وزارة التعليم العالي و البحث العلمي

Research center in Industrial Technologies -CRTI-

Near electrodes phenomena


High temperature phenomena detection and welding processes [2016-2018]

Welding is an energetic process characterized by strong gradients of temperature, current density and particles. In particular, in the vicinity of electrodes where a difference in the local thermodynamic equilibrium, ETL, is found as well as the coexistence of several states of matter: Plasma (fourth state of matter), liquid (second state of matter).
the formation of a plasma and its attachment to the electrodes are accompanied by a significant release of heat characterized by high temperatures thus enabling the formation of various phases requiring such an order of magnitude of energy, in particular the formation of which play an important role in the behavior of high temperature materials such as viscosity, wettability and electrical conductivity. On the other hand, the installation of strong temperature gradients predominates, at the same time, the role of the forces of surface tension and accentuates the effect of the Marangoni forces.
Therefore, it is necessary to integrate the phenomena in the vicinity of the electrodes during the establishment of the welding processes in order to better control the appearance of the phases forming the oxide layers thus allowing a better transfer of the metal on the side of the welding wire and better fluidity and wettability on the side of the melt. Thus, taking into account, at the same time, the phenomena in the vicinity of the electrodes and the various variables related to the innovations materials (aluminum alloys, titanium alloy, stainless steels, composite materials ...) and to the imposed design, we can answer the requirements of the new applications of welding technologies and related techniques increasingly binding in the industry such as the automotive industry, the steel industry, the shipbuilding industry, the oil industry ... require a deep understanding of the phenomena in the vicinity of the electrodes where the arc plasma penetrated by strong welding currents.

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