CN113165041A - Defect grinding method for round steel and method for manufacturing steel - Google Patents

Defect grinding method for round steel and method for manufacturing steel Download PDF

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Publication number
CN113165041A
CN113165041A CN201980078989.9A CN201980078989A CN113165041A CN 113165041 A CN113165041 A CN 113165041A CN 201980078989 A CN201980078989 A CN 201980078989A CN 113165041 A CN113165041 A CN 113165041A
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Prior art keywords
grinding
defect
mark
round steel
map
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CN201980078989.9A
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CN113165041B (en
Inventor
佐藤匡将
田中美喜雄
田中雄翔
松本实
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JFE Steel Corp
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JFE Steel Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C51/00—Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/24—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B27/00—Other grinding machines or devices
    • B24B27/033—Other grinding machines or devices for grinding a surface for cleaning purposes, e.g. for descaling or for grinding off flaws in the surface
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques

Abstract

Provided are a method for grinding a defect of a round bar and a method for manufacturing a steel material, by which a defective portion of the round bar can be automatically ground without performing erroneous grinding in which a deviation occurs between the position of the defective portion and the grinding position. The method for grinding defects of round steel comprises a marking step (step S2) of applying a mark M to a defect part of a predetermined depth or more detected in a flaw detection step (step S1), a defect part map creation step (step S3) of creating a defect part map (50) based on the flaw detection result in the flaw detection step, and a defect part grinding step (step S4) of grinding the defect part. In the mark portion grinding step (step S47) in the defect portion grinding step, the grinding position matching in the longitudinal direction of the round bar S is determined with reference to the defect portion map (50), the grinding position matching in the circumferential direction of the round bar S is determined with reference to the extraction result of the mark (M) in the mark detection step (step S46), and the grinding depth is determined by referring to the extraction results of the defect portion map (50) and the mark (M).

Description

Defect grinding method for round steel and method for manufacturing steel
Technical Field
The present invention relates to a defect grinding method for round steel and a method for manufacturing steel material, which automatically grind defective portions such as surface defects and surface defects of round steel.
Background
Generally, a round steel sheet (for example, round billet) having a circular cross section is directly manufactured by casting, or manufactured by cogging-rolling a cast steel sheet. Moreover, the round steel piece often has surface defects (opening defects) and surface layer defects (internal defects) in the manufacturing process thereof. These defective portions become obstacles in the subsequent process. That is, for example, when a round steel sheet is hot-rolled, defects such as flaws that cause these defective portions remain in the steel after hot rolling, or breakage of the steel occurs during hot rolling. Therefore, before the round steel piece is sent to the post-process, a so-called "trimming operation" of grinding and removing the defective portion is performed. Further, since a defective portion may occur in a production process of a bar product or a product steel pipe such as a round bar, a trimming operation is also performed on the round bar product or the product steel pipe.
As a conventional automatic defect grinding method for a round bar material for grinding a surface defect and a surface layer defect of the round bar material, for example, a method shown in patent document 1 is known.
The automatic grinding method for a round bar material disclosed in patent document 1 detects a flaw while relatively rotating the round bar material and a flaw detection head and grinds a defective portion based on the result of the detection. In the automatic grinding method, an origin mark serving as a reference at the time of creating a flaw map (map) is added to a material, a surface defect of the material is detected with the origin mark as the reference, a depth position of a surface layer defect of the material is measured and inspected with the origin mark as the reference, the flaw map of the surface defect and the flaw map of the surface layer defect are synthesized with the origin mark as the reference, the maximum depth of the surface defect and the surface layer defect existing at the same position are obtained, and the position and the depth of the defect to be ground are set.
According to the automatic grinding method for a round bar material disclosed in patent document 1, surface defects and surface layer defects can be ground without excessive grinding.
As a conventional apparatus for repairing a flaw on the surface of a round bar, for example, an apparatus shown in patent document 2 is known.
The round steel surface flaw dressing apparatus shown in patent document 2 includes: the surface flaw detection device detects a surface flaw by reciprocating in the axial direction of a rotating round steel and contacting the round steel, the marking device sprays a marking liquid to the position of the detected surface flaw to add a mark, and the workbench trims the marked surface flaw.
According to the round bar surface flaw dressing apparatus disclosed in patent document 2, since the position of the detected surface flaw is marked, the grinding position of the worker can be accurately determined, and the grinding work can be quickly performed.
Prior art documents
Patent document
Patent document 1: japanese patent laid-open publication No. 2000-141198
Patent document 2: japanese laid-open patent publication No. 2002-28724
Disclosure of Invention
Problems to be solved by the invention
However, the automatic grinding method for round bars shown in patent document 1 and the round bar surface flaw conditioning device shown in patent document 2 have the following problems.
That is, in the case of the automatic grinding method for a round bar material disclosed in patent document 1, when creating a flaw map, an origin marking device for adding an origin mark serving as a reference in the circumferential direction and the longitudinal direction of the round bar material to the round bar material is necessary, and the cost for introduction and maintenance thereof becomes high, and the cost cannot be reduced. Further, when the roundness of the round bar is low, the round bar may be erroneously ground with a deviation between the defective portion position and the grinding position, and the round bar may need to be inspected again and ground again, which may hinder the production efficiency.
In the case of the surface flaw dressing apparatus for round steel disclosed in patent document 2, an operator visually recognizes a mark applied to the position of a detected surface flaw and grinds the position.
Here, the size and shape of the mark applied to the surface of the round steel at the position of the flaw may change depending on the spraying of the marking liquid, and the operator may not easily visually recognize the mark. Therefore, in the method of visually recognizing the mark by the operator, there is a high risk of missing the mark, and as a result, erroneous grinding in which a shift occurs between the defective portion position and the grinding position may be performed, and round steel in which all the flaws to be removed are not completely removed may be conveyed to a subsequent process.
The present invention has been made to solve the above conventional problems, and an object of the present invention is to provide a defective grinding method for round steel, which can automatically grind a defective portion of the round steel with inexpensive equipment without performing erroneous grinding in which a deviation occurs between a defective portion position and a grinding position, and a method for manufacturing a steel material using the defective grinding method.
Means for solving the problems
In order to achieve the above object, a method for grinding a defect in a round bar according to an aspect of the present invention is a method for grinding a defect in a round bar automatically, the method for grinding a defect in a round bar including: a flaw detection step of detecting the defective portion of the round steel; a marking step of applying a mark to the defect portion detected at a predetermined depth or more in the flaw detection step; a flaw portion map creating step of creating a flaw portion map in which the depth of the flaw portion on the surface of the round steel, the circumferential position and the longitudinal position of the flaw portion are determined, based on the flaw detection result in the flaw detection step; and a defective portion grinding process of grinding the defective portion of the round steel, the defective portion grinding process including: and a mark portion grinding step of grinding the marked portion extracted in the mark detection step, wherein in the mark portion grinding step, the position matching of the marked portion in the longitudinal direction of the round bar is determined with reference to the defect portion map, the position matching of the marked portion in the circumferential direction of the round bar is determined with reference to the extraction result of the mark, and the grinding depth of the marked portion is determined with reference to the defect portion map and the extraction result of the mark.
A round bar defect grinding method according to another aspect of the present invention is a defect grinding method for automatically grinding a defective portion of a round bar, the round bar defect grinding method including: a flaw detection step of detecting the defective portion of the round steel; a marking step of applying a mark to the defect portion detected at a predetermined depth or more in the flaw detection step; a flaw portion map creating step of creating a flaw portion map in which the depth of the flaw portion on the surface of the round steel, the circumferential position and the longitudinal position of the flaw portion are determined, based on the flaw detection result in the flaw detection step; and a defective portion grinding process of grinding the defective portion of the round steel, the defective portion grinding process including: a determination step of determining whether or not an area ratio of the defect portion of a predetermined depth or more on the surface of the round bar is smaller than a predetermined threshold value with reference to the defect portion map, a mark detection step of performing image processing on an image in a circumferential direction of the surface of the round bar and extracting the mark when the area ratio of the defect portion of the predetermined depth or more on the surface of the round bar determined in the determination step is smaller than the predetermined threshold value, a mark portion grinding step of grinding the portion of the mark extracted in the mark detection step, and a full-face grinding step of performing full-face grinding of the surface of the round bar when the area ratio of the defect portion of the predetermined depth or more on the surface of the round bar determined in the determination step is equal to or larger than the predetermined threshold value, in the mark portion grinding step, and determining the position matching of the marked part in the longitudinal direction of the round steel by referring to the defect part map, determining the position matching of the marked part in the circumferential direction of the round steel by referring to the extraction result of the mark, and determining the grinding depth of the marked part by referring to the defect part map and the extraction result of the mark.
A 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 defective portion of a round bar having a circular cross section is subjected to surface grinding and then the round bar is treated in a post-process, and the method for grinding a defective portion of a round bar according to one or another aspect of the present invention is performed by the surface grinding.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the method for grinding a defect in a round bar of the present invention, it is possible to provide a method for grinding a defect in a round bar, which can automatically grind a defect in a round bar with inexpensive equipment without performing erroneous grinding in which a shift occurs between a position of the defect and a grinding position. Further, according to the method for producing a steel material of the present invention, since the above-described erroneous grinding can be suppressed, it is possible to provide a method for producing a steel material in which an obstacle or a defective product in a subsequent step is suppressed from flowing out.
Drawings
Fig. 1 is a schematic configuration diagram of a defective grinding system to which a defective grinding method for round steel according to an embodiment of the present invention is applied.
Fig. 2 is a schematic configuration diagram of the mark detection device in the defect grinding system shown in fig. 1, as viewed from the front side.
Fig. 3 is a diagram of a schematic configuration of the mark detection device in the defect grinding system shown in fig. 1, as viewed from the right side surface side.
Fig. 4 is a diagram for explaining the specification of a line sensor camera (line sensor camera) constituting an imaging device in the mark detection device.
Fig. 5 is a flowchart illustrating steps of a defective grinding method of round steel using the defective grinding system shown in fig. 1.
Fig. 6 is a diagram for explaining an example of a defective portion map.
Fig. 7 is a flowchart showing a step of step S4 (defective portion grinding process) in the flowchart shown in fig. 5.
Fig. 8 is a flowchart showing a step of step S46 (mark detection process) in the flowchart shown in fig. 7.
Fig. 9 is a flowchart showing a step of step S462 (image processing process) in the flowchart shown in fig. 8.
Fig. 10 is a flowchart showing a step of step S463 (mark extraction step) in the flowchart shown in fig. 8.
Fig. 11 is a diagram showing an example of an image after the original image joining process, a binarized image after the binarization noise removal, and an image of the mark extraction result, divided into three parts from one end surface of the round steel in the axial direction to a first position in the axial direction, from the first position to a second position, and from the second position to a third position.
Fig. 12 is a diagram showing a part of an example of a binarized image after binarization noise removal.
Fig. 13 is a diagram for explaining an example of the development view.
Fig. 14 is a flowchart showing a step of step S47 (mark portion grinding step) in the flowchart shown in fig. 7.
Fig. 15 is a view of another schematic configuration of the mark detection device in the defect grinding system viewed from the front side.
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are intended to exemplify apparatuses and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention are not intended to limit the materials, shapes, structures, arrangements, and the like of the constituent members to the embodiments described below. In addition, the drawings are schematic. Therefore, it should be noted that the relationship, ratio, and the like between the thickness and the plane size are different from the actual ones, and the relationship, ratio, and the like between the sizes are also different from each other in the drawings.
Fig. 1 shows a schematic configuration of a defect grinding system to which a defect grinding method for round steel according to an embodiment of the present invention is applied, and the defect grinding system 1 is provided in the middle of a conveyance path for conveying round steel S produced by cogging rolling or the like to a downstream process.
The flaw grinding system 1 includes a leakage flux flaw detector (MLFT)11A for detecting surface flaws that are flaws in the round steel S and an ultrasonic flaw detector (AUT)11B for detecting surface flaws that are flaws in the round steel S.
The leakage flux flaw detector 11A is provided at a position deviated from the conveyance path, and detects surface defects existing on the surface of the round steel S rotating in the circumferential direction on the rotating roller 13A. The flaw detection of the surface defect of the round steel S by the leakage flux flaw detection device 11A is performed by rotating the round steel S in the circumferential direction over the entire length in the longitudinal direction. The ultrasonic flaw detector 11B is provided downstream of the leakage flux flaw detector 11A, and detects surface defects of the round steel S that is transferred from the rotating roller 13A to the rotating roller 13B by a conveyor (not shown) and rotates in the circumferential direction on the rotating roller 13B. The flaw detection of the surface layer flaw of the round steel S by the ultrasonic flaw detection device 11B is performed by rotating the round steel S in the circumferential direction over the entire length in the longitudinal direction thereof.
The defect grinding system 1 further includes a first marking device 12A attached to the leakage flux flaw detector 11A and a second marking device 12B attached to the ultrasonic flaw detector 11B. The first marking device 12A applies a mark to a 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 flux flaw detector 11A. The leakage flux flaw detector 11A sends the depth information of the detected surface defect to the first marker 12A. The second marking device 12B applies a mark to a surface layer defect of a predetermined depth or more (0.3 mm or more in the present embodiment) among the surface layer defects detected by the ultrasonic flaw detector 11B. The ultrasonic flaw detector 11B sends the depth information of the detected surface layer flaw to the second marking device 12B.
The flaw grinding system 1 further includes a flaw portion map creation device 15, and the flaw portion map creation device 15 creates a flaw portion map 50 (see fig. 6) in which the depth of each of the surface flaw and the surface layer flaw on the surface of the round steel S, the circumferential position y and the longitudinal position x of each of the surface flaw and the surface layer flaw are determined, based on the flaw detection results of the leakage flux flaw detection device 11A and the ultrasonic flaw detection device 11B, respectively. When creating the defective portion map 50, the defective portion map creating device 15 creates a defective portion map divided into a plurality of regions (6 regions in the present embodiment) a to F along the longitudinal direction of the round bar S on the surface of the round bar S, as shown in fig. 6. In the defect map 50 shown in fig. 6, the depth of each surface defect and surface layer defect is indicated by a number of an integral multiple of 0.1mm as 1.
The leakage flux flaw detector 11A sends the depth information of the detected surface flaw and the information of the longitudinal position x of the surface flaw from the longitudinal end face of the round steel S (the end face is set to 0) to the flaw portion map creation device 15. Further, the rotating 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 rotating roller 13A from the start of detection by the leakage flux flaw detector 11A until the surface defect is detected. The defect map creation device 15 calculates a rotation angle of the round steel S from the flaw detection start point to the flaw detection point of the surface defect based on the rotation speed r received from the pulse generator 14A, calculates a length of the round steel S in the circumferential direction from the flaw detection start point to the flaw detection point of the surface defect based on the rotation angle and the diameter of the round steel S, and specifies the circumferential position y of the surface defect.
The ultrasonic flaw detector 11B sends the detected depth information of the surface layer flaw and the information of the longitudinal position x of the surface layer flaw from the longitudinal end face of the round steel S (the end face is set to 0) to the flaw part map creation device 15. Further, the rotating roller 13B is also provided with a pulse generator 14B as a rotation detector, and the pulse generator 14B detects the rotation speed r of the rotating roller 13B from the start of detection by the ultrasonic flaw detector 11B to the detection of the surface defect. The defect map creation device 15 calculates a rotation angle of the round steel S from the flaw detection start point to the flaw detection point of the surface layer defect based on the rotation speed r received from the pulse generator 14B, calculates a length of the round steel S in the circumferential direction from the flaw detection start point to the flaw detection point of the surface layer defect based on the rotation angle and the diameter of the round steel S, and specifies the circumferential position y of the surface layer defect.
The defect grinding system 1 further includes a defect grinding device 20 for grinding the surface defect and the surface layer defect of the round steel S.
When the mark is extracted by the mark detection device 30 described later, the defective portion grinding device 20 grinds the mark M portion of each region corresponding to each of the regions a to F on the defective portion map 50 on the surface of the round steel S.
The flaw portion grinding device 20 is provided downstream of the ultrasonic flaw detector 11B, and grinds a marked portion of each area of the round steel S that is transferred from the rotating roller 13B to the rotating roller 25 by a conveyor (not shown) and rotates in the circumferential direction on the rotating roller 25 or the entire surface of each area (hereinafter, also referred to as surface grinding). The turning roller 25 is rotatably provided on a carriage 27 which is movable by a carriage driving device 28 between the defective portion grinding device 20 and a mark detecting device 30 described later. Further, the rotating roller 25 is provided with a pulse generator 26 as a rotation angle detector.
The defective portion grinding device 20 includes a grinding machine 21 that grinds the marked portions of each area of the round bar S or the entire surface of each area, a grinding control device 22 that controls the grinding machine 21 and the carriage drive device 28, and an end surface detection sensor 24 that detects the end surface of the round bar S in the longitudinal direction on the rotating roller 25. The grinding control device 22 is connected to the defective portion map creation device 15, the grinding machine 21, the upper computer 23, the end surface detection sensor 24, the pulse generator 26, the carriage drive device 28, the camera control device 32 described later, and the development map creation device 38. 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 ROM, RAM, CPU, and the like, and executes various dedicated programs stored in advance in the ROM and the like to realize the functions in software.
The defect grinding system 1 further includes a mark detection device 30, and the mark detection device 30 detects a mark M (see fig. 12) applied to the position of the surface defect or the surface layer defect of the round steel S based on a determination result (step S45) described later by the grinding control device 22.
In the present embodiment, the size of the round bar S marked by the first marking device 12A and the second marking device 12B is any size between the minimum diameter Φ 80mm and the maximum diameter Φ 450mm, and in fig. 2 to 4, the round bar S with the maximum diameter is shown as S1, and the round bar S with the minimum diameter is shown as S2. The color of the mark applied to the surface defect or the surface layer defect of the round steel S by the first marking device 12A and the second marking device 12B is preferably different from the color of illumination (color similar to white) by the illumination device 5 described later. This makes it possible to easily detect the mark without confusing the color of the mark with the color of the illumination.
As shown in fig. 1 to 3, the mark detection device 30 includes a plurality of imaging devices 31 that image the surface of the round steel S that is moved from the defective portion grinding device 20 and that rotates in the circumferential direction on the turning roller 25 on the carriage 27, a computer system 35, and a development view creation device 38. The turning roller 25 rotates the round steel S in the circumferential direction (the direction indicated by the arrow in fig. 2 and 4) at a predetermined rotational speed (in the present embodiment, about 1500mm/S, for example).
As shown in fig. 2 and 3, in the mark detection device 30, 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. A second support member 42 is attached to the first support member 41 so as to be orthogonal to the first support member 41. Further, a plurality of third support members 43 are attached to the plurality of support legs 40 at positions above the portions where the first support members 41 are attached so as to be orthogonal to the support legs 40. Further, a fourth support member 44 is attached to the third support members 43 so as to be orthogonal to the third support members 43.
Further, each imaging device 31 is attached to the front end of the fourth support member 44.
Each imaging device 31 is configured by a line sensor camera, and is provided such that the direction in which the imaging line (imaging line) of the line sensor camera extends coincides with the axial direction of the round steel S as shown in fig. 3, and that an angle δ formed by an optical axis L31 of the line sensor camera and a tangent line TL that is tangent to the uppermost position P of the round steel S when viewed from the axial direction of the round steel S becomes 90 degrees as shown in fig. 2. The angle δ formed by the optical axis L31 and the tangent line TL is not limited to 90 degrees, and a range in which the acute angle side is 30 degrees or more is suitable.
As shown in fig. 4, the installation height of the line sensor cameras constituting each imaging device 31 is set so that the distance WD between the lens of the line sensor camera and the round steel S is a predetermined distance (the distance WD (Φ max): 900mm in the case of the round steel S1 having the largest diameter, and the distance WD (Φ min): 1270mm in the case of the round steel S2 having the smallest diameter).
When the line sensor camera constituting each imaging device 31 is selected, the depth of field is calculated, and a camera having a lens that can be focused even when the uppermost position P1 on the surface of the round steel S1 having the largest diameter and the uppermost position P2 on the surface of the round steel S2 having the smallest diameter are both selected as the subject. In the case of the present embodiment, the depth of field is 771mm, and a lens capable of focusing in any case where the diameter of the round steel S1 with the largest diameter is phi 450mm and the diameter of the round steel S2 with the smallest diameter is phi 80mm is selected.
Then, the line sensor camera constituting each imaging device 31 images the uppermost position (specific position) P in the circumferential direction of the surface of the round steel S in one rotation of the round steel S rotating in the circumferential direction on the turning roller 25 at a predetermined cycle with a resolution smaller than the size of the mark M (see fig. 12) to be measured. Each imaging device 31 images, at a predetermined cycle, the uppermost position P of the surface of the round steel S (the uppermost position of the surface of the round steel S1 having the largest diameter is P1, and the uppermost position of the surface of the round steel S2 having the smallest diameter is P2) during one rotation of the round steel S rotating in the circumferential direction. In the case of the present embodiment, the size of the mark M is a circle having a diameter of about 4mm, and the resolution of the line sensor camera, that is, the width R in the circumferential direction of each pixel n (see fig. 4) in one line is 630 μ M/pix in terms of the width R (Φ max) in the circumferential direction of each pixel n when the round bar S1 having the largest diameter is photographed, and is 889 μ M/pix in terms of the width R (Φ min) in the circumferential direction of each pixel n when the round bar S2 having the smallest diameter is photographed. In the case of the present embodiment, the rotation speed of the round steel S is 1500mm/S, and the cycle of imaging by the line sensor camera is 1/2381S, so that the circumferential surface of the round steel S can be imaged without a gap.
Note that the imaging start point in the circumferential direction of the round steel S by each imaging device 31 is the same as the flaw detection start point in the circumferential direction of the round steel S by the leakage flux flaw detection device 11A and the flaw detection start point in the circumferential direction of the round steel S by the ultrasonic flaw detection device 11B.
The number of pixels n in one line constituting the line sensor camera of each imaging device 31 was 2048pix, the width R (Φ max) in the axial direction of each pixel n when the round bar S1 having the maximum diameter was imaged was 630 μm/pix, and the width R (Φ min) in the axial direction of each pixel n when the round bar S2 having the minimum diameter was imaged was 889 μm/pix. Therefore, the visual field width L (Φ max) when the round steel S1 with the maximum diameter was photographed was 1290mm, and the visual field width L (Φ min) when the round steel S2 with the minimum diameter was photographed was 1821 mm. The plurality of imaging devices 31 are provided along the axial direction of the round steel S, and can image the entire length of the round steel S1 having the largest diameter and the entire length of the round steel S2 having the smallest diameter. Specifically, two imaging devices 31 are provided in each of the regions of the round steel S corresponding to the regions a to F of the defect portion map shown in fig. 6.
Here, the reason why the imaging device 31 is a line sensor camera in which the imaging line extends in the axial direction of the round steel S is as follows. That is, since the surface of the round steel S is circular when the round steel S is viewed in the axial direction, when the imaging device 3 is an area sensor camera, the distance from the area sensor camera to the surface of the round steel S differs in the circumferential direction, and the angle formed by the straight line connecting the position on the surface of the round steel S and the camera when viewed in the axial direction of the round steel S and the surface of the round steel S at that position differs in the circumferential direction. Therefore, when the imaging device 31 is an area sensor camera, the appearance of the shape of the mark applied to the surface of the round steel S in the captured image changes along the circumferential direction of the round steel S. When the angle formed by the straight line connecting the position on the surface of the round steel S and the camera and the surface of the round steel S at that position becomes an acute angle, the area of the mark in the captured image becomes small, and it becomes difficult to discriminate between the mark and noise. The imaging device 31 is configured by a line sensor camera, and the imaging device 3 is disposed so that an imaging line thereof extends in the axial direction of the round steel S, and images the position of the uppermost position P on the surface of the round steel S rotating in the circumferential direction along the axial direction. As will be described later, the image of the uppermost position (specific position) P captured by the line sensor camera is joined in the circumferential direction, and the mark is extracted from the image. Accordingly, when viewed in the axial direction of the round steel S, the distance from the line sensor camera to the position of the uppermost position P on the surface of the round steel S does not change, and the angle formed by the line connecting the camera and the uppermost position P and the surface of the round steel S at the uppermost position P is constant, thereby eliminating such a problem. Therefore, by using the line sensor camera as the imaging device 31, the shape of the mark applied to the surface of the round steel S to be imaged can be appropriately detected.
Each imaging device 31 is connected to a camera control device 32 that controls a power supply, an imaging cycle, and the like, not shown. The camera control device 32 is connected to the grinding control device 22, and receives the result of the determination by the grinding control device 22 (step S45). When the determination result is yes (when the area ratio of the defective portions (surface defects and surface layer defects) in the respective regions a to F is smaller than a predetermined threshold), the camera control device 32 transmits a signal to start imaging by the imaging device 31 corresponding to the regions a to F to the imaging device 31.
As shown in fig. 2 to 4, the mark detection device 30 includes a plurality of illumination devices 33.
Each lighting device 33 is rotatably attached to the front end of the second support member 42.
Each of the illumination devices 33 is configured by two rows of stripe illumination for continuously illuminating the surface of the round steel S, particularly, the vicinity of the uppermost position P to be photographed. The color of the illumination is a color similar to white. As shown in fig. 2, the angle θ formed by the optical axis L33 of the lighting device 33 and the vertical line VL can be adjusted, and irradiation can be performed in all cases from the vicinity of the uppermost position P2 of the round steel S2 having the smallest diameter to the vicinity of the uppermost position P1 of the round steel S1 having the largest diameter. The plurality of illumination devices 33 are provided along the axial direction of the round steel S, so that the entire length of the round steel S1 having the largest diameter and the entire length of the round steel S2 having the smallest diameter can be illuminated.
Each lighting device 33 is connected to a lighting control device 34 that controls a lighting power supply, brightness of lighting, and the like, not shown.
The computer system 35 further includes an image processing unit 36 and a mark extraction unit 37, the image processing unit 36 processing images obtained by joining the images at the uppermost position (specific position) P captured by the respective imaging devices 31 in the circumferential direction, and the mark extraction unit 37 extracting a mark M (see fig. 12) from the image processed by the image processing unit 36. Each of the cameras 31 and the 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 marker extracting unit 37 by executing a program on computer software. The computer system is configured to include a ROM, a RAM, a CPU, and the like, and executes various dedicated programs stored in advance in the ROM and the like to realize the above functions in software.
The development view creation device 38 creates a development view 60 shown in fig. 13 based on the mark M extracted by the mark extraction unit 37, the circumferential position y of the mark M from the imaging start point, and the longitudinal position x of the mark M from the longitudinal end surface. The developed view 60 shown in fig. 13 corresponds to the defect map 50 shown in fig. 6, and is divided into a plurality of regions (6 regions in the present embodiment) a to F along the longitudinal direction of the round steel S on the surface of the round steel S, and the region having the mark M is indicated by numeral 1.
Then, the information of the development figure creation device 38 is sent to the grinding control device 22.
The functions of the image processing unit 36, the marker extracting unit 37, and the development view creating device 38 will be described in detail later.
Next, a method of defect grinding of the round steel S using the defect grinding system 1 will be described in detail with reference to fig. 5 to 14.
First, in step S1, the leakage flux flaw detector 11A detects surface defects existing on the surface of the round steel S rotating in the circumferential direction on the rotating roller 13A, and the ultrasonic flaw detector 11B detects surface defects of the round steel S rotating in the circumferential direction on the rotating roller 13B (flaw detection step). Here, the flaw detection of the surface defect of the round steel S by the leakage flux flaw detection device 11A is performed by rotating one round in the circumferential direction over the entire length of the round steel S in the longitudinal direction, and the flaw detection of the surface defect of the round steel S by the ultrasonic flaw detection device 11B is performed by rotating one round in the circumferential direction over the entire length of the round steel S in the longitudinal direction. Then, the leakage flux flaw detector 11A sends the depth information of the detected surface flaw to the first marking device 12A, and the ultrasonic flaw detector 11B sends the depth information of the detected surface flaw to the second marking device 12B.
Next, in step S2, the first marking device 12A applies the mark M (see fig. 12) to the surface defect at a position of the surface defect of a predetermined depth or more (0.3 mm or more in the present embodiment) among the surface defects detected by the leakage flux flaw detection device 11A, and the second marking device 12B applies the mark M to the surface defect at a position of the 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 detection device 11B (marking step). Here, the color of the mark applied to the position of the surface defect and the surface layer defect of the round steel S by the first marking device 12A and the second marking device 12B is preferably a color different from the color of the illumination by the illumination device 5 (color similar to white).
Next, in step S3, the defect map creating device 15 creates a defect map 50 (see fig. 6) in which the depth of each of the surface defect and the surface layer defect on the surface of the round steel S, and the circumferential position y and the longitudinal position x of each of the surface defect and the surface layer defect are specified, based on the flaw detection results of the leakage flux flaw detection device 11A and the ultrasonic flaw detection device 11B, respectively (a defect map creating step).
Here, when creating the defective portion map 50, the defective portion map creation device 15 creates the defective portion map 50 divided into a plurality of regions (6 regions in the present embodiment) a to F along the longitudinal direction of the round steel S on the surface of the round steel S, as shown in fig. 6. In the defect map 50 shown in fig. 6, the depth of each surface defect and surface layer defect is indicated by a number of an integral multiple of 0.1mm as 1.
The leakage flux flaw detector 11A sends the detected depth information of the surface defect and the information of the longitudinal position x of the surface defect from the longitudinal end face of the round steel S (the end face is set to 0) to the defect part map creation device 15, and the defect part map creation device 15 receives the information. Further, the defect map creation device 15 receives the rotation speed r of the rotating roller 13A from the start of detection by the leakage flux flaw detection device 11A to the detection of the surface defect from the pulse generator 14A, calculates the length of the round steel S in the circumferential direction from the flaw detection start point to the flaw detection point of the surface defect from the rotation speed r and the diameter of the rotating roller 13A, and specifies the circumferential position y of the surface defect.
The ultrasonic flaw detector 11B sends the detected depth information of the surface layer flaw and the information of the longitudinal position x of the surface layer flaw from the longitudinal end face of the round steel S (the end face is set to 0) to the flaw part map creation device 15, and the flaw part map creation device 15 receives the information. The defect portion map creation device 15 receives the rotation speed r of the rotating roller 13B from the start of the detection by the ultrasonic flaw detection device 11B to the detection of the surface layer defect from the pulse generator 14A, calculates the length of the round steel S in the circumferential direction from the flaw detection start point to the flaw detection point of the surface layer defect from the rotation speed r and the diameter of the rotating roller 13B, and specifies the circumferential position y of the surface layer defect.
The defective portion map creation device 15 sends the information of the defective portion map 50 to the grinding control device 22.
Next, in step S4, the defective portion grinding device 20 grinds the surface defect and the surface layer defect of the round steel S (defective portion grinding step).
The defective portion grinding process will be described in detail below with reference to fig. 7, and first, in step S41, the defective portion grinding apparatus 20 receives the round bar S. The round steel S positioned on the turning rollers 13B is transferred to the turning rollers 25 on the carriage 27 by a conveyor (not shown), thereby receiving the round steel S.
Next, in step S42, the grinding control device 22 determines the grinding amount for each pass.
The grinding control device 22 acquires product information of the round steel S from the host computer 23, and determines the grinding amount per pass based on the product information of the round steel S.
Next, in step S43, the end face detection sensor 24 detects the end face of the round steel S in the longitudinal direction on the rotating roller 25, and sends this information to the grinding control device 22.
After step S43, the grinding control device 22 controls the carriage drive device 28 to move the carriage 27 so that the longitudinal end surface of the round steel S on the turning roller 25 comes directly below the end surface detection sensor 24.
Next, in step S44, the grinding control device 22 refers to the defect map 50, and controls the carriage drive device 28 to move the carriage 27 so that the imaging device 31 is positioned in the area of the round steel S corresponding to the areas a to F having the defect (surface defect and surface layer defect) closest to the end surface in the longitudinal direction of the round steel S.
Thereafter, in step S45, the grinding control device 22 refers to the defect map 50, and determines whether or not the area ratio of the defect at a predetermined depth or more (0.3 mm or more in the present embodiment) in the region of the surface of the round steel S corresponding to the corresponding region a to F as the destination of movement is smaller than a predetermined threshold value (determination step).
Here, when the area of the corresponding regions a to F in the defect map 50 is a1 and the area of a defect at a predetermined depth or more (0.3 mm or more in the present embodiment) is a2, the predetermined threshold value is a value represented by a2/a 1.
Next, the process proceeds to step S46 when the determination result is yes, and proceeds to step S49 when the determination result is no.
Then, in step S46, the mark detection device 30 performs image processing on the circumferential image of the region of the surface of the round steel S corresponding to the corresponding regions a to F to extract the mark M (see fig. 12) (mark detection step).
In the mark detection process described below 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 sends an imaging start signal to the imaging device 31 that images the area on the surface of the round steel S corresponding to the corresponding areas a to F. Then, the line sensor camera constituting the imaging device 31 images the uppermost position (specific position) P in the circumferential direction of the region on the surface of the round steel S corresponding to the respective regions a to F of the round steel S in one rotation of the round steel S rotating in the circumferential direction on the turning roller 25 at a predetermined cycle with a resolution smaller than the size of the mark M to be measured (imaging step). In the case of the present embodiment, the size of the mark M is a circle having a diameter of about 4mm, and the resolution of the line sensor camera, that is, the width R in the circumferential direction of each pixel n (see fig. 4) in one line is 630 μ M/pix in terms of the width R (Φ max) in the circumferential direction of each pixel n when the round bar S1 having the largest diameter is photographed, and is 889 μ M/pix in terms of the width R (Φ min) in the circumferential direction of each pixel n when the round bar S2 having the smallest diameter is photographed. In the case of the present embodiment, the rotation speed of the round steel S is 1500mm/S, and the cycle of imaging by the line sensor camera is 1/2381S, so that the front surface of the round steel S in the circumferential direction can be imaged without a gap. Note that the imaging start point in the circumferential direction of the round steel S by the imaging device 31 is the same as the flaw detection start point in the circumferential direction of the round steel S by the leakage flux flaw detection device 11A and the flaw detection start point in the circumferential direction of the round steel S by the ultrasonic flaw detection device 11B.
Next, in step S462, the image processing unit 36 of the computer system 35 processes (image processing step) images obtained by circumferentially joining the images of the uppermost position (specific position) P captured by the line sensor camera constituting the imaging device 31.
As shown in fig. 9, the image processing step is described in detail below, and in step S4621, the image processing unit 36 first acquires original images (images at a plurality of uppermost positions P) from the line sensor camera constituting the imaging device 31.
Next, in step S4622, the image processing unit 36 joins the captured original images (images at the plurality of uppermost positions P) in the circumferential direction of the round bar S. An upper part of fig. 11 shows an example of an image obtained by joining the original image in the circumferential direction of the round steel S. Since it is difficult to detect the mark M in the image in which the original image is joined in the circumferential direction of the round steel S, the binarization processing is performed thereafter.
Thereafter, in step S4623, the image processing unit 36 performs noise removal processing other than labeling on the joined original images.
Next, in step S4624, the image processing unit 36 performs binarization processing on the original image from which the noise has been removed.
Further, in step S4625, the image processing unit 36 performs noise removal processing other than labeling on the binarized image. An example of the noise-removed image is shown in the middle of fig. 11.
Thereafter, in step S4626, the binarized image from which noise has been removed is output to the marker extracting unit 37.
Thereby, the image processing step ends.
Then, after the image processing step, in step S463, the marker extracting section 37 of the computer system 35 extracts the marker M from the image after the image processing is performed in the image processing step (marker extracting step).
As shown in fig. 10, the marker extracting unit 37 first takes in the binarized image from the image processing unit 36 in step S4631.
Next, in step S4632, the marker extracting unit 37 determines whether or not the acquired binarized image includes the set region a (see fig. 12) of the pixel n1 (see fig. 12) having the pixel value 0 (white) of a predetermined area or more. In fig. 12, a pixel having a pixel value of 1 (black) is shown by n 2.
Then, when the result of step S4632 is "yes", the process proceeds to step S4633, and when the result is "no", the process proceeds to step S4634.
In step S4633, the marker extracting unit 37 determines the region a as the marker M, and in step S4635, the marker extracting unit 37 specifies the circumferential position y and the longitudinal position x of the marker M (see the lower stage in fig. 11).
In addition, the circumferential position y of the mark M refers to a length in the circumferential direction of the round steel S from the shooting start point to the mark M. The rotation speed of the rotating roller 25 is input from the pulse generator 26 to the mark extracting unit 37, and the mark extracting unit 37 calculates the length of the round steel S in the circumferential direction from the imaging start point to the mark M based on the input rotation speed of the rotating roller 25 and the diameter of the rotating roller 25, and determines the circumferential position y of the mark M. The longitudinal position x of the mark M is a length from the end face of the round steel S in the axial direction to the mark M in the axial direction. The mark extracting unit 9 calculates the length of the round steel S in the axial direction from the end face to the mark M based on the number of pixels n from the end face to the mark M in the axial direction of the round steel S and the width R in the axial direction of each pixel n, and determines the longitudinal position x of the mark M.
Then, after the circumferential position y and the longitudinal position x of the marker M are determined in step S4635, the marker extracting unit 37 outputs the marker extraction result to the development map creating device 38 in step S4636.
Fig. 11 shows an example of a marker extraction result in the lower stage, in which the marker M, the circumferential position y of the marker M, and the longitudinal position x are extracted. In the lower part of fig. 11, the circumferential position of the specific mark M is indicated by y1, and the longitudinal position is indicated by x 1.
On the other hand, when the result of step 4632 is yes and the process proceeds to step S4634, the marker extracting unit 37 determines that there is no marker M and outputs the result to the development map creating device 38 in step S4636.
Then, after step S463, as shown in fig. 8, in step S464, the development view creation means 38 creates the development view 60. Fig. 13 shows an example of creating an expanded view 60 for each of the areas corresponding to all of the areas a to F, and a portion having a mark M is shown by numeral 1. The development view creation device 38 creates a development view 60 shown in fig. 13 based on the mark M extracted by the mark extraction section 37, the circumferential position y of the mark M from the shooting start point, and the longitudinal position x of the mark M from the longitudinal end surface.
The information from the development figure creation device 38 is sent to the grinding control device 22.
Thereby, the mark extraction step is ended, and the mark detection step is ended.
After the mark detection step is completed, as shown in fig. 7, in step S47, the grinding control device 22 controls the grinding machine 21, the carriage drive device 28, and the turning rollers 25 to grind the part of the mark M extracted in the mark detection step in the region of the surface of the round steel S corresponding to the corresponding regions a to F (a mark part grinding step).
As shown in fig. 14, the grinding control device 22 first acquires the extraction result of the mark M in step S471. Specifically, the grinding control device 22 acquires information from the development figure creation device 38.
Next, in step S472, the grinding control device 22 determines whether or not the mark M on the developed view 60 continuously extends over a plurality of areas on the defect map 50.
Then, if the determination result is "no", that is, if the mark M on the developed view 60 does not continuously span a plurality of areas on the defect portion map 50, the part of the mark M on the surface of the area of the round steel S corresponding to the corresponding areas a to F is ground independently in step S473.
Here, when independently grinding the positions of the marks M, the grinding control device 22 determines the grinding position matching in the longitudinal direction of the round bar S with reference to the defective portion map 50 shown in fig. 6. 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 at the time of grinding.
When independently grinding the positions of the marks M, the grinding control device 22 refers to the extraction result of the marks M and determines the grinding position matching in the circumferential direction of the round steel S. This is because, when the circumferential position y of the defective portion on the defective portion map 50 is set to the grinding position in the circumferential direction, if the roundness of the round steel S is low, erroneous grinding in which a deviation occurs between the defective portion position and the grinding position may be performed, and re-inspection and re-grinding may be necessary, which may hinder the production efficiency. As will be described in detail below, the grinding control device 22 rotates the round steel S in the circumferential direction on the turning roller 25 while referring to the development view 60 as the extraction result of the mark M, and if the imaging device 31 captures the mark M, stops the rotation of the round steel S at that position and sets the round steel S at the grinding position in the circumferential direction. Then, the grinding control device 22 controls the movement of the carriage 27 in the longitudinal direction so that the mark M is directly below the grinding machine 21 in a state where the rotation of the round steel S is stopped, and the grinding of the mark M is performed by the grinding machine 21 in this state. The grinding position in the longitudinal direction at this time is the longitudinal position x of the defective portion on the defective portion map 50.
When independently grinding the positions of the marks M, the grinding control device 22 determines the grinding depth by comparing the defect map 50 and the extraction result of the marks M. Specifically, the depth of the defective portion corresponding to each mark M is detected by referring to the longitudinal direction position x and the circumferential direction 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 longitudinal direction position x and the circumferential direction position y of the plurality of marks M on the development map 60.
Then, the grinding control device 22 obtains the maximum depth among the depths of the plurality of defective portions corresponding to the plurality of marks M in the detected corresponding regions a to F. Then, the maximum depth of the defect is set to the grinding depth of the portion corresponding to the plurality of marks M in the regions a to F.
Then, the grinding depth of the mark M is divided by the grinding amount per pass determined in step S42, thereby determining the number of times of grinding.
Here, when the number of grinding operations is determined, d represents the maximum depth among the depths of the plurality of defective portions corresponding to the plurality of marks M in the corresponding regions a to FmaxD is obtained by assuming the grinding amount per pass determined in step S42 as gmax(ii) in terms of/g. Then, d is calculatedmaxThe number of times of the/g is greater than the allowable limit number NmaxIn the case of (2), the allowable limit number N of timesmaxThe number of grinding times is set.
Here, the allowable limit number NmaxAccording to the actual diameter D and the introduction allowable limit depth G of the round steel S measured by the profilometermaxIs set to Nmax＝(D-Gmax)/g。
Next, the grinding control device 22 controls the grinding machine 21, the carriage drive device 28, and the turning roll 25 so as to grind the position of the mark M on the surface of the round steel S in the region of the round steel S corresponding to the respective regions a to F independently by the number of grinding times. Thereby, all the portions of the mark M on the surface of the region of the round steel S corresponding to the respective regions a to F are ground.
On the other hand, if the determination result in step S472 is "no", that is, if the mark M on the developed view 60 continuously extends over a plurality of areas on the defective portion map 50, the part of the mark M on the surface of the area of the round steel S extending over the plurality of areas is continuously ground in step S474.
In this continuous grinding, the grinding control device 22 determines the grinding position matching in the longitudinal direction of the round steel S with reference to the defective portion map 50 shown in fig. 6, in the same manner as the independent grinding of the mark M in step S474. The grinding control device 22 determines the grinding position matching in the circumferential direction of the round steel S with reference to the extraction result of the mark M.
The grinding control device 22 determines the grinding depth by referring to the defect map 50 and the extraction result of the mark M. Specifically, the depth of the defective portion corresponding to each mark M is detected by referring to the longitudinal direction position x and the circumferential direction position y of the defective portion in the plurality of regions on the defective portion map 50, the depth of each defective portion, and the longitudinal direction position x and the circumferential direction position y of the plurality of marks M on the development map 60.
Then, the grinding control device 22 obtains the maximum depth among the depths of the plurality of defective portions corresponding to the marks M in the plurality of detected regions. Then, the maximum depth of the defective portion is set to the grinding depth at the position of the plurality of marks M in the continuous grinding.
Then, the grinding depth of the mark M is divided by the grinding amount per pass determined in step S42, thereby determining the number of times of grinding.
Here, when the number of grinding operations is determined, d is the maximum depth among the depths of the defective portions corresponding to the marks M in the plurality of continuously crossing regionsmaxD is obtained by assuming the grinding amount per pass determined in step S42 as gmax(ii) in terms of/g. Then, d is calculatedmaxThe number of times of the/g is greater than the allowable limit number NmaxIn the case of (2), the allowable limit number N of timesmaxThe number of grinding times is set.
Thereby, the mark portion grinding process of step 47 is ended.
On the other hand, if the determination result at step S45 is no, the process proceeds to step S49, that is, if the grinding control device 22 refers to the defect map and the area ratio of the defect at a predetermined depth or more (0.3 mm or more in the present embodiment) in the region of the surface of the round steel S corresponding to the corresponding region a to F as the destination of movement is equal to or greater than a predetermined threshold value, at step S49, the grinding control device 22 controls the grinding machine 21, the carriage drive device 28, and the rotating roller 25 to grind the entire surface of the region of the surface of the round steel S corresponding to the corresponding region a to F (entire surface grinding step).
In this full-face grinding step, the full face of the region of the surface of the round steel S corresponding to the respective regions a to F is uniformly ground without detecting the mark M.
In the full-face grinding, the grinding control device 22 determines matching of the grinding position in the longitudinal direction and the circumferential direction of the round steel S with reference to the defect portion map 50 shown in fig. 6.
The grinding control device 22 determines the maximum depth of the depths of the plurality of defective portions in the corresponding regions a to F by referring to the defective portion map 50, sets the maximum depth of the defective portion as the grinding depth in the corresponding regions a to F, and divides the grinding depth by the grinding amount per pass determined in step S42 to determine the number of times of grinding. Will allow a limited number of times NmaxThe method of setting the maximum number of grinding times is the same as the grinding of the mark portion in step S47.
After step S47 and step S49 are completed, in step S48, the grinding control device 22 determines whether or not a defective portion remains on the defective portion map shown in fig. 6.
Then, if the determination result is yes, step S44, step S45, step S46, step S47, step S49, and step S48 are repeated. That is, after the grinding work for the area a is finished, the steps S44, S45, S46, S47, S49, and S48 are repeated in the order of the area B, the area C, the area D, the area E, and the area F.
If the determination result is "no", the process proceeds to step S50, and the defective portion grinding device 20 discharges the round bar S.
Thereby, the defective grinding method of the round steel S is ended.
As described above, the method for grinding defects in round steel S according to the present embodiment includes: the flaw detection method includes a flaw detection step (step S1) of detecting a flaw in the round steel S, a marking step (step S2) of applying a mark M to a flaw detected at a predetermined depth or more in the flaw detection step, a flaw map creation step (step S3) of creating a flaw map 50 in which the depth of the flaw on the surface of the round steel S, the circumferential position y and the longitudinal position x of the flaw are determined based on the flaw detection result in the flaw detection step, and a flaw grinding step (step S4) of grinding the flaw in the round steel S. The defective portion grinding step includes: a determination step of determining whether or not the ratio of the area a1 of the defect portion of a predetermined depth or more on the surface of the round steel S is smaller than a predetermined threshold value with reference to the defect portion map 50 (step S45), a mark detection step of extracting the mark M by performing image processing on the circumferential image of the surface of the round steel S when the ratio of the area a1 of the defect portion of the predetermined depth or more on the surface of the round steel S determined in the determination step is smaller than the predetermined threshold value (step S46), a mark portion grinding step of grinding the portion of the mark M extracted in the mark detection step (step S47), and a full-face grinding step of grinding the full face of the surface of the round steel S when the ratio of the area of the defect portion of the predetermined depth or more on the surface of the round steel S determined in the determination step is equal to or more than the predetermined threshold value (step S49). In the mark portion grinding step, the grinding position matching in the longitudinal direction of the round steel S is determined with reference to the defect portion map 50, the grinding position matching in the circumferential direction of the round steel S is determined with reference to the extraction result of the mark M, and the grinding depth is determined by referring to the defect portion map 50 and the extraction result of the mark M.
Thus, it is possible to provide a defective grinding method for round steel, which can automatically grind a defective portion of the round steel with inexpensive equipment without performing erroneous grinding in which a deviation occurs between the position of the defective portion and the grinding position.
In this method for grinding a defect of a round bar, it is not necessary to add an origin marking device to the round bar S, which is an origin mark serving as a reference in the circumferential direction and the longitudinal direction of the round bar S.
In addition, by performing image processing on the circumferential image of the surface of the round steel S and extracting the mark M, the operator does not need to visually find the mark M, and there is no risk of overlooking.
Next, the method for producing a steel material according to the present invention is a method for producing a round steel material, in which a round steel material obtained by surface-grinding a defective portion by the method for grinding a defect of a round steel material according to the above-described embodiment of the present invention is sent to a post-process and processed. The post-process refers to all subsequent processes in which a round steel having a defect portion ground on its surface is treated. That is, in the case of a bar product or a product steel pipe in which the round steel is round bar steel, the finishing step, the shipment step, and the like are performed after the defect grinding. When round steel is a rolling material, it is a rolling step, a finishing step and a shipping step performed thereafter.
According to the method for producing a steel product of the present invention, the round steel from which the defect is removed without being ground by mistake is sent to a post-process by the method for grinding a defect of a round steel of the present invention, and therefore, it is possible to suppress an obstacle in the post-process. That is, when the post-process is a rolling process, it is possible to suppress the occurrence of defects such as scratches due to defective portions remaining due to erroneous grinding in the rolled steel material or breakage starting from the defective portions during rolling, and when the post-process is a finishing process or a shipping process, it is possible to suppress the occurrence of defects such as defective products flowing out.
If the steel material at the stage of the grinding defect is a round-section steel material, i.e., a round-section steel material, the steel material treated in the post-process is not necessarily a round steel material, and the steel material treated in the post-process may be a square-section steel material.
In the case of manufacturing a bar product such as a round bar using a round bar such as a round billet as a raw material, the defect grinding method for a round bar according to the present invention can be applied to any of defect grinding of a raw material and defect grinding of a bar product. That is, in the method for producing a steel material according to the present invention, when both the raw material and the product are round bar steels, the defective grinding according to the present invention may be used only for defective grinding of the raw material, the defective grinding according to the present invention may be used only for defective grinding of the product, and the defective grinding according to the present invention may be used for both the defective grinding of the raw material and the defective grinding of the product.
While the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various changes and improvements can be made.
For example, in the defective portion grinding step (step S4), a determination step (step S45) of determining whether or not the ratio of the area a1 of the defective portion having a predetermined depth or more on the surface of the round steel S is smaller than a predetermined threshold value with reference to the defective portion map 50 is not necessarily required. In this case, after step S44, the mark detection step is performed as it is (step S45), and the full-surface grinding step is not performed (step S49). Therefore, in this case, in the defective portion grinding step, a marker detection step (step S45) of extracting the marker M by performing image processing on the image in the circumferential direction of the surface of the round steel S and a marker portion grinding step (step S47) of grinding the marker M portion extracted in the marker detection step are performed without fail.
In the mark portion grinding step (step S47), the step of determining whether or not the mark M on the developed view 60 continuously extends over a plurality of areas on the defect map 50 by the grinding control device 22 (step S472) is not necessarily required. In this case, after step S471, the process of grinding the mark M portion of the surface of the round steel S independently is performed (step S473), and the continuous grinding process is not performed (step S474).
Further, the defect map 50 is divided into the plurality of regions a to F, but the number of divisions is not limited to this, and one region may be used instead of the plurality of regions.
When the defective portion map 50 is a single area, the determination step determines whether or not the area ratio of the defective portion having a predetermined depth or more over the entire surface of the round steel S is smaller than a predetermined threshold value with reference to the defective portion map 50. In the mark detection step, when the area ratio of the defect portion of the predetermined depth or more over the entire surface of the round steel S determined in the determination step is smaller than the predetermined threshold value, the mark M is extracted by performing image processing on the circumferential image over the entire surface of the round steel S. In the mark portion grinding step, the portion of the mark M extracted in the mark detection step on the entire surface of the round steel S is ground. In the whole-surface grinding step, when the area ratio of the defect portion of the entire surface of the round steel S determined in the determination step, which is at least a predetermined depth, is at least a predetermined threshold value, the whole surface of the round steel S is ground.
In addition, although a line sensor camera is used as the imaging device 31, an area sensor camera may be used. In this case, as shown in fig. 15, it is preferable that an angle α (acute angle side) formed by a line connecting the imaging device 31 and a position P on the surface of the round steel S to be imaged and the surface of the round steel S at the position P on the surface is 30 degrees or more as a visual field range on the surface of the round steel S (visual field range of one captured image to be joined) obtained by one-time imaging by the imaging device 31 serving as the area sensor camera. When α is 30 degrees or more, the marker and noise are easily discriminated, and the detection accuracy of the marker is improved.
Description of reference numerals
1 Defect grinding System
11A leakage magnetic flux flaw detection device
11B ultrasonic flaw detection device
12A first marking device
12B second marking device
13A rotating roller
13B rotating roller
14A pulse generator
14B pulse generator
15 defective portion map creation device
20 defective portion grinding device
21 grinding machine
22 grinding control device
23 host computer
24 end face detection sensor
25 rotating roller
26 pulse generator
27 trolley
28 trolley driving device
30 mark detection device
31 image pickup device
32 camera control device
33 Lighting device
34 illumination control device
35 computer system
36 image processing part
37 mark extracting part
38 development figure creation device
39 pedestal portion
40 support leg
41 first support member
42 second support member
43 third support member
44 fourth support member
50 map of defect
60 expanded view
P uppermost position
And (5) making the S-shaped steel.

Claims (5)

1. A defect grinding method of round steel is a defect grinding method for automatically grinding a defect part of the round steel, and is characterized by comprising the following steps of:
a flaw detection step of detecting the defective portion of the round steel;
a marking step of applying a mark to the defect portion detected at a predetermined depth or more in the flaw detection step;
a flaw portion map creating step of creating a flaw portion map in which the depth of the flaw portion on the surface of the round steel, the circumferential position and the longitudinal position of the flaw portion are determined, based on the flaw detection result in the flaw detection step; and
a defective portion grinding step of grinding the defective portion of the round bar,
the defective portion grinding process includes: a mark detection step of performing image processing on an image of the surface of the round steel in the circumferential direction to extract the mark, and a mark portion grinding step of grinding the mark portion extracted in the mark detection step,
in the marked portion grinding step, the grinding position matching in the longitudinal direction of the round bar is determined with reference to the defect portion map, the grinding position matching in the circumferential direction of the round bar is determined with reference to the extraction result of the mark, and the grinding depth is determined with reference to the defect portion map and the extraction result of the mark.
2. A defect grinding method of round steel is a defect grinding method for automatically grinding a defect part of the round steel, and is characterized by comprising the following steps of:
a flaw detection step of detecting the defective portion of the round steel;
a marking step of applying a mark to the defect portion detected at a predetermined depth or more in the flaw detection step;
a flaw portion map creating step of creating a flaw portion map in which the depth of the flaw portion on the surface of the round steel, the circumferential position and the longitudinal position of the flaw portion are determined, based on the flaw detection result in the flaw detection step; and
a defective portion grinding step of grinding the defective portion of the round bar,
the defective portion grinding process includes: a determination step of determining whether or not an area ratio of the defect portion of a predetermined depth or more on the surface of the round bar is smaller than a predetermined threshold value with reference to the defect portion map, a mark detection step of performing image processing on an image in a circumferential direction of the surface of the round bar and extracting the mark when the area ratio of the defect portion of the predetermined depth or more on the surface of the round bar determined in the determination step is smaller than the predetermined threshold value, a mark portion grinding step of grinding the portion of the mark extracted in the mark detection step, and a full-face grinding step of performing full-face grinding of the surface of the round bar when the area ratio of the defect portion of the predetermined depth or more on the surface of the round bar determined in the determination step is equal to or larger than the predetermined threshold value,
in the marked portion grinding step, the grinding position matching in the longitudinal direction of the round bar is determined with reference to the defect portion map, the grinding position matching in the circumferential direction of the round bar is determined with reference to the extraction result of the mark, and the grinding depth is determined with reference to the defect portion map and the extraction result of the mark.
3. The round steel defect grinding method according to claim 2,
in the defect map creating step, a defect map divided into a plurality of regions along a longitudinal direction of the round bar at a surface of the round bar is created when creating the defect map.
4. The round steel defect grinding method according to claim 3,
in the determination step, it is determined whether or not an area ratio of a defective portion having a predetermined depth or more in a surface region of the round steel corresponding to each of the plurality of divided regions is smaller than a predetermined threshold value with reference to the defective portion map,
in the mark detection step, when the area ratio of the defect portion of a predetermined depth or more in the round steel surface region corresponding to each of the plurality of divided regions of the defect portion map determined in the determination step is smaller than the predetermined threshold value, the mark portion grinding step grinds the portion of the mark extracted in the mark detection step in the round steel surface region corresponding to each of the plurality of divided regions of the defect portion map,
in the full-face grinding step, when the area ratio of the defective portion of a predetermined depth or more in the round steel surface region corresponding to each of the plurality of divided regions of the defective portion map determined in the determination step is equal to or greater than the predetermined threshold value, the full-face grinding is performed on the round steel surface region corresponding to each of the plurality of divided regions of the defective portion map.
5. A method for producing a steel material, comprising grinding a defective portion of a round bar having a circular cross section, and then treating the round bar in a post-process,
the surface grinding is performed by the method for defect grinding of round steel according to any one of claims 1 to 4.
CN201980078989.9A 2018-11-29 2019-11-29 Defect grinding method for round steel and method for manufacturing steel Active CN113165041B (en)

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