WO2023223485A1

WO2023223485A1 - Welding device and welding method

Info

Publication number: WO2023223485A1
Application number: PCT/JP2022/020778
Authority: WO
Inventors: 達輝三皷; 武彦斎藤; 良祐光岡
Original assignee: ＰｒｉｍｅｔａｌｓＴｅｃｈｎｏｌｏｇｉｅｓＪａｐａｎ株式会社
Priority date: 2022-05-19
Filing date: 2022-05-19
Publication date: 2023-11-23

Abstract

The purpose of the present invention is to provide a welding device and a welding method with which it is possible to properly comprehend welding defects including abnormal shapes, which are linked to fold defects, and the generation of dust.　This welding device 1 comprises: a welding unit 10 that joins, by means of resistance welding, a region where a first sheet member 21 and a second sheet member 22 overlap, and forms a welding region 20 along a welding direction y that crosses the sheet passing direction x of the first sheet material 21 and the second sheet material 22; a rolling reduction unit 30 that applies rolling reduction to the welding region 20; a shape acquiring unit 70 that acquires the shape of the welding region 20 before and/or after the rolling reduction has been applied by the rolling reduction unit 30; and a moving body 40 that is configured to be able to reciprocate in the welding direction y and supports the welding unit 10 and the rolling reduction unit 30 while arranging the welding unit 10 and the rolling reduction unit 30 side by side in the welding direction y.

Description

Welding equipment and welding method

The present invention relates to an apparatus and method for joining mutually overlapping regions of two plate materials by resistance welding.

A welding machine installed in a continuous plate processing line, such as a continuous annealing line or a continuous plating line, moves in a direction perpendicular to the threading direction (Threading direction, Passing direction, Line direction, etc.) while welding the preceding plate. The tail end and the tip of the trailing plate are connected by welding. For example, the seam welding machine described in Patent Document 1 includes an electrode disk (electrode wheel) and a pressure roll (rolling down roll) that are both rotatably supported by a carriage and arranged above and below a strip. and move the carriage while rotating the pressure roll. By doing so, welded joints are continuously formed in the width direction of the strips while running the electrode disk and then the pressure roll in the overlapping region of the leading strip and the trailing strip.

The seam welding machine of Patent Document 1 measures the temperature of the welded joint immediately after welding in order to determine the quality of the welded joint. Such a seam welding machine includes a plurality of condensing lenses installed between an upper electrode disk and an upper pressure roll, optical fibers each connected to the condensing lenses, and a plurality of condensing lenses installed at respective positions of the condensing lenses through the optical fibers. and a temperature detector that detects the temperature corresponding to the temperature. The plurality of condensing lenses are arranged side by side in the width direction (sheet passing direction) of the region where the leading strip and the trailing strip overlap.

The temperature measurement value of the welded joint is also used to determine whether dust has occurred due to the spouting of molten metal during welding. For example, according to the seam weld determination method disclosed in Patent Document 2, the average temperature and temperature difference of a welded joint are calculated over a predetermined range in the welding direction, and a threshold value is applied to each of the average temperature and temperature difference. , the presence or absence of dust is determined.

Japanese Patent Application Publication No. 7-195179 International publication 2018/181398

A welded joint formed by welding plate materials in a stepped state often maintains the stepped shape even after welding, although it depends on the plate thickness. According to the research conducted by the inventors of the present disclosure, if an eave-like step shape appears in the welded joint immediately after passing the electrode wheel, folding flaws occur in the welded joint that has passed the reduction roll. If a plate material with folding flaws is supplied to a rolling process, the dimensional ratio of the folding flaws to the thickness of the plate increases due to rolling. Therefore, especially in continuous rolling lines, it is highly necessary to prevent breakage of welded joints due to folding flaws.
However, unfavorable shapes appearing in welded joints, such as the shape of eaves, cannot necessarily be detected by temperature measurements. That is, even if the temperature measurement value of the welded joint is within an appropriate range, the welding state of the welded joint may not be appropriate.
Further, since the temperature measurement values vary widely due to the surface condition of the electrode ring, etc., it may not be possible to distinguish between cases where dust is generated and cases where dust is not generated.

In view of the above, an object of the present disclosure is to provide a welding device and a welding method that can appropriately grasp welding defects, including abnormal shapes that lead to folding defects and the occurrence of dust.

The welding device of the present disclosure joins the overlapped region of the first plate material and the second plate material by resistance welding, and the welding area is welded along a welding direction that intersects with the threading direction of the first plate material and the second plate material. A welding part that forms a weld, a rolling part that rolls down the welding area, and a shape acquisition part that acquires the surface shape of the welding area at least one of before and after being rolled down by the rolling part, and is configured to be movable back and forth in the welding direction. and a movable body that supports the welding part and the rolling part in a state in which they are lined up in the welding direction.

Unless otherwise specified in the specification, "swaging" in the present disclosure refers to a flattening process performed by a rolling part following welding by a welding part.

In the welding device of the present disclosure, the shape acquisition unit includes a laser information acquisition unit that emits a band-shaped laser to irradiate a linear range of the welding area, and receives the laser reflected from the welding area with an image sensor, The laser information acquisition unit is disposed above or below the welding area, the linear range intersects the welding direction, and the optical axis of the laser emitted by the laser information acquisition unit is It is preferable that the first plate material and the second plate material are set to be inclined with respect to the vertical direction toward a step formed in the welding area.

In the welding apparatus of the present disclosure, it is preferable that the optical axis forms an angle of 30 degrees or more with respect to the horizontal plane.

In the welding device of the present disclosure, the laser information acquisition section is supported by the frame of the moving body, and at least one of the welding section and the rolling section is disposed in the projection range of the laser information acquisition section in the sheet passing direction. is preferred.

In the welding device of the present disclosure, the shape acquisition unit acquires shape data indicating the shape of the step by calculation using information on a change from the laser emitted by the laser information acquisition unit to the laser reflected by the welding area. The welding apparatus includes a step shape data acquisition section that displays at least one of a display section that displays the shape data and a first determination section that determines whether the welding state of the welding area is good or bad using the shape data. It is preferable to have one.

In the welding apparatus of the present disclosure, the shape acquisition section includes an angle acquisition section that acquires the angle of the step by calculation using the shape data, and the first determination section determines whether the welding state of the welding area is good or bad using the angle. It is preferable that the configuration is such that it can be determined.

The welding device of the present disclosure includes a temperature measurement unit that measures the temperature of the welding area before being rolled down by the rolling unit, and the angle acquisition unit uses shape data to acquire at least the angle of the step before being rolled down. The first determination unit may perform the pre-rolling quality determination by applying threshold values to the angle before rolling acquired by the angle acquisition unit and the temperature of the welding area before rolling measured by the temperature measuring unit, respectively. preferable.

In the welding device of the present disclosure, the shape acquisition unit calculates the angle after rolling from the angle before rolling acquired by the angle acquiring unit, based on the correlation information between the angle before and after the rolling by the rolling part. The first determination section applies a first threshold value to the angle before rolling acquired by the angle acquiring section to determine the quality of the before rolling. It is preferable to apply a second threshold smaller than the first threshold to the obtained angle after reduction to determine the quality after reduction.

In the welding apparatus of the present disclosure, the shape acquisition unit includes a laser information acquisition unit that irradiates a laser to the welding area and receives the laser reflected from the welding area, and a laser information acquisition unit that determines the shape of the area above and below the welding area. a height measurement value acquisition unit that acquires a measurement value of the height of the welding area in the welding direction using information on a change from the laser emitted from at least one of the laser beams to the laser reflected by the welding area; The welding device includes a display section that displays at least one of the measured value, the amount of change between the measured values, and the presence or absence of the measured value; It is preferable to include at least one of a second determination unit that determines whether the welding state of the welding area is good or bad using at least one of the information.

Further, the welding method of the present disclosure welds the overlapping region of the first plate material and the second plate material, and the welding area is welded along the welding direction that intersects with the threading direction of the first plate material and the second plate material. a welding step for forming, a rolling down step for rolling down the welding area, a shape acquisition step for acquiring the shape of the welding area at least one of before or after being rolled down by the rolling down step, and a welding part for forming the welding area by resistance welding. and a forward step in which a movable body that supports the rolling part that lowers the welding area is aligned in the welding direction is moved from a predetermined retreat position to a predetermined forward position, and a backward step in which the movable body is moved from the forward position to the retreat position. and.
During one of the forward and backward steps, a welding step, a reduction step, and a shape acquisition step are performed.

In the welding method of the present disclosure, the shape acquisition step includes emitting a band-shaped laser to the welding area, irradiating it to a linear range intersecting the welding direction, and receiving the laser reflected from the welding area by an imaging device. In the laser information acquisition step, the optical axis of the laser emitted from at least one of the upper side and the lower side of the welding area is set at the step formed by the first plate material and the second plate material in the welding area. It is preferable to set it so that it is inclined with respect to the vertical direction.

In the welding method of the present disclosure, the shape acquisition step indicates the shape of the step using information about the laser information acquisition step and the change from the laser emitted in the laser information acquisition step to the laser reflected by the welding area. The welding method includes a shape data acquisition step of acquiring shape data by calculation, a display step of displaying the shape data, and a first determination step of determining whether the welding condition of the welding area is good or bad using the shape data. It is preferable to include at least one of them.

In the welding method of the present disclosure, the shape acquisition step includes an angle acquisition step of calculating the angle of the step using the shape data, and the first determination step uses the angle to determine whether the welding state of the welding area is good or bad. It is preferable to judge.

In the welding method of the present disclosure, the shape acquisition step calculates the angle after reduction from the angle before reduction obtained in the angle acquisition step, based on correlation information between the angle before and after the reduction in the reduction step. The first determination step applies a first threshold value to the angle before rolling obtained by the angle acquiring step to determine the quality of the before rolling. It is preferable to apply a second threshold smaller than the first threshold to the obtained angle after reduction to determine the quality after reduction.

In the welding method of the present disclosure, the shape acquisition step includes a laser information acquisition step of irradiating the welding area with a laser and receiving the laser reflected from the welding area; a height measurement value obtaining step of obtaining a measured value of the height of the welding area over the welding direction using information on a change from the laser emitted from at least one of the laser beams to the laser reflected by the welding area; The welding method includes a display step for displaying at least one of the measured value, the amount of change between the measured values, and information on the presence or absence of the measured value; It is preferable to include at least one of a second determination step of determining whether the welding state of the welding area is good or bad using at least one of the information.

The welding apparatus and welding method of the present disclosure may perform only the first determination regarding the step shape, or may perform only the second determination regarding the welding height. It is sufficient for the welding apparatus of the present disclosure to include only the determining section to be used out of the first determining section and the second determining section. The same applies to the welding method of the present disclosure.

According to the welding device and welding method of the present disclosure, the surface shape of the step included in the welding area and the surface shape of exposed molten metal are obtained, so such surface shape can be confirmed on the screen of a display device, for example. By calculating the surface shape data and automatically determining whether the surface shape is good or bad, it becomes possible to appropriately understand welding defects, including abnormal shapes that lead to folding defects and the occurrence of dust.

(a) is a side view schematically showing a welding device of the present disclosure. (b) is a partial sectional view taken along the line Ib-Ib in (a). (a) and (b) are diagrams illustrating one form of a plurality of processing units included in the welding device. (a) is a schematic diagram showing rolling down rolls arranged above and below the plate material with their axial directions intersecting. (b) is a schematic diagram showing the rolling direction with respect to the welding area. (a) is an enlarged cross-sectional view of the welding area. (b) and (c) are schematic diagrams showing the cross-sectional shape of a welding area including a step. (a) and (b) are schematic diagrams showing the cross-sectional shape of a welding area including a step. (a) is a diagram showing the cross-sectional shape of the welding area immediately after welding and before rolling by the rolling part. (b) is a diagram showing the cross-sectional shape of the welding area after rolling down by the rolling part. (c) is a diagram showing a cross-sectional shape of a welded region after rolling by a rolling device. FIG. 2 is a functional block diagram regarding determination of quality of welding. It is a side view which shows a welding part, a rolling part, and a laser information acquisition part from the same direction as Fig.1 (a). (a) is a diagram showing a rolling part and a laser information acquisition part from the welding direction. (b) is a schematic diagram showing the optical axis of the laser emitted from the laser information acquisition unit and the welding area irradiated by the laser. 9 is a diagram showing the laser information acquisition unit from the direction of the X arrow in FIG. 8. FIG. It is a figure which shows the process step regarding quality determination of a welding state. (a) and (b) are schematic diagrams showing display examples of welding quality determination results. (a) is a graph for explaining the quality determination of the welding area before reduction. (b) shows a table showing the relationship between the step angle before rolling and the presence or absence of folding flaws after rolling. (a) to (c) are graphs for explaining the quality determination for each plate thickness in the pre-reduction welding area. (a) and (b) are sectional views showing the welding area before and after rolling down when the step angle is larger than a threshold value. (a) and (b) are sectional views showing the welding area before and after rolling down when the step angle is smaller than a threshold value. (a) to (c) are graphs showing the relationship between the measured temperature in the welding area and the Erichsen value base metal ratio for each plate thickness of common steel. (a) to (c) are graphs showing the relationship between the measured temperature in the welding area and the Erichsen value base metal ratio for each plate thickness of high-strength steel. It is a graph showing the correlation between the step angle before rolling and the step angle after rolling. It is a figure which shows the correspondence between the step angle before a rolling process, and the state of a flaw after a rolling process. (a) is a plan view of the welding area. (b) and (c) are graphs showing height measurements obtained over the weld length. (a) and (b) are graphs showing the amount of change between height measurements. FIG. 3 is a plan view of a welding area. FIG. 6 is a diagram illustrating an example in which laser information acquisition units are installed both above and below the welding area.

Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the accompanying drawings.
〔overall structure〕
The welding apparatus 1 shown in FIG. 1(a) joins the tail end of the preceding steel plate 2 and the tip of the following steel plate 2 by overlapping and resistance welding. The welding device 1 is installed and operated in a continuous cold rolling line (not shown). In a continuous cold rolling line, for example, a coil of hot rolled steel plate is unwound and passed through the line, and a device such as a looper is used to roll the preceding steel plate without stopping the central part of the line (rolling mill). and the trailing steel plate are welded and passed continuously. Such a continuous rolling line includes, for example, a payoff reel, a welding device 1, a short looper, a rolling mill, and a tension reel, and passes the strip through the rolling mill in one direction while circulating the coil, thereby rolling the strip multiple times to a predetermined thickness. Roll for .

[Welding equipment and welding process]
As shown in FIGS. 1(a) and 1(b), the welding device 1 welds the overlapping area of the leading steel plate 21 gripped by the leading clamp C1 and the trailing steel plate 22 gripped by the trailing clamp C2. Continuous welding is performed in a predetermined welding direction by heating with electricity and crushing with pressure. That is, the welding device 1 performs mash seam welding (JIS Z 3001) to form the welding region 20 along a predetermined welding direction. The welding direction by the welding device 1 corresponds to the y direction orthogonal to the threading direction x in which the steel plate 2 is conveyed.
The welding apparatus 1 flattens the shape of the welding area 20 by pressurizing the welding area 20 with the rolling part 30 following welding by the welding part 10 . The plastic working performed by the rolling part 30 is called swaging.

The welding device 1 includes a welding section 10 that forms a welding region 20 by welding the overlapping region of a leading steel plate 21 and a following steel plate 22, a rolling section 30 that rolls down the welding region 20, and a welding section 10 and a rolling section 30 that rolls down the welding region 20. The movable body 40 supports the lower part 30 in a line in the welding direction y, and the control unit 50 controls the operation of each part of the welding device 1.
The welding part 10 includes electrode rings 11 and 12 that face each other across the steel plate 2 in the vertical direction z (vertical direction). Similarly, the rolling part 30 includes rolling rolls 31 and 32 that are adjacent to the

electrode wheels

11 and 12 and face each other across the position of the steel plate 2 in the vertical direction z.

The movable body 40 includes a frame 41 that rotatably supports both the welding section 10 and the rolling section 30, a plurality of wheels 42 that support the frame 41, and drives the frame 41 in the welding direction y to A drive device 45 for reciprocating the running path 44 is provided.
The frame 41 is formed into a substantially C-shape when viewed from the side in the sheet passing direction x. Drive device 45 includes a servo motor 451 and a ball screw 452. The frame 41 is provided with a current applying device 46 including a transformer and a diode.

In addition to the welded part 10 and the rolled part 30, the frame 41 has the steel plate 2 subjected to treatments such as removing coatings such as oxide scale, cutting, cooling, and heating, as shown in FIGS. 2(a) and 2(b).

Processing units

61, 62, 63, and 64 may be provided to perform processing on each of the processing units, respectively. By providing these processing sections in the frame 41, not only welding and rolling but also a series of processing from film removal to heat treatment can be smoothly performed.
The coating removal unit 61 that performs coating removal processing includes, for example, brush rolls 611 and 612 that are rotatably driven and equipped with brushes on their outer peripheries, and are used to clean both the front and back sides of the leading steel plate 21 and the trailing steel plate 22 for stable resistance welding. to grind. The cutting section 62 that performs the cutting process includes, for example, a pair of

shearing blades

621 and 622 that face each other in the vertical direction z (vertical direction) and move up and down with respect to the steel plate 2, and cuts off an end portion of the steel plate 2. Coating removal and cutting are performed on the tail end region of the leading steel plate 21 and the leading end region of the trailing steel plate 22 before welding.

On the other hand, cooling and heating are performed on the welding area 20 after welding. The cooling unit 63 that performs the cooling process performs hardening by, for example, spraying water onto the welding area 20 to rapidly cool it. The heating unit 64 that performs the heat treatment performs tempering by heating the welding region 20 by induction heating, for example. After the welding process consisting of a series of treatments performed in the order of film removal, cutting, welding, reduction, cooling, and heating, the steel plate 2 radiates heat to the surrounding air at room temperature and is subjected to a rolling process.
The brush roll 611, shear blade 621, electrode ring 11, and roll-down roll 31, all of which are arranged above the steel plate 2, are moved by their respective elevating mechanisms ( 13, 33, etc.). Therefore, the film removal section 61, the cutting section 62, the welding section 10, and the rolling section 30 do not come into contact with the steel plate 2 throughout the welding process except during processing.

The frame 41 is moved in the welding direction between a retracted position P1 (FIG. 2(a)) where the steel plate 2 is retracted backward with respect to the conveyance path through which the steel plate 2 is passed, and a forward position P2 (FIG. 2(b)). It is possible to move back and forth along y.
In the example shown in FIGS. 2(a) and 2(b), the frame 41 includes a heating section 64, a film removing section 61, a cooling section 63, a rolling section 30, a welding section 10, and , and the cutting section 62 are provided in this order. A series of processes in the welding process is performed during one cycle of the welding process including a step of advancing the frame 41 from the retreated position P1 to the forward position P2, and a step of retreating the frame 41 from the forward position P2 to the retreated position P1.

As shown in FIG. 1(a), for example, the welding apparatus 1 of this embodiment has a steel plate 2 received between an upper frame 411 and a lower frame 412 through an opening 410 in the front of a frame 41, and an upper electrode. The wheel 11 and the upper reduction roll 31 are lowered toward the reference plane 100 (FIG. 1(b)) by the lifting

mechanisms

13, 33, and the frame 41 is moved back from the forward position P2 to the backward position P1, while welding and Perform the rolling process. At this time, the welding direction y is a direction from the forward position P2 to the backward position P1.
The reference plane 100 is set horizontally, for example, at the position of the outer peripheral surfaces of the lower electrode wheel 12 and the reduction roll 32.

The axial width w1 of the

electrode wheels

11 and 12 is wider than the width (overlap margin w) by which the leading steel plate 21 and the trailing steel plate 22 are overlapped in the sheet passing direction x before welding. It is preferable that the electrode rings 11 and 12 are arranged at the center of the overlap w in the sheet passing direction x.
The axial width of the reduction rolls 31 and 32 is also wider than the overlap w. It is preferable that the reduction rolls 31 and 32 are also arranged at the center of the overlap w in the sheet passing direction x.

The outer peripheral surface of each of the electrode rings 11 and 12 is slightly curved in an arc shape with a large radius of curvature over the entire width. The upper electrode ring 11 is curved so as to protrude in a convex direction (downward) with respect to the reference surface 100 at the center of the sheet passing direction x. The lower electrode ring 12 is curved so as to protrude in a convex direction (upward) with respect to the reference surface 100 at the center of the sheet passing direction x.

During welding and rolling down, a current applying device 46 connected to the

electrode wheels

11 and 12 applies electricity to the steel plate 2, and a driving device including a motor (not shown) moves the

electrode wheels

11 and 12 and the rolling

roll

31, 32 are rotated about their respective axes in directions corresponding to the welding direction y.
The surface temperature of the welding region 20 immediately after passing through the electrode rings 11 and 12 exceeds, for example, 1,300°C. The temperature of the welding area 20 decreases to, for example, 900° C. or lower when the reduction rolls 31 and 32 contact the welding area 20, and then increases due to recuperation.

The axes of the reduction rolls 31 and 32 may be set parallel to the sheet passing direction x, similar to the axes of the

electrode wheels

11 and 12, but as shown in FIG. 3(a), the shear forces F1, In order to achieve more sufficient flattening by applying F2, the axes of the reduction rolls 31 and 32 may be inclined with respect to the sheet passing direction x. In this case, the axis of the reduction roll 31 and the axis of the reduction roll 32 intersect in plan view. For example, each axis of the reduction rolls 31 and 32 can be inclined by 3 degrees with respect to the sheet passing direction x.

After being rolled down by the rolling rolls 31 and 32, the steel plate 2 is supplied to a rolling process. In FIG. 3(b), the rotation direction RD of a pair of rolling rolls used in the rolling process is indicated by an arrow. A step is formed in the welding region 20 shown in FIG. Since it is crushed to about 1.1 to 1.2 times its size, it is flattened before the rolling process.

[Details of welding area]
Now, as shown in FIG. 1(b), mash seam welding is performed by the welding section 10 with the end of one steel plate 2 superimposed on the lower end of the other steel plate 2. The ends of the two steel plates 2 are overlapped in the threading direction x, for example, with a width equivalent to the thickness of a single steel plate 2.
In this embodiment, the end of the trailing steel plate 22 is stacked on the lower side of the end of the leading steel plate 21. However, the present invention is not limited to this, and the end of the leading steel plate 21 may be stacked on the lower side of the end of the trailing steel plate 22.
When a current is applied to the overlapping region of the two steel plates 2 through the

electrode wheels

11 and 12, it is heated by heat generation corresponding to the electrical resistance, and is also pressurized in the vertical direction z by the

electrode wheels

11 and 12. transform. At this time, for example, as shown in FIG. 4(a), the electrode rings 11, 12 (FIG. 1(b)) are in contact with the steel plate 2 (the range of overlap w before welding shown in FIG. 1(b)). Current flows through the area (corresponding to the area) and generates heat, and the area is pressurized. Then, the two steel plates 2 are joined over a joining range r wider in the sheet passing direction x than the overlap w before welding. The welding region 20 formed along the welding direction y as a welded joint corresponds to the joining range r. Note that the range r1 shown in FIG. 4(a) corresponds to the range where the steel plate 2 is thermally affected by heat input during welding.

Before welding, the leading steel plate 21 and the trailing steel plate 22 have an end face 21A of the leading steel plate 21 rising up from the upper surface of the trailing steel plate 22, and an end face 21A of the leading steel plate 21 rising from the bottom surface of the leading steel plate 21, as shown in FIG. 1(b), for example. The trailing steel plates 22 are stacked so that the end surfaces 22A thereof stand up. At this time, the leading steel plate 21 and the trailing steel plate 22 form an upper step ST1 and a lower step ST2.

FIG. 4(a) illustrates a cross section of the welding region 20 after joining and before reduction. The inside of the broken line indicated by N indicates a portion melted due to heat generation, and this portion becomes a nugget N when solidified. The steps ST1 and ST2 before welding are crushed by the electrode rings 11 and 12, and are transformed into

steps

201 and 202, for example, as shown in the state after welding in FIG. 4(a). At this time, although the height of the step decreases through the joining process, the step is maintained even after welding.
In the example shown in FIG. 4A, steps 201 and 202 are formed approximately 180 degrees symmetrically with respect to the center of the cross section of the nugget N on both the upper and lower sides of the welding region 20. However, the present invention is not limited to this, and only one of the upper step 201 and the lower step 202 may be formed.

In this embodiment, a reference plane 100 is set at the outer circumferential surface of the lower electrode ring 11, and the steel plate 2 is pressurized by pushing the upper electrode ring 11 down toward the reference plane 100. In that case, if a gap is formed between the end of the upper steel plate 2 and the surface of the lower steel plate 2 at the start of welding, the lower steel plate is pressed against the upper steel plate 2 between the electrode rings 11 and 12. The heat input to the end of the upper steel plate 2 precedes the heat input to the end of the upper steel plate 2, and deformation of the lower steel plate 2 at high temperature progresses. Therefore, the step 202 is less likely to be formed on the lower side, and the step 201 is more likely to be formed on the upper side.

The welding region 20 includes the above-mentioned joining range r, the step 201 between the two steel plates 2, and the like. The shape of the step 201 in the welding region 20 varies, for example, as schematically shown in FIGS. 4(b) and 4(c). The respective angles α of the step 201-1 and the step 201-2 are different.

Here, the angle (α) of the step included in the welding region 20 and appearing in the cross section of the welding region 20 is defined as follows for both the upper step and the lower step. Any one of the two steel plates 2 will be referred to as a first plate material (leading steel plate 21 or trailing steel plate 22), and the other will be referred to as a second plate material (tracing steel plate 22 or leading steel plate 21). At this time, the step angle α in one cross section of the welding area 20 is relative to the straight line L1 extending the surface s where the first plate is exposed without being covered by the second plate toward the second plate. This corresponds to the angle formed by the straight line L2 of the end surface of the second plate. The lower step angle α is shown in FIG. 3(b).
In the example shown in FIGS. 4(b) and 4(c), the straight line L1 is a line extending parallel to the sheet passing direction x, with the surface s facing the second plate material side. The same applies to the straight line L1 shown in FIG. 5(a).
Alternatively, the straight line L1 may be a line extending parallel to the surface s in the vicinity of the step 201-4, with the surface s facing the second plate side, as shown in FIG. 5(b).

The first quality determination described below will be explained using the step angle α defined above and the threshold value corresponding to the step angle α. However, in addition to being expressed by α, the angle of the step included in the welding area 20 can also be expressed by the inner angle α ₁ or the outer angle α ₂ formed by the straight line L2 with respect to the exposed surface s. . When angle α ₁ or angle α ₂ is used for quality determination, a threshold value suitable for angle α ₁ or angle α ₂ may be calculated and used.

As shown in FIGS. 4(b) and 4(c), it is not always the case that the external corner 201A and the internal corner 201B that form a step are clearly understood. For example, as shown in FIG. 6(a), the outer shape of the cross section of the step 201-3 may consist of a curved line. Even in such a case, a straight line connects the inflection point p1 of the inside corner located on the base end side of the curve c rising against the exposed surface s and the inflection point p2 of the out corner located on the tip side of the curve c. L3 is obtained by calculation, the straight line L3 is treated as the straight line L2 of the end surface, and the step angle α can be specified by the above definition.
The angle α of the step 201-3 exceeds 90 degrees. This step 201-3 is formed in the shape of an eave so as to cover the exposed surface s of the first plate material.

If the welding area 20 including the step 201-3 shown in FIG. 6(a) is rolled down by the rolling part 30, the eave-shaped part before rolling is crushed as shown in FIG. 6(b). This may cause folding flaws 203.
Furthermore, if the welding area 20 including the folding flaw 203 is supplied to the rolling process, the folding flaw 203 is shown in FIG. As shown in (c), it may remain as a crack-like folding flaw. At this time, even if the depth of the folding flaw 203 has not changed from before rolling, the ratio of the flaw depth to the plate thickness increases. If the welding region 20 were to break during the rolling process, the subsequent annealing process, etc. due to such folding flaws 203, the operating rate of the line would decrease because it would take time to recover.
[Reference 1]
Takehiko Saito, Noriaki Tominaga, Shinichi Kaga, Hirotomo Tagata, Nobuki Yukawa, Takashi Ishikawa: Plasticity and Processing (Journal of the Japan Society for Plastic Processing), Vol. 54, No. 627 (2013-4), pp. 368-372. "Effect of step fold flaws on rolling fracture"

Additionally, a phenomenon called "dust" may occur in the welding area 20 due to molten metal ejecting onto the surface. The dust (expulsion) is raised from the surface of the welding area 20 where no dust is generated, and typically, a plurality of dusts are formed in the welding area 20 in a state where they are scattered in the welding direction y. When molten metal adheres to the electrode rings 11 and 12 due to the generation of dust, the electrode rings 11 and 12 must be cleaned.

[Welding area shape acquisition section and pass/fail judgment section]
In the present embodiment, welding defects such as folding defects and dust generation are detected before the rolling process, and a steel plate 2 having welding defects is prevented from being supplied to the rolling process. Then, even if the welding process is stopped for re-welding or maintenance of the

electrode wheels

11 and 12, the rolling process can be avoided and the line operating rate can be maintained at a high level.

In order to understand welding defects, the welding apparatus 1 of this embodiment acquires the surface shape of the welding area 20. As shown in FIG. 7, the welding apparatus 1 includes a shape acquisition unit 70 that acquires the surface shape of the step in the welding area 20, a temperature measurement unit 77, a display unit 80, and a first determination unit 81 that determines the quality of welding. and a second determination section 82. Note that FIG. 7 shows an example of a functional configuration related to welding quality determination.
The shape acquisition unit 70 includes a laser information acquisition unit 71 , a step shape data acquisition unit 72 , a height measurement value acquisition unit 73 , an angle acquisition unit 74 , a step height acquisition unit 75 , and a post-rolling angle acquisition unit 76 It is equipped with

The laser information acquisition unit 71 irradiates the welding area 20 with a band-shaped laser from the emission unit 711 and receives the laser reflected from the welding area 20 with the imaging element 712 . As the laser information acquisition unit 71, for example, a two-dimensional laser displacement meter 700 can be used.
The step shape data acquisition unit 72 calculates shape data indicating the shape of the step in the welding area 20 using information on the change from the laser emitted by the laser information acquisition unit 71 to the laser reflected by the welding area 20. Obtained by

The laser information acquisition unit 71 of this embodiment irradiates the welding region 20 with a laser before being rolled down by the rolling section 30. Therefore, the shape acquisition section 70 acquires the shape of the welding region 20 before rolling by the rolling section 30.

The height measurement value acquisition unit 73 uses information about the change from the laser emitted by the laser information acquisition unit 71 to the laser reflected by the welding area 20 to obtain a measurement value indicating the height of the welding area 20. Obtain iteratively along the direction y. The measured height value is used to determine whether or not dust is generated. The height measurement value acquisition unit 73 can acquire the surface shape corresponding to the height change over the welding length while irradiating the welding region 20 with laser from the laser displacement meter 700 moving in the welding direction y.

The angle acquisition unit 74 uses the shape data of the step to obtain the angle α of the step included in the welding region 20 by calculation.
The step height acquisition unit 75 calculates and obtains the height of the step included in the welding region 20 using the shape data and the angle α.
The post-rolling angle obtaining section 76 calculates the post-rolling angle from the pre-rolling angle obtained by the angle obtaining section 74 based on the correlation information between the angle before and after the rolling by the rolling section 30. do.

The temperature measuring section 77 measures the surface temperature of the welding area 20 immediately after passing through the

electrode wheels

11 and 12 and before being rolled down by the rolling section 30.

The display unit 80 displays the shape data of the step, the step angle α, the measurement data of the height of the welding area 20, etc. on the screen of the monitor 801. The monitor 801 is provided in the control unit 50, for example.
The first determination unit 81 is capable of determining an abnormality in the step shape that leads to folding defects. The first determination unit 81 is configured to be able to determine whether the welding state of the welding area 20 is good or bad using the step angle α acquired by the angle acquisition unit 74.
The second determination unit 82 is capable of determining whether or not dust has occurred. The second determination unit 82 is configured to be able to determine the quality of the welding state of the welding area 20 using the amount of change between the height measurement values acquired by the height measurement value acquisition unit 73.

Step shape data acquisition section 72, height measurement value acquisition section 73, angle acquisition section 74, step height acquisition section 75, post-rolling angle acquisition section 76, display section 80, first determination section 81, and second determination section 82 can be configured as a module of a program that operates on a computer equipped with an arithmetic unit, a memory, a storage unit, an input/output unit, and the like. The computer is included in the control unit 50, for example.

When the laser displacement meter 700 including the laser information acquisition section 71 has a built-in computer, the step shape data acquisition section 72, the height measurement value acquisition section 73, the angle acquisition section 74, the step height acquisition section 75, and the after-rolling At least a portion of the angle acquisition section 76, the display section 80, the first determination section 81, and the second determination section 82 may be program modules that operate in the computer of the laser displacement meter 700.

In the computer built into the laser displacement meter 700 of this embodiment, program modules corresponding to the step shape data acquisition section 72 and the height measurement value acquisition section 73 operate. Therefore, the pixel information of the image received and imaged by the image sensor 712 of the laser information acquisition section 71 is directly passed from the image sensor 712 to the step shape data acquisition section 72 and the height measurement value acquisition section 73. . The shape data obtained by the step shape data acquisition section 72 and the height measurement value obtained by the height measurement value acquisition section 73 are obtained from the laser displacement meter 700 and are executed by a computer included in the control section 50 etc. It is passed to the angle acquisition unit 74, step height acquisition unit 75, post-rolling angle acquisition unit 76, display unit 80, first determination unit 81, and second determination unit 82 as program modules to be executed.

In other words, program modules corresponding to each of the step shape data acquisition section 72, height measurement value acquisition section 73, angle acquisition section 74, display section 80, first determination section 81, and second determination section 82 are installed on a plurality of computers. For example, it may be configured such that the computer built in the laser displacement meter 700 and the computer built in the control unit 50 are distributed and operated in cooperation with each other. A plurality of computers can be connected so as to be able to send and receive data via, for example, a cable, a wired LAN (Local Area Network), a wireless LAN, or the World Wide Web.

[Laser information acquisition section]
As described above, in this embodiment, the step 201 is likely to be formed above the welding region 20, and the eave-like step 201-3, which causes folding defects, is formed above the welding region 20. Even if a step is formed on the lower side of the welding region 20, an eave-like step is not formed on the lower side.
Therefore, as shown in FIGS. 8, 9(a), and 10, it is sufficient that the laser displacement meter 700 including the laser information acquisition section 71 is disposed only above the welding area 20. This embodiment uses shape data obtained from information indicating a change from a laser emitted towards the welding area 20 to a laser reflected by the welding area 20 (correlation information between the emitted laser and the reflected laser). , determine the quality of welding regarding folding defects. At the same time, the quality of the welding regarding the generation of dust is also determined using the height measurement value of the welding area 20 obtained from the information indicated by the change in the laser beam.

The laser displacement meter 700 irradiates the welding area 20 with a band-shaped laser LS1 (see FIG. 9(a)) based on the optical cutting method, and determines the shape of the step in the welding area 20 (cross section) based on the change in the reflected light. profile) can be measured. Further, the laser displacement meter 700 can perform one-dimensional measurements such as height and width by emitting a linear laser in addition to emitting the band-shaped laser LS1.

The laser information acquisition unit 71 includes an emission unit 711 that emits a band-shaped laser LS1 to irradiate a linear range 20L of the welding area 20, and a laser information acquisition unit 71 that emits a band-shaped laser LS1 to irradiate a linear range 20L of the welding area 20. It includes an image sensor 712 such as a CMOS (Complementary Metal Oxide Semiconductor) that receives the laser LS2 and forms an image.
It is preferable that the linear range 20L is perpendicular to the welding direction y. In other words, the linear range 20L extends along the sheet passing direction x.

The image sensor 712 is separated from the emission section 711 in the welding direction y. Therefore, the optical axis A2 of the laser LS2 intersects the optical axis A1 of the laser LS1 when viewed from the sheet passing direction x. The laser displacement meter 700 is supported by the upper frame 411 so that the entire welding region 20 in the sheet passing direction x falls within the irradiation range 20L (FIG. 9(a)). The irradiation range 20L is located between the lower end of the electrode ring 11 and the lower end of the reduction roll 31, as shown in FIG. Although the intersection of the optical axis A1 and the optical axis A2 is located at a position that bisects the distance between the lower end of the electrode ring 11 and the lower end of the reduction roll 31, this is not a limitation. There are no obstacles in the optical path of either the emitted laser LS1 or the reflected laser LS2.

As shown in FIGS. 9(a) and 9(b), the optical axis A1 of the laser LS1 emitted by the laser information acquisition unit 71 is directed from the emission unit 711 toward the step in the welding area 20 with respect to the vertical direction z. Set at an angle.

Since the optical axis A1 is inclined with respect to the vertical direction z, the step angle α exceeds 90 degrees, as in the step 201-3 shown in FIG. 9(b) and the step 201-2 shown in FIG. 4(c). Even in this case, the laser LS1 emitted from the emitting section 711 can be made to enter the inside of the step. The laser LS1 emitted from the emitting section 711 linearly enters the step 201 in the sheet passing direction x, and the reflected laser LS2 is received by an image sensor 712 that is away from the emitting section 711 in the welding direction y. Since the laser LS2 changes depending on the surface shape of the welding area 20 over the linear irradiation range 20L, data indicating the surface shape can be obtained by capturing the change.

Contrary to this embodiment, when the end of the leading steel plate 21 is overlapped with the lower end of the trailing steel plate 22, shape data of a step formed above the welding area 20 is obtained. In this case, the shape of the step is reversed in the left-right direction (sheet threading direction x) with respect to the shape of the step (201-3) shown in FIG. 9(b). In that case, it is preferable to install the laser displacement meter 700 on the upper frame 411 on the right side in FIG. 9(a), and irradiate the laser LS1 from the emission part 711 toward the step. The optical axis A1 of the laser LS1 is also set to be inclined with respect to the vertical direction z.

The angle γ that the optical axis A1 makes with respect to the horizontal plane (for example, the reference plane 100) is preferably 30 degrees or more. If the angle is 30 degrees or more, an image can be formed on the image sensor 712 by the laser LS2 reflected from the surface of the welding region 20. However, if the angle is less than 30 degrees, it becomes difficult for the reflected laser LS2 to enter the image sensor 712, so it is difficult to form an image of the reflected laser LS2 on the image sensor 712.
The inclination angle γ of the optical axis A1 of the output laser LS1 in this embodiment is set within the range of about 50 degrees to about 55 degrees. However, the inclination angle γ can be set to an angle smaller than 90 degrees and larger than 30 degrees, as long as data on the shape of the step can be obtained even if there is an eave-like step.

The laser displacement meter 700 is supported by an upper frame 411 via a support member 413 as shown in FIG. 8, with a housing 701 housed in a protective cover 702 as shown in FIG. As the moving body 40 travels, the laser displacement meter 700 moves in the welding direction y with respect to the steel plate 2.
The laser displacement meter 700 may be configured such that the inclination angle γ of the optical axis A1 with respect to the horizontal plane can be adjusted.

Support parts

415 and 416 that respectively support the electrode ring 11 and the reduction roll 31 on the upper frame 411 and members such as the temperature measurement part 77 are arranged close to each other in the welding direction y. The space between and above it is narrow. Therefore, it is difficult to arrange the laser displacement meter 700 on the straight line L4 that connects the upper frame 411 and the irradiation range 20L that is spaced downward from the upper frame 411 due to installation space constraints.

However, since the optical axis A1 is set to be inclined with respect to the vertical direction toward the step of the welding area 20, the position of the laser displacement meter 700 of this embodiment is in the threading direction x with respect to the straight line L4. It's shifting. Then, regardless of the space between the welding part 10 and the rolling part 30, the laser displacement meter 700 will not interfere with the welding part 10, the rolling part 30, or the clamps C1 and C2. The straight movement of the emitting laser LS1 and the reflected laser LS2 is not hindered.
At this time, with reference to FIG. 8, at least one of the welding part 10 and the rolling part 30 is arranged in the projection range of the laser displacement meter 700 in the sheet passing direction x. The support member 413 to which the laser displacement meter 700 is attached can be installed, for example, on the side surface of the upper frame 411.
Since the sheet passing direction x is a direction perpendicular to the paper surface of FIG. 8, the projection range of the laser displacement meter 700 in the sheet passing direction overlaps with

Since the optical axis A1 is set to be inclined with respect to the vertical direction z, even if the step angle α is larger than 90 degrees, the output laser can be made to enter the inside of the step and the step can be corrected. The shape can be obtained, and it is possible to obtain the step angle α from the shape data indicating the step shape, and to make a pass/fail judgment according to the step angle α.

[Temperature measurement section]
As shown in FIG. 8, the temperature measuring section 77, which is a radiation thermometer, is arranged between the electrode wheel 11 and the reduction roll 31 in the welding direction y, with the temperature sensing section (not shown) facing the lower end of the electrode wheel 11. ing. The infrared rays emitted from the surface of the welding region 20 enter the temperature sensing section provided in the temperature measuring section 77 immediately after passing through the

electrode wheels

11 and 12. The temperature measuring section 77 measures the surface temperature of the welding area 20 in a non-contact manner based on the intensity of infrared rays incident on the temperature measuring section. The temperature measuring section 77 is supported by the upper frame 411 via a suitable member, and is arranged in the gap between the electrode wheel 11 and the reduction roll 31.
It is preferable that the measurement location by the temperature measurement unit 77 be set at the center of the overlap w in the welding area 20.
The temperature measurement unit 77 moves in the welding direction y together with the

electrode wheels

11 and 12 and the reduction rolls 31 and 32 as the moving body 40 travels.

[Overview of welding quality judgment]
By using the welding device 1 of this embodiment, for example, as shown in the outline in FIG. Then, the shape acquisition section 70 acquires the step shape of the welding region 20 before rolling (step shape acquisition step S2). Thereafter, using the data indicating the step shape, the first determination unit 81 determines whether or not the step shape, which may be a cause of folding defects, is good or bad (first determination step S3).
In addition, in parallel with the processing by the welding part 10 and the rolling part 30 (welding/rolling step S1), the height measurement value acquisition part 73 acquires the height of the welding area 20 before rolling (height measurement value acquisition step S4) Using the data indicating the height of the welding area 20, the second determination section 82 performs a quality determination regarding the occurrence of dust (second determination step S5).

The results of the first and second determinations are displayed on the screen 801A of the monitor 801 by the display unit 80, for example, as shown in FIGS. 12(a) and 12(b) (display step S6). If it is determined that welding is defective, it is preferable to notify the operator of the welding apparatus 1 by, for example, sounding a buzzer provided in the control unit 50 or the like. A buzzer is an example of an output unit that notifies that a welding defect has been determined. The results of the first and second determinations may not be displayed on the screen 801A, but may be notified to the operator only by a buzzer.
Further, data indicating the step shape or the height of the welding area 20 may be displayed on the screen 801A without determining whether the step shape or the occurrence of dust is good or bad. Furthermore, the operator may judge whether the welding is good or bad by visually checking the display on the screen 801A.

If a defective step shape occurs, processing such as rewelding is performed. If dust occurs, maintenance such as cleaning the

electrode wheels

11 and 12 is performed. By starting preparations for re-welding, maintenance, etc. as soon as such welding defects are discovered, the time required to stop the welding process can be kept short.
According to the present embodiment, a welding defect is detected during the welding process, and the welding area 20 in which the defective occurs is not supplied to the rolling process. 2 is supplied, the continuous rolling line can be stably operated at a high operating rate while preventing breakage of the welding area 20.

The welding apparatus 1 may be configured to be able to switch whether or not to perform the first determination regarding the step shape and the second determination regarding the occurrence of dust by mode selection. In that case, both the first determination step S3 and the second determination step S5 are not necessarily performed, and depending on the mode selection state, only the first determination or only the second determination is performed. Is possible.
Hereinafter, an example of a specific method for each of the first determination and the second determination will be described. The threshold value used for the first determination and the second determination and the information indicating the correlation of data may be stored in advance in, for example, a storage unit provided in the control unit 50, and may be referenced by the program module that performs the determination.

[First judgment regarding step shape]
The first determination step S3 will be explained below. The first determination step S3 includes the following two quality determinations.
(1) Pre-reduction determination From the shape data indicating the step shape, the angle acquisition section 74 acquires the step angle α of the welding area 20 before reduction by the reduction section 30, and the step angle α and the temperature measurement section 77 measure the step angle α. Based on the temperature τ, a threshold value is applied to the step angle α and the temperature τ, respectively, to determine the quality of welding before reduction.

(2) Post-rolling determination Using information showing the correlation between the step angle A before rolling and the step angle B after rolling based on the test, the post-rolling angle acquisition unit 76 determines the before rolling angle acquired by the angle acquiring unit 74. The step angle β after rolling is calculated from the step angle α. A threshold smaller than the threshold applied to the pre-reduction step angle α is applied to the step angle β, and the quality of welding after reduction is determined.

In this embodiment, in addition to the pre-rolling determination, the post-rolling determination is performed. However, if it is determined to be defective in the pre-rolling determination, it is not necessarily necessary to perform the post-rolling determination, and it is preferable to proceed to necessary processing such as re-welding at the time when it is determined to be defective in the pre-rolling determination.

Example of pre-reduction judgment:
The pre-rolling determination will be described with reference to FIGS. 13 to 18. FIG. 13(a) collectively shows the data in FIGS. 14(a) to 14(c), which are the test results (for each plate thickness) obtained from a welding test in which the welding process was repeated using the welding device 1. . Each plot shown in FIGS. 13(a) and 14(a) to (c) corresponds to one welding region 20 (seam) formed along the welding direction y by one welding process.

The thicknesses of the steel plates 2 used in the welding test were 1.6 mm, 3.2 mm, and 6.0 mm. The steel type of the steel plate 2 used in the test was a hot rolled steel plate of low carbon steel, which is ordinary steel.
14(a) to (c) respectively show the step angle A of the welding area 20 before rolling calculated from the shape data obtained by the laser displacement meter 700, and the welding area immediately after welding measured by the temperature measurement unit 77. The relationship between temperature T and temperature T of 20 is shown.
The temperature T corresponds to the average temperature measured over the welding length by the temperature measuring section 77.

In the welding test, the shape of the welding area 20 after reduction was also measured in order to set a threshold value for post-reduction determination, which will be described later.

In the welding test, a band-shaped laser is linearly incident on the welding area 20 along the sheet passing direction x, and the reflected laser is received by the image sensor 712 to obtain shape data indicating the step shape of the welding area 20. Then, the step angle A before rolling was calculated from the shape data through calculation processing by the angle acquisition section 74. In this welding test, a plurality of measurement positions where the laser is incident were set in the welding direction y. The step angle A corresponds to the average step angle before rolling calculated from the shape data obtained for a plurality of measurement positions. The step angle B after rolling (FIG. 19) also corresponds to the average angle of the step angles after rolling calculated from the shape data obtained for a plurality of measurement positions.
The step angles A and B follow the definition of the step angle α described above. In other words, the step angles A and B are the straight line L1 extending the surface s of the trailing steel plate 22 exposed from the leading steel plate 21 toward the leading steel plate 21, similar to the step angle α shown in FIG. 4(a). This corresponds to the angle that the straight line L2 of the end face of the preceding steel plate 21 makes with respect to the straight line L2. For example, as shown in FIG. 6A, the step angles A and B can be specified by treating the straight line L3 calculated from the inflection points p1 and p2 as the straight line L2 of the end face.

The table shown in FIG. 13(b) shows the step angle A before rolling obtained at one predetermined position in the welding direction y in the same manner as the above welding test, and the cross section after rolling at the same position in the welding direction y ( The results of an investigation into the presence or absence of folding flaws based on visual inspection of the image (xz plane) are shown. The steel plate 2 used in this investigation is also a hot rolled steel plate, and the data in the table includes a mixture of plate thicknesses of 1.6 mm, 3.2 mm, and 6.0 mm. The steel type is a hot-rolled steel plate of low carbon steel, which is ordinary steel, as in FIG. 13(a).
15(a), (b) and FIG. 16(a), (b) show images extracted from a plurality of images taken for the investigation.

The upper part of FIG. 15(a) shows the cross-sectional image before rolling, and the lower part of FIG. 15(a) shows the cross-sectional image after rolling (after flattening by rolling part 30) at the same position in the welding direction y. The image is shown. The same applies to FIG. 15(b), FIG. 16(a), and FIG. 16(b).
Both of FIGS. 15A and 15B correspond to cases in which the step angle A before rolling exceeds 90 degrees, and folding flaws 203 occur after rolling. If the step angle A exceeds 90 degrees before rolling down, the convex portion 204 of the step is likely to be deformed in the direction of falling and folding inside the step during rolling down. Even if a laser is irradiated toward the folding flaw 203, the laser does not enter the gap of the folding flaw 203, so the folding flaw 203 cannot be imaged on the imaging element 712 by the reflected laser.

On the other hand, in both FIGS. 16(a) and 16(b), the step angle A before rolling is less than 90 degrees, and folding flaws 203 do not occur after rolling. If the step angle A is less than 90 degrees before rolling down, the step is deformed in the direction d in which the step opens during rolling down.

Based on the correspondence between the step angle A before rolling shown in FIG. 13(b) and the occurrence of folding flaws 203 due to rolling, it is applied to the step angle α before rolling obtained by the angle acquisition unit 74 during line operation. The first angle threshold t1 can be set to 90 degrees, for example.
Here, even if the plate thicknesses are different, the same first angle threshold value t1 can be used, which is convenient.
In addition, the temperature threshold tt applied to the temperature τ immediately after welding measured by the temperature measurement unit 77 during line operation as the temperature necessary to obtain sufficient welding strength is determined by the plate thickness, steel type, and line threading conditions. The temperature can be set at an appropriate temperature by considering the following.
The "line threading conditions" correspond to the supply destination of the welded steel sheets 2 (rolling process or other processes such as pickling process), etc.

The larger the plate thickness, the higher the meter side temperature τ, so it is preferable to set a higher temperature threshold tt. As an example of the temperature threshold value tt, FIGS. 14(a) to 14(c) show temperatures tt-a, tt-b, and tt-c for each plate thickness.
The distribution state of each plot in FIGS. 14(a) to (c) is determined to be OK depending on the first angle threshold value t1 and the temperature threshold value (tt-a, tt-a, tt-c) for each plate thickness. It matches well with the area judged as .

The temperature threshold tt may be set variably depending on the steel type. FIGS. 17(a) to (c) and FIGS. 18(a) to (c) show examples in which the temperature threshold value tt is set for each plate thickness for ordinary steel and high-strength steel. Each graph shows the relationship between the temperature T of the welding area 20 immediately after welding measured in the above-mentioned welding test and the base metal ratio of the Erichsen value (indicating the elongation at break) of the welding area 20 based on the Erichsen test. ing. Based on these data, for example, a temperature T at which the Erichsen value of the welding region 20 is 60% or more of the Erichsen value of the base metal can be adopted as the temperature threshold value tt for each steel type and plate thickness. The temperature thresholds tt-a, tt-b, and tt-c shown in FIGS. 14(a) to (c) correspond to 600°C, 650°C, and 700°C shown in FIGS. 17(a) to (c), respectively. There is.

From the above, the first determination unit 81 of the present embodiment determines that when the step angle α before rolling is less than or equal to the first angle threshold t1, and when the temperature τ is greater than or equal to the temperature threshold tt, the step angle α and the temperature τ Since all of these are OK, it is determined that the welding condition before rolling down is good. In other cases, the first determination unit 81 determines that the welding state before rolling is poor.

By obtaining the shape before rolling using the laser displacement meter 700, it is possible to eliminate the possibility of folding defects before the step is bent due to the rolling process by the rolling unit 30 and the shape cannot be measured with a laser. It is possible to detect abnormalities in the shape of certain steps. In addition, the scale adhesion state generated on the surface of the welding region 20 due to the rolling process does not affect the measured value of the surface shape, so that the surface shape can be measured stably and accurately.

The first determination unit 81 can perform a quality determination based on not only the temperature τ and the step angle α but also the step height h after welding and before reduction (FIG. 4(b)). Based on FIG. 7 described in Reference 2 below, the larger the step height h is, the greater the depth of the fold-in flaw when it occurs.
[Reference 2]
Takehiko Saito, Noriaki Tominaga, Tomomi Kawazumi, Hirotomo Tagata, Nobuki Yukawa, Takashi Ishikawa: Plasticity and Processing (Journal of the Japan Society for Plastic Processing), Vol. 55, No. 647 (2014-5), pp. 451-455. "Effect of cross swaging on leveling of mash seam welds"

Therefore, during line operation, the first determination unit 81 determines that when the measured temperature τ is equal to or higher than the temperature threshold value tt, the step angle α is equal to or less than the first angle t1, and the step height h is equal to or less than a predetermined threshold value. Therefore, it is possible to determine that the welding condition is "good". The step height h can be obtained from the shape data of the welding region 20 obtained by the step shape data acquisition section 72 through calculation by the step height acquisition section 75 .

When it is ensured that the temperature τ is equal to or higher than the temperature threshold tt, for example, when the operator visually confirms the red-hot state of the welding area 20, the pre-rolling step angle α obtained from the shape data is Only by applying the one-angle threshold value t1, it is possible to judge the quality of welding before reduction.

The first angle threshold value t1 and the temperature threshold value tt may be determined as follows depending on the line threading conditions.
When welded steel plates are supplied to the rolling process (this embodiment):
In this case, high welding strength is required, and compared to a non-rolling line, there is a high possibility that the step will become a folding flaw and the weld area 20 will break. Therefore, in order to obtain a joint strength that can withstand rolling, it is preferable to set the temperature threshold value tt higher than that of a non-rolling line, and to set the first angle threshold value t1 to 90 degrees.

If the welded steel plate is not fed into the rolling process:
For example, this applies when only pickling is performed on the welded steel plates 2. In such a case, welding strength is not so required, and the possibility of breakage from folding flaws is low. Therefore, it is preferable to set the temperature threshold value tt to be lower than that of the rolling line. If the steel plate 2 is a low-tension steel type and is not supplied to the rolling process, the temperature T at which the Erichsen value base material ratio is, for example, 30% (FIGS. 17(a) to (c)) is set as the temperature. The threshold value tt can be set.
If the welded steel plate 2 is not supplied to the rolling process, it is not necessary to set the first angle threshold t1. In other words, if there is a low possibility that a break will occur in the welding area 20 in view of the line threading conditions, it is not necessarily necessary to calculate the step angle α from the shape data obtained using the laser displacement meter 700. In that case, it is permissible for the first determination unit 81 to determine the quality of the welding state based only on the measured temperature τ instead of the step angle α.

Example of judgment after reduction:
Referring to FIG. 19, the post-rolling determination will be described. If the step angle after rolling is large, there is a high possibility that folding defects will occur during the rolling process and breakage will occur during the rolling process or subsequent processes. Therefore, in addition to the pre-rolling determination based on the step angle before rolling, it is preferable to also perform the post-rolling determination based on the step angle after rolling.

FIG. 19 shows the step angle A before reduction obtained during the welding test explained with reference to FIGS. 13(a) and 14(a) to (c), and the step angle A obtained during the same test. The relationship with the step angle B after rolling down is shown.
The measurement of the step shape after rolling in this welding test is performed by the same laser displacement meter 700 used for measuring the step shape before rolling. Therefore, after the welding step and the rolling step that are performed while moving the moving body 40 backward, the step shape is measured by the laser displacement meter 700 while moving the moving body 40 forward and backward again while holding the steel plate 2 with the clamps C1 and C2. Measure. When retreating again, the

electrode wheels

11 and 12 and the reduction rolls 31 and 32 are retracted from the steel plate 2.
Although there are variations in the plots shown in FIG. 19, there is a correlation between the step angle A before rolling and the step angle B after rolling. In other words, the larger the value εA obtained by multiplying the step angle A before rolling by the coefficient ε on the horizontal axis, the larger the step angle B after rolling. It is possible to draw an approximate straight line L5 or an approximate curve from the plot.
When the steel types are different, the strength against tensile force under high temperature conditions is different, and this may be one reason why the slopes of the approximate curves may be different.

The coefficient ε is calculated based on the cross-sectional area of the part of the steel plate 2 that is rolled down by the rolling rolls 31 and 32 (corresponding to the product of the overlap w after welding and before rolling and the step height h), and the ease with which the rolled part is deformed. It can be determined from the relationship between the temperature (depending on the measured temperature T) and the swaging pressure of the reduction rolls 31 and 32. Note that the larger the step height h, the larger the step angle B after rolling down by the rolling down rolls 31 and 32 tends to be.

During line operation, the post-rolling angle acquisition section 76 obtains the step angle β after rolling down by calculation using the step angle α before rolling obtained by the angle acquiring section 74, the coefficient ε, and the approximate straight line L5. Can be done.

When the value of the step angle β after rolling is large, the possibility of folding defects occurring in the rolling process increases compared to when the step angle α before rolling is the same value. Therefore, the second angle threshold t2 applied to the post-rolling step angle β acquired by the post-rolling angle acquisition unit 76 during line operation can be set to, for example, 75 degrees. The second angle threshold t2 is preferably smaller than the first angle threshold t1.
In FIG. 19, a plot of white circles indicates that the step angle B after rolling is 75 degrees or more, and a plot of black circles indicates that the step angle B is less than 75 degrees.
The second angle threshold t2 may be determined to be 60 degrees or more and 75 degrees or less, for example, based on the correlation between the step angle β after rolling and before rolling shown in FIG. 20 and the state of flaws after rolling. preferable. FIG. 20 corresponds to FIG. 7 described in Reference 3 below.
[Reference 3]
Takehiko Saito, Noriaki Tominaga, Nobuki Yukawa, Takashi Ishikawa, Hirotomo Tagata, Keiichi Sato: Plasticity and Processing (Journal of the Japan Society for Plastic Processing), Vol. 54, No. 626 (2013-3), pp. 267-271. "Development of a mash seam welding machine that prevents step bending deformation of welded parts"

From the above, the first determination unit 81 of the present embodiment determines that the welding condition after reduction is good if the step angle β after reduction is less than 75 degrees, and the step angle β after reduction is determined to be good. If it is 75 degrees or more, it is determined that the welding condition after reduction is poor.

Like the first angle threshold t1, the second angle threshold t2 can be set to an appropriate value depending on the plate thickness, steel type, and line threading conditions.
Regarding the plot in FIG. 19, within the range of plate thickness from 1.6 to 6.0 mm, the plot variations show the same tendency even if the plate thickness is different. Therefore, even if the plate thicknesses are different, the same second angle threshold value t2 can be used, which is convenient. In addition, when the dispersion of the plot distribution for each plate thickness is large, it is preferable to set the second angle threshold value t2 for each plate thickness.

In addition to determining the quality of the welding state before rolling, we also determine the quality of the welding after rolling. Even if the welding state is determined to be good before rolling, the subsequent rolling process is determined based on the step angle β after rolling. It is possible to catch cases that lead to folding defects in the process.
Here, assuming a case where folding flaws occur during rolling as shown in Figures 15(a) and (b), since the laser does not enter the gap of folding scratches, the step shape is obtained only after rolling. However, if a pass/fail judgment is only made based on the step angle β corresponding to the step shape, it is not possible to detect an abnormal shape when a folding flaw occurs during rolling down.
As described above, the quality determination based on the step shape before rolling and the quality determination based on the step shape after rolling are in a complementary relationship.

Even if the step angles are obtained both before and after rolling down to determine the quality, as in this embodiment, based on the correlation between the step angle A before rolling and the step angle B after rolling, as shown in FIG. Since the post-rolling step difference angle β is calculated from the pre-rolling step difference angle α, it is sufficient to install only one laser displacement meter 700 to obtain the shape before rolling.
According to this embodiment, only one laser displacement meter 700 is installed in the welding device 1 during production, so two laser displacement meters 700 are installed in the frame 41, and each of the laser displacement meters 700 is installed before and after rolling down. Compared to the case where shape data is acquired and the same process is repeated by the angle acquisition unit 74 using the shape data before rolling and the shape data after rolling to obtain the step difference angle α before rolling and the step difference angle β after rolling, the apparatus is Costs can be reduced.

[Second judgment regarding dust outbreak]
Next, the second determination step S5 will be explained with reference to FIGS. 21 and 22. The determination as to whether or not dust has occurred is made based on the shape that shows the height change that appears in the welding direction y in the welding area 20 when dust is generated. As the moving body 40 on which the laser displacement meter 700 is installed moves, the height is measured while moving the irradiation position p3 where the linear laser is irradiated along the welding direction y as shown in FIG. 21(a). By periodically acquiring the values, for example, data shown in FIG. 21(b) or (c) can be obtained. At this time, the irradiation position p3 is set, for example, at the center of the overlapping margin of the two steel plates 2 in the sheet passing direction x, where the current density is high.

The laser displacement meter 700 can measure the distance between the emitting part 711 and the welding area 20 (the height of the welding area 20) by triangulation using the emitted laser and the reflected laser. Since the laser emitted from the emission part 711 of the laser displacement meter 700 is irradiated to the welding area 20 between the welding part 10 and the rolling part 30, before the dust is crushed by the rolling rolls 31 and 32, Dust can be detected by acquiring data indicating the height of the welding area 20.

In performing the quality determination regarding dust generation, a measurement test of the height of the welding area 20 was conducted using a laser displacement meter 700 installed in the welding apparatus 1. FIG. 21(b) shows the height of the welding area 20 periodically measured over the welding length when no dust is generated by a laser displacement meter 700 that moves in the welding direction y as the frame 41 travels. Shows a collection of measured values.
FIG. 21(c) shows a set of height measurement values similarly measured when dust occurs. Measured values are fluctuating due to the occurrence of dust.

If the steel plate 2 is flat and the welding area 20 is hardly displaced in the height direction (vertical direction z) over the welding length under normal conditions, a threshold value is applied to the height measurement value of the welding area 20 to remove dust. It is possible to determine whether or not this has occurred.
However, as shown in Fig. 21(b), even under normal conditions when no dust occurs, changes in the height in the welding direction y may be observed due to changes in the overlap margin in the welding direction y. . In such a case, it is difficult to set a threshold value for determining when dust is occurring and when dust is not occurring. Since it is difficult to reduce the threshold value, it is difficult to detect small particles that protrude from the surface.

However, due to the phenomenon of dust ejecting molten metal, the height of the part where dust exists in the welding area 20 changes rapidly compared to the surface where dust does not exist, as shown in FIG. 21(b). .
FIG. 22(a) shows the calculated amount of change between adjacent height measurement values, excluding the unsteady range r3 at both ends of the welding length from the height data shown in FIG. 21(b). FIG. 22(b) shows the calculated amount of change between adjacent height measurement values, excluding the unsteady range r3 at both ends of the welding length from the height data shown in FIG. 21(c).

As shown in FIG. 22(a), the amount of change in height under normal conditions is substantially 0, so the amount of change in height includes the height measurement shown in FIGS. 21(b) and (c). It is possible to provide a smaller threshold value th compared to the case where a threshold value is given to the value. Therefore, regardless of the scale of the dust, dust can be detected with high accuracy based on the amount of change in the height of the welding region 20 indicated by the shape of the dust. The threshold value th can be set to 0.5 mm, for example, in the case of the data shown in FIGS. 22(a) and 22(b).

If the scale of the dust is large relative to the thickness of the plate, especially if the thickness of the plate is thin, holes penetrating in the thickness direction of the plate may be formed where the dust occurs. In that case, the laser displacement meter 700 becomes unable to measure because there is no reflected laser corresponding to the emitted laser, and there is no measured value data (missing) over a section corresponding to the opening size of the through hole.

As described above, the second determination unit 82 of the present embodiment calculates the amount of change from the height measurement value acquired by the height measurement value acquisition unit 73 during line operation, and determines that the amount of height change is the threshold value. In addition to the case where the measured value data exceeds th, it can be determined that dust has occurred when the measured value data is missing over a predetermined section using information indicating the presence or absence of the measured value data.
The screen 801A in FIG. 12(b) displays, as information regarding the presence or absence of measured value data, that there is a through hole at the location where dust is generated. In addition, on the screen 801A, the height measurement values shown in FIGS. 21(b) and 21(c) and the height change amount shown in FIGS. 22(a) and 22(b) are displayed on the display unit 80 You can also do it.

In the second determination step S5 of the present embodiment, since dust can be detected with high accuracy based on the shape of the molten metal exposed in the welding area 20, the temperature measured by the temperature measuring section 77 is used for dust determination. Therefore, there is no need to use them together. The temperature measurement values obtained by the temperature measuring section 77 vary widely due to temperature unevenness due to roughness of the surfaces of the

electrode wheels

11 and 12 with which the welding region 20 comes into contact. Therefore, even if the average temperature, temperature difference, etc. of temperature measurement values over the welding length are calculated, it is difficult to distinguish between a normal state and a state where dust occurs from the temperature data.
According to this embodiment, occurrence of dust can be detected with high accuracy based only on the surface shape of the welding area 20 without using other physical quantities such as temperature and voltage in combination.

When the first determination step S3 is performed, the laser displacement meter 700 emits a band-shaped laser beam at at least one location in the welding length to obtain the surface shape of the step before reduction, and emit a laser beam in a line shape to the welding area 20. need to be irradiated. The laser displacement meter 700 can measure the height over the welding length in parallel with the processing by the welding part 10 and the rolling part 30, except when emitting a belt-shaped laser beam.

Note that if only the second judgment regarding the occurrence of dust is performed without measuring the surface shape of the step, the two-dimensional laser displacement meter 700 is not necessary, and a one-dimensional laser displacement meter or laser distance meter is used. can do.
In that case, there is no need to tilt the optical axis A1 of the emitted laser with respect to the vertical direction z, so the laser displacement meter or laser distance meter used can be As long as it does not interfere with the member, the laser displacement meter 700 can be placed on the straight line L4 connecting the upper frame 411 and the irradiation position p3, and the output optical axis A1 can be set along the vertical direction z.

For the second determination, it is also possible to use a long laser displacement meter that is equipped with a large number of emission parts 711 lined up in the welding direction y and that can measure the height over the welding length. When using such a laser displacement meter, the position of the laser displacement meter is fixed at a position where the laser is irradiated over the welding length, and the welding is performed before dust is rolled down between the welding part 10 and the rolling part 30. It is preferable to measure the height of the region 20 multiple times. By connecting multiple pieces of height measurement data obtained by dividing the weld length into several parts, it is possible to obtain height measurement data as shown in Figures 21(b) and (c). It is also possible to obtain height change amounts as shown in FIGS. 22(a) and 22(b) from the height measurement value data.

[Measurement position of step shape]
FIG. 23 shows the position m at which the surface shape of the step is measured. The measurement position m may be one or more arbitrary positions in the welding direction y of the welding area 20. When measuring at a plurality of measurement positions m, the average angle of the step angles calculated from the shape data obtained for each position can be determined, and the average step angle can be used to determine the quality of the step shape.
Note that FIG. 23 shows the dimensions in the welding direction y smaller than the actual dimensions.

[Good/fail judgment without specifying step angle]
In the pre-rolling determination, if the step angle α is 90 degrees or more, it is uniformly determined that the step shape is abnormal, and there may be cases where it is not necessary to specify the value of the step angle α. In that case, it can be determined from the shape data acquired using the laser displacement meter 700 whether the step angle α is 90 degrees or more. The determination result may be displayed on the screen 801A by the display unit 80.

[Other variations]
If the device cost and installation space allow, two laser displacement meters 700 can be installed on the frame 41 in order to measure the shape of the welding area 20 before and after rolling down, respectively. Before rolling and after rolling, the angle acquisition section 74 repeats the same process to obtain the step difference angle before rolling α and the step difference angle after rolling β.
As for the quality judgment after rolling, for example, based on the correlation between the step angle β after rolling and before rolling as shown in FIG. It can be determined that

In addition, under conditions where folding defects do not occur during rolling down by the rolling down rolls 31 and 32, the shape data of the step in the welding area 20 is obtained by the laser displacement meter 700 only after rolling down, and the step angle calculated from the shape data is used. It is also permissible to judge pass/fail.
Therefore, the step shape data acquisition unit 72 and the step shape acquisition step S2 of the present disclosure are allowed to acquire the shape of the welding region 20 at least either before or after being rolled down by the rolling part 30.

As shown in FIG. 4(a), steps 201 and 202 are formed 180 degrees symmetrically on both the upper and lower sides of the welding area 20, and not only the upper step but also the lower step is bent. This may lead to defects. In that case, as shown in FIG. 24, similarly to the

steps

201 and 202, the laser displacement gauges 700 are arranged 180 degrees symmetrically, and the quality of the welding condition is determined based on the data of the upper and lower step shapes. It is preferable.

In addition to the above, it is possible to select the configurations mentioned in the above embodiments or to change them to other configurations as appropriate, without departing from the gist of the present invention.

[Additional note]
According to the description of this specification and the drawings, in addition to the configurations described above, the configurations described below can also be understood.
The welding device joins the overlapping region of the first plate material and the second plate material by resistance welding, and joins the welding area along a welding direction that intersects with the threading direction of the first plate material and the second plate material. The welding part includes a welded part to be formed, a rolling part that rolls down the welding area, and a shape acquisition part that acquires a surface shape of the welding area at least one of before and after being rolled down by the rolling part.
The shape acquisition unit includes a laser information acquisition unit that emits a band-shaped laser beam to irradiate a linear range of the welding area, and receives the laser beam reflected from the welding area with an image sensor, The acquisition unit is disposed above and below the welding area, the linear range intersects with the welding direction, and the linear range intersects with the welding direction, and the acquisition unit is configured to detect the laser beam emitted by the laser information acquisition unit. The optical axis is set to be inclined with respect to the vertical direction toward a step formed by the first plate material and the second plate material in the welding area.

The present invention can be developed into a rolling line equipped with the welding device disclosed in this specification and the drawings, and a rolling device that rolls the plate material welded by the welding device.

1 Welding device 2 Steel plate (plate material)
10 Welding parts 11, 12 Electrode wheels 13, 33 Lifting mechanism 20 Welding area 20L Irradiation range 21 Leading steel plate 21A End face 22 Trailing steel plate 22A End face 30 Rolling section 31, 32 Rolling down roll 40 Moving body 41 Frame 42 Wheel 43 Base 44 Running path 45 Drive device 46 Current application device 50 Control section 61 Film removal section 62 Cutting section 63 Cooling section 64 Heating section 70 Shape acquisition section 71 Laser information acquisition section 72 Step shape data acquisition section 73 Height measurement value acquisition section 74 Angle acquisition section 75 Step height acquisition section 76 Post-rolling angle acquisition section 77 Temperature measurement section 80 Display section 81 First judgment section 82 Second judgment section 100 Reference planes 201, 202 Steps 201A, 201B Corner 203 Folding flaw 204 Part 410 Opening 411 Upper frame 412 Lower frame 413 Support member 415, 416 Support part 451 Servo motor 611, 612 Brush roll 621, 622 Shear blade 700 Laser displacement meter 701 Housing 702 Protective cover 711 Emitting part 712 Image pickup element 801 Monitor 801A Screen A Step angle before rolling B Step angle after rolling A1, A2 Optical axis c Curve C1 Leading clamp C2 Trailing clamp d Direction F1, F2 Shear force h Step height L1, L2, L3, L4 Straight line L5 Approximate straight line LS1 Output laser LS2 Reflected laser N Nugget m Measurement Position P1 Retracted position P2 Forward position p1, p2 Inflection point p3 Irradiation position RD Rotation direction r Joining range r1 Range r3 Unsteady range s Surface S1 Welding/rolling down step S2 Step shape acquisition step S3 First judgment step S4 Height measurement value Acquisition step S5 Second judgment step S6 Display steps ST1, ST2 Step T Temperature w Overlapping margin w1 Width x Threading direction y Welding direction z Vertical direction α Step angle before rolling α ₁ , α ₂ angle β Step angle after rolling γ Angle

Claims

A welding part where the overlapping region of a first plate material and a second plate material is joined by resistance welding, and a welding area is formed along a welding direction that intersects with the threading direction of the first plate material and the second plate material. and,
a rolling part that rolls down the welding area;
a shape acquisition unit that acquires the surface shape of the welding area at least either before or after being rolled down by the rolling unit;
A welding device comprising: a movable body configured to be reciprocally movable in the welding direction and supporting the welding part and the rolling part in a state lined up in the welding direction.
The shape acquisition unit is
comprising a laser information acquisition unit that emits a band-shaped laser beam to irradiate a linear range of the welding area, and receives the laser beam reflected from the welding area with an imaging device;
The laser information acquisition unit is arranged at least one of above and below the welding area,
The linear range intersects with the welding direction,
The optical axis of the laser emitted by the laser information acquisition unit is set to be inclined with respect to the vertical direction toward a step formed by the first plate material and the second plate material in the welding area.
The welding device according to claim 1.
The optical axis makes an angle of 30 degrees or more with respect to a horizontal plane,
The welding device according to claim 2.
The laser information acquisition unit is supported by a frame of the moving body,
At least one of the welding part and the rolling part is arranged in a projection range of the laser information acquisition part in the sheet passing direction,
The welding device according to claim 2 or 3.
The shape acquisition unit is
a step shape data acquisition unit that acquires shape data indicating the shape of the step by calculation using information on a change from the laser emitted by the laser information acquisition unit to the laser reflected by the welding area; Prepare,
The welding device includes:
a display section that displays the shape data;
comprising at least one of a first determination unit that determines the quality of the welding state of the welding area using the shape data;
The welding device according to any one of claims 2 to 4.
The shape acquisition unit includes an angle acquisition unit that acquires the angle of the step by calculation using the shape data,
The first determination unit is configured to be able to determine the quality of the welding state of the welding area using the angle.
The welding device according to claim 5.
The welding device includes a temperature measurement unit that measures the temperature of the welding area before being rolled down by the rolling unit,
The angle acquisition unit uses the shape data to acquire at least the angle of the step before being rolled down,
The first determination unit performs a pre-rolling quality determination by applying threshold values to the angle before rolling acquired by the angle acquiring unit and the temperature of the welding area before rolling measured by the temperature measuring unit, respectively. ,
The welding device according to claim 6.
The shape acquisition unit is configured to perform a rolling operation that calculates an angle after rolling from an angle before rolling acquired by the angle acquiring unit based on correlation information between an angle before rolling and an angle after rolling by the rolling unit. Equipped with a rear angle acquisition section,
The first determination unit applies a first threshold value to the pre-rolling angle acquired by the angle acquiring unit to determine the quality of the before rolling. applying a second threshold value smaller than the first threshold value to perform a pass/fail determination after rolling down;
The welding device according to claim 6 or 7.
The shape acquisition unit is
a laser information acquisition unit that irradiates the welding area with a laser and receives the laser reflected from the welding area;
The laser information acquisition unit determines the height of the welding area using information on a change from the laser emitted from at least one of above and below the welding area to the laser reflected by the welding area. a height measurement value acquisition unit that acquires a height measurement value across the welding direction;
The welding device includes:
a display unit that displays at least one of the measured value, the amount of change between the measured values, and information on the presence or absence of the measured value;
and a second determination unit that determines the quality of the welding state of the welding area using at least one of the measured value, the amount of change between the measured values, and information on the presence or absence of the measured value. prepare,
The welding device according to claim 1.
a welding step of welding an overlapping region of a first plate material and a second plate material to form a welding region along a welding direction that intersects with the threading direction of the first plate material and the second plate material;
a rolling down step of rolling down the welding area;
a shape obtaining step of obtaining a surface shape of the welding area at least either before or after being rolled down in the rolling down step;
an advancing step of moving a movable body that supports a welding part that forms the welding area by resistance welding and a rolling part that rolls down the welding area in a state lined up in the welding direction from a predetermined retreat position to a predetermined forward position;
a retreating step of moving the movable body from the forward position to the retreating position,
The welding method, wherein the welding step, the rolling step, and the shape acquisition step are performed in one of the forward step and the backward step.
The shape acquisition step includes emitting a band-shaped laser to the welding area, irradiating it to a linear range intersecting the welding direction, and receiving laser information reflected from the welding area by an imaging device. includes an acquisition step;
In the laser information acquisition step, the optical axis of the laser emitted from at least one of above and below the welding area is directed toward a step formed by the first plate material and the second plate material in the welding area. and is set at an angle with respect to the vertical direction.
The welding method according to claim 10.
The shape obtaining step includes:
A shape data acquisition step of acquiring shape data indicating the shape of the step by calculation using information on a change from the laser emitted in the laser information acquisition step to the laser reflected by the welding area. ,
The welding method includes:
a display step of displaying the shape data;
comprising at least one of a first determination step of determining the quality of the welding state of the welding area using the shape data;
The welding method according to claim 11.
The shape obtaining step includes an angle obtaining step of obtaining the angle of the step by calculation using the shape data,
The first determination step uses the angle to determine whether the welding state of the welding area is good or bad.
The welding method according to claim 12.
The shape obtaining step is a rolling operation in which an angle after rolling is obtained by calculation from an angle before rolling obtained in the angle obtaining step, based on correlation information between an angle before rolling and an angle after rolling in the rolling step. Equipped with a rear angle acquisition step,
The first determination step applies a first threshold value to the pre-rolling angle obtained in the angle obtaining step to determine whether the pre-rolling is good or bad, and also applies the first threshold to the pre-rolling angle obtained in the post-rolling angle obtaining step. applying a second threshold value smaller than the first threshold value to perform a pass/fail determination after rolling down;
The welding method according to claim 13.
The shape obtaining step includes:
a laser information acquisition step of irradiating the welding area with a laser and receiving the laser reflected from the welding area;
In the laser information acquisition step, the height of the welding area is determined using information on a change from the laser emitted from at least one of above and below the welding area to the laser reflected by the welding area. a height measurement value acquisition step of acquiring height measurement values across the welding direction;
The welding method includes:
a display step of displaying at least one of the measured value, the amount of change between the measured values, and information on the presence or absence of the measured value;
and a second determination step of determining the quality of the welding state of the welding area using at least one of the measured value, the amount of change between the measured values, and information on the presence or absence of the measured value. prepare,
The welding method according to claim 10.