation / movement control of the rotating grindstone 15 by. The second and subsequent finish grinding programs and data are sent from the data processing device 18 based on the judgment of the data processing device 18. Here, the data processing device 18 and the NC grinder control device 19 are divided according to their roles, but these processes may be performed by one device.

  FIG. 8 is a flowchart of a grinding procedure for the rolling roll 10. After the rolling operation is completed, the rolling roll 10 for grinding is extracted from the rolling mill and set in a rolling roll grinding apparatus. First, rough grinding is performed for M passes under the grinding conditions stored in the storage means in the NC grinder control device 19 (S1). In rough grinding, grinding is performed to remove thermal and mechanical damage of a depth of 0.05 mm or more received by the rolling roll 10 during rolling from the roll surface.

  Further, finish grinding is performed in N passes under the grinding conditions stored in advance in the storage means in the NC grinder controller 19 so that the roughness of the outer peripheral surface of the rolling roll 10 is smooth (S2). Then, after the Nth pass, which is the final pass of the finish grinding, or after the end of the N pass (finish of finish grinding), the data processing device 18 detects a detection signal ( Based on the electrical signal), surface defect detection is performed for a fine surface defect having a depth of 0.05 mm or less caused by scratches, chatter, feed marks, etc., caused by grinding (S3). At that time, the data processing device 18 converts the detection signal from the light receiving means 7 into light intensity data. If it is determined that the value of the data is smaller than a predetermined threshold value, it is determined that the rolling roll 10 has no surface defects to be removed, and finish grinding is finished (S4).

  On the other hand, when it is determined that the value of the light intensity data based on the detection signal is equal to or greater than a predetermined threshold value, the data processing device 18 determines the grinding condition for the next pass of the finish grinding or the subsequent pass. And / or reset the number of passes (S5), and send the program and data for causing the grinding device to perform grinding again by the finish grinding again to the NC grinder control device 19 (detect surface defects for each pass) In this case, N = 1). The NC grinder control device 19 performs finish grinding again by the grinding device based on the program and data. Here, when the data processing device 18 sets the number of passes, the cutting depth, the grinding wheel rotational speed, the rolling roll rotational speed, and the feed of the rotating grindstone 15 per one roll rotation in the axial direction of the rolling roll are set. Of the quantity, one or more conditions may be changed. When changing the conditions, it is preferable to change the cutting depth and feed amount so that the grinding wheel rotational speed is increased and the rolling roll rotational speed is decreased. About the rotating grindstone 15, the same thing as the first finish grinding may be used, and you may replace | exchange for a thing with a high particle size (a thing with a small abrasive particle diameter). If they are the same, the replacement time can be omitted. When the particle size is changed to a higher one, fine grinding according to the level of surface defects can be performed. You may perform both change of grinding conditions, and replacement | exchange of the rotating grindstone 15. FIG.

  Then, during or after finishing grinding again, surface defect detection is performed again, and finishing grinding and surface defect detection are performed until the value represented by the light intensity data based on the detection signal becomes smaller than a predetermined threshold value. Repeat.

  As described above, according to the fourth embodiment, when it is determined that there is a surface defect to be removed based on the light intensity data included in the detection signal by the surface defect detection unit, the data processing device 18 , Change one or more conditions among the conditions of cutting depth, feed amount, grinding wheel rotation speed or rolling roll rotation speed, and perform grinding after the next pass or the next pass, or change the conditions The number of passes to be ground is determined, finish grinding is performed with the number of passes, or both are performed, and surface defects are detected and finish grinding is performed until it is determined that there are no surface defects to be removed. Therefore, automatic grinding by a rolling roll grinding device can be performed until the surface defect is eliminated based on the surface defect detection result. At that time, if a grindstone having a high particle size is used for the next finish grinding, finer grinding can be performed.

Example 1.
Next, an example will be described in which surface defect detection is performed using two types of cold rolling work rolls having a surface defect and having a target finish roughness of a roll diameter of 500 mm as different targets. Here, the average roughness Ra specified by JIS-B0601 Ra = 0.55 μm (FIG. 4A: roll with a large finishing roughness) and Ra = 0.15 μm (FIG. 4B: mirror finish roll). Use a roll with a finish roughness. As can be seen from FIG. 4, the defect portions of the two rolls are very fine concave surface defects each having a width of 200 μm or less and a depth of 10 μm or less (still larger than the grinding marks).

  As the laser light source 6 used in this embodiment, a semiconductor laser having an output of 50 mW, a wavelength of 685 nm, and an irradiation area of 35 mm is used. On the other hand, a CCD camera with 240,000 pixels is used as the light receiving means 7. Further, as the signal processing means 8, an image processing device that processes an image captured by the CCD camera is used.

  FIG. 9 is a view showing an image obtained by capturing a defective portion of the roll with a CCD camera as the light receiving means 7. FIG. 9A is a photograph of a roll surface of Ra = 0.55 μm with a laser beam irradiation angle of 80 ° and a CCD camera light reception angle of −20 °. Here, in this embodiment, the irradiation angle is positive in the clockwise direction in FIG. 2, and the light receiving angle is positive in the counterclockwise direction. In FIG. 9A, the reflected light interferes with each other in the normal portion, and the received light is weakened. The light that has received the reflected light clearly appears in the defective portion. FIG. 9B is an image of the same surface as FIG. 9A taken with an irradiation angle of 80 ° and a light receiving angle of 0 °. Even if the reflected lights interfere with each other, it is difficult to specify the defective portion because the difference in the intensity of the received light between the normal portion and the defective portion is small. FIG. 9C is an image of a roll surface with Ra = 0.15 μm, with an irradiation angle of 70 ° and a light receiving angle of 0 °. The reflected light interferes with each other in the normal portion, and the received light is weakened. The light that has received the reflected light clearly appears in the defective portion. In this example, a defective portion having a wrinkle depth of 5 μm or less can also be determined and detected.

  FIG. 10 is a diagram showing a detection result when the irradiation angle and the light receiving angle are changed. 10A shows a case where a roll surface with Ra = 0.55 μm is detected, and FIG. 10B shows a case where a roll surface with Ra = 0.15 μm is detected. According to FIG. 10, even if the surface of the rolling roll, the laser light source 6 and the light receiving means 7 are the same, there is a range where detection cannot be performed depending on the irradiation angle (laser light incident angle) or the light receiving angle (laser light reflection angle). I understand. This is because the grain size of the selected grindstone varies depending on the finishing roughness of the target rolling roll, and thus the width d of the grinding mark also varies. Therefore, in order to perform highly accurate detection, it is necessary to adjust the positions of the laser light source 6 and the light receiving means 7 in accordance with the target finishing roughness of the rolling roll. In addition, it is necessary to consider the width of the eyelid to be detected. This can be dealt with by checking in advance and setting the optimum position for each finishing roughness of the target rolling roll.

  Table 1 shows the inspection results obtained by the surface defect detection method described above. Prior to the inspection of the rolling roll by the above-described method, the result of visual evaluation by an operator usually performed after finish grinding is also shown. Conventionally, fine defects were also detected by visual evaluation. At the time of the rolling roll inspection, the rolling roll to be inspected was rotated at a rotational speed of 40 rpm and a feed amount of 500 mm / min, as in finish grinding. Here, Condition 1 is an irradiation angle of 70 ° and a light receiving angle of 0 °. On the other hand, Condition 2 is an irradiation angle of 80 ° and a light receiving angle of −20 °.

  For a rolling roll with Ra = 0.55 μm, only condition 2 is in good agreement with the operator's visual evaluation. On the other hand, in the roll of Ra = 0.15 μm, both the conditions 1 and 2 are in good agreement with the visual evaluation of the operator, and the irradiation angle and the light receiving angle are optimized according to the finishing roughness of the target rolling roll ( It can be seen that fine surface defects can be detected by optimizing the positions of the laser light source 6 and the light receiving means 7). By performing defect detection by such a method, it becomes possible to perform surface defect detection in parallel with grinding.

Example 2
Table 2 shows that the slit width is 0.3 mm, 1.0 mm, 2.8 mm, and 6.5 mm under the above-described condition 1 where the irradiation angle is 70 ° and the light receiving angle is 0 °, and the incident / reflection angle of the laser beam is set. The inspection results with four different masking slits 20 attached are shown in comparison with the detection results without the masking slits 20 and the operator's visual inspection results. At the time of the roll inspection, the roll to be inspected was rotated at a rotational speed of 40 rpm and a feed amount of 500 mm / min, as in the finish grinding step.

  In the state where there is no masking slit 20, the intensity of reflected light from a part of the grinding marks other than the defective part is large due to the variation of the grinding marks, which is overdetection and cannot be detected. Even when the masking slit 20 having a slit width of 6.5 mm is installed, high-frequency component filtering is insufficient, and some grinding marks are overdetected, making detection impossible. When the masking slit 20 having a slit width of 2.8 mm or 1.0 mm is installed, only the intensity of reflected light from the defect portion can be emphasized by the filtering effect by optical Fourier transform, which is the same as the visual evaluation. It was possible to detect from the defective part. On the other hand, when the masking slit 20 having a slit width of 0.3 mm is used, the amount of light entering the light receiving means 7 becomes too small, so that the intensity of the reflected light from the defective portion becomes small and detection is impossible. .

  As described above, by performing the filtering process based on the principle of optical Fourier transform, it is possible to weaken the reflected light component from the grinding mark, which is a normal part, and to clarify the contrast with the reflected light from the defective part. Thus, even a roll having a large finishing roughness can be detected with higher accuracy by combining the interference phenomenon and the optical Fourier transform. Further, the width of the masking slit 20 for performing the filtering process has an optimum value according to the width of the grinding mark, and can be dealt with by adjusting the slit width obtained in advance according to the finish roll roughness.

Example 3
The target rolling roll is a cold rolling roll having a diameter of 500 mm and a body length of 2 m, and the finishing roughness is an average roughness Ra = 0.15 μm defined by JIS-B0601-2001 and JIS-B0651-2001. It is. Incidentally, the reference length lr (λc) for the roughness curve is 0.8 mm, the reference length lw (λf) for the waviness curve is 8 mm, and the reference length lp (evaluation length ln) for the sectional curve is 40 mm. It was measured.

  As a result of using this rolling roll for temper rolling, rough surfaces due to wear, fine scratches, and the like occurred on the roll surface. Therefore, this rolling roll was ground using the rolling roll grinding apparatus described in the third embodiment. In this example, first, as preset in the NC grinder controller 19, rough grinding was performed for 6 passes to remove surface irregularities, cracks, and the like due to wear. Thereafter, finish grinding was performed for 4 passes to finish the finish.

  Even when the surface defect detection is performed independently, it is necessary to rotate the rolling roll and relatively move the surface defect detection unit 9 and the rolling roll. For this purpose, the rotational speed of the rolling roll and the condition of the feed amount of the grinding wheel in the axial direction of the rolling roll per rotation of the rolling roll are stored in advance in the storage means in the NC grinder controller 19. In the present embodiment, the roll speed is 40 rpm and the feed amount is 50 mm / min, which is the same as that for finish grinding, the rolling roll is rotated, and the surface defect detection unit 9 and the rolling roll are relatively moved to detect surface defects. went. Here, the rotating grindstone 15 is separated from the rolling roll, and the rotation is stopped. Also in this example, a semiconductor laser having an output of 50 mW, a wavelength of 685 nm, and an irradiation area of 35 mm was used as the laser light source 6, and the irradiation angle was 80 °. As the light receiving means 7, a 240,000 pixel CCD camera was used, and the light receiving angle was set to -20 °.

  FIG. 11 is a diagram showing the relationship between the light intensity based on the detection signal and the position in the axial direction of the rolling roll. The vertical axis represents a value indicating an index of light intensity based on the detection signal (hereinafter referred to as luminance), and the horizontal axis represents the position of the center of the light receiving unit in the rolling roll axis direction. Here, in this embodiment, the movement distance in the coaxial direction per rotation of the rolling roll is 8 mm. Therefore, the light intensity data within 8 mm corresponds to data at each position on the outer peripheral surface for one rotation of the rolling roll.

  Here, regarding the brightness, the intensity of reflected light by an ideal smooth surface is 0%, and the intensity of reflected light when laser light is interfered and strengthened by an optical path difference that is an integral multiple of the wavelength is 100%. Represents. In FIG. 11, it can be seen that a portion where the reflected light is strong can be detected at a position of 800 mm in the axial direction of the rolling roll. FIG. 4B of Example 1 of the previous operation shows an actual measurement profile of this defective portion. As a result of investigating the relationship between the dimensions such as the actual width and depth of the defect and the intensity of the reflected light, the threshold value for determining whether or not to perform finish grinding again is set to 20% luminance. Is determined to be 20% or more, finish grinding is performed again.

  Table 3 shows the grinding conditions when finishing grinding is performed again after receiving the result of the surface defect detection, and the determination result of whether or not the surface defect can be removed after each pass. Three cases were set as the grinding conditions, and the surface defects to be removed in each case were the surface defects having the same depth and size as the surface defects at a position of 800 mm in the rolling roll axial direction in FIG.

  Case 1 is a condition in which the number of rotations of the rolling roll is reduced (40 rpm → 30 rpm) from the initial grinding condition. Surface defects were detected for each pass in finish grinding, and the luminance based on the detection signal was smaller than a threshold value of 20% in the fifth pass, and it was determined that the grinding was finished. Case 2 is a condition in which the number of rotations of the rolling roll and the feed amount are reduced (40 rpm → 30 rpm, 500 mm / min → 300 mm / min) compared to the initial grinding conditions. In this case, in the third pass, the luminance based on the detection signal became smaller than the threshold value of 20%, and it was determined that the grinding was finished. Case 3 further reduces the rolling roll rotation speed, feed rate, and cutting depth (40 rpm → 30 rpm, 500 mm / min → 300 mm / min, 3 μm → 2 μm) and has a higher grain size than the initial grinding conditions. (# 120 → # 270). In this case, in the second pass, the luminance based on the detection signal became smaller than the threshold value 20%, and it was determined that the grinding was finished.

  As described above, for a certain surface defect, finish grinding is performed with various grinding conditions and a grindstone, and if the number of finish grinding passes in which the brightness is smaller than the threshold is empirically determined and determined in advance, in actual grinding, When a surface defect is detected, the number of passes to be ground can be determined by changing the grinding conditions when performing finish grinding again. Thus, it is possible to automatically perform finish grinding for detecting surface defects and removing surface defects.

It is the figure which showed typically the rolling roll surface after grinding. It is a figure which shows the surface defect detection apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the rolling roll grinding apparatus containing the surface defect detection part. It is a figure which shows the profile of a defective part. It is the figure which showed optical Fourier transform typically. It is a figure which shows the surface defect detection apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure containing the apparatus for controlling a rolling roll grinding apparatus. FIG. 3 is a diagram showing a flowchart of a grinding procedure for a rolling roll 10. It is a figure which shows the image which imaged the defective part with the CCD camera which is the light-receiving means. It is a figure which shows the detection result at the time of changing an irradiation angle and a light-receiving angle. It is a figure which shows the relationship between the light intensity based on a detection signal, and a rolling roll axial direction position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Grinding mark 2 Surface defect 3 Laser beam 4, 5 Optical path 6 Laser light source 7 Light receiving means 8 Signal processing means 8A AD conversion part 8B Data processing part 8C Display part 8D Data storage part 9 Surface defect detection part 10 Roll roll 11 Base 12 1st drive source 13 1st moving body 14 2nd moving body 15 Rotary grindstone 16 2nd drive source 17 Support | pillar 18 Data processing device 19 NC grinder control device B, C Optical axis D Axial direction 20 Masking slit L1 1st Lens L2 Second lens

Claims (14)

A laser light source for irradiating the outer peripheral surface of the rolling roll with laser light;
Light receiving means for receiving reflected light from the laser light from the outer peripheral surface and converting it into a signal representing the intensity of the light;
A rolling roll surface defect detection device comprising: processing means for determining the presence or absence of defects on the outer peripheral surface based on a signal from the light receiving means.   2. The rolling roll according to claim 1, wherein the processing means determines the presence or absence of the defect by determining a difference in intensity of the reflected light between a normal portion and a defective portion based on the signal. Surface defect detection device.   The optical axes of the laser light source and the light receiving means are arranged in a plane including the rolling roll axis, and the irradiation angle by the laser light source or the light receiving angle of the light receiving means can be changed. The surface defect detection apparatus of the roll for rolling of Claim 1 or 2 to do.   The irradiation angle and / or the light reception based on the target finish roughness of the rolling roll so that the difference in intensity of reflected light between the normal part and the defective part on the outer peripheral surface is a certain level or more. 4. The surface defect detection device for a roll for rolling according to claim 3, wherein the angle is adjusted. A first lens having a focal length f for collecting the reflected light between the outer peripheral surface and the light receiving means;
A masking slit for blocking a specific frequency component of the reflected light collected by the first lens;
A second lens having the same focal length f as the first lens,
Along the optical path of the reflected light, the outer peripheral surface, the first lens, the masking slit, the second lens, and the light receiving means are arranged in this order at equal intervals of the focal length f. The surface defect detection device for a roll for rolling according to any one of claims 1 to 4.   6. The surface defect detection device for a roll for rolling according to claim 5, wherein the width of the masking slit is variable. A driving body for rotating the rolling roll around the rolling roll axis, and a platform for supporting the rolling roll;
Grinding means for grinding the outer peripheral surface of the rotating roll for rotation;
A laser light source for irradiating the outer peripheral surface with laser light;
Light receiving means for receiving reflected light from the laser light from the outer peripheral surface and converting it into a signal representing the intensity of the light;
A moving body for moving the grinding means, the laser light source, and the light receiving means in the rolling roll axis direction;
A roll grinding apparatus for rolling.   Based on the intensity of the reflected light of the laser beam irradiated toward the outer peripheral surface of the rolling roll, received in a certain plane including the rolling roll axis, the intensity of the reflected light of the normal part and the defective part A method for detecting surface defects on a roll for rolling, wherein the presence or absence of defects on the outer peripheral surface of the roll for rolling is detected based on the difference between the two. Before irradiating the laser beam,
An irradiation angle and / or the outer periphery of a laser light source that irradiates laser light toward an outer peripheral surface of the rolling roll at an angle in a range determined in advance based on a finishing roughness of the rolling roll as a target. The surface defect detection of a rolling roll according to claim 6, wherein the light receiving means for receiving the reflected light from the laser beam from the surface and converting it into a signal representing the intensity of the light is adjusted. Method.   A first lens having a focal length f, a masking slit, and a second lens having a focal length f are arranged along the optical path of the reflected light along the outer peripheral surface, the first lens, the masking slit, and the second lens. The lens and the light receiving means for receiving the reflected light from the laser beam and converting it into a signal representing the intensity of the light are arranged at equal intervals of the focal length f, and the specific frequency component of the reflected light by the masking slit The method for detecting surface defects of a roll for rolling according to claim 8 or 9, wherein:   Based on the comparison of the intensity of the reflected light of the laser beam irradiated toward the outer peripheral surface of the rolling roll received in a plane including the rolling roll axis and a predetermined threshold value. A program for detecting surface defects of a rolling roll, wherein the presence or absence of defects on the outer peripheral surface of the rolling roll is detected by a computer. In the rolling roll grinding method for grinding the outer peripheral surface of the rolling roll by controlling the grinding device by the control means,
Perform rough grinding and finish grinding with a predetermined number of passes and conditions,
In the final pass of the finish grinding or after the finish grinding, surface defect detection is performed by the surface defect detection method according to any one of claims 8 to 10,
If it is determined from the surface defect detection result that there is a surface defect to be removed, the rolling roll shaft of the grindstone per rotation of the rolling roll is determined based on a predetermined relationship with respect to the surface defect. Of the conditions related to the feed amount in the central direction, the grindstone rotation speed, or the roll rotation speed for rolling, one or more conditions are changed and finish grinding is performed.
The rolling roll grinding method, wherein the surface defect detection and the finish grinding are performed until it is determined that there is no surface defect to be removed. In the rolling roll grinding method for grinding the outer peripheral surface of the rolling roll by controlling the grinding device by the control means,
Perform rough grinding and finish grinding with a predetermined number of passes and conditions,
In the final pass of the finish grinding or after the finish grinding, surface defect detection is performed by the surface defect detection method according to any one of claims 8 to 10,
If it is determined from the surface defect detection result that there is a surface defect to be removed, the rolling roll shaft of the grindstone per rotation of the rolling roll is determined based on a predetermined relationship with respect to the surface defect. Among the conditions of feed amount in the central direction, grinding wheel rotation speed or rolling roll rotation speed, one or a plurality of conditions are changed to determine the number of passes for finish grinding, and finish grinding is performed with the number of passes, The roll grinding method for rolling, wherein the surface grinding is performed again by the surface defect detection and the determined number of finish grinding passes until it is determined that there is no surface defect to be removed. The rolling roll grinding method according to claim 12 or 13, wherein the grindstone used for finish grinding after determining that the surface defect to be removed exists is changed to a grindstone having a high particle size.

Images