| abstract |
The invention provides a mash seam welding method and equipment. A pair of upper and lower electrode rings (1, 2) are arranged such that their axes (17, 18) incline in the opposite directions in a horizontal plane against a line (Y) perpendicularly intersecting a welding line (X) formed at the overlapping portion (L) of two metal plates (5, 6), and mash seam welding is performed while driving the electrode rings (1, 2) positively by means of electric motors (61, 62). Consequently, increase in thickness and level difference gradient can be reduced remarkably at the joint, and high joint strength can be assured by reducing stress concentration coefficient. Furthermore, a nugget (N) is jointed not to come off from the joint interface. The axes (17, 18) of the electrode rings (1, 2) incline in such a direction as the advancing direction portions (1A, 2A) of the electrode rings (1, 2) are directed to the direction where a metal plate touching the electrode rings (1, 2) at first exists in the horizontal plane. Consequently, the end portion of the metal plate at the overlapping portion (L) can be prevented from biting into the electrode rings (1, 2) to cause a flaw thereto or generation of dust can be prevented at the time of welding. |