On the Thermal and Electrical Characteristics of the Hybrid Plasma-MIG Welding Process

Abstract

The theoretical analysis of the influence of the plasma discharge temperature with non-consumable electrode on the melting of the electrode wire was carried out. The dynamics of the melting of the electrode wire and dynamics of circuit with consumable electrode arc were been investigation. The estimation of maximum values of the temperature of plasma have been made. Influence of the MIG process on the volt-ampere characteristics of the plasma discharge have been studied. These results were used for carrying out the technological experiments.

Hybrid welding of aluminium 1561 and 5083 ALLOYS USING Plasma-arc and consumable electrode arc (plasma-MIG)

“…In addition, the plasma-arc helps to eliminate undercuts and create a smoother transition from the upper bead to the base metal. An increase in voltage on the arc of the nonconsumable electrode predicted in [12] with an increase in the consumption of plasma-forming gas (from 5 to 25 l/min) was confirmed in practice and amounted to about 1−2 V, which is not a quite significant index, but in general has a positive effect on weld formation.…”

“…During welding of aluminium alloys with a thickness of 5−12 mm, it can be about 7300−7400 K. This indicates the danger of burnout low-melting alloying elements that are a part of the electrode wire and the base metal, which can lead to weakening of the produced joints. In addition, in [12] a tendency of increasing the voltage on the arc of the nonconsumable electrode with an increased flow rate of the plasma-forming gas and its temperature is observed. Such a feature of the hybrid process should be taken into account when selecting welding modes, in particular, optimizing the power ratio of plasma and arc components.…”

“…Reduction in the plasma current density can contribute to arising spattering of the metal by the arc of the consumable electrode. In [10,12] the peculiarities of the behavior of both electric arcs, their influence on each other, on the formation of a liquid metal drop and the process of mass transfer were studied quite deeply.…”

“…The model of heating the electrode wire in the process of hybrid plasma-arc welding using consumable electrode (Plasma-MIG) proposed in [12] allowed carrying out a preliminary evaluation of the plasma temperature of an integrated gas discharge. During welding of aluminium alloys with a thickness of 5−12 mm, it can be about 7300−7400 K. This indicates the danger of burnout low-melting alloying elements that are a part of the electrode wire and the base metal, which can lead to weakening of the produced joints.…”

Comparing features in metallurgical interaction when applying different techniques of arc and plasma surfacing of steel wire on titanium

“…Given the high enough thermal locality, this technology is also of interest for research. Soft (that is weakly compressed) plasma arc of variable polarity is usually used to solve tasks related to welding aluminum alloys [15,16]. The process of surfacing with soft plasma (more precisely, plasma surfacing with an indirect arc with a conductive filler wire) has a reduced arc pressure, which helps maintain a stable keyhole in the welding bath.…”