| 摘要 |
PURPOSE:To perform stable joining of superposed plates and efficient arc spot welding by forming a plug hole to the upper plate of the superposed plates by the current having a reversed polarity then passing the current having a straight polarity and filling the plug hole with the molten metal of a wire. CONSTITUTION:The side of a welding wire 3 of a consumable electrode let off from a welding wire reel 5 is connected to a positive electrode and the side of materials 7 to be welded which are superposed plates consisting of an upper plate 1 and a lower plate 2 is connected to a negative pole and the current having a reversed polarity is passed thereto by using change-over terminals 6, 8 to form a plug hole 4 to the plate 1 in the initial period of conducting electricity in the stage of subjecting the materials 7 to be welded to arc spot welding by a DC arm welding power source 9 using said wire 3. The current having the straight polarity to make the wire 3 side negative and the material 7 side positive is passed to melt the wire 3 and fill the hole 4 with the molten metal of the wire in the late period of conducting electricity. The stable joining of the superposed plates is efficiently accomplished irrespectively of the presence or absence of the space between the plates 1 and 2. |
