Research On The Effect Of The Parameters On Arc Stability Of Rotating TIG Welding

The rotating TIG welding is a kind of welding method that uses rotating arc sensor on TIG welding. It not only has the advantages of general TIG welding, but also can track the weld seam, and it is easy to realize the welding automation, has more and more broad application prospects. Arc is used to heat base metal and welding wire directly in the rotating TIG welding, and then weld seam forms. So the shape, behavior and stability of welding arc have important effects on the welding process and quality.In this paper, firstly, a mathematical model of welding arc that is suitable for rotating TIG welding arc and non-rotating TIG welding arc is built based on MHD theory and some assumes. The difference is whether the centrifugal force is need to be added when calculating. Commercial CFD software FLUENT is used to simulate and the function of FLUENT is developed secondly by UDF functions. Then the arc temperature field, velocity field and pressure field of rotating TIG arc and non-rotating TIG arc are simulated respectively. It is found that the shape,temperature, velocity and pressure of rotating TIG arc plasma and non-rotating TIG arc plasma arc have no significant difference by contrast, and the rotation of arc doesn't have obvious effect on welding arc, because the stiffness of TIG welding arc is very good, and the centrifugal force can be ignored in contrast with the electromagnetic force. A high speed camera platform is built to prove the results of simulation, and it is found that the results of experiment are in high agreement with the results of simulation.Six parameters are selected to research the stability of rotating TIG arc in this paper, they are welding voltage, welding current, welding speed, the gas flow,rotational frequency and the tungsten extended length. The pictures of welding process are obtained by the high speed camera platform, and the cycle diagrams of current and voltage are obtained by the multi-channel data acquisition system. The results show that the additional welding wire can influence the shape of rotating TIG arc obviously; Welding voltage, welding current and rotational frequency of arc haveobvious effect on the stability of rotating TIG arc. Within the range of experiment parameters in this paper, the stability of rotating TIG arc will decrease with the increase of welding voltage and rotational frequency, and the stability will increase with the increase of welding current. Welding speed, the gas flow and the tungsten extended length don't have much effect on the stability of rotating TIG arc.