OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 3 2024 purpose of the work was to describe the characteristic wear patterns of nozzles and electrodes of the plasma torch during operation and to identify the causes of its occurrence. After obtaining experimental samples of worn-out plasma torch nozzles and electrodes, specimens for structural studies were cut out of it using the electrical discharge machining (DK7750 machine). Structural studies were carried out on an optical microscope Altami MET 1C, laser scanning microscope Olympus LEXT 4100 and scanning electron microscope Zeiss LEO EVO 50. Results and discussion Plasma cutting of hot-rolled products at currents of more than 300 A results in significant damage to consumables (Figure 2). The most significant damage occurs during the starting of process during operation of the starting arc, after that the main mechanism of nozzle and electrode wear is erosion during interaction with the gas-plasma flow. At the initial stage of the process, the accuracy of the interface between the nozzle and the electrode is of particular importance, the gap in which for a plasma torch of this design should be about 1.0–1.5 mm. Fig. 2. The appearance of nozzles (a, c, e, g, i, k) and electrodes (b, d, f, h, j, l) before testing (a, b), when tested in the condition of non-observance of the gap between the nozzle and electrode (c, d), when testing with melting of the gas supply holes in the swirl ring (e, f), when testing without turning off the starting arc (g, h) and with insufficiently precise manufacturing of the nozzle (i, j) under conditions of low gas pressure, and when tested in optimal cutting conditions without defects (k, l)
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