OBRABOTKAMETALLOV technology Vol. 26 No. 2 2024 Thus, the dissolution of tool steel U10A in a 10 % aqueous NaCl solution has an active character within the potential ranges φ = 0.3...2.1 V, φ = 2.7...3.8 V and φ = 4.4...8.0 V. Thus, a voltage of 8 V was chosen to determine the output technological performance parameters, namely, the current output for the main reaction and the rate of electrochemical dissolution. To calculate the current output according to the formula [29], we determine the necessary values. Experimental studies were carried out to determine the volume of the removed metal, which in turn allowed for determining the mass of the dissolved material during electrochemical dissolution of U10A steel. Fig. 8 shows that the average value of the current with an interelectrode gap of 0.1 mm at the initial time was 0.099 A. The duration of the experiment equal to 7 minutes is due to the stabilization of the current value, i.e. the interelectrode gap increased by the maximum permissible value at the specified initial parameters. To determine the mass of the dissolved material, a series of experiments was carried out at a constant current I = 0.099 A and an initial end-to-end interelectrode gap Δf = 0.1 mm. Figure 9 shows a graph of voltage versus time for a series of experiments for 3 minutes. Fig. 8. Graph of current versus time at constant voltage Fig. 9. Graph of voltage versus time at a constant current of 0.099 A As a result of weighing, the following masses mfact were obtained: for the first experiment, 0.0054 g; for the second experiment, 0.0047 g; for the third experiment, 0.0053 g. Thus, the arithmetic mean mass is 0.0051 ± 0.0009 g. Figure 10 shows photos of the resulting hole and its profile. Notably, the formation of a taper is typical for processing with a fixed cathode tool. a b Fig. 10. A hole in 10 % NaCl with a stationary cathode-tool of circular cross-section with outer and inner diameters of 0.908 mm and 0.603 mm with a duration of 7 minutes: a – top view; b – profile
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