Résumé
Welding is a key process in nuclear industry. The use of this assembly process is needed to ensure chemical and physical continuity required for installations safety. For the firm AREVA, one of the major axis of development is improving the productivity of nuclear components with the guaranty of optimum quality.Experimental approach presented in the present work has the double objectives of proposing a monitoring device for temperature fields of liquid metal and characterizing its dynamic behavior in GMAW. A two color measurement method has been developed for in-situ surface temperature measurement of liquid zones. First tests realized in an industrial configuration allow to consider this method as a possible real-time control device for welding. This two color pyrometer, coupled to the observation and the study of droplets deformations during their transfer, allows to study the influence of temperature on surface tension, with the interaction of arc plasma. Main role of surface tension on liquid phase behavior is clearly exposed in the obtained results. The developed investigating and analysis tools have been used to study a GMAW controlled short arc process. So, it is possible to analyse liquid bridge rupture, but also liquid metal deposition behavior, which can induce shape defects, and mass transfer dynamic to identify the apparition of operative defects.