화학공학소재연구정보센터
Materials Science Forum, Vol.426-4, 4087-4092, 2003
Effect of activating fluxes on the penetration capability of the TIG welding arc: study of fluid-flow phenomena in weld pools and the energy concentration in the anode spot of a TIG arc plasma
Increase in depth of weld bead penetration has been demonstrated using gas tungsten arc process (TIG) with activating fluxes composed of oxides and fluorides (A-TIG). However, the mechanism of increasing the penetration are no commonly agreed. In order to explain and clarify theses mechanisms, the weld pool have been studied and in particular the activity of surfactants include in flux have been demonstrated. Furthermore, the constriction observed in the plasma arc have been analysed by Spectroscopic measurement in order to demonstrate the activity of halides in the constriction arc phenomena. These two mechanisms are generally founded in literature, the present work evaluates the capability to separate these two phenomena and demonstrates the role of each other. The effect of flux constituents on the weld pool has been proved. Indeed, the detection of oxygen in weld pool after welding, which is a great surfactant, explains the modification of convection current (Marangoni effect). Spectroscopic analysis of arc during A-TIG welding has proved that anode roots are strongly related to metal vapours from the weld pool and electronegative molecules vaporised from the activating fluxes, in particular fluorides and chlorides radicals.