Study on Low Speed DC-TIG Welding Method(Report 2). Penetration Form and Welding of Practical Joint Using Traveling TIG Arc.

Penetration form and welding of practical joint of SUS 304 in traveling DC TIG arc welding are investigated.Welding bead with large penetration ratio (penetration depth/bead width) can be obtained in low speed welding. In particular, since the anode-spot is fixed at the center of the molten pool in He-DC TIG, deep penetration with narrow bead width is effectively formed.Transition current, in which bead width of face side has the minimum value under penetration bead (uranami bead) formation, increases in Ar arcs as the thickness of the base metal increases. Step movement welding method, in which stationary arc is struck after traveling in a short distance, is effective to obtain stable uranami bead in the plate thickness above 6 mm. Moreover, when flux-cored wire is applied to this method, stability of uranami bead formation is more improved.