Abstract: A semi-automatic hot wier TIG (Tungsten Inert Gas) welding equipment comprising: a portable TIG arc torch; a portable filler wire feed torch; a hot wire switching power source for energizing the TIG arc torch, the filler wire feed torch and a base metal; a filler wire feeding device for feeding the wire to the wire feeding torch at a desired rate; a welding condition control device for controlling wire heating power so as to provide wire heating power commensurate to the wire feed rate; means for measuring the resistance value of the wire extension section between the terminal end of the wire and the terminal end of the filler wire feed torch; and means for controlling said filler wire feeding means to change the wire feed rate in response to the detected wire extension.

Abstract: A hot wire TIG welding apparatus has a current detector for detecting the peak period and base period of the arc current. The welding apparatus further has a controller which controls, in response to the detection signal from the current detector, the operation of the wire heating power supply such that the wire heating power is supplied only during the base period of the arc current. According to this arrangement, a hot wire switching TIG welding apparatus can be produced using commercially available power supply systems for TIG arc welders, without requiring substantial change or modification of the control circuits in the TIG arc welders.

Abstract: A hot-wire TIG welding apparatus capable of performing a stable welding regardless of change in the welding conditions. The welding apparatus comprises a hot-wire feed speed control means for controlling the speed of feed of a hot wire, and a heating power control means adapted to control the electric power for heating the hot wire. The condition of the control in either one of the control sections is changed in accordance with a change in the control condition of the other.