EXPERIMENTAL RESEARCH OF HYBRID WELDING PROCESSES IN COMBINATION OF GAS TUNGSTEN ARC WITH CO_2- OR YB:YAG-LASER BEAM

摘要

Hybrid welding is a field in welding technology in which several welding procedures are combined to operate in one weld bath. An attempt is being made to combine the positive properties of the processes in a way that synergy effects take place and can be taken advantage of. Comparative experimental analysis of hybrid welding processes is carried out. The used hybrid welding process is a combination of tungsten cathode in argon shielding gas atmosphere and laser beam of different wave lengths (CO_2- and Yb:YAG laser). Both lasers were used in heat transfer mode, without keyhole. To carry out these experiments, a special hybrid welding torch was developed to combine arc and laser heat sources in one common weld pool. Depth of penetration and the area of welds' cross sections for pure TIG, TIG plus CO_2 Laser and TIG plus Yb:YAG laser were compared. High-speed video images (500 frames per second) with synchronized current and voltage recording were used. The experimental results demonstrate a different behavior of the arc in CO_2- and Yb:YAG laser hybrid welding. It is shown that in case of hybrid welding the efficiency of input energy from the arc is higher than the sum of two separately used heat sources.