The Study Of The Characteristics Of Plasma-MIG Complex Arc's Strike And Stabilization

Plasma-MIG welding is a kind of advanced welding method, which uses plasma-arc and MIG-arc burning in the same blowtorch, so that weld-penetration and melting-width are properly distributed, and it can get high welding quality and efficency.In contrast with general welding method of single arc, the forms of Plasma-MIG welding arc are more complicated. In order to analyse the rule of striking the welding arc, this paper made use of ANSYS infinite element analysis software to simulate the fluid and temperature distribution of arc space, and used correlative theory of gas breakdown to compare with practical observation, analysed the rule of striking the welding arc, improved the welding gun of Plasma-MIG, in the end, under various experimental conditions, it made welding experiment.First, through the theory of gas breakdown, under the case of Plasma-MIG complex arcs, it analysed the process of striking the welding arc and arc's stability, and put forward a new method, which made use of Paschen's independent variable Pd/T to determine the position of striking the plasma-arc. Through Paschen's theory, it succeeded in explaining the process how the plasma-arc strikes. Through the simulation of arc spatial fluid and temperature field simulation and comparison of Paschen' s independent variable, it studied the impacts on striking the plasma-arc and arc's stability when in case of various guiding-arc-point's position, dimension, height of weld path , daggling of welding arc and nozzle's drop etc.Secondly, according to the theory analysis, it improved the existing Plasma-MIG welding torch, redesigned the process of striking the welding arc. This torch compresses the double arcs to small-radius's arcs with the same axis, thus in this case, this kind of welding arc has great power of penetration and effect of beating up the melt pool, so it's fit for the welding of almuniu with big thickness.Finally, under various experimental conditions, such as changing MIG's current> MIG's voltage â– > plasma's current etc, it made some welding experiments, and verified the effect of improvement of welding torch.