Effect of Ternary Fluxes on Depth of Penetration in A-TIG Welding of AISI 409 Ferritic Stainless Steel

Abstract

TIG welding is a preferred process for producing quality weld joints. However, because of its characteristic shallow depth of penetration, productivity achieved by this process is low. Depth of penetration of conventional TIG welding can be improved by Activated TIG (A-TIG) welding. In A-TIG welding, a thin layer of flux comprising mixtures of oxides, fluorides and chlorides is applied in the area to be welded to obtain two to three fold increase in depth of penetration. In this study, three single component fluxes viz., SiO2, TiO2 and Cr2O3 were employed for welding of AISI 409 ferritic stainless steel. Experimental trials were designed for the use of ternary fluxes. From the obtained results on bead geometry, using Minitab 16 software coupled with Matlab R2010 an optimum combination of these fluxes for maximum penetration was estimated. Confirmation test showed that two fold increase in depth of penetration could be achieved in A-TIG welding by using this flux combination over conventional TIG welding.