Study On The Mechanism Of Welded Form With CO₂Welding Of Short-circuit Transfer In Longitudinal Magnetic Field

Welding with magnetic field is more and more perfect in recent years as a new welding technology, its application is becoming increasingly widespread. Arc can act with the magnetic field, has electrical quasi-neutral and electrical conductivity which is composed of the ion with positive and negative charge and the electrons. So the running and shape of the arc can be controlled by external magnetic field, metal transfer in the arc also can be impacted by external magnetic field; external magnetic field can also change the direction of crystal grains, refine organizational, reduce segregation and improve the mechanical properties of the weld; reduce pores, cracks and other defects of the sensitivity; and effectively reduce residual stresses. Therefore, the welded joints can be improved by adding the appropriate quality of magnetic field.Based on this, the paper, with low carbon steel Q235as the experimental object, under different welding technology parameters in the longitudinal magnetic field with a plus the CO2welding of comparative experiments, and by changing plus dc longitudinal magnetic field, which explores the CO2welding under the action of plus dc longitudinal magnetic field. The paper, by means of advanced high-speed video dynamic arc welding process monitoring tools; arc behavior and short circuit behavior of CO2welding in longitudinal magnetic field applied dc was monitored, at the same time, real-time welding current and welding voltage value was captured using Hannover Quality Analyzer; The arc behavior, the frequency and the shape of the short-circuit transfer was studied, and their regularities under longitudinal magnetic field were summing-up. The mechanism of welded form in longitudinal magnetic field was explored. They lay a solid foundation to research the mechanism of short-circuit transfer of CO2welding under longitudinal magnetic field. The results show that under the certain welding specifications, puls dc longitudinal magnetic field has certain effect on arc welding, short-circuit transfer and welded form in the short-circuit transfer process of CO2welding; under the welding process parameters in this experiment, When the excitation current is at OA-0.5A range, the shape of arc gradually expands, short-circuit transfer frequency gradually increases; when the excitation current is at0.5A-1.5A range, the shape of arc gradually contracts, short-circuit transfer frequency gradually decreases; under the role of the external longitudinal magnetic field, the depth of fusion first increases then reduces, the width of fusion first increases then reduces, and the pile of fusion first increases slightly then reduces; under the welding process parameters in this experiment, there is a best parameter of the magnetic field, When the excitation current is at0.5A, the shape of the arc has obvious expansion and assumes bell-shaped shape, short-circuit transfer frequency is the largest, the depth of the fusion is the largest, the width, pile of the fusion moderates, and welded form is the best.