Effect of Flux Density and Addictive Presence on ATIG Welding of Austenitic Stainless Steel

• Published in: Soldagem e Inspecao / Welding and Inspection Vol. 18; no. 2; pp. 118 - 126
• Main Authors: Modenesi, Paulo J, Neto, Pedro Colen, Apolinario, Eustaquio Roberto, Dias, Kassia Batista
• Format: Journal Article
• Language: Portuguese
• Published: 01.06.2013
• Subjects: Austenitic stainless steels; Beads; Electric potential; Penetration; Voltage; Weld metal pool; Welded joints; Welding
• ISSN: 0104-9224
• DOI: 10.1590/S0104-92242013000200005

Active fux TIG (ATIG) welding is a simple variant of conventional TIG welding that allows a major improvement in weld bead penetration. Different mechanisms have been proposed to explain the effect of fux. The most accepted ones consider the arc contraction by negative ions vaporized from the fux and liquid metal fow alterations in the weld pool caused by changes the surface tension values. This paper evaluates the effect of one component (Cr(2)O(3)) fux concentration and additions of KClO(4) and Al(2)O(3) on ATIG welding bead shape. Three sets of bead-on-plate weld tests were performed on 5 mm thick AISI 304 steel plates. Electric current and voltage were measured during each welding trial and the resulting bead geometry was evaluated in cross sections of the weld. Results indicated only minor variations in voltage during the transition from TIG to ATIG welding. Surface fux concentration affected weld bead penetration, and maximum penetration was obtained with fux densities between 15 and 60 g/m(2). On the other hand, the addition of KCLO(4), despite this being a strong oxidizer, reduced weld penetration. A similar effect was linked to additions of Al(2)O(3) to the fux.