A Study of the Performance of Dissimilar A-TIG welds

Abstract

The performance of dissimilar activated tungsten inert gas (A-TIG) welding on the welds morphology, angular distortion, and mechanical properties in dissimilar metal plates were investigated. Autogenous TIG welding process was applied to the JIS G3131 mild steel and type 316L stainless steel through a thin layer of activating flux to produce a butt-joint weld. CaO, SiO2, Fe2O3, and Cr2O3 fluxes were used as the activating fluxes. The experimental results indicated that the SiO2, Fe2O3, and Cr2O3 fluxes can increase joint penetration in both of the 316L stainless steel and the JIS G3131 mild steel. The CaO flux only can increase the joint penetration of the mild steel. The reversed Marangoni convection are considered to the main factors for increasing penetration of A-TIG on dissimilar welds in this study. Furthermore, TIG welding with SiO2 powder can significantly reduce the angular distortion and increase the tensile strength of the dissimilar weldment.