Experimental research on machinability of different electrode materials for SEAM of the nickel-based superalloy GH4169

Abstract

The short electric arc machining technology is a technical category of electrical machining in the special machining industry. It further improves machining efficiency (1.92 × 105 mm3/min) in comparison to other electrical machining. In short electric arc machining, the electrode materials directly affect the surface quality of the workpiece, electrode loss, and dimensional accuracy. Therefore, the selection of the electrode material is particularly important. Using the nickel-based superalloy GH4169 machining as the research object, the study aimed to improve the material removal rate, while reducing the electrode loss. The experimental research on the short electric arc machining properties (machining surface quality, inter-polar voltage and current waveform, electrode loss analysis, surface morphology, microstructure, chemical components analysis, etc.) of four types of tool electrode materials (graphite, copper, Q235, and aluminum) separated by two groups was conducted, in the first group: under the certain technological parameter, machining the GH4169 by four kinds of tool electrode materials respectively. In the second group, the influence of different tool electrode materials on the material removal rate was studied by using graphite and copper as the tool electrode materials under the different process parameters of discharge current, pulse time, pulse interval, and air pressure. The results show that the mechanical properties of the electrode materials differed due to the different thermal properties of the electrode materials under the same process parameters. Furthermore, the different physical properties of the electrode material caused different effects on the residual heat, resulting in differences in the material removal rate. Under most of the discharge conditions, MRR occupied a large proportion in the graphite electrode, and the relative mass loss of the electrode was about 16.7% of that of copper, providing a solid theoretical basis for the electrode selection of the short electric arc machining hard surface materials.