OBRABOTKAMETALLOV technology Vol. 26 No. 2 2024 UShS-3. The root seam was welded without separation using a reverse polarity welding current of 90 A (see Fig. 3, a, b). The next layer of the weld is the filling layer. Welding was carried out with a welding current of reverse polarity 90 A, as when welding the root weld. It took two electrodes to fill, which allows us to conclude that welding was carried out with separation (see Fig. 3, c). As can be seen from the photo of the root weld (see Fig. 3, a) there is no sputtering of metal on the specimen; slag is difficult to remove only after cooling using an angle grinder (see Fig. 3, b). When welding the filler layer, excessive spattering of molten metal is visible. Removing flash spatter using a welder’s hammer is difficult. Flash sputter and slag after welding can only be removed mechanically. Before welding the facing seam, the specimen was completely cleaned of flash sputter. When making a facing seam, as well as during the root and filling seams forming, there was unstable arcing. The facing seam required 3 electrodes (see Fig. 3, d). As in the case of the filling layer of the seam, welding was carried out with a separation between electrode replacements. The current parameters were the same as in the case of welding the root and filling layers of the seam. On the facing seam, as well as on the filling seam, a fairly large amount of sputtering is visible, which is also a signs of a defect. The flash sputter was removed in preparation for further testing for the mechanical properties of the weld overlaid metal using only an angle grinder. The slag on the facing seam was removed with difficulty using a welder’s hammer, since the impact of an angle grinder on the facing layer of the weld seam is prohibited. Fig. 2. Formation of a fingernail after welding on TMU-21U electrodes produced by “Sudislavsky Welding Materials Plant”, LLC a b c d Fig. 3. Appearance of the welded seam after filling with TMU-21U electrodes: a – the root of the seam; b – the root of the seam after stripping with a machine; c – the filling seam; d – the facing seam
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