OBRABOTKAMETALLOV Vol. 26 No. 4 2024 TECHNOLOGY The results of ultrasonic processing tests of the upper bead are shown in Fig. 8. Traces of plastic deformation are visible in the microstructure image (Fig. 8, a). Processing time aff ects the microhardness values (Fig. 8, b). Research and discussion According to numerous studies on welded arc additive manufacturing (WAAM) [2–10,18–28], in order to obtain excellent quality of surfaced metal without any defects, it is necessary to carefully select and implement a combination of process parameters, such as wire diameter, wire feed, travel speed, welding Ta b l e 2 Results of impact bending tests Specimen identifi cation mark Test temperature, °С Geometric dimensions of the specimen Work of fracture (KU), kg/cm Impact strength, (KCU), J/cm2 Note Width, mm Height, mm (at the point of incision) Cross-sectional area, cm2 4 20 9.95 7.94 0.790 15.6 183.5 Surfacing 5 20 9.94 7.9 0.785 14.8 194.7 6 20 10.01 7.92 0.792 21.5 255.7 Surfacing with machining 7 20 9.96 7.95 0.791 21.2 268.3 Steel 0.09 C-2 Mn-Si (GOST) 20 Not less than 59 Steel 0.09 C-2 Mn-Si (Fact) 20 115 a b Fig. 7. Fracture analysis of specimens with machining (a) and without (b)
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