The welding head is a special welding head designed for TIG welding of inner bore tubes and tube sheets. The welding materials can be carbon steel, stainless steel, etc., and the inner hole diameter of the tube sheet is ≥ Φ25mm; according to the needs of the welding process, self-melting, wire filling or first welding can be selected. Filling wire after self-fusing, etc. It can be used together with iOrbital5000 programmable welding power source, which can precisely realize all-position TIG inner hole welding, with high reproducibility of welding results and ideal welding results. It is mainly used for automatic welding of special tube sheet forms in boilers, heat exchangers, electric power construction, chemical industry and other industries.