JP7356022B2 - Slag determination method, slag determination device, and welded joint manufacturing method - Google Patents

Description

The present invention relates to a slag determination method, a slag determination device, and a welded joint manufacturing method.

When manufacturing various parts using steel materials, it is often necessary to connect a first steel material and a second steel material. In such a case, a welding technique such as arc welding or laser welding may be used to weld the first steel material and the second steel material using, for example, a solid wire for welding containing iron as a main component. Welding is performed using As a result, a welded joint is formed in which the first steel material, the weld metal, and the second steel material are connected. The weld metal, a portion of the first steel material near the weld metal, and a portion of the second steel material near the weld metal may be collectively referred to as a "weld zone."

Here, elements such as silicon (Si), aluminum (Al), manganese (Mn), and titanium (Ti) are generally added to steel materials as alloying elements intentionally added or as impurities. Contains.

Among the elements contained in steel materials, elements that are relatively easily oxidized are oxidizing gases (such as carbon dioxide gas) contained in the shielding gas used in gas-shielded arc welding and oxygen in the atmosphere. reacts with to form a composite oxide. Such composite oxides are generated as so-called slag in the above-mentioned welds.

On the other hand, in the above-mentioned welded parts, the corrosion resistance often decreases as a result of welding, compared to the positions of the steel material other than the welded parts. Therefore, various techniques have been proposed to improve the corrosion resistance of such welded parts. For example, Patent Document 1 below proposes a technique that improves the corrosion resistance of the welded part by adjusting the inclination angle of the welding torch to an appropriate angle when performing gas-shielded arc welding between a bare steel sheet and a zinc-plated steel sheet. has been done.

Japanese Patent Application Publication No. 2017-164798

After welding, the steel members are electrodeposited to improve their corrosion resistance. At this time, the chemical composition of the weld metal produced during welding and the composition of the slag produced on the weld metal (for example, the composition of the composite oxide produced) depend on the chemical composition of the steel materials and welding wire to be welded. ) are different, and the electrocoatability of the weld metal also exhibits different behavior. Normally, when evaluating the electrodeposition coating properties of weld metal, a welding test piece is prepared separately using the steel material and welding wire used for welding, and the welding test piece is subjected to electrodeposition coating. Electrodeposition coating properties on metals are evaluated. However, such an evaluation method of electrodeposition coating property requires a lot of time and cost to reach the evaluation. Furthermore, although the evaluation of the welded test piece is performed by an evaluator, the accuracy of the evaluation results varies greatly depending on the skill level of the evaluator. Therefore, there is a need for a technique that can more easily and accurately evaluate the electrodeposition coating properties of weld metal, regardless of the skill level of the evaluator.

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to more easily and accurately measure the electrodeposition coating properties of weld metal, regardless of the skill level of the evaluator. It is an object of the present invention to provide a method and device for determining slag that can be evaluated, and a method for manufacturing a welded joint that has excellent electrodeposition coating properties.

As a result of intensive studies on the electrocoatability of weld metals as described above, the inventors of the present invention found that among various complex oxides produced during welding, complex oxides containing Si have a low electrical resistance value. It was revealed that as a result of extremely high conductivity and low conductivity, it becomes a factor that deteriorates electrodeposition coating properties. Therefore, if it is possible to determine whether or not the slag generated on the weld metal contains the above-mentioned Si-containing complex oxide (hereinafter simply referred to as "Si complex oxide"), We were able to obtain the knowledge that it is possible to more easily evaluate the electrodeposition coating properties of weld metal.

Based on the above knowledge, the present inventor conducted further studies on Si composite oxides, and found that such Si composite oxides have a characteristic color and have a translucent yellowish brown color. It turned out that there was. Therefore, by focusing on the color of the surface of weld metal, we came up with the idea that the presence of slag, which adversely affects the electrodeposition coating properties, can be determined more easily and with high precision, and we will discuss the following. The present invention as described has now been completed.
The gist of the present invention, which was completed based on this idea, is as follows.

(1) It is possible to irradiate white light from an illumination light source to an imaging area that includes a portion where multiple steel materials are connected to each other via weld metal, and to perform color imaging of the imaging area that is irradiated with the white light. an imaging step of generating a processing target image by capturing an image with an imaging device; extracting a predetermined color component from among the color components constituting the processing target image; and binarizing each of the extracted color components. and an image processing step of determining whether or not slag containing Si composite oxide is present on the weld metal by carrying out the above step.
(2) The slag determination method according to (1), wherein the white light is diffused light.
( 3 ) In the image processing step, an R (red) component or a C (cyan) component, and a B (blue) component or a Y (yellow) component are extracted from the image to be processed, and the extracted A portion of the weld metal corresponding to the weld metal in which the slag exists is identified from the image composed of the R component or the C component, and from the image composed of the extracted B component or Y component, the The slag determination method according to (1) or (2) , wherein a portion of the weld metal corresponding to the weld metal in which the slag does not exist is identified.
( 4 ) The area ratio occupied by the slag in the weld metal is calculated based on information regarding the portion corresponding to the weld metal where the slag exists and information regarding the portion corresponding to the weld metal where the slag does not exist. , the slag determination method described in ( 3 ).
( 5 ) The method according to any one of (1) to ( 4 ), wherein the color component extraction process and the binarization process are performed after cutting out the part corresponding to the weld metal from the processing target image. How to determine slag.
( 6 ) The method for determining slag according to any one of (1) to ( 5 ), wherein the white light has a color temperature of 4200K or more and 8000K or less.
( 7 ) The method for determining slag according to any one of (1) to ( 6 ), wherein the average color rendering index (Ra) of the illumination light source is 70 or more.
( 8 ) Any one of (1) to ( 7 ), wherein the imaging process by the imaging device is performed in an environment where the illuminance is 0 lux or more and 50 lux or less when the illumination light source is not turned on. The slag determination method described in.
( 9 ) The imaging device images the imaging region such that the intensity of the luminance signal constituting the image to be processed is 90% or less of the maximum value of the intensity of the luminance signal output from the imaging device. , the method for determining slag according to any one of (1) to ( 8 ).
( 10 ) The slag determination method according to any one of (1) to ( 9 ), wherein the ISO sensitivity of the imaging device is set to 600 or less.
( 11 ) The illumination light source irradiates the white light such that the brightness of the white light at the position of the imaging area is 20 lumens or more, according to any one of (1) to ( 10 ). How to determine slag.
( 12 ) When there is at least either a portion where the weld metal has a reinforcement angle of 30° or more, or a portion where the weld metal has a reinforcement height of 2.5 mm or more, the imaging device The slag determination method according to any one of (1) to ( 11 ), wherein the F value is set to 6 or more and 12 or less.
( 13 ) The method for determining slag according to any one of (1) to ( 12 ), wherein the plurality of steel materials are connected by arc welding or laser welding.
( 14 ) An illumination light source that irradiates white light as illumination light to an imaging region including a portion where a plurality of steel materials are connected to each other via weld metal; An imaging device that captures an image to generate a processing target image, extracts a predetermined color component from among the color components forming the processing target image, and performs binarization processing on each of the extracted color components. A slag determination device comprising: a calculation processing unit that determines whether or not slag containing Si composite oxide is present on the weld metal.
( 15 ) A method for manufacturing a welded joint in which a plurality of steel materials are connected to each other via weld metal, the welding in which the plurality of steel materials are connected to each other to form a welded joint having a welded part that includes weld metal. step and the slag determination method described in any one of (1), (2), (3), (5) to ( 13 ) to determine the Si composite oxide present on the weld metal. A method for manufacturing a welded joint, comprising: a slag identifying step of identifying slag contained; and a removing step of removing at least a portion of the slag containing the Si composite oxide.
( 16 ) The method for manufacturing a welded joint according to ( 15 ), further comprising an electrodeposition coating step of electrodeposition coating the welded portion from which at least a portion of the slag containing the Si composite oxide has been removed.
( 17 ) A method for manufacturing a welded joint in which a plurality of steel materials are connected to each other via weld metal, which involves welding the plurality of steel materials to each other to form a welded joint having a welded part that includes weld metal. and an area ratio calculation step of calculating the area ratio occupied by the slag containing Si composite oxide on the weld metal using the slag determination method described in ( 4 ), and the area ratio is 8% or less. a removing step of removing at least a portion of the slag containing the Si composite oxide, and electrocoating the welded portion from which at least a portion of the slag containing the Si composite oxide has been removed so that A method for manufacturing a welded joint, comprising: an electrodeposition coating process.
( 18 ) The method for manufacturing a welded joint according to ( 17 ), wherein in the removing step, at least a portion of the slag containing the Si composite oxide is removed so that the area ratio is 5% or less.

As explained above, according to the present invention, it is possible to evaluate the electrocoatability of weld metal more easily and with high precision, regardless of the skill level of the evaluator, and thereby, the electrocoatability of weld metal can be evaluated more easily and with high accuracy. It becomes possible to manufacture excellent welded joints.

1 is a block diagram showing the overall configuration of a slag determination device according to an embodiment of the present invention. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 3 is an explanatory diagram for explaining an imaging unit included in the slag determination device according to the embodiment. FIG. 2 is a block diagram showing an example of the configuration of an arithmetic processing unit included in the slag determination device according to the embodiment. It is a block diagram showing an example of the composition of the arithmetic processing part which the arithmetic processing unit concerning the same embodiment has. FIG. 3 is an explanatory diagram for explaining slug determination processing performed by the arithmetic processing unit according to the embodiment. FIG. 3 is an explanatory diagram for explaining slug determination processing performed by the arithmetic processing unit according to the embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of an arithmetic processing unit according to the same embodiment. It is a flowchart which showed an example of the flow of the slag determination method concerning the same embodiment. It is a flowchart which showed an example of the flow of the manufacturing method of the welded joint concerning the same embodiment. It is a flowchart which showed another example of the flow of the manufacturing method of the welded joint concerning the same embodiment. FIG. 2 is an explanatory diagram for explaining sample materials manufactured in Examples. FIG. 2 is an explanatory diagram for explaining sample materials manufactured in Examples. These are images to be processed and binarized images of each sample material manufactured in Examples.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

(About slag determination device)
First, a slag determination device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG. 1 is a block diagram showing the overall configuration of a slag determination device according to this embodiment. 2A to 6 are explanatory diagrams for explaining an imaging unit included in the slag determination device according to the present embodiment. In addition, below, two steel materials, a first steel material and a second steel material, will be taken up as an example of a plurality of steel materials, and a case where these two steel materials are welded will be cited as an example and explained.

<About the overall configuration of the slag determination device>
As schematically shown in FIG. 1, the slag determination device according to the present embodiment has a first steel material 11A and a second steel material 11B connected to each other via weld metal (hereinafter simply referred to as "imaging"). This is a device that images the object 1) and determines whether or not slag containing Si composite oxide is present on the surface of the formed weld metal (also referred to as the weld bead) 13. . In the following, for convenience, the welding (line) direction of the imaging target 1 is referred to as the x-axis direction, the direction perpendicular to the welding line of the imaging target 1 is referred to as the y-axis direction, and the thickness of the imaging target 1 is referred to as the y-axis direction. (plate thickness) direction is the z-axis direction. Further, the first steel material 11A and the second steel material 11B are subjected to a welding method such as arc welding (for example, gas shielded arc welding, submerged arc welding, etc.) or laser welding along the x-axis direction. , shall be welded together.

Here, the first steel material 11A and the second steel material 11B that constitute the imaged object 1 are not particularly limited, and various steel materials can be used. Further, the welding wire for forming the weld metal used during welding is not particularly limited, and various known welding wires containing iron (Fe) as a main component can be used. As mentioned earlier, various steel materials and welding wires contain Si, and the yellow-brown Si composite oxide that is the focus of this embodiment can be produced by arc welding or laser welding. Further, during the imaging process by the slag determination device 10, the relative positional relationship between the imaging target 1 and the imaging unit 100 may be fixed, or, for example, the imaging target 1 may be transported by a transport line or the like. It may be in a state of change as a result of being changed.

As schematically shown in FIG. 1, the slag determination device 10 includes an imaging unit 100 and an arithmetic processing unit 200.
The imaging unit 100 is a unit that irradiates a predetermined illumination light onto an imaging region including weld metal 13 produced by welding, captures a color image of the imaging region irradiated with the illumination light, and generates a processing target image. be. In addition, the arithmetic processing unit 200 centrally controls the imaging processing by the imaging unit 100 and performs predetermined image processing on the processing target image generated by the imaging unit 100 so that the surface of the weld metal 13 is , is a unit that determines whether or not a yellowish brown Si composite oxide is present. The imaging unit 100 and the arithmetic processing unit 200 perform predetermined processing while cooperating with each other.

<About the imaging unit 100>
The imaging unit 100 according to the present embodiment is a unit that images an imaging region including the weld metal 13 in the imaging target 1 and generates a processing target image.

This imaging unit 100 includes an illumination light source 101 that irradiates a predetermined illumination light onto an imaging area that includes at least weld metal 13, and a color imaging device that takes a color image of the imaging area that is irradiated with the illumination light. It has at least an area camera 103. Here, the illumination light source 101 and the color area camera 103 are fixed by known means (not shown) so that their respective set positions do not change.

Illumination light source 101 irradiates an imaging region including weld metal 13 with predetermined illumination light. Here, the illumination light emitted from the illumination light source 101 is assumed to be white light. The illumination light source 101 is not particularly limited, and various known light sources can be used as long as they can irradiate white light over the entire weld metal 13. Examples of such a white light source include a white light emitting diode (WLED), a xenon lamp, and the like. Note that it is preferable that the illumination light emitted from the illumination light source 101 becomes diffused light before reaching the imaging area. Since the illumination light is diffused light, it becomes possible to reliably illuminate a wider area of the imaging area including the weld metal 13. Further, it is possible to prevent halation from occurring due to illumination light being concentrated only in a certain part of the imaging region.

Further, as the color area camera 103, which is an example of an imaging device, various known cameras can be used as long as they are capable of capturing color images. As such a color area camera 103, for example, an RGB camera that can image a red (R) component, a green (G) component, and a blue (B) component while distinguishing them from each other, or a cyan (C) component, a magenta ( Examples include a CMYK camera that can image an M) component, a yellow (Y) component, and a black (K) component while distinguishing them from each other. The number of pixels and pixel size of an image sensor such as a CMOS sensor or a CCD sensor provided in the color area camera 103 are not particularly specified, but an image sensor with a larger number of pixels or an image sensor with a smaller pixel size may be used. It is preferable to use a color area camera provided with such an image sensor, since it is possible to generate a higher-definition image to be processed by using the color area camera.

Here, as shown in FIG. 2A, the color area camera 103 is preferably provided above the weld metal 13 in the vertical direction, and the angle between the optical axis of the color area camera 103 and the horizontal direction is approximately 90°. It is preferable that This makes it possible to image the imaging region including the weld metal 13 while suppressing the occurrence of imaging distortion. Although FIG. 2A shows a case in which one color area camera 103 is provided, multiple A color area camera 103 may also be provided.

Further, the number of illumination light sources 101 is not particularly limited, and one illumination light source 101 may be provided as shown in FIG. 2A, or multiple illumination light sources may be provided as shown in FIG. 2B. may be provided. Here, FIG. 2B illustrates a case where two illumination light sources 101A and 101B are provided.

When one illumination light source 101 is provided as shown in FIG. 2A, the illumination light source 101 is preferably provided near the color area camera 103, and the optical axis of the illumination light source 101 and the light It is more preferable that the illumination light source 101 is provided such that the absolute value of the angle it makes with the axis is, for example, 5° or less.

In addition, when a plurality of illumination light sources 101 are provided, as shown in FIG. 2B, an illumination light source 101A that emits white light obliquely from the front side and a back It is preferable to provide an illumination light source 101B that emits white light obliquely from the side.

Here, the illumination light source 101A and the illumination light source 101B are preferably provided symmetrically with respect to the color area camera 103, as shown in FIGS. 2B and 3. Further, it is preferable that the absolute value of the angle θ between the optical axes of the illumination light sources 101A and 101B and the optical axis of the color area camera 103 is, for example, about 30° to 60°.

In addition, in the imaging unit 100 according to the present embodiment, in order to more reliably convert the white light that functions as illumination light into diffused light, various kinds of lights are placed on the optical axis of the illumination light source 101, as shown in FIG. It is more preferable to provide a diffusion plate 105.

Here, in the slag determination device 10 according to the present embodiment, among the slag containing various composite oxides that may be generated on the surface of the weld metal 13, attention is paid to the yellow-brown Si composite oxide. do. Therefore, in order to make the difference in the color of the slag more clear and to more reliably image the color of the slag, it is more preferable that the imaging unit 100 according to the present embodiment satisfies the following specific conditions. .

As mentioned earlier, there are areas where the weld metal 13 mainly composed of Fe is exposed without slag present on the surface, and weld metal 13 where slag not containing Si composite oxide is present on the surface. (These parts have excellent electrodeposition coating properties.) and the parts of the weld metal 13 where slag containing Si composite oxide, which has poor electrodeposition coating properties, exists on the surface. The colors are different because different wavelengths of light are reflected at the surface. Here, the yellow-brown slag containing Si complex oxide, which is the focus of this embodiment, mainly contains red components in order to reflect relatively long wavelength light in the visible light wavelength band. There is. On the other hand, the weld metal surface mainly contains blue components because it reflects relatively short wavelength light in the visible light wavelength band.

In order to make such a difference in color clearer, it is preferable that the color temperature of the white light emitted from the illumination light source 101 configuring the imaging unit 100 according to this embodiment is 4200K or higher. By setting the color temperature of white light to 4200K or higher, it is possible to more reliably distinguish between the color of the slag containing Si complex oxide and the color of the parts other than the slag containing Si complex oxide. becomes. The color temperature of the white light is more preferably 6000K or higher. On the other hand, when the color temperature of the white light exceeds 8000K, the proportion of red components in the white light becomes relatively large, and the slag containing the Si complex oxide and the part other than the slag containing the Si complex oxide, The identification accuracy may decrease. Therefore, the color temperature of white light is preferably 8000K or less. The color temperature of the white light is more preferably 6500K or less. Note that the color temperature of white light can be measured using various known color thermometers.

In the illumination light source 101 according to the present embodiment, in order to more reliably ensure color rendering properties and further improve the accuracy of identifying slag containing Si complex oxide and parts other than slag containing Si complex oxide. It is preferable to use an illumination light source having an average color rendering index (Ra) of 70 or more, which is an index indicating the degree of color rendering. The upper limit of the average color rendering index (Ra) of the illumination light source is not particularly defined, and the higher it is, the better. The average color rendering index (Ra) of the illumination light source may be 100. The average color rendering index (Ra) of an illumination light source can be measured in accordance with the method specified in JIS Z8726:1990 (method for evaluating color rendering properties of light sources).

Further, the illumination light source 101 emits white light such that the brightness of the white light at the position of the imaging region (more specifically, the surface of the imaging target 1 included in the imaging region) is 20 lumens (lm) or more. Irradiation is preferred. By irradiating white light to achieve such brightness, the imaging area can be illuminated more reliably. As a result, the luminance signal intensity output from the various image sensors provided in the color area camera 103 can be set to 5% or more of the maximum value of the luminance signal intensity output from the image sensors, making it more reliable. It is now possible to generate a processing target image, and the accuracy of color identification can be further improved. The brightness of the white light at the position of the imaging area is more preferably 100 lumens or more. On the other hand, the upper limit value of the brightness of white light at the position of the imaging area is not particularly specified and can be set to any brightness, but it is necessary to prevent the intensity of the light that forms an image on the color area camera 103 from becoming saturated. It is preferable to set Note that the illuminance at the position of the imaging area as described above can be measured using various known illuminometers.

When the first steel material 11A and the second steel material 11B are welded, a step may occur in the weld metal 13, as in overlap fillet welding schematically shown in FIG. 1, etc. Furthermore, depending on the method of welding, the weld metal 13 may have irregularities, and it is also assumed that the residual position of slag may differ depending on the chemical composition of the steel material and welding wire, and the welding conditions. At this time, the identification accuracy changes depending on the residual position of the slag, and while slag in the center of the weld metal can be easily identified, it is difficult to identify the slag present in the weld toe where the weld metal becomes steep. It is possible that it will happen.

The reason why identification is difficult in such a situation is that a dark shadow appears on the weld metal surface at the above locations. Therefore, in order to more reliably prevent the occurrence of dark shadows, as schematically shown in FIG. It is preferable to ensure that the illumination light is irradiated.

Although the detailed reflection position of the reflection plate 107 is not particularly limited, it is preferable to arrange the reflection plate 107 on the side in the direction in which the dark shadow is thought to extend from the irradiation direction of the illumination light. In the example shown in FIG. 4, there is a possibility that a dark shadow will appear on the side of the second steel material 11B arranged below the step. Therefore, by arranging the reflective plate 107 on the side of the second steel material 11B, it is possible to more reliably prevent the occurrence of dark shadows.

Next, in the color area camera 103, which is an example of an imaging device, the luminance signal intensity constituting the processing target image is 90% higher than the maximum value of the luminance signal intensity output from the image sensor provided in the color area camera 103. % or less. By performing imaging processing to obtain such a signal strength, it becomes possible to more reliably suppress the occurrence of halation, and it becomes possible to more reliably improve color identification accuracy.

The ISO sensitivity of the color area camera 103 is preferably set to 600 or less. By setting the ISO sensitivity of the color area camera 103 to 600 or less, even if the conditions of the illumination light source 101 change, it becomes possible for the color area camera 103 to respond to changes in the conditions of the illumination light source 101. The lower the ISO sensitivity of the color area camera 103 is, the more preferable it is because it becomes possible to obtain an image with less noise. On the other hand, if the ISO sensitivity of the color area camera 103 is set to less than 100, the exposure time required for image capturing processing becomes longer, which may reduce convenience. Therefore, the ISO sensitivity of the color area camera 103 is preferably 100 or more.

Also, depending on the welding method, the reinforcement angle of the weld metal 13 (angle φ shown in FIG. 5) may be 30 degrees or more, or the reinforcement height of the weld metal 13 (the height shown in FIG. 5) may be 30 degrees or more. It is also conceivable that the size of h) is 2.5 mm or more. Therefore, if there is at least one of a portion where the reinforcement angle is 30° or more or a portion where the reinforcement height is 2.5 mm or more in the weld metal 13, the F value of the color area camera 103 is is preferably set to 6 or more and 12 or less. By setting the F value of the color area camera 103 within the above range, it is possible to achieve an appropriate depth of field, and it is possible to generate an image to be processed in which the entire imaging area is in focus. Become. The F value of the color area camera 103 is more preferably 8 or more and 10 or less.

In order to more reliably improve color identification accuracy, the image capturing process by the color area camera 103 is performed in an environment where the illuminance is 0 lux (lx) or more and 50 lux or less when the illumination light source 101 is not turned on. It is preferable to carry out below. By performing imaging processing under such an environment, it is possible to prevent light other than white light from the illumination light source 101 from being irradiated onto the imaging area, and unintended colors will be superimposed on the image to be processed. This can be prevented. The lower the illuminance of the environment in which the above-described imaging processing is performed, the better. Such an imaging environment can be easily realized, for example, by providing the imaging unit 100 inside various darkrooms 109, including a simple darkroom such as a color box, as schematically shown in FIG. be able to. Further, the illuminance as described above can be measured using various known illuminometers.

The imaging unit 100 according to this embodiment has been described in detail above with reference to FIGS. 2A to 6.

<About the arithmetic processing unit 200>
Next, the arithmetic processing unit 200 included in the slag determination device 10 according to the present embodiment will be described in detail with reference to FIGS. 7 to 10.
FIG. 7 is a block diagram showing an example of the configuration of the arithmetic processing unit included in the slag determination device according to the present embodiment, and FIG. 8 is a block diagram showing an example of the configuration of the arithmetic processing unit included in the arithmetic processing unit according to the present embodiment. FIG. FIGS. 9 and 10 are explanatory diagrams for explaining the slug determination process performed by the arithmetic processing unit according to the present embodiment.

The arithmetic processing unit 200 according to the present embodiment centrally controls the imaging processing performed by the imaging unit 100, extracts a predetermined color component from among the color components forming the processing target image, and extracts the extracted color component. By performing binarization processing on each, it is determined whether or not slag containing Si composite oxide exists on the surface of weld metal 13.

As shown in FIG. 7, the arithmetic processing unit 200 according to the present embodiment includes an imaging control section 201, an image data acquisition section 203, an arithmetic processing section 205, an output control section 207, a display control section 209, It mainly includes a storage section 211.

The imaging control unit 201 is realized by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The imaging control unit 201 comprehensively controls the imaging process of the imaging target 1 by the imaging unit 100 according to the present embodiment. More specifically, when starting to image the imaging target 1, the imaging control unit 201 sends a control signal to the illumination light source 101 of the imaging unit 100 to start emitting white light, which is illumination light. Send each.

Further, when the illumination light source 101 starts irradiating the surface of the imaging area with white light, the imaging control unit 201 causes the color area camera 103 to capture an image including the weld metal 13 present on the surface of the imaging target 1. Send out a trigger signal to image the area. Further, when the imaged object 1 is being transported on various conveyance lines, the imaged object 1 is periodically sent out from a drive mechanism or the like that changes the relative position between the imaged object 1 and the imaging unit 100. A trigger signal for starting measurement may be sent to the color area camera 103 based on the PLG signal (for example, a PLG signal output every time the imaged object 1 moves by 1 mm, etc.).

This allows the imaging unit 100 to generate entity data (data regarding the brightness value of reflected light) of the processing target image regarding the imaging region including the weld metal 13.

The image data acquisition unit 203 is realized by, for example, a CPU, ROM, RAM, communication device, etc. The image data acquisition unit 203 acquires substantial data of the processing target image generated by the imaging unit 100 and output from the imaging unit 100, and transmits it to the arithmetic processing unit 205, which will be described later. Further, the image data acquisition unit 203 may associate the acquired entity data of the processing target image with time information regarding the date and time when the data was acquired, etc., and store the data in the storage unit 211, which will be described later, as history information.

The arithmetic processing unit 205 is realized by, for example, a CPU, ROM, RAM, or the like. The arithmetic processing unit 205 performs arithmetic processing as described in detail below using the entity data of the processing target image generated by the imaging unit 100, so that the surface of the weld metal 13 reflected in the processing target image is It is determined whether slag containing Si composite oxide is present.

Further, the arithmetic processing unit 205 may calculate various types of secondary information regarding the slag by further utilizing the determination result regarding the presence or absence of the slag and various data used to obtain the determination.

The arithmetic processing unit 205 outputs data regarding the determination result regarding the presence or absence of slag and data regarding the calculated secondary information to the output control unit 207.

Note that this arithmetic processing unit 205 will be described in detail below.

The output control unit 207 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, and the like. The output control unit 207 performs control when outputting information regarding the presence or absence of slag containing Si complex oxide, which is generated by the arithmetic processing unit 205. More specifically, the output control unit 207 can control the output of information regarding the presence or absence of generated slag and secondary information based on this information as a paper medium via a printer or the like. . Further, the output control unit 207 controls the output of information regarding the presence or absence of generated slag and secondary information based on this information to various electronic devices such as external computers, servers, process computers, etc. be able to. Furthermore, the output control unit 207 displays information regarding the presence or absence of generated slag and secondary information based on such information on various displays such as a display included in the slag determination device 10, in cooperation with a display control unit 209 described later. It is possible to control the output as an image to the device or various display devices such as a display provided outside the slag determination device 10.

The display control unit 209 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, and the like. The display control unit 209 displays information regarding the presence or absence of generated slag and secondary information based on this information on various display devices such as a display included in the slag determination device 10 or provided outside the slag determination device 10. Performs display control when displaying on various display devices such as displays. Thereby, the user of the slag determination device 10 can grasp on the spot information regarding the presence or absence of the generated slag and secondary information based on this information.

The storage unit 211 is realized, for example, by a RAM, a storage device, or the like included in the arithmetic processing unit 200 according to the present embodiment. The storage unit 211 stores various parameters that need to be saved when the arithmetic processing unit 200 according to the present embodiment performs some processing, intermediate progress of processing, etc., various databases, programs, etc. recorded. This storage unit 211 allows the imaging control unit 201, image data acquisition unit 203, arithmetic processing unit 205, output control unit 207, display control unit 209, etc. to freely perform data read/write processing.

[About the configuration of the calculation processing unit 205]
Next, the configuration of the arithmetic processing section 205 included in the arithmetic processing unit 200 according to this embodiment will be described in detail with reference to FIG. 8.
The arithmetic processing unit 205 according to the present embodiment extracts predetermined color components from among the color components constituting the processing target image, and performs binarization processing on each of the extracted color components. It is determined whether or not slag containing Si composite oxide exists on the surface of 13. Further, the arithmetic processing unit 205 according to the present embodiment may calculate various types of secondary information regarding the slag using the obtained determination result and various types of information generated until the determination result is obtained. good. Furthermore, before performing the various processes described above, the arithmetic processing unit 205 may perform various pre-processing on the processing target image.

The arithmetic processing unit 205 having the above-mentioned functions includes, for example, as shown in FIG. It has a processing section 229 and an area ratio calculation section 231.

The determination area cutting unit 221 is realized by, for example, a CPU, ROM, RAM, or the like. The determination region cutting unit 221 cuts out a region in which the weld metal 13 is imaged (hereinafter, such a region is also referred to as a “determination region”) from the processing target image generated by the imaging unit 100. , a determination area image consisting of the determination area is generated. By cutting out the determination area from the image to be processed, it is possible to prevent color information other than slag and weld metal from being reflected in the process, and improve the accuracy of the process for determining the presence or absence of slag containing Si complex oxide. It becomes possible to further improve the

Here, the details of the process of cutting out the determination area are not particularly limited, and various known processes may be used. For example, after setting the placement position of the imaging target 1 in advance so that the weld metal 13 is located within a fixed range of the imaging area, from among the images to be processed, the placement position is matched to the above-mentioned placement position. Alternatively, the position of the weld metal 13 may be recognized using a known object recognition processing technique, and the corresponding position may be automatically cut out. Alternatively, the operator of the slag determination device 10 may manually cut out the determination area while viewing the processing target image on the screen.

The determination area image generated in this manner is output to the subsequent preprocessing section 223.

The preprocessing unit 223 is realized by, for example, a CPU, ROM, RAM, or the like. The preprocessing unit 223 calculates the difference between the color of the slag containing the Si composite oxide and the color of the portion other than the slag containing the Si composite oxide on the determination area image output from the determination area cutting unit 221. Perform pre-processing to make it clearer. Examples of such pre-processing include the following processing. Note that the specific methods (algorithms) for the various preprocessing steps described below are not particularly limited, and various known methods (algorithms) may be used.

(a) Processing to exclude color information other than the slag and weld metal surface (b) Processing to invert the gradation to emphasize color differences (c) Processing to increase the saturation of the welded part (d) Color balance Adjustment processing (e) Posterization processing to reduce the number of gradations

The various pretreatments described above may be performed singly or in combination as necessary. However, it is preferable to carry out the processes shown in (a) to (c) above as pre-processing because it is possible to further clarify the difference in color.

The preprocessing unit 223 performs various preprocessing as described above on the determination area image as necessary, and then outputs the determination area image to the component extraction unit 225 at the subsequent stage.

The component extraction unit 225 is realized by, for example, a CPU, ROM, RAM, or the like. The component extraction unit 225 is a processing unit that extracts a predetermined color component from among the color components that make up the determination area image. More specifically, the component extraction unit 225 extracts an R (red) component or a C (cyan) component, and a B (blue) component or a Y (yellow) component from the determination region image, and extracts the R component. (or C component) image and a B component (or Y component) image.

As mentioned earlier, the yellow-brown slag containing Si composite oxide is mainly composed of red components, while the part of the weld metal 13 where slag that does not contain Si composite oxide exists and The exposed surface of the Fe-based weld metal 13 in which no slag exists is mainly composed of blue components. Therefore, the extracted R component or C component reflects the color information of the slag containing Si composite oxide, which is the focus of this embodiment, and the extracted B component or Y component reflects the color information of the slag containing Si composite oxide, which is the focus of this embodiment. Color information of parts other than the contained slag is reflected. Therefore, by extracting only such components and performing binarization processing at a later stage, the color of the slag containing Si complex oxide and the color of the part other than the slag containing Si complex oxide can be differentiated. It is possible to reliably distinguish between the From the R component (or C component) image extracted in this way, a portion of the weld metal 13 corresponding to the weld metal 13 where slag containing Si composite oxide exists is identified, and the extracted B component is identified. (or Y component) From the image, a portion of the weld metal 13 corresponding to the weld metal 13 where no slag containing Si composite oxide is present is specified.

Here, whether to extract the R component and B component or the C component and Y component from the determination region image depends on what kind of output the color area camera 103 of the imaging unit 100 outputs. It may be determined as appropriate depending on the situation.

As shown in FIG. 9, when a certain processing target image is input to the determination area cutting unit 221, a determination area image is generated by cutting out the determination area from the image. This judgment region image is subjected to various preprocessing as necessary by the preprocessing section 223, and then input to the component extraction section 225. A component image of is generated.

After generating the two types of component images as described above, the component extraction unit 225 outputs the generated two types of component images to the binarization processing unit 227 at the subsequent stage.

The binarization processing unit 227 is realized by, for example, a CPU, ROM, RAM, or the like. The binarization processing unit 227 converts each of the two types of component images (that is, the R component (or C component) image and the B component (or Y component) image) generated by the component extraction unit 225 into predetermined intensities. It is binarized based on a threshold value to create a binarized image.

Here, the intensity threshold for binarizing each component image is not particularly limited, and may be determined as appropriate depending on the quality of electrodeposition coating required for the weld metal 13 of the imaged object 1. Bye. In other words, if the weld metal 13 is required to have a general level of electrodeposition coating properties, for example, 50% of the maximum strength that can be output may be set as the strength threshold. If paintability is required, a relatively small value may be set as the intensity threshold.

By performing such a binarization process, the location of the slag containing the Si composite oxide becomes clearer. In addition, in such a binarization process, the position where the R component (or C component) is cut off from the image (that is, the intensity is set to 0 by binarization) is where the slag containing Si complex oxide exists. Although there is a possibility that there are some, their abundance is thought to be at a level that does not reach the intensity threshold. Therefore, it is thought that the truncated position as described above has a small effect on the electrodeposition coating properties, and also has a small effect on the subsequent determination process.

When the binarization processing unit 227 generates binarized images from the R component (or C component) image and the B component (or Y component) image as described above, the generated binarized image is output to the subsequent determination processing section 229.

The determination processing unit 229 is realized by, for example, a CPU, ROM, RAM, or the like. The determination processing unit 229 uses the two types of binarized images generated by the binarization processing unit 227 to determine which parts of the weld metal 13 have slag containing Si composite oxide and which parts contain Si composite oxide. A portion where no slag is present (that is, a portion where slag that does not contain Si composite oxide is present, or a portion where no slag is present and the weld metal 13 is exposed) is determined.

More specifically, in the binarized image generated from the R component (or C component), the determination processing unit 229 determines that the portion where the brightness value is 1 is determined to be a part of the weld metal 13 that contains Si composite oxide. In the binarized image generated from the B component (or Y component), the part where the brightness value = 1 is determined to be the part where slag exists, and the part where the brightness value = 1 is determined to be the part where the Si composite oxide is present in the weld metal 13. It is determined that the area contains no slag. Thereby, in the weld metal 13, the portion where the slag containing Si composite oxide is present is automatically specified.

As described above, the determination processing unit 229 generates information (for example, , the binarized image itself, information regarding the pixel position corresponding to each corresponding part, information regarding the area of each corresponding part, etc.), these generated information are transmitted to the output control unit 207 and the area It is output to the rate calculation unit 231.

The area ratio calculation unit 231 is realized by, for example, a CPU, ROM, RAM, or the like. The area ratio calculation unit 231 calculates the area ratio of the entire weld metal 13 based on the information regarding the portion where slag exists and the information regarding the portion where the slag containing Si composite oxide does not exist, generated by the determination processing unit 229. , the area ratio occupied by the slag containing the Si composite oxide is calculated.

Specifically, the area ratio calculation unit 231 can calculate the area ratio of the slag containing Si composite oxide by performing calculations as shown in equation (101) below.

(Ratio of area covered by slag containing Si composite oxide after welding) =
(Area covered by slag containing Si composite oxide after welding) ÷ (Area of entire weld metal) x 100...Formula (101)

After calculating the ratio (area ratio) of the slag containing Si composite oxide to the entire weld metal 13 as described above, the area ratio calculation unit 231 controls the output of the calculated area ratio. 207. Further, the area ratio calculation unit 231 may output the obtained area ratio calculation result to the determination processing unit 229. As a result, the determination processing unit 229 further determines the quality of the electrodeposition coating property of the imaged object of interest based on the ratio (area ratio) of the slag containing Si composite oxide to the entire weld metal 13. It becomes possible to judge.

Furthermore, the above explanation focused on determining the presence or absence of slag containing Si composite oxide in the weld metal 13 after welding. Since the processability and electrodeposition coating properties are poor, this is an area in which no chemical conversion coating or electrocoating coating exists. Therefore, the above color-based judgment process can be performed after further chemical conversion treatment is applied after welding, or after further chemical conversion treatment is applied after welding, and then electrodeposition coating is performed. It is also possible to implement.

FIG. 10 shows the results of performing the above-described determination process based on the difference in color for the same imaging area of the same imaging target 1 after welding, after chemical conversion treatment, and after electrodeposition coating. . In each of the binarized images shown in FIG. 10, the white areas correspond to the positions of the weld metal 13 where slag containing Si composite oxide is present. As is clear from the binarized images shown in Figure 10, the locations where slag containing Si composite oxide exists after welding are the same even after chemical conversion treatment and electrodeposition coating. It can be seen that has not changed. Therefore, it can be seen that unless the slag present after welding is peeled off in the subsequent process, the position of the slag containing Si composite oxide remains almost unchanged in the subsequent process.

From this, the area ratio calculation unit 231 can also calculate the area ratio after chemical conversion treatment and the area ratio after electrodeposition coating based on the following equations (103) and (105). be.

(Ratio of area covered by slag containing Si composite oxide after chemical conversion treatment) =
(Area covered by slag containing Si composite oxide after chemical conversion treatment) ÷ (Area of entire weld metal) x 100...Equation (103)

(Ratio of area covered by slag containing Si composite oxide after electrodeposition coating) =
(Area covered by slag containing Si composite oxide after electrodeposition coating) ÷ (Area of entire weld metal) x 100...Formula (105)

An example of the functions of the arithmetic processing unit 200 according to this embodiment has been described above. Each of the above components may be constructed using general-purpose members and circuits, or may be constructed using hardware specialized for the function of each component. Further, the functions of each component may be entirely performed by a CPU or the like. Therefore, it is possible to change the configuration to be used as appropriate depending on the technical level at the time of implementing this embodiment.

Note that it is possible to create a computer program for realizing each function of the arithmetic processing unit according to the present embodiment as described above, and to implement it in a personal computer or the like. Further, a computer-readable recording medium storing such a computer program can also be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

<About the hardware configuration of the arithmetic processing unit 200>
Next, the hardware configuration of the arithmetic processing unit 200 according to this embodiment will be described in detail with reference to FIG. 11.

The arithmetic processing unit 200 mainly includes a CPU 901, a ROM 903, and a RAM 905. The arithmetic processing unit 200 further includes a bus 907, an input device 909, an output device 911, a storage device 913, a drive 915, a connection port 917, and a communication device 919.

The CPU 901 functions as a central processing device and control device, and controls the entire operation or a part of the operation within the arithmetic processing unit 200 according to various programs recorded in the ROM 903, RAM 905, storage device 913, or removable recording medium 921. do. The ROM 903 stores programs, calculation parameters, etc. used by the CPU 901. The RAM 905 temporarily stores programs used by the CPU 901 and parameters that change as appropriate during program execution. These are interconnected by a bus 907 constituted by an internal bus such as a CPU bus.

The bus 907 is connected to an external bus such as a PCI (Peripheral Component Interconnect/Interface) bus via a bridge.

The input device 909 is, for example, an operation means operated by a user such as a mouse, a keyboard, a touch panel, a button, a switch, a lever, or the like. Further, the input device 909 may be, for example, a remote control means (so-called remote control) using infrared rays or other radio waves, or an external connection device 923 such as a PDA that is compatible with the operation of the arithmetic processing unit 200. It's okay. Further, the input device 909 includes, for example, an input control circuit that generates an input signal based on information input by the user using the above-mentioned operating means and outputs it to the CPU 901. By operating this input device 909, the user can input various data to the arithmetic processing unit 200 and instruct processing operations.

The output device 911 is configured of a device that can visually or audibly notify the user of the acquired information. Examples of such devices include display devices such as CRT display devices, liquid crystal display devices, plasma display devices, EL display devices, and lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, and facsimiles. The output device 911 outputs, for example, results obtained by various processes performed by the arithmetic processing unit 200. Specifically, the display device displays the results obtained by various processes performed by the arithmetic processing unit 200 in text or images. On the other hand, the audio output device converts an audio signal consisting of reproduced audio data, audio data, etc. into an analog signal and outputs the analog signal.

The storage device 913 is a data storage device configured as an example of a storage section of the arithmetic processing unit 200. The storage device 913 is configured of, for example, a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like. This storage device 913 stores programs executed by the CPU 901, various data, and various data acquired from the outside.

The drive 915 is a reader/writer for recording media, and is either built into the arithmetic processing unit 200 or attached externally. The drive 915 reads information recorded on an attached removable recording medium 921 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and outputs it to the RAM 905. The drive 915 can also write records on a removable recording medium 921, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium 921 is, for example, CD media, DVD media, Blu-ray (registered trademark) media, or the like. Further, the removable recording medium 921 may be a CompactFlash (registered trademark) (CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Furthermore, the removable recording medium 921 may be, for example, an IC card (Integrated Circuit card) equipped with a non-contact IC chip, an electronic device, or the like.

Connection port 917 is a port for directly connecting equipment to arithmetic processing unit 200. Examples of the connection ports 917 include a USB (Universal Serial Bus) port, an IEEE1394 port, a SCSI (Small Computer System Interface) port, an RS-232C port, and an HDMI (registered trademark) (High-Definition Mu ltimedia Interface) port, etc. By connecting the externally connected device 923 to this connection port 917, the arithmetic processing unit 200 can directly acquire various data from the externally connected device 923 or provide various data to the externally connected device 923.

The communication device 919 is, for example, a communication interface configured with a communication device for connecting to the communication network 925. The communication device 919 is, for example, a communication card for wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). Further, the communication device 919 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), a modem for various types of communication, or the like. This communication device 919 can transmit and receive signals, etc., to and from the Internet or other communication devices, for example, in accordance with a predetermined protocol such as TCP/IP. Further, the communication network 925 connected to the communication device 919 is configured by a wired or wirelessly connected network, and may be, for example, the Internet, a home LAN, an in-house LAN, infrared communication, radio wave communication, or satellite communication. It's okay.

An example of the hardware configuration capable of realizing the functions of the arithmetic processing unit 200 according to the embodiment of the present invention has been described above. Each of the above components may be constructed using general-purpose members, or may be constructed using hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate depending on the technical level at the time of implementing this embodiment.

(About how to determine slag)
Next, with reference to FIG. 12, an example of the flow of a slag determination method using the slag determination apparatus 10 as described above will be briefly described. FIG. 12 is a flowchart showing an example of the flow of the slag determination method according to the present embodiment.

Here, prior to the slag determination method as described below, it is preferable to perform a process to remove fumes (metal vapor) generated during welding from the surface of the weld metal 13 of the imaged object 1. This is because if such fumes remain attached to the weld metal 13, the color of the slag containing the original Si composite oxide or the color of the portion where the slag does not exist may change. The process for removing such fumes is not particularly limited, and any known process may be applied, such as wiping the welded area with a rag soaked in ethanol.

In the slag determination method according to the present embodiment, first, for the imaged object after fume removal as described above, an imaged area including the weld metal 13 is imaged by the imaging unit 100 under the control of the arithmetic processing unit 200. (Step S101) to generate a processing target image. The generated entity data of the processing target image is output to the arithmetic processing unit 200. This step S101 corresponds to the imaging step.

The determination area cutting unit 221 of the arithmetic processing unit 200 cuts out a determination area from the generated processing target image to generate a determination area image (step S103). The generated entity data of the determination area image is output to the preprocessing unit 223.

Next, the preprocessing unit 223 performs various preprocessing on the generated determination region image, as necessary, to make the difference in color clearer (step S105). The determination region image, which has been preprocessed as necessary, is output to the component extraction unit 225.

The component extraction unit 225 extracts the above-mentioned predetermined color components from the determination area image output from the preprocessing unit 223 (step S107), and generates two types of component images. Thereafter, the component extraction unit 225 outputs the two types of generated component images to the binarization processing unit 227.

The binarization processing unit 227 performs the above-mentioned binarization processing on each of the two types of component images output from the component extraction unit 225 (step S109). Thereafter, the binarization processing unit 227 outputs the two types of generated binarized images to the determination processing unit 229.

The determination processing unit 229 performs the determination process as described above based on the two types of binarized images output from the binarization processing unit 227 (step S111). Thereby, in the weld metal 13, the position where the slag containing Si composite oxide is present is specified. The above steps S103 to S111 correspond to arithmetic processing steps. The determination processing unit 229 outputs information regarding the determination results obtained as described above to the area ratio calculation unit 231.

The area ratio calculation unit 231 uses the information output from the determination processing unit 229 to calculate the area ratio of the portion where the slag containing Si composite oxide exists (step S113). As a result, the size of the portion of the weld metal 13 where the slag containing Si composite oxide exists is quantified.

An example of the flow of the slag determination method according to the present embodiment has been briefly described above with reference to FIG. 12.

(summary)
As explained above, according to the slag determination method and slag determination device according to the present embodiment, it is easy to identify the slag types that cause electrodeposition coating defects, and a certain level of evaluation can be achieved regardless of the skill level of the operator. can be obtained in a simpler way. This makes it possible to accelerate the evaluation of electrodeposition coating properties at welded parts for products manufactured by welding, such as automobile suspension parts, and also eliminates redundant coating properties compared to conventional evaluation methods. It becomes possible to reduce labor and cost.

In addition, in the above explanation, two steel materials, the first steel material and the second steel material, were taken up as an example of a plurality of steel materials, but the same procedure as above is applied even when three or more steel materials are welded. It goes without saying that the slag determination method and slag determination apparatus according to the present embodiment can be applied to the present invention.

(About the manufacturing method of welded joints)
Next, a method for manufacturing a welded joint using the slag determination method as described above will be briefly described with reference to FIGS. 13A and 13B. FIG. 13A is a flowchart showing an example of the flow of the method for manufacturing a welded joint according to this embodiment, and FIG. 13B is a flowchart showing another example of the flow of the method for manufacturing a welded joint according to this embodiment. be.

As shown in FIG. 13A, in the method for manufacturing a welded joint according to the present embodiment, first, a plurality of steel materials are welded together using a welding wire (step S201: welding process), and a welded joint having a welded portion is formed. Manufacture. Here, the welded part is a part that is formed by welding and includes weld metal.

At this time, the steel material used is not particularly limited, and various steel materials can be used. Further, the welding wire for forming the weld metal used during welding is not particularly limited, and various known welding wires containing iron (Fe) as a main component can be used. The welding method is also not particularly limited, and any welding method such as arc welding (eg, gas shielded arc welding, submerged arc welding, etc.) or laser welding may be used.

Thereafter, using the slag determination method using the slag determination device as described above, slag containing Si composite oxide is identified in the welded portion of the manufactured welded joint (step S203: slag identification step). This makes it possible to identify the location of slag containing Si composite oxide, which affects the electrodeposition coating properties, in the welded part.

Thereafter, at least a portion of the slag containing the Si composite oxide is removed using various processing methods (step S205: removal step). The processing method used here is not particularly limited, and any various physical processing methods or chemical processing methods may be used as long as the slag containing Si composite oxide can be removed from the weld metal. It is possible to use processing methods.

Examples of such processing methods include lathe processing, in which a disk-shaped workpiece is rotated and brought into contact with the slag, milling, in which a rotating milling tool is brought into contact with the slag, and grinding, in which the slag is ground with a rotating whetstone. Processing, NC processing using NC machine tools equipped with various rotating tools, ultrasonic processing in which a tool using ultrasonic waves comes into contact with the slag, blasting in which fine particles collide with the slag, and slag cleaning by laser cleaning. Examples of methods include laser processing to remove the particles, and a method of blowing ultra-high pressure air.

Thereafter, electrodeposition coating is applied to the welded portion from which at least a portion of the slag containing the Si composite oxide has been removed (step S207: electrodeposition coating step). This makes it possible to manufacture a welded joint with excellent electrodeposition coating properties.

Further, as shown in FIG. 13B, in another example of the method for manufacturing a welded joint according to the present embodiment, first, a plurality of steel materials are welded together using a welding wire, as in the case shown in FIG. 13A. (Step S211: Welding process), a welded joint having a welded portion is manufactured.

Thereafter, the area ratio of slag containing Si composite oxide is calculated for the welded part of the manufactured welded joint using the slag determination method using the slag determination apparatus as described above (step S213: area ratio calculation process). This makes it possible to identify the location of slag containing Si composite oxide, which affects the electrocoatability of the weld, as well as quantify the amount of slag containing Si composite oxide. can be converted into

Thereafter, at least a portion of the slag containing the Si composite oxide is removed using various processing methods as previously described so that the area ratio of the slag containing the Si composite oxide is equal to or less than a predetermined threshold. (Step S215: Removal step). Here, the above threshold value can be set to 8%, for example. The threshold value is preferably 5% or less.

Thereafter, electrodeposition coating is applied to the welded portion from which at least a portion of the slag containing Si composite oxide has been removed (step S217: electrodeposition coating step). As a result, welded joints with excellent electrocoating properties, where the electrocoating defect rate is below a predetermined threshold (for example, 8% or less, or 5% or less) (in other words, improving the electrocoating defect rate) This makes it possible to manufacture (welded joints)

The method for manufacturing a welded joint using the slag determination method according to the present embodiment has been briefly described above with reference to FIGS. 13A and 13B.

Hereinafter, the slag determination method and slag determination device according to the present invention will be specifically explained while showing examples. The examples shown below are merely examples of the slag determining method and slag determining device according to the present invention, and the slag determining method and slag determining device according to the present invention are not limited to the following examples. do not have.

<Configuration of imaging unit>
In this example, a daylight color (color temperature: 6500K, average color rendering index Ra=95) white LED (EF-60A manufactured by OMNIVAS) was used as the illumination light source 101 of the imaging unit 100. The light from the illumination light source was transmitted through a diffuser plate as shown in FIG. 5, and then was irradiated onto the object to be imaged. Further, a reflector plate was arranged as shown in FIG.

Further, as the color area camera 103, a commercially available color digital still camera (manufactured by Nikon, RGB output) was used, and a telephoto lens with a focal length of 70 to 300 mm was attached. The image storage format was a JPEG format with a low compression ratio, and imaging parameters such as shutter speed, ISO sensitivity, and lens F value were set as follows.

・Shutter speed: 1/10 seconds to 1/20 seconds ・ISO sensitivity: 100
・F value: F6 to F12
・White balance: Preset (uses gray card with 18% reflectance)
・Exposure compensation: -3 or ±0

Then, imaging processing was performed while changing the shutter speed, F value, and exposure depending on the light source condition and the welding test piece. In order to avoid the influence of fluorescent lights and sunlight existing in the room, the imaging process was performed in a dark room with an illuminance of 48 lux (lx) with no illumination light source turned on. When the illumination light source was turned on, the brightness of the white light at the surface of the imaged object was 48 lumens (lm). When such white light was imaged, the intensity of the output luminance signal was 80% or less of the maximum output value of the sensor.

Two types of thin steel plates each having a thickness of 2.6 mm were used as the test steel plates. The tensile strength of such a thin steel plate is equivalent to 440 MPa or 780 MPa. The chemical composition of each thin steel sheet is summarized in Table 1 below.

The welding wire (welding metal) used for welding is a solid wire equivalent to JISZ3312:YGW17, a solid wire equivalent to JISZ3312:YGW16, a solid wire equivalent to JISZ3312:YGW12, a solid wire equivalent to JISZ3312:G49A0C0, a solid wire equivalent to JISZ3312:YGW13. I chose solid wire. The chemical composition of each welding wire is summarized in Table 2 below.

Using each test steel plate, lap fillet welding was performed by gas-shielded arc welding to produce welded test pieces with dimensions as shown in FIGS. 14A and 14B. The composition of the shielding gas was 80% Ar-20% CO2, and the flow rate was 20 L/min. Further, the welding speed was 80 cm/min.

After generating a determination area image from each of the obtained images to be processed, the pretreatment shown in (a) to (c) above is performed, and the weld metal 13 from which post-weld fume has been removed is subjected to Si composite oxidation. The presence or absence of slag containing substances was determined, and the area ratio of such slag was calculated.

Further, the welding test piece after the above judgment was subjected to electrodeposition coating treatment at a voltage of 150V to a thickness of 20 to 25 μm, and in the same manner as above, the weld metal 13 after electrodeposition coating was The presence or absence of slag containing Si composite oxide was determined, and the area ratio of slag was calculated.

The obtained results are shown in Table 3 below, and the images to be processed and the binarized images for each welding test piece are shown together in FIG. 15. In FIG. 15, the image shown in the upper row is the image to be processed, and the image shown in the lower row is a binarized image obtained by combining the R component image and the B component image after binarization.

For each of the above evaluation processes, the work time required for quantifying slag or electrodeposition coating defects per welding test piece was about 5 to 10 minutes. Conventionally, it took about 30 to 60 minutes, so it can be seen that the work time can be dramatically shortened.

Furthermore, referring to Table 3 above, the area ratio of slag containing Si composite oxide after welding and the area ratio of slag containing Si composite oxide after electrodeposition coating showed the same values. . Therefore, by using the slag determination method and slag determination device according to the present invention, it is possible to easily clarify the presence of slag that affects the electrodeposition coating properties, and also to determine the electrodeposition coating properties. , it became clear that it is possible to quantify it in the form of the area ratio of slag.

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

10 Slag determination device 11A First steel material 11B Second steel material 13 Weld metal 100 Imaging unit 101 Illumination light source 103 Color area camera 105 Diffusion plate 107 Reflection plate 109 Dark room 200 Arithmetic processing unit 201 Imaging control section 203 Image data acquisition section 205 Calculation Processing unit 207 Output control unit 209 Display control unit 211 Storage unit 221 Judgment area cutting unit 223 Preprocessing unit 225 Component extraction unit 227 Binarization processing unit 229 Judgment processing unit 231 Area ratio calculation unit

Claims (18)

An imaging device capable of irradiating white light from an illumination light source to an imaging region including a portion where a plurality of steel materials are connected to each other via weld metal, and color imaging the imaging region irradiated with the white light. an imaging step of generating a processing target image by imaging;
A predetermined color component is extracted from among the color components constituting the processing target image, and a binarization process is performed on each of the extracted color components, thereby containing Si composite oxide on the weld metal. an image processing step of determining whether or not a slag exists;
A method for determining slag, including: The slag determining method according to claim 1, wherein the white light is diffused light. In the image processing step,
An R (red) component or a C (cyan) component, and a B (blue) component or a Y (yellow) component are each extracted from the processing target image,
From the image composed of the extracted R component or C component, a portion of the weld metal corresponding to the weld metal where the slag is present is specified,
The slag determination method according to claim 1 or 2 , wherein a portion of the weld metal corresponding to the weld metal in which the slag does not exist is identified from an image composed of the extracted B component or Y component. . An area ratio occupied by the slag in the weld metal is calculated based on information regarding a portion corresponding to the weld metal where the slag is present and information regarding a portion corresponding to the weld metal where the slag is not present. 3. The slag determination method described in 3 . The slag determination method according to any one of claims 1 to 4 , wherein the color component extraction process and the binarization process are performed after cutting out a portion corresponding to the weld metal from the processing target image. . The method for determining slag according to any one of claims 1 to 5 , wherein the color temperature of the white light is 4200K or more and 8000K or less. The method for determining slag according to claim 1, wherein the average color rendering index (Ra) of the illumination light source is 70 or more . The slag according to any one of claims 1 to 7 , wherein the imaging process by the imaging device is performed in an environment where the illumination intensity is 0 lux or more and 50 lux or less when the illumination light source is not turned on. How to judge. The imaging device images the imaging region such that a luminance signal intensity constituting the processing target image is 90% or less of a maximum value of luminance signal intensity output from the imaging device. The method for determining slag according to any one of items 1 to 8 . 10. The slag determining method according to claim 1 , wherein the ISO sensitivity of the imaging device is set to 600 or less. The slag determination method according to any one of claims 1 to 10 , wherein the illumination light source irradiates the white light such that the brightness of the white light at the position of the imaging area is 20 lumens or more. . When there is at least one of a portion where the weld metal has a reinforcement angle of 30° or more, or a portion where the weld metal has a reinforcement height of 2.5 mm or more,
The slag determination method according to any one of claims 1 to 11 , wherein the F value of the imaging device is set to 6 or more and 12 or less. The method for determining slag according to claim 1 , wherein the plurality of steel materials are connected by arc welding or laser welding. an illumination light source that irradiates white light as illumination light to an imaging region including a portion where a plurality of steel materials are connected to each other via weld metal;
an imaging device that captures a color image of the imaging area irradiated with the white light to generate a processing target image;
A predetermined color component is extracted from among the color components constituting the processing target image, and a binarization process is performed on each of the extracted color components, thereby containing Si composite oxide on the weld metal. an arithmetic processing unit that determines whether or not a slug exists;
A slag determination device comprising: A method for manufacturing a welded joint in which a plurality of steel materials are connected to each other via weld metal, the method comprising:
a welding process in which a plurality of steel materials are connected to each other to form a welded joint having a welded part that includes weld metal;
A slag identifying step of identifying a slag containing Si composite oxide present on the weld metal using the slag determining method according to any one of claims 1, 2, 3, 5 to 13 ;
a removing step of removing at least a portion of the slag containing the Si composite oxide;
A method of manufacturing a welded joint, including: 16. The method for manufacturing a welded joint according to claim 15 , further comprising an electrocoating step of electrocoating the welded portion from which at least a portion of the slag containing the Si composite oxide has been removed. A method for manufacturing a welded joint in which a plurality of steel materials are connected to each other via weld metal, the method comprising:
a welding process in which a plurality of steel materials are connected to each other to form a welded joint having a welded part that includes weld metal;
an area ratio calculation step of calculating an area ratio occupied by slag containing Si composite oxide on the weld metal using the slag determination method according to claim 4 ;
a removal step of removing at least a portion of the slag containing the Si composite oxide so that the area ratio is 8% or less;
an electrodeposition coating step of electrodeposition coating the welded portion from which at least a portion of the slag containing the Si composite oxide has been removed;
A method of manufacturing a welded joint, including: 18. The method for manufacturing a welded joint according to claim 17 , wherein in the removing step, at least a portion of the slag containing the Si composite oxide is removed so that the area ratio is 5% or less.

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