Welding Condition And Mechanism Of Activation Of Stainless Steel Single-component Flux A-TIG Welding

TIG welding can be used in precision welding and high-quality welding occasion, which can obtain high quality weld and has been extensively used in production. But it has low penetration in a single weld and low productivity and its penetration is sensitive to composition of material . Activating TIG welding (A-TIG welding)is a new welding method in order to overcome these disadvantage, which can increase penetration greatly and decrease the sensitivity of penetration to composition of material and increase welding productivity.The purpose of the paper was to investigate 1Cr18Ni9Ti austenite stainless steel single-component flux A-TIG welding. The flux Cr₂O₃ which can greatly increase penetration is selected to be applied in welding process. Influence of welding current, arc length and welding speed to the appearance of the arc and the weld has been studied. Flux Cr₂O₃, SiO₂, MgO, Al₂O₃, NaF, TiO₂, CaO, NaHCO₃, CaCl₂, ZrO₂, Fe₂O₃, CaF₂, NaCl, Titanium powder and Y₂O₃ are selected to be applied.Influence of flux composition to the appearance of the arc and the weld and microscopic structure of the weld was studied, and then the mechanism of activation was studied.The experimental results show that the effect of flux build up with the increase of welding current when the arc length is lmm and welding speed is 9m/h. The flux can slower the change of penetration when the arc length is changed. When the arc length is lmm the effect of the flux and the weld is the best. Arc voltage ,welded width and penetration changed not too much when the welding speed is increased. The penetration ratio didn't change much . Cr₂O₃, SiO₂, MgO, Al₂O₃, TiO₂, NaF can greatly increase the penetration and the penetration ratio.flux Cr₂O₃, SiO₂, NaF, MgO, Al₂O₃ and the flux Y₂O₃, CaF₂ which can decrease the penetration can all make the arc constricted. Arc constriction is a main cause of increase of penetration ,but not the only cause.The change of weld figure and dimension is correlate to both the change ofliquid metal surface tension and the change of the dimension of the arc.Theinteraction of arc and metal can be characterized by the required balanced offorces in the welding zone.