Optimizing the design of silica coating for productivity gains during the TIG welding of 304L stainless steel

The performance of silica coatings on TIG (or GTA) welding of AISI304L stainless steel has been studied by investigating the effect of coating geometry and thickness on weld penetrations. Two coating designs are studied. One involves a 20 mm wide continuous coating across the weld zone and the second design formulates two parallel coatings 1–7 mm apart around the joint. The optimum thickness for continuous coatings is limited to about 50 μm whereas for 2 mm apart coatings, the optimum range extends from 70 to 200 μm. The presence of a narrow bare zone in the coating is suggested to be more practical for manual silica application. Tensile tests have been performed to identify the mechanical behavior in different characteristic zones of the welded specimens. The reduced tensile strength of the weld metal is attributed to the flux silica particles.