The arc-welding method and arc-welding joint of Zn system plating steel plate

摘要

A method of arc welding is described which suppresses the occurrence of bubbles in the start and end portions of welding on galvanized sheet steel, and reduces the occupancy rate of bubbles in the welded part as a whole and in a welded joint. The arc welding method for a galvanized sheet steel defines a sheet spacing of 0.2 to 1.5 mm, and includes a first step of moving welding media from a welding start point to a first welding speed, and performing welding by applying a first welding heat insert; a second step, after the first step, of moving the welding means to a second welding speed, and performing welding by applying a second welding heat insert; and a third step, after the second step, of stopping the movement of the welding means, and performing welding for 0.1 to 2 seconds at that stopping position. The first step includes welding being performed in a welding unit under conditions where the first welding speed is lower than the second welding speed, and the first welding heat insert exceeds the second welding heat insert. In the third stage, welding is performed with a lower welding current and welding voltage than those of the second stage.