Effect of Activated Flux on TIG Welding of 304 Austenitic Stainless Steel

Autogenous bead on plate (BOP) welding was performed on 3 mm thick AISI 304 stainless steel plate by flux activated TIG (A-TIG) welding and conventional TIG (C-TIG) welding process. TiO2, Al2O3 and CaF2 were employed as flux material, and their effect on the weld geometry, microstructure and micro-hardness value were analysed and compared with the C-TIG welding method. The experimental results showed that weld penetration depth enhanced approximately 75% for using TiO2 and 10 % for Al2O3 as compared to C-TIG welding; whereas, for using CaF2 the weld penetration depth reduced marginally Although the width of the A-TIG welded samples were higher than the C-TIG welded sample, it was evident that the weld aspect ratio improved significantly for using TiO2 as flux material. The micro structural analysis showed that spacing between the skeleton ferrite and the size of lathy ferrite structure is more for using TiO2 as activated flux. (C) 2019 Elsevier Ltd. All rights reserved.