Bilous V. Management of formation of the seam at welding of titanium-base alloys in the narrow-gap by the tungsten electrode with magnetically-impelled arc.

The work is dedicated to investigation of peculiarities of the processes occurring in narrow-gap welding with application of the controlling magnetic field, which is used to control deviation of the welding arc and regulate melting of the vertical walls of the gap. The effect of parameters of the controlling magnetic field on movement of the arc inside the narrow gap and weld formation was evaluated. Principles of movement of the anode spot inside the narrow gap under the effect of the external controlling magnetic field were established. The decisive role of gas-dynamic pressure of the arc plasma on surface of the molten metal in excitation of transverse oscillations of the weld pool metal and its wetting of the vertical edges was revealed. It was found that the tungsten electrode for narrow-gap welding using the external controlling magnetic field should have a tip of the special shape. The investigations conducted resulted in the development of technological recommendations for narrow-gap welding ofstructures of titanium alloys PT-3V and VT23, 20-100 mm thick, by using a forming backing, which provide the absence of such defects in the welded joints as lacks of fusion between the side walls and between the weld and base metals, and guarantee a high level of mechanical properties of the welded joints.