Mash seam welding method and device

Abstract

In order that in mash seam welding for metal plates with a thickness exceeding 2 mm, the joint strength is stabilized, the difference in the level of a joint part is reduced, high joint strength and reliability are ensured, and therefore metal plates with a thickness exceeding 4.5 mm can be also joined, two metal plates (5, 6) are grasped by first and second graspers (7, 8), respectively, ends of the two metal plates (5, 6) are overlapped , an overlap (L) therebetween is pressurized by a pair of upper and lower electrode wheels (1, 2) and continuously welded while a welding current is being passed to thereby join the two metal plates. While the overlap (L) is continuously welded while the welding current is being passed, welding pressure to be applied to the upper and lower electrode wheels (1, 2) is controlled such that upper and lower pressing forces acting on the overlap become equal.

Description

technical field [0001] The present invention relates to a mash seam welding method and device for joining two thick metal plates. Background technique [0002] Pressure seam welding is a welding method that overlaps the ends of two metal plates, pressurizes the overlapped part with a pair of electrode wheels, turns on the welding current, and performs welding continuously. The joint part heated to a high temperature state and softened is rolled, thereby reducing the thickness of the joint part. [0003] As the prior art of a mash seam welding apparatus for joining thick metal plates, for example, the techniques described in Patent Document 1 and Patent Document 2 are known. [0004] In Patent Document 1, the following problem is proposed as a problem in the case of joining thick metal plates: as in Patent Document 1, Figure 13 As shown, the sheet metal (the material to be welded) must be bent quite extreme, which exerts considerable force on the clamping device, thus causi...

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Problems solved by technology

[0004] In Patent Document 1, the following problem is proposed as a problem in the case of joining thick metal plates: as in Patent Document 1, Figure 13 As shown, the sheet metal (the material to be welded) must be bent quite extreme, which exerts considerable force on the clamping device, thus causing the clamping device to deform or even break

[0005] In Patent Document 2, as a problem in the case of joining high-strength steel plates, the following problems are raised: Referring to FIG. 20) is in contact with the electrode wheel, so the damage caused to the electrode wheel is relatively large, and because the welding current is concentrated at the corner of the lower metal plate (21 of Figure 8 of Patent Document 2), welding spatter (corner part The phenomenon that the current density is excessive, so that the melting is scattered, and the sputtering remains on the metal plate), and good welding results cannot be obtained.

Similarly, in the case of joining thick metal plates, the current needs to be increased due to the increase in the volume of the joint, and the pressing force of the electrode wheel must be increased because the rigidity of the metal plates becomes higher. The same principle will produce the same problem in the situation

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