혼합가스가 STS304의 TIG 아크용접에서 용접성에 미치는 영향

The Effect of Mixing Gas on Weldability in TIG Arc Welding of STS304

The effect of mixing gas on weldability in TIG arc welding of STS304 was studied in this thesis. Under four kinds of mixing gas such as Ar100%, Ar-3%H2, Ar-5%H2, Ar-7%H2 the penetration and machanical properties were investigated. The penetration and microstructure, hardness and tensile strength were observed from bead-on-plate welding and X-groove(1pass, thickness-6㎜) butt welding specimens. The results were as follows; 1) From TIG arc welding using mixed gas with hydrogen, welding voltage and penetration increased as hydrogen increasing, compared to oure as gas condition. 2) The hardness value of H.A.Z was higher than base metal and weld matal.(base metal>weld metal. 3) Tensile strength was higher under pure Ar gas condition than mixed gas conditions. As conten of hydrogen increasing, the tensile strength was decreased.