HEURISTIC STUDY OF SINGLE COMPONENT AND BINARY FLUXES ON THE DEPTH OF PENETRATION IN A-TIG WELDING OF INCOLOY 800H AUSTENITIC STAINLESS STEEL

A-TIG welding differs from conventional TIG welding process by the way of employing a thin layer of flux in the area to be welded. The flux can be a single component salt or a mixture of multiple salts. Usually these salts are of oxides, chlorides or fluorides. Use of these fluxes improves depth of penetration by two to three times in relation to the depth of penetration that can be achieved by conventional TIG welding. Though several mechanisms have been proposed for the improvement in depth of penetration, arc constrictions and/or reversal of Marangoni forces are considered as major influencing factors. The present aims to study the effect of single component fluxes viz., SiO2, ZnO and a combination of SiO2 and ZnO on the weld bead geometry in TIG welding of Incoloy 800H austenitic stainless steel. To study the effect of combination of these salts as flux mixture on the bead geometry several ternary flux mixtures were designed and used in producing autogenous TIG melt runs.