In the present paper, a new type GTA welding system using a hollow tungsten electorode is proposed to ignite and sustain a welding arc in a vacuum like the open space. In the developed system, Ar gas for discharge is supplied to arc space through the hollow tungsten electrode.
The results of the present work are summarized as follows,
(1) Even in a low pressure condition, a small quantity of Ar gas flow can ignite and sustain an arc discharge and the arc can melt the base metal.
(2) In a low pressure condition, a stationary arc follows a transient arc. The period of the transient arc discharge increases with the decrease of Ar gas flow rate.
(3) With the decrease of Ar gas flow rate, the arc voltage increases and the penetration of base metal (stainless steel) increases in size.
