Lendiel I. GMA surfacing in carbon dioxide with pulse feeding of electrode wire

The thesis is devoted to improving the efficiency of GMA surfacing in CO2 by applying the pulse feeding of electrode wire (PFEW), improving its technological and power characteristics, study of electrode metal transfer under the force of inertia, determination of influence of PFEW parameters on geometric and service characteristics of the deposited metal bead, resources and power saving. From the point of view of minimizing the penetration depth of base metal and electrode metal losses the rational range of change in PFEW parameters for surfacing process was determined which amounted to the frequency of 10…30 Hz and the duty cycle of 3...5 units. The influence of arc discharge of reverse polarity at PFEW on electrode metal transfer was investigated, the unique procedures were developed, the regression mathematical models for prediction of geometric parameters (convexity, width, penetration depth of base metal, mating angle) of deposited metal bead, electrode metal losses and power consumption were obtained and verified depending on the PFEW parameters. The evaluation of wear resistance of deposited metal, stress-strain state in HAZ and sanitary-hygienic characteristics was carried out. The evaluation of stability of welding process at PFEW, carried out according to the coefficient of variation and the mean square deviations, showed the improved results as compared to the continuous electrode wire feed. The new approach was presented, according to which the PFEW mechanism was created, where the high-speed, quick-response switch reluctance electric drive is used as a drive. The principal possibility of resource-saving and cost-effective repair and restoration of parts in the industrial conditions was shown.