Abstract
Active flux can modify the fusion zone geometry dramatically in GTA welding (A-TIG). In the present study, in order to investigate the effect of the active flux on the Marangoni convection in the welding pool, bead-on-plate specimens are made on SUS304 stainless steel pre-placed with single active flux, Cu2O, NiO, Cr2O3, SiO2 and TiO2 by the GTA process. Weld pool cross-sections and the bead surface morphology are analyzed by optical microscopy after welding. The oxygen content in the weld metal is measured using a HORIBA EMGA-520 Oxygen/Nitrogen Analyzer. The results showed that the depth/width ratio of the weld pool was closely related to the oxygen content in the pool. The oxygen content in the weld metal increases with the quantity of fluxes, Cu2O, NiO, Cr2O3, SiO2 and TiO2. However, for the TiO2 oxide flux, the highest oxygen content in the weld metal is below 200 ppm. As the oxygen content in the weld metal is in a certain range of 70–300 ppm, the depth/width ratio increases to 1.5 to 2.0 times. Too low or too high oxygen content in the pool does not increase the depth/width ratio. The oxygen from the decomposition of the flux in the welding pool alters the surface tension gradients on the weld pool surface, and hence, changes the Marangoni convection direction and the weld pool penetration depth.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
