JP6897889B2 - Defect grinding method for round steel and manufacturing method for steel - Google Patents

Description

The present invention relates to a method for grinding defects of a round steel material and a method for manufacturing a steel material, which automatically grinds defective portions such as surface defects and surface layer defects of the round steel material.

In general, round steel pieces having a circular cross section (for example, round billets) are manufactured directly by casting or by slab-rolling the cast steel pieces. Round steel pieces often have surface defects (opening defects) and surface layer defects (internal defects) in the manufacturing process. These defective parts become obstacles in the subsequent process. That is, for example, in the case of hot rolling a round steel piece, defects caused by these defects may remain in the steel material after hot rolling, or the steel material may be broken during hot rolling. Problems such as rolling out occur. Therefore, a so-called "maintenance work" is performed in which the defective portion is ground and eliminated before the round steel piece is sent to the subsequent process. In addition, since defective parts may occur in strip steel products such as round bar steel and product steel pipes in the manufacturing process, maintenance work is also performed on round bar steel such as strip steel products and product steel pipes.

As a conventional method for automatically grinding defects of a round bar material for grinding surface defects and surface layer defects of the round bar material, for example, the one shown in Patent Document 1 is known.
The automatic grinding method for a round bar material shown in Patent Document 1 is to detect a flaw while advancing while rotating the round bar material and the flaw detection head relative to each other, and grind a defective portion according to the flaw detection result. Then, in this automatic grinding method, an origin mark, which is a reference when creating a flaw map, is attached to the material, surface defects of the material are detected based on the origin mark, and the depth of surface defects of the material is detected based on the origin mark. The position should be measured and flawed, and the surface defect map and surface defect map should be combined based on the origin mark to determine the maximum depth of surface defects and surface defects existing at the same location, and then ground. I try to set the position and depth of the defect.
According to the automatic grinding method of the round bar material shown in Patent Document 1, surface defects and surface layer defects can be ground without over-grinding.

Further, as a conventional surface defect care device for a round steel material, for example, the one shown in Patent Document 2 is known.
The surface defect care device for the round steel material shown in Patent Document 2 is a surface defect inspection device that can reciprocate along the axial direction of the rotating round steel material and detects the surface defect in contact with the round steel material. It is equipped with a marking device that injects a marking liquid at the position of a surface defect to mark it, and a work deck for cleaning the marked surface defect.
According to the surface defect care device for round steel material shown in Patent Document 2, the position of the detected surface defect is marked, so that the operator can accurately determine the grinding position and perform the grinding operation quickly. it can.

Japanese Unexamined Patent Publication No. 2000-141198 JP-A-2002-28724

However, the conventional method for automatically grinding a round bar material shown in Patent Document 1 and the device for treating surface defects of a round steel material shown in Patent Document 2 have the following problems.
That is, in the case of the automatic grinding method for a round bar material shown in Patent Document 1, an origin marking device for attaching an origin mark, which is a reference in the circumferential direction and the longitudinal direction of the round bar material, to the round bar material is required when creating a defect map. , The cost was high for its introduction and maintenance, and the cost could not be reduced. In addition, if the round bar material has a low roundness, erroneous grinding may occur that causes a deviation between the position of the defective part and the grinding position, which requires re-inspection and re-grinding, resulting in production. It sometimes hindered efficiency.

Further, in the case of the surface defect care device for a round steel material shown in Patent Document 2, the operator visually finds the marking applied to the position of the detected surface defect and grinds the portion.
Here, the size and shape of the marking applied to the position of the surface flaw of the round steel material may change depending on the spraying condition of the marking liquid, and it may be difficult for the operator to visually find it. Therefore, in the method of visually finding the marking by the operator, there is a high risk of missing the marking, and as a result, erroneous grinding may occur in which a deviation occurs between the position of the defective portion and the grinding position, and the marking is eliminated. Round steel materials that did not completely remove all the flaws that should have been removed were sometimes sent to the subsequent process.

Therefore, the present invention has been made to solve these conventional problems, and an object of the present invention is to prevent erroneous grinding that causes a deviation between the position of the defective portion and the grinding position, and the cost is low. It is an object of the present invention to provide a defect grinding method for a round steel material capable of automatically grinding a defective portion of the round steel material with an equipment, and a method for manufacturing a steel material using this defect grinding method.

In order to achieve the above object, the method for grinding a defect in a round steel material according to one aspect of the present invention is a method for grinding a defect in a round steel material that automatically grinds a defective portion in the round steel material. From the flaw detection step of flaw detection, the marking step of applying marking to the defect portion having a predetermined depth or more detected in the flaw detection step, and the flaw detection result in the flaw detection step, the depth of the defect portion on the surface of the round steel material and the above. The defect portion grinding step includes a defect portion map creation step of creating a defect portion map in which the circumferential position and the longitudinal direction position of the defect portion are specified, and a defect portion grinding step of grinding the defect portion of the round steel material. Includes a marking detection step of processing an image of the surface of the round steel material in the circumferential direction to extract the marking, and a marking portion grinding step of grinding the marking portion extracted in the marking detection step. In the marking portion grinding step, the longitudinal alignment of the marking portion in the round steel material is determined with reference to the defect portion map, and the circumferential alignment of the marking portion in the round steel material is the extraction of the marking. The gist is that the grinding depth of the marking portion is determined by referring to the result, and is determined by referring to the defect portion map and the extraction result of the marking.

Further, the defect grinding method for a round steel material according to another aspect of the present invention is a defect grinding method for a round steel material that automatically grinds a defective portion of the round steel material, and is a flaw detection step for detecting the defective portion of the round steel material. Based on the marking step of applying marking to the defect portion having a depth equal to or greater than the predetermined depth detected in the flaw detection step and the flaw detection result in the flaw detection step, the depth of the defect portion on the surface of the round steel material and the circumferential direction of the defect portion. A defect portion map creation step for creating a defect portion map in which a position and a longitudinal position are specified, and a defect portion grinding step for grinding the defect portion of the round steel material are provided, and the defect portion grinding step includes the defect portion grinding process. A determination step of determining whether the ratio of the area of the defective portion having a predetermined depth or more on the surface of the round steel material is less than a predetermined threshold value with reference to the map, and a predetermined step on the surface of the round steel material determined in the determination step. A marking detection step of extracting the marking by image processing an image in the circumferential direction of the surface of the round steel material when the ratio of the area of the defect portion equal to or greater than the depth is less than the predetermined threshold, and the marking detection step. When the ratio of the area of the defect portion having a predetermined depth or more on the surface of the round steel material determined in the determination step to the marking portion grinding step for grinding the marking portion extracted in the above is equal to or greater than a predetermined threshold value. In the marking portion grinding step, the longitudinal alignment of the marking portion in the round steel material is determined with reference to the defect portion map. The circumferential alignment of the marking portion in the round steel material is determined by referring to the extraction result of the marking, and the grinding depth of the marking portion is determined by referring to the defect portion map and the extraction result of the marking. The gist is to do.

Further, the method for producing a steel material according to another aspect of the present invention is a method for producing a steel material in which a round steel material having a circular cross section is surface-ground at a defective portion of the round steel material and then processed in a post-process. The gist of the surface grinding is to carry out the defect grinding method for a round steel material according to one or another aspect of the present invention described above.

According to the method for grinding defects in round steel materials according to the present invention, defective parts in round steel materials are automatically ground with inexpensive equipment without erroneous grinding that causes a deviation between the position of the defective portion and the grinding position. It is possible to provide a method for grinding defects of round steel materials. Further, according to the method for producing a steel material according to the present invention, since the above-mentioned erroneous grinding can be suppressed, it is possible to provide a method for producing a steel material that suppresses an obstacle in a subsequent process or an outflow of a defective product.

It is a schematic block diagram of the defect grinding system to which the defect grinding method of a round steel material which concerns on one Embodiment of this invention is applied. It is a figure which looked at the schematic structure of the marking detection apparatus in the defect grinding system shown in FIG. 1 from the front side. It is a figure which looked at the schematic structure of the marking detection device in the defect grinding system shown in FIG. 1 from the right side. It is a figure for demonstrating the specification of the line sensor camera which comprises the image pickup apparatus in a marking detection apparatus. It is a flowchart which shows the procedure of the defect grinding method of a round steel material using the defect grinding system shown in FIG. It is a figure for demonstrating an example of a defect part map. It is a flowchart which shows the procedure of step S4 (defect part grinding process) in the flowchart shown in FIG. 6 is a flowchart showing the procedure of step S46 (marking detection step) in the flowchart shown in FIG. 7. It is a flowchart which shows the procedure of step S462 (image processing step) in the flowchart shown in FIG. It is a flowchart which shows the procedure of step S463 (marking extraction step) in the flowchart shown in FIG. An example of the image after the original image joining process, the binarized image after removing the binarized noise, and the image of the marking extraction result is shown from one end surface in the axial direction of the round steel material to the first position in the axial direction. It is the figure which showed by dividing into 3 from the 1st position to the 2nd position, and from the 2nd position to the 3rd position. It is a figure which shows a part of an example of the binarized image after the binarized noise is removed. It is a figure for demonstrating an example of the development view. 6 is a flowchart showing the procedure of step S47 (marking portion grinding step) in the flowchart shown in FIG. 7. It is the figure which looked at another schematic structure of the marking detection apparatus in a defect grinding system from the front side.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the material, shape, structure, arrangement, etc. of the components. It is not specified in the following embodiments. The drawings are schematic. Therefore, it should be noted that the relationship, ratio, etc. between the thickness and the plane dimension are different from the actual ones, and there are parts where the relationship and ratio of the dimensions are different between the drawings.

FIG. 1 shows a schematic configuration of a defect grinding system to which the defect grinding method for a round steel material according to an embodiment of the present invention is applied, and the defect grinding system 1 is manufactured by bulk rolling or the like. It is provided in the middle of a transport line for transporting the round steel material S to the downstream process.
The defect grinding system 1 includes a leakage magnetic flux flaw detector (MLFT) 11A for detecting surface defects as defects in the round steel material S, and an ultrasonic flaw detector (AUT) for detecting surface defects as defects in the round steel material S. It is equipped with 11B.

The leakage magnetic flux flaw detector 11A is installed at a location off the transport line and detects surface defects existing on the surface of the round steel material S rotating in the circumferential direction on the turning roller 13A. The flaw detection of the surface defect of the round steel material S by the leakage magnetic flux flaw detector 11A is performed for one round in the circumferential direction over the entire length of the round steel material S in the longitudinal direction. Further, the ultrasonic flaw detector 11B is installed on the downstream side of the leakage magnetic flux flaw detector 11A, and is transferred from the turning roller 13A onto the turning roller 13B by a transfer (not shown) on the turning roller 13B. The surface layer defect of the round steel material S rotating in the circumferential direction is detected. The flaw detection of the surface layer defect of the round steel material S by the ultrasonic flaw detection device 11B is performed for one round in the circumferential direction over the entire length of the round steel material S in the longitudinal direction.

Further, the defect grinding system 1 includes a first marking device 12A attached to the leakage magnetic flux flaw detection device 11A and a second marking device 12B attached to the ultrasonic flaw detection device 11B. The first marking device 12A applies the marking to the position of the surface defect having a predetermined depth or more (0.3 mm or more in the present embodiment) among the surface defects detected by the leakage magnetic flux flaw detecting device 11A. The leakage magnetic flux flaw detector 11A transmits the depth information of the flaw-detected surface defect to the first marking device 12A. Further, the second marking device 12B applies the marking to the position of the surface layer defect having a predetermined depth or more (0.3 mm or more in the present embodiment) among the surface layer defects detected by the ultrasonic flaw detecting device 11B. The ultrasonic flaw detector 11B sends the depth information of the surface defect detected to the second marking device 12B.

Further, the defect grinding system 1 is based on the flaw detection results of the leakage magnetic flux flaw detector 11A and the ultrasonic flaw detector 11B, and the depths of the surface defects and the surface layer defects on the surface of the round steel material S and the circumferences of the surface defects and the surface layer defects. A defect map creating device 15 for creating a defect map 50 (see FIG. 6) that specifies a directional position y and a longitudinal position x is provided. When creating the defect map 50, the defect map creating device 15 has a plurality of regions (in the present embodiment) along the longitudinal direction of the round steel S on the surface of the round steel S as shown in FIG. Creates a defect map divided into 6 regions) A to F. In the defect map 50 shown in FIG. 6, the depth of each surface defect and surface defect is indicated by an integral multiple of 0.1 mm as 1.

The leakage magnetic flux flaw detector 11A sends the depth information of the surface defect detected and the information of the longitudinal position x from the longitudinal end face (the end face is 0) of the round steel material S of the surface defect to the defect map creating device 15. Send out. Further, the turning roller 13A is provided with a pulse generator 14A as a rotation angle detector. The pulse generator 14A detects the rotation speed r of the turning roller 13A from the start of the leakage magnetic flux flaw detection device 11A to the flaw detection of the surface defect. The defect map creating device 15 calculates the rotation angle from the flaw detection start point of the round steel material S to the flaw detection point of the surface defect from the above-mentioned rotation speed r received from the pulse generator 14A, and this rotation angle and the round steel material S From the diameter, the length in the circumferential direction from the flaw detection start point in the circumferential direction of the round steel material S to the flaw detection point of the surface defect is calculated, and the circumferential position y of the surface defect is specified.

Further, the ultrasonic flaw detector 11B is a defect portion map creation device that obtains the depth information of the surface defect detected and the information of the longitudinal position x from the longitudinal end face (the end face is 0) of the round steel material S of the surface defect. Send to 15. Further, the turning roller 13B is also provided with a pulse generator 14B as a rotation detector, and the pulse generator 14B is the number of rotations of the turning roller 13B from the start of the ultrasonic flaw detection device 11B to the flaw detection of the surface defect. r is detected. The defect map creating device 15 calculates the rotation angle from the flaw detection start point of the round steel material S to the flaw detection point of the surface layer defect from the above-mentioned rotation speed r received from the pulse generator 14B, and this rotation angle and the round steel material S From the diameter, the length in the circumferential direction from the flaw detection start point in the circumferential direction of the round steel material S to the flaw detection point of the surface layer defect is calculated, and the circumferential position y of the surface layer defect is specified.

Further, the defect grinding system 1 includes a defect grinding device 20 for grinding surface defects and surface layer defects of the round steel material S.
When the marking is extracted by the marking detection device 30 described later, the defect portion grinding device 20 is a marking M of each region corresponding to each region A to F on the defect portion map 50 on the surface of the round steel material S. Grind the part.
The defect grinding device 20 is installed on the downstream side of the ultrasonic flaw detector 11B, and goes around the turning roller 25, which is transferred from the turning roller 13B onto the turning roller 25 by a transfer (not shown). The marking portion of each region of the round steel material S rotating in the direction or the entire surface of each region is ground (also referred to as surface grinding in the following description). The turning roller 25 is rotatably installed on a carriage 27 that can be moved between the defect grinding device 20 and the marking detection device 30 described later by the carriage driving device 28. Further, the turning roller 25 is provided with a pulse generator 26 as a rotation angle detector.

Further, the defect portion grinding device 20 includes a grinder 21 that grinds a marking portion of each region of the round steel material S or the entire surface of each region, a grinding control device 22 that controls the grinder 21 and the trolley drive device 28, and a turning roller 25. It is provided with an end face detection sensor 24 that detects the end face of the upper round steel material S in the longitudinal direction. The grinding control device 22 is connected to a defect map creation device 15, a grinder 21, a host computer 23, an end face detection sensor 24, a pulse generator 26, a trolley drive device 28, a camera control device 32 described later, and a development drawing creation device 38. There is. The function of the grinding control device 22 will be described in detail later. The grinding control device 22 is a computer system having an arithmetic processing function for realizing each function described later by executing a program on computer software. The computer system is configured to include a ROM, a RAM, a CPU, and the like, and each function is realized on software by executing various dedicated programs stored in the ROM and the like in advance.

Further, the defect grinding system 1 detects markings M (see FIG. 12) applied to the positions of surface defects and surface defects of the round steel material S according to a determination result (step S45) described later by the grinding control device 22. The detection device 30 is provided.
The size of the round steel material S marked by the first marking device 12A and the second marking device 12B is an arbitrary size between the minimum diameter φ80 mm and the maximum diameter φ450 mm in the present embodiment, and FIG. In FIG. 4, the maximum diameter round steel material is shown by S1, and the minimum diameter round steel material is shown by S2. The marking colors applied to the positions of the surface defects and the surface layer defects of the round steel material S by the first marking device 12A and the second marking device 12B are the colors of the illumination by the illumination device 5 (a color close to white) described later. It is preferable to use different colors. This makes it easier to detect the marking without confusing the color of the marking with the color of the illumination.

As shown in FIGS. 1 to 3, the marking detection device 30 captures a plurality of images of the surface of the round steel material S rotating in the circumferential direction on the turning roller 25 on the carriage 27 that has been moved from the defect grinding device 20. It includes an image pickup device 31, a computer system 35, and a development drawing creation device 38. The turning roller 25 rotates the round steel material S at a predetermined rotation speed (for example, about 1500 mm / s in this embodiment) in the circumferential direction (direction indicated by the arrow in FIGS. 2 and 4).

In the marking detection device 30, as shown in FIGS. 2 and 3, a plurality of first support members 41 are attached to a plurality of support legs 40 erected on the pedestal portion 39 so as to be orthogonal to the support legs 40. Has been done. The second support member 42 is attached to the first support member 41 so as to be orthogonal to the first support member 41. Further, at a position above the portion of the plurality of support legs 40 to which the first support member 41 is attached, the plurality of third support members 43 are attached so as to be orthogonal to the support leg 40. Further, the fourth support member 44 is attached to the third support member 43 so as to be orthogonal to the third support member 43.

Each image pickup device 31 is attached to the tip of the fourth support member 44.
Each image pickup device 31 is composed of a line sensor camera, and the direction in which the image pickup line of the line sensor camera extends coincides with the axial direction of the round steel material S as shown in FIG. The angle δ formed by the optical axis L31 of the line sensor camera and the tangent line TL in contact with the uppermost position P of the round steel material S when viewed from the axial direction of the steel material S is 90 degrees. The angle δ formed by the optical axis L31 and the tangent line TL is not limited to 90 degrees, and is suitable as long as the acute angle side is in the range of 30 degrees or more.

As shown in FIG. 4, the installation height of the line sensor cameras constituting each imaging device 31 is such that the distance WD between the lens of the line sensor camera and the round steel material S is a predetermined distance (the maximum diameter of the round steel material S1). The distance WD (Φmax): 900 mm in the case of the case, and the distance WD (Φmin): 1270 mm in the case of the round steel material S2 having the smallest diameter) are set.
When selecting the line sensor cameras that make up each image pickup device 31, the depth of field is calculated, and the top position P1 on the surface of the maximum diameter round steel material S1 and the top position on the surface of the minimum diameter round steel material S2, which are the subjects. Select a camera that has a lens that is in focus even in the case of P2. In the case of the present embodiment, a lens is selected in which the depth of field is 771 mm, the diameter of the round steel material S1 having the maximum diameter is Φ450 mm, and the diameter of the round steel material S2 having the minimum diameter is Φ80 mm.

Then, the line sensor camera constituting each image pickup apparatus 31 measures the uppermost position (specific position) P in the circumferential direction of the surface of the round steel material S rotating in the circumferential direction on the turning roller 25 (FIG. 12). The image is taken for one round of the round steel material S at a predetermined cycle with a resolution smaller than the dimension of (see). Each image pickup apparatus 31 has an uppermost position P on the surface of the round steel material S rotating in the circumferential direction (the uppermost position on the surface of the round steel material S1 having the maximum diameter is P1, and the uppermost position on the surface of the round steel material S2 having the smallest diameter is P2). The position is imaged for one round of the round steel material S at a predetermined cycle. In the case of the present embodiment, the size of the marking M is a circle having a diameter of about 4 mm, and the resolution of the line sensor camera, that is, the width R in the circumferential direction of each pixel n (see FIG. 4) of one line is a circle having the maximum diameter. The circumferential width R (Φmax) of each pixel n when imaging the steel material S1 is 630 μm / pix, and the circumferential width R (Φmin) of each pixel n when imaging the smallest diameter round steel material S2 is 889 μm / pix. It is a pixel. Further, in the case of this embodiment, the rotation speed of the round steel material S is 1500 mm / s, and the period of imaging by the line sensor camera is 1/2381 s so that the surface of the round steel material S in the circumferential direction can be imaged without a gap. It has become.

The circumferential imaging start point of the round steel material S by each imaging device 31 is the circumferential flaw detection start point of the round steel material S by the leakage magnetic flux flaw detector 11A and the circumferential flaw detection of the round steel material S by the ultrasonic flaw detector 11B. Same as the starting point.
Further, the number of pixels n in one line of the line sensor camera constituting each imaging device 31 is 2048 pix, and the axial width R (Φmax) of each pixel n when imaging the round steel material S1 having the maximum diameter is 630 μm /. The width R (Φmin) of each pixel n in the axial direction when imaging the round steel material S2 having the smallest diameter is 889 μm / pix. Therefore, the visual field width L (Φmax) when imaging the round steel material S1 having the maximum diameter is 1290 mm, and the visual field width L (Φmin) when imaging the round steel material S2 having the minimum diameter is 1821 mm. A plurality of image pickup devices 31 are installed along the axial direction of the round steel material S so that the total length of the round steel material S1 having the maximum diameter and the total length of the round steel material S2 having the minimum diameter can be imaged. Specifically, two image pickup devices 31 are installed for each region corresponding to each region A to F of the defect portion map shown in FIG. 6 of the round steel material S.

Here, the reason why the image pickup apparatus 31 is a line sensor camera in which the image pickup line extends in the axial direction of the round steel material S is as follows. That is, when the round steel material S is viewed from the axial direction, the surface of the round steel material S is circular. Therefore, when the image pickup device 3 is an area sensor camera, the distance from the area sensor camera to the surface of the round steel material S. Is different along the circumferential direction, and the angle formed by the straight line connecting the camera and the position on the surface of the round steel S when viewed from the axial direction of the round steel S with the surface of the round steel S at this position is the circumferential direction. Different along. Therefore, when the image pickup apparatus 31 is an area sensor camera, the appearance of the markings applied to the surface of the round steel material S in the captured image changes along the circumferential direction of the round steel material S. When the angle between the straight line connecting the position on the surface of the round steel material S and the camera at this position with the surface of the round steel material S becomes an acute angle, the marking area in the captured image becomes small, and the marking and noise can be distinguished. It becomes difficult. The image pickup device 31 is composed of a line sensor camera, the image pickup device 3 is arranged so that the image pickup line extends in the axial direction of the round steel material S, and the position of the uppermost position P on the surface of the round steel material S rotating in the circumferential direction is set. The image is taken along the axial direction. Then, as will be described later, an image obtained by connecting the images of the uppermost position (specific position) P captured by the line sensor camera in the circumferential direction is obtained, and markings are extracted from this image. As a result, there is no change in the distance from the line sensor camera to the position of the uppermost position P on the surface of the round steel material S when viewed from the axial direction of the round steel material S, and the line connecting the camera and the uppermost position P Since the angle formed by the surface of the round steel material S at the uppermost position P is constant, such inconvenience is eliminated. Therefore, by using the image pickup device 31 as a line sensor camera, the shape of the marking applied to the surface of the round steel material S to be imaged can be appropriately detected.

Each image pickup device 31 is connected to a camera control device 32 that controls a power supply (not shown), an image pickup cycle, and the like. Further, the camera control device 32 is connected to the grinding control device 22 and receives the result of the determination (step S45) by the grinding control device 22. The camera control device 32 corresponds to the regions A to F when the determination result is YES (when the ratio of the areas of the defective portions (surface defects and surface layer defects) in the regions A to F is less than a predetermined threshold value). A signal for starting imaging by the imaging device 31 is sent to the imaging device 31.

Further, as shown in FIGS. 2 to 4, the marking detection device 30 includes a plurality of lighting devices 33.
Each lighting device 33 is rotatably attached to the tip of the second support member 42 described above.
Each of the lighting devices 33 is composed of two rows of bar lighting that continuously lights the surface of the round steel material S, particularly the vicinity of the uppermost position P to be imaged. The color of the illumination is a color close to white. Then, as shown in FIG. 2, the angle θ formed by the optical axis L33 of the lighting device 33 and the vertical line VL is from the vicinity of the uppermost position P2 of the round steel material S2 having the smallest diameter to the uppermost position P1 of the round steel material S1 having the largest diameter. It is adjustable so that it can be irradiated in all cases up to the vicinity of. A plurality of lighting devices 33 are installed along the axial direction of the round steel material S so that the total length of the round steel material S1 having the maximum diameter and the total length of the round steel material S2 having the minimum diameter can be illuminated.
Each lighting device 33 is connected to a lighting power supply (not shown), a lighting control device 34 that controls the brightness of the lighting, and the like.

Further, the computer system 35 has an image processing unit 36 and an image processing unit 36 that process an image obtained by connecting the images of the above-mentioned uppermost position (specific position) P captured by each imaging device 31 in the circumferential direction. It is provided with a marking extraction unit 37 that extracts a marking M (see FIG. 12) from the image processed in 1. Each imaging device 31 and pulse generator 26 are connected to a computer system 35.
The computer system 35 is a computer system having an arithmetic processing function for realizing each function of the image processing unit 36 and the marking extraction unit 37 by executing a program on computer software. Then, this computer system is configured to include a ROM, a RAM, a CPU, etc., and realizes each of the above-mentioned functions on software by executing various dedicated programs stored in the ROM or the like in advance.

Further, the development drawing creating device 38 is based on the marking M extracted by the marking extraction unit 37, the circumferential position y of the marking M from the imaging start point, and the longitudinal position x of the marking M from the longitudinal end face. The development drawing 60 shown in the above is created. The developed view 60 shown in FIG. 13 has a plurality of regions (6 in the present embodiment) along the longitudinal direction of the round steel material S on the surface of the round steel material S corresponding to the defect map 50 shown in FIG. Area) A to F, where the marking M is located is indicated by the number 1.
Then, the information of the development drawing creating device 38 is transmitted to the grinding control device 22.
Each function of the image processing unit 36, the marking extraction unit 37, and the development drawing creating device 38 will be described in detail later.

Next, a defect grinding method for the round steel material S using the defect grinding system 1 will be described in detail with reference to FIGS. 5 to 14.
First, in step S1, the leakage magnetic flux flaw detector 11A detects surface defects existing on the surface of the round steel material S rotating in the circumferential direction on the turning roller 13A, and the ultrasonic flaw detector 11B rotates on the turning roller 13B. A flaw is detected on the surface layer of the round steel material S rotating in the direction (fault detection step). Here, the flaw detection of the surface defect of the round steel material S by the leakage magnetic flux flaw detector 11A is performed for one round in the circumferential direction over the entire length in the longitudinal direction of the round steel material S, and the flaw detection of the surface layer defect of the round steel material S by the ultrasonic flaw detector 11B. Is performed for one round in the circumferential direction over the entire length of the round steel material S in the longitudinal direction. Then, the leakage magnetic flux flaw detector 11A sends the depth information of the surface defect detected to the first marking device 12A, and the ultrasonic flaw detector 11B sends the depth information of the surface defect detected to the second marking device 12B. To do.

Next, in step S2, the first marking device 12A marks the position of the surface defect of the predetermined depth or more (0.3 mm or more in the present embodiment) among the surface defects detected by the leakage magnetic flux flaw detector 11A. M (see FIG. 12) is applied, and the second marking device 12B has a surface defect of a predetermined depth or more (0.3 mm or more in the present embodiment) among the surface defects detected by the ultrasonic flaw detector 11B. Marking M is applied to the position of (marking step). Here, the color of the marking applied to the positions of the surface defect and the surface layer defect of the round steel material S by the first marking device 12A and the second marking device 12B is different from the color of the illumination by the illumination device 5 (a color close to white). It is preferably a color.

Next, in step S3, the defect map creating device 15 determines the depths and surface defects of the surface defects and the surface layer defects on the surface of the round steel material S from the flaw detection results of the leakage magnetic flux flaw detector 11A and the ultrasonic flaw detector 11B, respectively. A defect map 50 (see FIG. 6) in which the circumferential position y and the longitudinal position x of the surface layer defects are specified is created (defect map creation step).
Here, when the defect map creating device 15 creates the defect map 50, as shown in FIG. 6, a plurality of regions (the present embodiment) along the longitudinal direction of the round steel material S on the surface of the round steel material S are used. In this case, a defect map 50 divided into 6 regions) A to F is created. In the defect map 50 shown in FIG. 6, the depth of each surface defect and surface defect is indicated by an integral multiple of 0.1 mm as 1.

The leakage magnetic flux flaw detector 11A sends the depth information of the surface defect detected and the information of the longitudinal position x from the longitudinal end face (the end face is 0) of the round steel material S of the surface defect to the defect map creating device 15. The defect portion map creation device 15 that sends out receives the information. Further, the defect map creating device 15 receives the rotation speed r of the turning roller 13A from the start of the leakage magnetic flux flaw detection device 11A to the flaw detection of the surface defect from the pulse generator 14A, and the rotation speed r and the turning. The circumferential length from the flaw detection start point of the round steel material S to the flaw detection point of the surface defect is calculated from the diameter of the roller 13A, and the circumferential position y of the surface defect is specified.

Further, the ultrasonic flaw detector 11B is a defect portion map creation device that obtains the depth information of the surface defect detected and the information of the longitudinal position x from the longitudinal end face (the end face is 0) of the round steel material S of the surface defect. The defect map creating device 15 sends the information to the 15 and receives the information. Further, the defect map creating device 15 receives the rotation number r of the turning roller 13B from the start of the ultrasonic flaw detection device 11B to the flaw detection of the surface layer defect from the pulse generator 14A, and the rotation number r and the turning. From the diameter of the roller 13B, the length in the circumferential direction from the flaw detection start point in the circumferential direction of the round steel material S to the flaw detection point of the surface layer defect is calculated, and the circumferential position y of the surface layer defect is specified.
The defect map creating device 15 sends the information of the defect map 50 to the grinding control device 22.
Next, in step S4, the defect portion grinding device 20 grinds the surface defects and the surface layer defects of the round steel material S (defect portion grinding step).

The defect grinding process will be described in detail with reference to FIG. 7. First, in step S41, the defect grinding apparatus 20 receives the round steel material S. The acceptance of the round steel material S is achieved by transferring the round steel material S on the turning roller 13B onto the turning roller 25 on the carriage 27 by a transfer (not shown).
Next, in step S42, the grinding control device 22 determines the grinding amount per pass.
The grinding control device 22 acquires the product information of the round steel material S from the host computer 23, and determines the grinding amount per pass based on the product information of the round steel material S.

Next, in step S43, the end face detection sensor 24 detects the end face of the round steel material S on the turning roller 25 in the longitudinal direction, and sends the information to the grinding control device 22.
After step S43, the grinding control device 22 controls the carriage driving device 28 to move the carriage 27 so that the longitudinal end surface of the round steel material S on the turning roller 25 is directly below the end face detection sensor 24.
Next, in step S44, the grinding control device 22 refers to the defect portion map 50 and refers to the circle corresponding to the regions A to F having the defect portion (surface defect and surface layer defect) closest to the end face in the longitudinal direction of the round steel material S. The carriage driving device 28 is controlled to move the carriage 27 so that the imaging device 31 is located in the region of the steel material S.
After that, in step S45, the grinding control device 22 refers to the defect portion map 50 and has a predetermined depth or more in the surface region of the round steel material S corresponding to the corresponding regions A to F of the movement destination (in the present embodiment). It is determined whether the ratio of the area of the defective portion (0.3 mm or more) is less than a predetermined threshold value (determination step).

Here, the predetermined threshold value is when the area of the corresponding regions A to F of the defect portion map 50 is a1 and the area of the defect portion having a predetermined depth or more (0.3 mm or more in this embodiment) is a2. It is a value represented by a2 / a1.
Next, when the determination result is YES, the process proceeds to step S46, and when the determination result is NO, the process proceeds to step S49.
Then, in step S46, the marking detection device 30 performs image processing on an image in the circumferential direction of the surface region of the round steel material S corresponding to the corresponding regions A to F to extract the marking M (see FIG. 12) (marking detection). Process).

The marking detection step will be described with reference to FIG. 8. First, in step S461, the camera control device 32 receives the determination result from the grinding control device 22, and the area of the surface of the round steel material S corresponding to the corresponding areas A to F. An imaging start signal is sent to the imaging device 31 that images the image. Then, the line sensor camera constituting the image pickup apparatus 31 is located at the highest position (specification) in the circumferential direction of the region on the surface of the round steel material S corresponding to the corresponding regions A to F of the round steel material S rotating in the circumferential direction on the turning roller 25. Position) P is imaged for one round of the round steel material S at a predetermined cycle with a resolution smaller than the dimension of the marking M to be measured (imaging step). In the case of the present embodiment, the size of the marking M is a circle having a diameter of about 4 mm, and the resolution of the line sensor camera, that is, the width R in the circumferential direction of each pixel n (see FIG. 4) of one line is a circle having the maximum diameter. The circumferential width R (Φmax) of each pixel n when imaging the steel material S1 is 630 μm / pix, and the circumferential width R (Φmin) of each pixel n when imaging the smallest diameter round steel material S2 is 889 μm / pix. It is a pixel. Further, in the case of this embodiment, the rotation speed of the round steel material S is 1500 mm / s, and the period of imaging by the line sensor camera is 1/2381 s so that the front surface of the round steel material S in the circumferential direction can be imaged without a gap. It has become. The circumferential imaging start point of the round steel material S by the imaging device 31 is the circumferential flaw detection start point of the round steel material S by the leakage magnetic flux flaw detector 11A and the circumferential flaw detection start point of the round steel material S by the ultrasonic flaw detector 11B. Same as the point.

Next, in step S462, the image processing unit 36 of the computer system 35 processes an image obtained by joining the images of the uppermost position (specific position) P captured by the line sensor cameras constituting the image pickup device 31 in the circumferential direction. (Image processing step).
The image processing step will be described in detail. As shown in FIG. 9, in step S4621, the image processing unit 36 first first obtains an original image (an image of a plurality of top positions P) from a line sensor camera constituting the image pickup apparatus 31. To capture.
Next, in step S4622, the image processing unit 36 connects the captured original images (images of the plurality of top positions P) in the circumferential direction of the round steel material S. An example of an image after connecting the original images in the circumferential direction of the round steel material S is shown in the upper part of FIG. Since it is difficult to detect the marking M in the image in which the original image is joined in the circumferential direction of the round steel material S, the binarization process is performed later.

After that, in step S4623, the image processing unit 36 performs noise removal processing other than marking on the spliced original images.
Next, in step S4624, the image processing unit 36 performs binarization processing on the spliced original image from which noise has been removed.
Further, in step S4625, the image processing unit 36 performs noise removal processing other than marking on the image after the binarization processing. An example of the image after noise removal is shown in the middle of FIG.
Then, in step S4626, the binarized image from which noise has been removed is output to the marking extraction unit 37.
This ends the image processing step.

Then, after the image processing step, in step S463, the marking extraction unit 37 of the computer system 35 extracts the marking M from the image processed in the image processing step (marking extraction step).
The marking extraction step will be described in detail. As shown in FIG. 10, first, the marking extraction unit 37 captures a binarized image from the image processing unit 36 in step S4631.

Next, in step S4632, the marking extraction unit 37 has a region a (see FIG. 12) of a set of pixels n1 (see FIG. 12) having a pixel value of 0 (white) having a predetermined area or more in the captured binarized image. Determine if it exists. In FIG. 12, a pixel having a pixel value of 1 (black) is indicated by n2.
Then, if the result of step S4632 is YES, the process proceeds to step S4633, and if the result is No, the process proceeds to step S4634.
In step S4633, the marking extraction unit 37 determines the region a as marking M, and in step S4635, the marking extraction unit 37 determines the circumferential position y and the longitudinal position x of the marking M (see the lower row in FIG. 11). Identify.

Further, the circumferential position y of the marking M means the length in the circumferential direction from the imaging start point in the circumferential direction of the round steel material S to the marking M. The rotation speed of the turning roller 25 is input to the marking extraction unit 37 from the pulse generator 26, and the marking extraction unit 37 is in the circumferential direction of the round steel material S from the input rotation speed of the turning roller 25 and the diameter of the turning roller 25. The length in the circumferential direction from the imaging start point to the marking M is calculated, and the circumferential position y of the marking M is specified. Further, the position x in the longitudinal direction of the marking M means the length in the axial direction from the end face of the round steel material S in the axial direction to the marking M. The marking extraction unit 9 has the number of pixels n from the end face of the round steel material S in the axial direction to the marking M and the width R of each pixel n in the axial direction from the end face of the round steel material S in the axial direction to the marking M. The length in the axial direction is calculated, and the position x in the longitudinal direction of the marking M is specified.

Then, after specifying the circumferential position y and the longitudinal position x of the marking M in step S4635, the marking extraction unit 37 outputs the marking extraction result to the development drawing creating device 38 in step S4636.
An example of the marking extraction result is shown in the lower part of FIG. 11, and the marking M and the circumferential position y and the longitudinal position x of the marking M are extracted. In the lower part of FIG. 11, the circumferential position of the specific marking M is shown as y1 and the longitudinal position is shown as x1.
On the other hand, when the result of step 4632 shifts to step S4634 with No, the marking extraction unit 37 determines that there is no marking M, and outputs the result to the development drawing creating device 38 in step S4636.

Then, after step S463, as shown in FIG. 8, in step S464, the development drawing creation device 38 creates the development drawing 60. FIG. 13 shows an example in which a developed view 60 is created for each region corresponding to all the regions A to F, and the portion with the marking M is indicated by the number 1. The development drawing creating device 38 is shown in FIG. 13 based on the marking M extracted by the marking extraction unit 37, the circumferential position y of the marking M from the imaging start point, and the longitudinal position x of the marking M from the longitudinal end face. A development view 60 is created.
The information from the development drawing creating device 38 is sent to the grinding control device 22.
As a result, the marking extraction step is completed, and the marking detection step is completed.

After the marking detection step is completed, as shown in FIG. 7, in step S47, the grinding control device 22 controls the grinder 21, the trolley drive device 28, and the turning roller 25, and circles corresponding to the corresponding areas A to F. The portion of the marking M extracted in the marking detection step in the surface region of the steel material S is ground (marking portion grinding step).
The marking step grinding process will be described in detail. As shown in FIG. 14, first, the grinding control device 22 acquires the extraction result of the marking M in step S471. Specifically, the grinding control device 22 acquires information from the development drawing creating device 38.

Next, in step S472, the grinding control device 22 determines whether or not the marking M on the developed view 60 continuously spans a plurality of regions on the defect map 50.
Then, when the determination result is No, that is, when the marking M on the developed view 60 does not continuously span the plurality of regions on the defect map 50, in step S473, the round steel materials S corresponding to the corresponding regions A to F The marking M on the surface of the region is individually ground.
Here, when grinding each marking M portion individually, the grinding control device 22 determines the grinding alignment of the round steel material S in the longitudinal direction with reference to the defect portion map 50 shown in FIG. That is, the longitudinal position x of the defective portion on the defective portion map 50 is set as the grinding position in the longitudinal direction during grinding.

Further, when grinding each marking M portion individually, the grinding control device 22 determines the grinding alignment of the round steel material S in the circumferential direction with reference to the extraction result of the marking M. Assuming that the circumferential position y of the defective portion on the defective portion map 50 is the grinding position in the circumferential direction, if the round steel material S has a low roundness, a deviation occurs between the position of the defective portion and the grinding position. This is because grinding may be performed, which requires re-inspection and re-grinding, which may hinder production efficiency. Specifically, the grinding control device 22 rotates the round steel material S in the circumferential direction with the turning roller 25 while referring to the development drawing 60 which is the extraction result of the marking M, and when the imaging device 31 projects the marking M, the marking M is projected. The rotation of the round steel material S is stopped at the position, and the grinding position is set in the circumferential direction. Then, the grinding control device 22 controls the movement of the trolley 27 in the longitudinal direction so that the marking M is directly below the grinder 21 while the rotation of the round steel material S is stopped, and in that state, the marking M is ground by the grinder 21. Do. The grinding position in the longitudinal direction at this time is the longitudinal position x of the defect portion on the defect portion map 50 described above.

Further, when grinding each marking M portion individually, the grinding control device 22 determines the grinding depth by collating the defect portion map 50 and the extraction result of the marking M. Specifically, the longitudinal position x and the circumferential position y of the plurality of defective portions in the corresponding regions A to F on the defective portion map 50, the depth of each defective portion, and the plurality of markings M on the developed view 60. The longitudinal position x and the circumferential position y are collated to detect the depth of the defective portion corresponding to each marking M.
Then, the grinding control device 22 obtains the maximum depth among the depths of the plurality of defective portions corresponding to the plurality of markings M in the detected corresponding regions A to F. Then, the maximum depth of the defective portion is defined as the grinding depth of the plurality of markings M in the corresponding regions A to F.

Then, the grinding depth of the marking M is divided by the grinding amount per pass determined in step S42 to determine the number of grindings.
Here, when determining the number of times of grinding, the maximum depth among the depths of the plurality of defective portions corresponding to the plurality of markings M in the corresponding regions A to F is set to d _max, and the grinding per pass determined in step S42 is performed. Let the amount be g, and _{obtain d max} / g. Then, the obtained _{d max} / g is the greater than the permissible limit number _{N max} is the allowable limit number _{N max} grinding times.
Here, the permissible limit number N _max is N _max = ( _{DG max} ) / g from the actual diameter D of the round steel material S measured by the profile meter and the introduction permissible limit depth G _max.

Next, the grinding control device 22 uses the grinder 21 and the bogie drive device 28 so as to individually grind the marking M portion on the surface of the round steel material S in the region of the round steel material S corresponding to the corresponding regions A to F by this number of grinding times. And the turning roller 25 are controlled. As a result, all the markings M on the surface of the area of the round steel material S corresponding to the corresponding areas A to F are ground.
On the other hand, when the determination result in step S472 is No, that is, when the marking M on the developed view 60 continuously spans a plurality of regions on the defect map 50, in step S474, the region of the round steel material S spanning the plurality of regions The marking M on the surface is continuously ground.

In this continuous grinding, the grinding control device 22 determines the grinding alignment of the round steel material S in the longitudinal direction with reference to the defect map 50 shown in FIG. 6, similarly to the individual grinding of the marking M in step S474. Further, the grinding control device 22 determines the grinding alignment of the round steel material S in the circumferential direction with reference to the extraction result of the marking M.
Further, the grinding control device 22 determines the grinding depth by collating the extraction results of the defect portion map 50 and the marking M. Specifically, the longitudinal position x and the circumferential position y of the defect portion in the plurality of regions on the defect portion map 50, the depth of each defect portion, the longitudinal position x of the plurality of markings M on the developed view 60, and The depth of the defective portion corresponding to each marking M is detected by collating with the circumferential position y.

Then, the grinding control device 22 obtains the maximum depth among the depths of the plurality of defective portions corresponding to the marking M in the detected plurality of regions. Then, the maximum depth of the defective portion is defined as the grinding depth of a plurality of markings M in continuous grinding.
Then, the grinding depth of the marking M is divided by the grinding amount per pass determined in step S42 to determine the number of grindings.
Here, when determining the number of times of grinding, the maximum depth among the depths of the defective portions corresponding to the marking M in a plurality of continuously straddling regions is set to d _max, and the grinding amount per pass determined in step S42 is g. And d _max / g is obtained. Then, the obtained _{d max} / g is the greater than the permissible limit number _{N max} is the allowable limit number _{N max} grinding times.
As a result, the marking portion grinding step according to step 47 is completed.

On the other hand, when the determination result in step S45 becomes No and the process proceeds to step S49, that is, the grinding control device 22 refers to the defect portion map and refers to the surface of the round steel material S corresponding to the corresponding regions A to F of the destination. When the ratio of the area of the defective portion having a predetermined depth or more (0.3 mm or more in this embodiment) in the region is set to be equal to or more than a predetermined threshold value, in step S49, the grinding control device 22 is the grinder 21 and the trolley. The driving device 28 and the turning roller 25 are controlled to grind the entire surface region of the round steel material S corresponding to the corresponding regions A to F (total grinding step).
In this full surface grinding step, the marking M is not detected, and the entire surface area of the surface of the round steel material S corresponding to the corresponding areas A to F is uniformly ground.
At the time of this full surface grinding, the grinding control device 22 determines the grinding alignment in the longitudinal direction and the circumferential direction of the round steel material S with reference to the defect portion map 50 shown in FIG.

Further, the grinding control device 22 obtains the maximum depth among the depths of the plurality of defective portions in the corresponding regions A to F with reference to the defective portion map 50, and sets the maximum depth of the defective portions as the corresponding regions A to F. The number of times of grinding is determined by dividing by the amount of grinding per pass determined in step S42. The method of setting the allowable limit number N _max to the maximum number of grindings is the same as the grinding of the marking portion in step S47.
Then, after the steps S47 and S49 are completed, in step S48, the grinding control device 22 determines whether or not the defective portion remains on the defective portion map shown in FIG.

If the determination result is YES, step S44, step S45, step S46, step S47, step S49 and step S48 are repeated. That is, when the grinding operation for the area A is completed, step S44, step S45, step S46, step S47, step S49 and step S48 are repeated in the order of area B, area C, area D, area E, and area F.
Further, when the determination result becomes No, the process proceeds to step S50, and the defective portion grinding device 20 pays out the round steel material S.
This completes the defect grinding method for the round steel material S.

As described above, in the defect grinding method for the round steel material S according to the present embodiment, the flaw detection step (step S1) for detecting the defect portion of the round steel material S and the defect portion having a predetermined depth or more detected in the flaw detection step are performed. A defect map that identifies the depth of the defect on the surface of the round steel material S, the circumferential position y of the defect, and the longitudinal position x from the flaw detection result in the marking step (step S2) of applying the marking M and the flaw detection step. A defect portion map creating step (step S3) for creating 50 and a defect portion grinding step (step S4) for grinding the defective portion of the round steel material S are provided. Then, the defect portion grinding step is a determination step (step S45) of determining whether the ratio of the defect portion area a1 having a predetermined depth or more on the surface of the round steel material S is less than a predetermined threshold value with reference to the defect portion map 50. When the ratio of the area a1 of the defect portion having a predetermined depth or more on the surface of the round steel material S determined in the determination step is less than a predetermined threshold value, the image in the circumferential direction of the surface of the round steel material S is image-processed and marked. A marking detection step (step S46) for extracting M, a marking location grinding step (step S47) for grinding the marking M portion extracted in the marking detection step, and a predetermined position on the surface of the round steel material S determined in the determination step. The entire surface grinding step (step S49) is provided in which the entire surface of the round steel material S is ground when the ratio of the area of the defective portion equal to or greater than the depth is equal to or greater than a predetermined threshold value. Then, in the marking portion grinding step, the grinding alignment in the longitudinal direction of the round steel material S is determined with reference to the defect portion map 50, and the grinding alignment in the circumferential direction of the round steel material S is determined with reference to the extraction result of the marking M. The grinding depth is determined by collating the extraction results of the defect map 50 and the marking M.

This provides a defect grinding method for round steel materials that can automatically grind defective parts of round steel materials with inexpensive equipment without performing erroneous grinding that causes a deviation between the position of the defective part and the grinding position. it can.
Here, in this defect grinding method of the round steel material, an origin marking device for attaching an origin mark as a reference in the circumferential direction and the longitudinal direction of the round steel material S to the round steel material S is unnecessary, and the introduction and maintenance thereof are costly. There is no.
Further, by performing image processing on the image of the surface of the round steel material S in the circumferential direction to extract the marking M, the operator does not have to visually find the marking M, and there is no risk of overlooking.

Next, the method for producing a steel material according to the present invention is to feed the round steel material whose defect portion is surface-ground by the above-mentioned defect grinding method for the round steel material according to the embodiment of the present invention to a subsequent process. .. The post-process refers to the entire subsequent processing process for a round steel material whose defective portion has been surface-ground. That is, when the round steel material is a strip steel product such as round bar steel or a product steel pipe, it is a rectification process, a shipping process, etc. performed after defect grinding. When the round steel material is a material for rolling, it is a rolling process, a rectifying process performed thereafter, a shipping process, and the like.

According to the method for producing a steel material according to the present invention, the round steel from which defects have been removed without being erroneously ground is sent to a post-process by the defect grinding method for a round steel material according to the present invention. Obstacles can be suppressed. That is, when the post-process is a rolling process, it is possible to suppress obstacles such as defects caused by defects remaining due to erroneous grinding in the rolled steel material and fractures starting from the defects during rolling. Further, when the post-process is a purification process or a shipping process, it is possible to suppress an obstacle that a defective product flows out.
If the steel material at the stage of grinding the defect is a round steel material, that is, a steel material having a circular cross section, the steel material after the treatment in the post-process does not necessarily have to be the round steel material, but after the treatment in the post-process. The steel material may be a steel material having a square cross section.

In the case of manufacturing a bar steel product such as a round bar steel using a round steel material such as a round billet as a material, the defect grinding method for the round bar steel according to the present invention is for defect grinding of the material and defect grinding of the bar steel product. Applicable to both. That is, in the method for producing a steel material according to the present invention, when both the material and the product are round bar steel, the defect grinding of the present invention may be used only for defect grinding of the material, or defects of the product. The defect grinding of the present invention may be used only for grinding, or the defect grinding of the present invention may be used for both the defect grinding of a material and the defect grinding of a product.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and various modifications and improvements can be made.
For example, in the defect portion grinding step (step S4), a determination step of determining whether the ratio of the area a1 of the defect portion having a predetermined depth or more on the surface of the round steel material S is less than a predetermined threshold value with reference to the defect portion map 50 (step S4). Step S45) is not always necessary. In this case, the marking detection step (step S45) is directly performed after step S44, and the entire surface grinding step (step S49) is not performed. Therefore, in this case, in the defect grinding step, the marking detection step (step S45) in which the image in the circumferential direction of the surface of the round steel material S is image-processed to extract the marking M, and the marking M extracted in the marking detection step The marking portion grinding step (step S47) for grinding the portion is always performed.

Further, in the marking portion grinding step (step S47), the step (step S472) in which the grinding control device 22 determines whether or not the marking M on the developed view 60 continuously spans a plurality of regions on the defect portion map 50. Not necessarily necessary. In this case, after step S471, the step of individually grinding the marking M portion on the surface of the round steel material S (step S473) is performed, and the continuous grinding step (step S474) is not performed.
Further, the defect map 50 is divided into a plurality of regions A to F, but the number of divisions is not limited to this, and the defect map 50 may be one region without being divided into a plurality of regions.

When the defect portion map 50 is one region, the determination step refers to whether the ratio of the area of the defect portion having a predetermined depth or more to the entire surface of the round steel material S is less than a predetermined threshold value with reference to the defect portion map 50. To judge. Further, in the marking detection step, when the ratio of the area of the defective portion having a predetermined depth or more on the entire surface of the round steel material S determined in the determination step is less than a predetermined threshold value, the circumference of the entire surface of the round steel material S is The marking M is extracted by performing image processing on the image in the direction. Further, in the marking portion grinding step, the marking M portion extracted in the marking detection step is ground on the entire surface of the round steel material S. Further, in the total surface grinding step, when the ratio of the area of the defective portion having a predetermined depth or more to the entire surface of the round steel material S determined in the determination step is equal to or more than a predetermined threshold value, the entire surface of the round steel material S is the entire surface. Grind.

Further, although the line sensor camera is used as the image pickup apparatus 31, an area sensor camera may be used. In this case, as shown in FIG. 15, the visual field range on the surface of the round steel material S obtained by one imaging with the imaging device 31 which is an area sensor camera (the visual field range of one captured image to be joined) is set. The range in which the angle α (acute angle side) formed by the line connecting the image pickup device 31 and the position P on the surface of the round steel material S to be imaged and the surface of the round steel material S at the position P on the surface is 30 degrees or more. It is preferable to do so. When α is 30 degrees or more, it becomes easy to distinguish between marking and noise, and marking detection accuracy is improved.

1 Defect grinding system 11A Leakage magnetic flux flaw detector 11B Ultrasonic flaw detector 12A 1st marking device 12B 2nd marking device 13A Turning roller 13B Turning roller 14A Pulse generator 14B Pulse generator 15 Defect map making device 20 Defect grinding device 21 Grinder 22 Grinding control device 23 Upper computer 24 End face detection sensor 25 Turning roller 26 Pulse generator 27 trolley 28 trolley drive device 30 Marking detection device 31 Imaging device 32 Camera control device 33 Lighting device 34 Lighting control device 35 Computer system 36 Image processing unit 37 Marking extraction Part 38 Development drawing device 39 Pedestal part 40 Support leg 41 First support member 42 Second support member 43 Third support member 44 Fourth support member 50 Defect part map 60 Development view P Top position S Round steel material

Claims (5)

This is a method for grinding defects in round steel that automatically grinds defects in the round steel.
A flaw detection process for detecting the defect portion of the round steel material and
A marking step of applying marking to the defect portion having a predetermined depth or more detected in the flaw detection step, and a marking step.
A defect map creation step of creating a defect map that specifies the depth of the defect on the surface of the round steel material and the circumferential position and the longitudinal position of the defect from the flaw detection result in the flaw detection step.
It is provided with a defect grinding step for grinding the defect portion of the round steel material.
The defect grinding step includes a marking detection step of image-processing an image of the surface of the round steel material in the circumferential direction to extract the marking, and a marking spot polishing step of grinding the marking spot extracted in the marking detection step. With process
In the marking portion grinding step, the grinding alignment in the longitudinal direction of the round steel material is determined by referring to the defect portion map, and the grinding alignment in the circumferential direction of the round steel material is determined by referring to the extraction result of the marking. A method for grinding a defect in a round steel material, wherein the grinding depth is determined by collating the defect map and the extraction result of the marking. This is a method for grinding defects in round steel that automatically grinds defects in the round steel.
A flaw detection process for detecting the defect portion of the round steel material and
A marking step of applying marking to the defect portion having a predetermined depth or more detected in the flaw detection step, and a marking step.
A defect map creation step of creating a defect map that specifies the depth of the defect on the surface of the round steel material and the circumferential position and the longitudinal position of the defect from the flaw detection result in the flaw detection step.
It is provided with a defect grinding step for grinding the defect portion of the round steel material.
The defect grinding step includes a determination step of determining whether the ratio of the area of the defect portion having a predetermined depth or more on the surface of the round steel material is less than a predetermined threshold value with reference to the defect portion map, and the determination step. When the ratio of the area of the defective portion having a predetermined depth or more on the determined surface of the round steel material is less than the predetermined threshold value, the image in the circumferential direction of the surface of the round steel material is image-processed to extract the marking. The marking detection step, the marking location grinding step for grinding the marking portion extracted in the marking detection step, and the area of the defect portion having a predetermined depth or more on the surface of the round steel material determined in the determination step. When the ratio of is equal to or greater than a predetermined threshold value, the entire surface of the round steel material is ground with a full surface grinding step.
In the marking portion grinding step, the grinding alignment in the longitudinal direction of the round steel material is determined by referring to the defect map, and the grinding alignment in the circumferential direction of the round steel material is determined by referring to the extraction result of the marking. A method for grinding a defect in a round steel material, wherein the grinding depth is determined by collating the defect map and the extraction result of the marking. The defect map creating step is characterized in that, when creating the defect map, a defect map divided into a plurality of regions along the longitudinal direction of the round steel material on the surface of the round steel material is created. The method for grinding defects in a round steel material according to claim 2. In the determination step, it is determined whether or not the ratio of the area of the defect portion having a predetermined depth or more in the region of the surface of the round steel material corresponding to each of the regions divided into a plurality of regions is less than a predetermined threshold value with reference to the defect portion map. Judge,
In the marking detection step, the ratio of the area of the defect portion having a predetermined depth or more in the region of the surface of the round steel material corresponding to each of the plurality of regions of the defect portion map determined in the determination step is the said. When it is less than a predetermined threshold value, the image in the circumferential direction in the surface region of the round steel material is image-processed to extract the marking, and the marking portion grinding step is performed on the region divided into a plurality of the defect portion maps. In the area of the surface of the round steel material corresponding to each, the marking portion extracted in the marking detection step is ground.
In the total surface grinding step, the ratio of the area of the defect portion having a predetermined depth or more in the region of the surface of the round steel material corresponding to each of the plurality of regions of the defect portion map determined in the determination step is the said. The defect of the round steel material according to claim 3, wherein when the value is equal to or greater than a predetermined threshold value, the entire surface region of the round steel material corresponding to each of the plurality of regions of the defect portion map is ground. Grinding method. This is a method for manufacturing a steel material in which a round steel material having a circular cross section is surface-ground at a defective portion of the round steel material and then processed in a subsequent process.
The surface grinding is a method for producing a steel material, which comprises carrying out the method for grinding defects of a round steel material according to any one of claims 1 to 4.

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