PURPOSE: To decrease the defects to be produced by the unstable state in the initial period of welding in TIG welding considerably by controlling arc current, as well as the feed rate and inserting position of a wire and growing the pool in the initial period of welding stably.
CONSTITUTION: As shown in a time chart of the figure, an arc is generated and after a few seconds of conduction of initial electric current, a carriage is started; at the same time, the arc current and the feed rate of a wire are increased gradually. The arc current and the feed rate of the wire are so increased that both attain the prescribed values in a regular welding state in a few seconds after stabilization of the pool. Therefore, the wire feeding of the rate conforming to the size of the pool is made possible, and it is possible to feed the wire to fill recesses while taking balance with the digging of the pool despite the use of the high current. Further the arc voltage is controlled from right after the end of the initial current and the set voltage is beforehand set at the value at which the adequate arc length of the arc current in the regular welding state is attained.
WATARIDO MASAYUKI
SHIINA IKUO
OOWAKI KATSURA
SAITOU TATSUO
