JP6769770B2 - Seam welding method - Google Patents

Description

The present invention relates to a seam welding method.

Conventionally, a seam welding method for seam welding two metal plates to each other is known (see, for example, Patent Document 1). Specifically, two metal plates are overlapped and sandwiched between a pair of roller electrodes, and the electrodes are rotated while energizing the pair of electrodes to seam weld the two metal plates to each other. ..

Here, when two metal plates are joined by seam welding, there is a problem that the metal plate after welding is likely to be warped and deformed. Therefore, in Patent Document 1, warpage deformation is suppressed by welding in a state where one roller electrode of the pair of roller electrodes is offset in front of the other roller electrode in the traveling direction of the metal plate. There is.

Japanese Unexamined Patent Publication No. 2012-66305

However, in the warp prevention method described in Patent Document 1, the amount of offset between one roller electrode and the other roller electrode in the front-rear direction is slightly different depending on the material of the metal plate, the plate thickness, and the like. There is a problem that the calculation of the offset amount corresponding to each metal plate to be welded is troublesome and complicated.

Therefore, the present invention provides a seam welding method capable of easily suppressing warpage deformation that may occur in a metal plate after welding.

In the seam welding method according to the present invention, two metal plates are sandwiched between a pair of roller electrodes in a state of being overlapped with each other, and the roller electrodes are rotated while energizing the pair of roller electrodes. This is a seam welding method in which metal plates of the above are seam welded together.

An embossing step of forming a plurality of embosses arranged side by side at predetermined intervals along a welding line on each of the two metal plates and projecting toward the surface side of the metal plates, and the two metal plates. Regarding the metal plate, the surface of one metal plate and the surface of the other metal plate are overlapped with each other so that the embossing of one metal plate and the embossing of the other metal plate face each other, and the embossing of one metal plate is performed. And the embossing of the other metal plate are arranged in parallel along the welding line, and the two metal plates are sandwiched between the pair of roller electrodes, and at least one side of the pair of roller electrodes. It has a welding step of rotating the roller electrodes of the above and performing seam welding along a plurality of embosses of the metal plate while crushing the embossing of one metal plate and the embossing of the other metal plate by the pair of roller electrodes.
Further, the surface of the one metal plate has the embossing and a general portion other than the embossing, and the surface of the other metal plate has the embossing and a general portion other than the embossing. In the metal plate stacking step of superimposing the surface of one metal plate and the surface of the other metal plate facing each other, the embossing of the one metal plate is arranged so as to face the general portion of the other metal plate. To do.
Then, in an example of the seam welding method according to the present invention, the embossing of the one metal plate and the embossing of the other metal plate are alternately arranged along the welding line.
Further, in another example of the seam welding method according to the present invention, the plurality of embosses of the one metal plate are all arranged at equal intervals, and the plurality of embosses of the other metal plate are formed on the one metal plate. The metal plate stacking step is performed by arranging all the embosses at equal intervals at the same distance as the embossing intervals and arranging the embossing of the one metal plate facing the central portion of the adjacent embosses on the other metal plate. In, the embossing of the one metal plate and the embossing of the other metal plate are all arranged in parallel at equal intervals.

According to the seam welding method according to the present invention, the two metal plates are seam welded while the embossing of one metal plate and the embossing of the other metal plate on the two metal plates are alternately crushed. Here, when the embossing is crushed, a stress that the material (metal plate) spreads and extends in the plane direction is generated in the welded portion. Further, after seam welding, the welded portion is cooled and contracted, so that a stress is generated in which the material contracts in the plane direction. As a result, the stress that extends in the plane direction and the stress that contracts, which act on the material, cancel each other out. Since this cancellation occurs on both of the two metal plates, the warp of the metal plates after welding is suppressed. Therefore, the warp deformation that may occur in the metal plate after seam welding can be easily suppressed.

FIG. 1 is a perspective view showing a seam welding apparatus and a metal plate according to an embodiment of the present invention. 2A and 2B show a metal plate on which embossing is formed, FIG. 2A is a perspective view of the metal plate, and FIG. 2B is an enlarged view showing a portion in the vicinity of the embossing. FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2A. FIG. 4 is a cross-sectional view taken along the line BB of FIG. 2 (b). FIG. 5 is a cross-sectional view in which two metal plates are opposed to each other and arranged apart from each other. FIG. 6 is a cross-sectional view in which two metal plates are overlapped with each other. FIG. 7 is a cross-sectional view showing a state in which the two metal plates of FIG. 6 are sandwiched between a pair of rotating roller electrodes and seam welding is performed while crushing the embossing of the metal plates. FIG. 8 is a cross-sectional view of the first embossing adopted in the embodiment. FIG. 9 is a cross-sectional view of the second embossing adopted in the embodiment. FIG. 10 is a diagram showing a method of measuring the amount of warpage deformation of the metal plate obtained in the examples.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, for convenience, the moving direction of the metal plate sandwiched between the pair of roller electrodes is referred to as the front FR in the traveling direction, and the opposite side of the front side in the traveling direction is referred to as the rear RR in the traveling direction.

As shown in FIG. 1, the seam welding apparatus 1 according to the embodiment of the present invention includes a pair of roller electrodes separated in the vertical direction. Specifically, a disk-shaped upper roller electrode 3 arranged on the upper side, a rotating shaft 5 for supporting the upper roller electrode 3, a disk-shaped lower roller electrode 7 arranged on the lower side, and a lower roller electrode. A rotating shaft 9 for supporting the 7 is provided. A state in which a metal plate 11 to be welded is sandwiched between the upper roller electrode 3 and the lower roller electrode 7 is shown. In the metal plate 11, one metal plate 13 arranged on the lower side and the other metal plate 15 arranged on the upper side are overlapped with each other.

As shown in FIGS. 2A and 3, one of the metal plates 13 to be welded has a plurality of embosses 21 projecting convexly toward the upper side (the surface side of the metal plate 13) in the drawing. Are linearly arranged in parallel at equal intervals along the welding line W. Hereinafter, a specific description will be given.

As shown in FIGS. 2 (b) and 4 of the embossed 21 according to the present embodiment, the outer surface is formed in a spherical crown shape. Here, the "spherical cap" is meant to mean "a portion of a spherical surface on one side of a plane when the sphere intersects the plane". Therefore, the spherical cap when the plane passes through the center of the sphere is a hemisphere. As shown in FIG. 4, the outer surface of the embossed 21 according to the present embodiment is formed in an arc having a radius r1 with the center O in the cross-sectional view. Further, the inner surface of the emboss 21 is formed in an arc having a radius r2 with the center O in the cross-sectional view. Further, the embossing 21 according to the present embodiment is obtained by sandwiching a flat metal plate between a male type having a spherical crown-shaped convex portion and a female type having a concave portion corresponding to the spherical crown-shaped convex portion. Is formed, so that the plate thickness t1 of the emboss 21 and the plate thickness t2 of the general portion 23 other than the emboss are formed to be the same. However, the present invention is not limited to this, and the plate thickness t1 of the embossing 21 and the plate thickness t2 of the general portion 23 other than the embossing may be different.

As shown in FIGS. 2A and 3, the surface of the metal plate 13 is composed of a convex emboss 21 and a flat plate-shaped general portion 23 other than the emboss. The embosses 21 are arranged at equal intervals along the welding line W with the same distance L. The heights of the embossed 21 are all formed to be the same height H.

Then, the metal plate 15 (hereinafter, the other metal plate 15) having the same shape as the metal plate 13 (hereinafter, one metal plate 13) in FIG. 3 is turned upside down, and one metal plate 13 is shown as shown in FIG. Is arranged so that the surface of the metal plate 15 faces the surface of the other metal plate 15. Here, since the other metal plate 15 is formed in the same shape as the one metal plate 13, the surface of the metal plate 15 is composed of a convex emboss 25 and a flat plate-shaped general portion 27 other than the emboss. Has been done. The embosses 25 are arranged at equal intervals along the welding line W with the same distance L. The heights of the embosses 25 are all formed to be the same height H.

Then, as shown in FIGS. 5 and 6, the surface of one metal plate 13 and the surface of the other metal plate 15 face each other so that the emboss 21 of one metal plate 13 and the emboss 25 of the other metal plate 15 face each other. Are overlapped with each other facing each other, and the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 are arranged in parallel along the welding line W. When the surface of one metal plate 13 and the surface of the other metal plate 15 are overlapped with each other facing each other, the embossed 21 of one metal plate 13 is arranged so as to face the general portion 27 of the other metal plate 15. There is. Specifically, by arranging the embossing 21 of one metal plate 13 facing the central portion of the adjacent embosses on the other metal plate 15, the embossing 21 of one metal plate 13 and the other metal plate 15 The embossed 25s are all arranged in parallel at equal intervals at the same distance L / 2. In this way, the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 are alternately arranged along the welding line W.

As shown in FIG. 7, the upper roller electrode 3 on the driving side and the lower roller electrode 7 arranged on the lower side of the upper roller electrode 3 are arranged in a pair. With the two metal plates 11 shown in FIG. 6 overlapped, they are sandwiched between the upper roller electrode 3 and the lower roller electrode 7, and the upper roller electrode 3 and the lower roller electrode 7 are rotated while being energized. To seam weld the two metal plates together. The front FR in the traveling direction of the metal plate 11 is in the left direction in FIG. 7. Since the two metal plates 11 are sandwiched between the upper roller electrode 3 and the lower roller electrode 7, the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 can be crushed.

Here, as shown in FIG. 7, the two metal plates 11 are composed of one metal plate 13 arranged on the lower side and the other metal plate 15 arranged on the upper side. The embossing 21 of one metal plate 13 projects upward, the embossing 25 of the other metal plate 15 projects downward, and the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 form a welding line W. They are arranged alternately along.

Therefore, when the two metal plates 11 are sent to the front FR in the traveling direction and the emboss 25 of the other metal plate 15 is crushed, the emboss 25 of the other metal plate 15 is the general of the one metal plate 13 as shown by the arrow. The portion 23 is pressed downward. Next, when the two metal plates 11 are further fed, the embossing 21 of one metal plate 13 presses the general portion 27 of the other metal plate 15 upward as shown by the arrow. In this way, the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 are seam-welded while being alternately crushed by the general portions of each other.

Next, a seam welding method according to the present embodiment will be described.

First, in the embossing process, a mold (not shown) is used to weld one metal plate 13 and the other metal plate 15 (two metal plates) described above, as shown in FIGS. 2 and 3, respectively. A plurality of embosses are formed which are arranged in parallel along the line W at predetermined intervals and project toward the surface side of the metal plate.

Next, in the metal plate stacking step, as shown in FIGS. 5 and 6, the surface of one metal plate 13 and the surface of the other metal plate 15 are opposed to each other with respect to the two metal plates 11. In a state where the embossed 21 of the metal plate 13 and the embossed 25 of the other metal plate 15 are arranged in parallel along the welding line W, one metal plate 13 and the other metal plate 15 are overlapped with each other.

Then, as shown in FIG. 7, in the welding step, the two metal plates 11 are sandwiched between the upper roller electrode 3 and the lower roller electrode 7, and the upper roller electrode 3 (of the pair of roller electrodes). (At least one roller electrode) is rotated, and the upper roller electrode 3 and the lower roller electrode 7 crush the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 while crushing a plurality of embossing of the metal plate 11. Seam welding is performed along.

The present invention will then be described in more detail through examples.
(1) Test piece The test piece (metal plate) used in the examples is a high-strength steel plate (980 MPa) formed in a rectangular shape having a width of 80 mm and a length of 400 mm. The plate thickness of the test piece was 1.0 mm and 1.6 mm.
(2) Two types of embossing shown in FIGS. 8 and 9 were formed on the embossed test piece. The first emboss 31 shown in FIG. 8 is formed in a circular shape having a diameter of 10 mm and a height of 1 mm in a circular arc shape in a plan view. The distance between the adjacent first embosses is 15 mm. The second emboss 32 shown in FIG. 9 is formed in a circular shape having a diameter of 5 mm and a height of 1 mm in a circular arc shape in a plan view. The distance between the adjacent second embosses is 30 mm.

In addition, "embossing: none" shown in the experimental result (8) described later means that the test piece was not subjected to the embossing process of the present invention, and the metal plate stacking step and the welding step were carried out as the test piece. The result.
(3) Seam welding / roller electrode: The diameter of the upper roller electrode is 220 mm, the diameter of the lower roller electrode is 185 mm, the roller width of both the upper roller electrode and the lower roller electrode is 8 mm, and the pressing force by the roller electrode is 5 kN.
・ Roller electrode drive: Upper roller electrode is drive (feed) side, lower roller electrode is non-drive side ・ Welding current: 12kA DC inverter power supply, upper roller electrode is positive electrode, lower roller electrode is negative electrode ・ Welding speed: 1.0 m / min
(4) Embossing As shown in FIG. 2A, the above-mentioned first embossing 31 and second embossing 32 are embossed at equal intervals at the above-mentioned distances along the longitudinal direction in the center of the width direction of the test piece. Was given.
(5) Welding Two test pieces were overlapped. In the case of the embossed test pieces, the embossed surfaces were opposed to each other and overlapped. Specifically, by arranging the embossing of the lower first test piece so as to face the central portion of the adjacent embosses in the upper second test piece, the embossing of the first test piece and the embossing of the second test piece are performed. And were all arranged in parallel at the same distance at equal intervals.

Next, seam welding was performed while crushing the embossing of the test piece with the roller electrode. Seam welding was performed over the entire length of the test piece in the longitudinal direction.
(6) Method for Measuring Warpage Deformation As shown in FIG. 10, the test piece 40 after welding was completed, one end side in the longitudinal direction was fixed with a jig 41, and the height D on the other end side was measured. The upward warp was shown as a positive value, and the downward warp was shown as a negative value (when measuring, the test piece 40 was inverted and measured).
(7) Example (7-1) Example 1
The plate thickness of the first test piece placed on the lower side and the second test piece placed on the upper side were both 1 mm. The embossing was the first embossing 31 shown in FIG.
(7-2) Example 2
The plate thickness of the first test piece placed on the lower side and the second test piece placed on the upper side were both 1 mm. The embossing was the second embossing 32 shown in FIG.
(7-3) Example 3
The plate thickness of the first test piece placed on the lower side and the second test piece placed on the upper side were both 1.6 mm. The embossing was the first embossing 31 shown in FIG.
(7-4) Example 4
The plate thickness of the first test piece placed on the lower side and the second test piece placed on the upper side were both 1.6 mm. The embossing was the second embossing 32 shown in FIG.
(7-5) Example 5
The plate thickness of the first test piece placed on the lower side was 1.6 mm. The plate thickness of the second test piece placed on the upper side was 1.0 mm. The embossing was the first embossing 31 shown in FIG.
(7-6) Example 6
The plate thickness of the first test piece placed on the lower side was 1.6 mm. The plate thickness of the second test piece placed on the upper side was 1.0 mm. The embossing was the second embossing 32 shown in FIG.
(7-7) Example 7
The plate thickness of the first test piece placed on the lower side was 1.0 mm. The plate thickness of the second test piece placed on the upper side was 1.6 mm. The embossing was the first embossing 31 shown in FIG.
(7-8) Example 8
The plate thickness of the first test piece placed on the lower side was 1.0 mm. The plate thickness of the second test piece placed on the upper side was 1.6 mm. The embossing was the second embossing 32 shown in FIG.
(8) Experimental results (8-1) Results of Example 1

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding. The amount of warpage deformation after welding was smaller when the first test piece or the second test piece was embossed than when neither the first test piece nor the second test piece was embossed. ..
(8-2) Result of Example 2

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding.
(8-3) Result of Example 3

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding. The amount of warpage deformation after welding was smaller when the first test piece or the second test piece was embossed than when neither the first test piece nor the second test piece was embossed. ..
(8-4) Result of Example 4

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding.
(8-5) Result of Example 5

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding. The amount of warpage deformation after welding was smaller when the first test piece or the second test piece was embossed than when neither the first test piece nor the second test piece was embossed. ..
(8-6) Results of Example 6

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding. The amount of warpage deformation after welding was smaller when the first test piece or the second test piece was embossed than when neither the first test piece nor the second test piece was embossed. ..
(8-7) Result of Example 7

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding.
(8-8) Result of Example 8

The one in which embossing was formed on both the first test piece and the second test piece had the smallest amount of warp deformation after welding.
(8-9) Results of All Examples In all the examples, those having embossing on both the first test piece and the second test piece had the effect of reducing the amount of warpage deformation after welding most. Further, both the first embossing and the second embossing had the effect of reducing the amount of warp deformation after welding.

The effects of the seam welding method according to this embodiment will be described below.

(1) In the seam welding method according to the present embodiment, the upper roller electrode 3 and the lower roller electrode 7 (a pair) in a state where one metal plate 13 and the other metal plate 15 (two metal plates 11) are overlapped with each other. This is a seam welding method in which the two metal plates are seam-welded to each other by sandwiching them between the roller electrodes) and rotating the roller electrodes while energizing the pair of roller electrodes.

An embossing step of forming a plurality of embosses 21 and 25 which are arranged in parallel on each of the two metal plates 11 at predetermined intervals along the welding line W and project toward the surface side of the metal plate. With respect to the two metal plates 11, the surface of one metal plate 13 and the surface of the other metal plate 15 face each other so that the emboss 21 of one metal plate 13 and the emboss 25 of the other metal plate 15 face each other. The metal plate superimposing step in which the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 are paralleled along the welding line W, and the above 2 between the pair of roller electrodes. A sheet of metal plates 11 is sandwiched, the roller electrodes on at least one side of the pair of roller electrodes are rotated, and the pair of roller electrodes pushes the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15. It has a welding step of performing seam welding along a plurality of embosses of a metal plate while crushing.

As shown in FIG. 7, the two metal plates 11 are composed of one metal plate 13 arranged on the lower side and the other metal plate 15 arranged on the upper side. The embossing 21 of one metal plate 13 projects upward, the embossing 25 of the other metal plate 15 projects downward, and the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 form a welding line W. They are arranged alternately along.

Therefore, when the two metal plates 11 are sent to the front FR in the traveling direction and the emboss 25 of the other metal plate 15 is crushed, the emboss 25 of the other metal plate 15 faces downward on one metal plate 13 as shown by the arrow. Press on. Next, when the two metal plates 11 are further sent to the front FR in the traveling direction, the emboss 21 of one metal plate 13 presses the other metal plate 15 upward as shown by the arrow. In this way, the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 are seam-welded while being alternately crushed. When the embosses 21 and 25 are crushed, stress that the material (metal plate) spreads and extends in the plane direction is generated in the welded portion. Further, after seam welding, the welded portion is cooled and contracted, so that a stress is generated in which the material contracts in the plane direction. As a result, the stress that extends in the plane direction and the stress that contracts, which act on the material, cancel each other out. Since this cancellation occurs on both of the two metal plates 13 and 15, warpage after welding is suppressed. Therefore, the warp deformation that may occur in the metal plate after seam welding can be easily suppressed.

(2) The surface of the one metal plate 13 has the emboss 21 and a general portion 23 other than the emboss, and the surface of the other metal plate 15 has the emboss 25 and a general portion other than the emboss. It has a part 27. In the metal plate laminating step of superimposing the surface of the one metal plate 13 and the surface of the other metal plate 15 facing each other, the embossing 21 of the one metal plate 13 is formed on the general portion of the other metal plate 15. It is preferable to be arranged so as to face 27.

In this way, since the embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 do not overlap, the stress of extending the material (metal plate) is evenly distributed in the welded portion. Therefore, the warp deformation that may occur in the metal plate after seam welding can be more easily suppressed.

(3) The embossing 21 of the one metal plate 13 and the embossing 25 of the other metal plate 15 may be alternately arranged along the welding line W.

Therefore, the stress of extending the material (metal plate) is more evenly distributed in the welded portion. Therefore, the warp deformation that may occur in the metal plate after seam welding can be more easily suppressed.

(4) The outer surfaces of the embosses 21 and 25 may be formed in a spherical crown shape.

Since the outer surfaces of the embosses 21 and 25 are spherical crown-shaped, the embosses 21 and 25 are evenly crushed toward the periphery. Therefore, the stress of extending the material (metal plate) is more evenly distributed in the welded portion. Therefore, the warp deformation that may occur in the metal plate after seam welding can be more easily suppressed.

(5) The embossing 21 of the one metal plate 13 and the embossing 25 of the other metal plate 15 may all be formed at the same height.

Therefore, the stress of extending the material (metal plate) is more evenly distributed in the welded portion. Therefore, the warp deformation that may occur in the metal plate after seam welding can be more easily suppressed.

(6) The plurality of embosses 21 of the one metal plate 13 are all arranged at equal intervals, and the plurality of embosses 25 of the other metal plate 15 are equivalent to the intervals of the embosses 21 of the one metal plate 13. By arranging all of them at equal intervals at a distance and arranging the embossing 21 of the one metal plate 13 facing the central portion of the adjacent embosses on the other metal plate 15, in the metal plate stacking step, the said The embossing 21 of one metal plate 13 and the embossing 25 of the other metal plate 15 may all be arranged in parallel at equal intervals.

Therefore, the stress of extending the material (metal plate) is more evenly distributed in the welded portion. Therefore, the warp deformation that may occur in the metal plate after seam welding can be more easily suppressed.

The present invention is not limited to the above-described embodiment, and various modifications and modifications can be made.

For example, in the above-described embodiment, the outer surface of the embossed 21 and 25 is formed in a spherical crown shape, but the outer surface shape of the embossed 21 and 25 is not limited and may be a convex portion protruding toward the surface side.

3 Upper roller electrode (pair of roller electrodes)
7 Lower roller electrode (pair of roller electrodes)
11 Two metal plates 13 One metal plate 15 The other metal plate 21,25 Embossed 23,27 General part

Claims (4)

A seam that seam-welds the two metal plates by sandwiching them between a pair of roller electrodes with the two metal plates overlapped and rotating the roller electrodes while energizing the pair of roller electrodes. It is a welding method
An embossing step of forming a plurality of embosses on each of the two metal plates, which are arranged in parallel at predetermined intervals along the welding line and project toward the surface side of the metal plate.
With respect to the two metal plates, the surface of one metal plate and the surface of the other metal plate are opposed to each other so that the embossing of one metal plate and the embossing of the other metal plate face each other, and one of them is overlapped. A metal plate stacking process in which the embossing of a metal plate and the embossing of the other metal plate are arranged in parallel along the welding line,
The two metal plates are sandwiched between the pair of roller electrodes, the roller electrodes on at least one side of the pair of roller electrodes are rotated, and the pair of roller electrodes emboss one metal plate and the other metal. A welding process in which seam welding is performed along multiple embosses of a metal plate while crushing the embossing of the plate.
Have a,
The surface of the one metal plate has the embossing and a general portion other than the embossing.
The surface of the other metal plate has the embossing and a general portion other than the embossing.
In the metal plate stacking step of superimposing the surface of one metal plate and the surface of the other metal plate facing each other, the embossing of the one metal plate is arranged so as to face the general portion of the other metal plate. A seam welding method, characterized in that the embossing of the one metal plate and the embossing of the other metal plate are alternately arranged along the welding line . A seam that seam-welds the two metal plates by sandwiching them between a pair of roller electrodes with the two metal plates overlapped and rotating the roller electrodes while energizing the pair of roller electrodes. It is a welding method
An embossing step of forming a plurality of embosses on each of the two metal plates, which are arranged in parallel at predetermined intervals along the welding line and project toward the surface side of the metal plate.
With respect to the two metal plates, the surface of one metal plate and the surface of the other metal plate are opposed to each other so that the embossing of one metal plate and the embossing of the other metal plate face each other, and one of them is overlapped. A metal plate stacking process in which the embossing of a metal plate and the embossing of the other metal plate are arranged in parallel along the welding line,
The two metal plates are sandwiched between the pair of roller electrodes, the roller electrodes on at least one side of the pair of roller electrodes are rotated, and the pair of roller electrodes emboss one metal plate and the other metal. A welding process in which seam welding is performed along multiple embosses of a metal plate while crushing the embossing of the plate.
Have,
The surface of the one metal plate has the embossing and a general portion other than the embossing.
The surface of the other metal plate has the embossing and a general portion other than the embossing.
In the metal plate stacking step of superimposing the surface of one metal plate and the surface of the other metal plate facing each other, the embossing of the one metal plate is arranged so as to face the general portion of the other metal plate. And
The plurality of embosses on one of the metal plates are all arranged at equal intervals.
The plurality of embosses on the other metal plate are all arranged at equal intervals at the same distance as the embossing intervals on the other metal plate.
By arranging the embossing of one of the metal plates so as to face the central portion of the adjacent embosses on the other metal plate,
A seam welding method characterized in that, in the metal plate stacking step, the embossing of one metal plate and the embossing of the other metal plate are all arranged in parallel at equal intervals . The seam welding method according to claim 1 or 2 .
A seam welding method characterized in that the outer surface of the emboss is formed in a spherical crown shape. The seam welding method according to any one of claims 1 to 3 .
A seam welding method characterized in that the embossing of one metal plate and the embossing of the other metal plate are all formed at the same height.

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