Effects of processing parameters on the surface quality of wrought Ni-based superalloy by ultrasonic-assisted electrochemical grinding

Abstract

Ni-based GH625 superalloy has been widely employed in the aerospace industry due to its high strength, outstanding corrosion resistance and high temperature resistance. A novel hybrid processing method of ultrasonic-assisted electrochemical grinding (UAECG) can achieve the high-effective removal rate for difficult-to-process materials and thereby avoids the stray corrosion during the process. This study systematically investigated the electrochemical dissolution behaviors of GH625 alloy at low current density and effects of processing parameters on its surface roughness. A qualitative model was proposed to further reveal its removal mechanism for GH625 alloy during UAECG process. Polarization curves depicted that an efficient and stable electrochemical dissolution was achieved at an appropriate temperature (20℃) and concentration (10 wt.%) of NaNO3 electrolyte. The findings also revealed that selective corrosion preferentially occurred on the grain boundary or near the NbC carbides under different current density corrosion circumstance. Compared with ECG process, the excellent surface quality (Ra = 0.37 μm) and taper of the small holes (taper = 0.04 ± 0.005°) are obtained at the optimized condition of pulse voltage of 5.8V, feed rate of 0.6mm /min, cathode speed of 12kr /min and ultrasonic drive amplitude of 60 % by UAECG technology.

Study of machining performance for electrochemical grinding of difficult-to-cut alloy U71Mn

“…Figure 7 shows graphically the effects of applied voltage on MRR and surface roughness at the constant value of grinding wheel speed 1,500 rpm and machining time 60 s. The MRR increases with the applied voltage when the applied voltage increases from 9 to 17 V. According to Faraday’s law, the MRR is proportional to the current density. Because the applied voltage directly affects the current density of the machining area, the MRR increases with the increase of the applied voltage (Ma et al , 2022). It can be seen from Figure 7(a) that the MRR increased by 0.138 g/min when the applied voltage is increased from 9 to 17 V in the 15 Wt.% NaCl electrolyte.…”

Wear mechanism of aggregated cBN grains during single-grain ultrasonic vibration-assisted grinding of γ-TiAl alloys

“…In recent years, the introduction of ultrasonic vibration in grinding is a new method to improve the grinding quality of di cult-to-machine materials such as titanium alloys, nickel-based high-temperature alloys, ceramics and other materials in the aerospace industry [18][19][20][21][22][23][24][25][26]. Studies have shown that ultrasonic vibration-assisted grinding (UVAG) can introduce high-frequency micro-amplitude vibration, change the relative motion trajectory between the abrasive grain and the workpiece, so that the relative percentage of abrasive grain rubbing, ploughing, cutting effect changes, which can effectively reduce the grinding force and the grinding temperature, and enhance the integrity of the surface of the workpiece [26][27][28][29][30].…”

Ultrasonic-Assisted Surface Finishing of STAVAX Mold Steel Using Lab-Made Polishing Balls on a 5-Axis CNC Machining Center

“…Ultrasonic-assisted welding is one of the important applications of ultrasonic technology with a high frequency (15 kHz to 40 kHz) and a low amplitude [2]. Different kinds of ultrasonic vibration-assisted machining processes, such as milling [3,4], turning [5,6], grinding [7,8], drilling [9,10], deburring [11,12], diamond machining (cutting) [13,14], electrical discharge machining (EDM) [15,16], abrasive water jet machining [17], hybrid laser-and ultrasonic-assisted machining [18,19], and surface finishing [20][21][22], etc., have been developed in recent years. The materials processed by the ultrasonic-assisted machining processes [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], in general, can be classified as brittle materials, hard-machining metallic materials, composite materials, and non-metallic materials, etc.…”

“…The damage characteristics of ultrasonic vibration-assisted grinding of a C/SIC composite material has been studied in [7]. The effects of processing parameters on the surface quality of wrought Ni-based superalloy by ultrasonic-assisted electrochemical grinding has been investigated in [8]. The chip generation mechanism of Inconel 718 with ultrasonic-assisted drilling by step drill has been studied in [9].…”