METHOD AND APPARATUS FOR AUTOMATIC ARC WELDING IN A VERTICAL POSITION

A method of arc welding in a vertical direction and an arc-welding machine for automatically performing the steps of the same are provided. According to the arc welding method of the invention, the advancement of a consumable electrode wire is accelerated and the welding voltage of the welding torch is increased as the torch crosses the centerline of a generally vertically extending weaving pattern it is caused to follow during a welding operation. After passing the centerline, the voltage is decreased to its original level, as it is on the return stroke also. This method is further improved by increasing the welding current of the torch slightly after increasing the welding voltage and further by decelerating or stopping the weaving motion at both sides and at the center of the weaving path of the wire. The apparatus for automatically carrying out this arc welding method comprises, in conjunction with an advancing consumable electrode wire and a welding torch adapted to follow a weaving path in a generally vertical direction, means for changing certain of the welding conditions, such as the advancing speed of the metal wire, the welding voltage and current, the weaving speed, and means for aligning the centerline of the weaving path or width to the welding centerline of a base metal.