Poklyatsky A. Peculiarities of formation and methods of prevention of oxide inclusions in welds in welding of aluminium alloys by pulsate arc.

The thesis is devoted to find and to elaborate of the technological methods for reduction of the extent of oxide film inclusions in welds and to improve the quality of welded joints of aluminium alloys, produced by TIG welding in argon. It provides theoretical substantiation and experimental confirmation of the fact that use of asymmetrical square-wave current with prevailing current amplitude at straight polarity and current duration at reverse polarity promotes a deeper immersion of the arc into the molten metal, activation of the processes of cathode breaking up of the oxide film, intensification of the convective flows in the bottom part of the weld pool and mechanical breaking up of oxide inclusions. Practical application of the developed technological processes of prevention of oxide film inclusions allows a significant reduction of the length of defective sections in welds, provision of stable high mechanical properties of welded joints and reducing the repair cost in making of critical products of alloy AMg6.