Research on pitting control technology of titanium alloy cascade trepanning electrochemical machining

To improve the pitting problem of titanium alloy cascade electrochemical machining (ECM) and improve the processing accuracy, this paper starts with the development of electrolyte formulation and cathode structure design. Firstly, experiments on the electrochemical properties of titanium alloys and experiments on the improvement of electrolyte formulations were carried out. The experimental results show that the machining accuracy and surface quality of the machining were significantly improved by using a composite electrolyte mixed with 10% NaCl and saturated EDTA-2Na, and the pitting phenomenon on the blade surface was significantly controlled. Secondly, the blade full profile trepanning cathode is designed, the flow field model of the gap between the cascade ECM was established, and the cathode system of the cascade ECM was optimised by flow field simulation analysis using Fluent software, and the cathode structure of the liquid feed on two sides was determined. Finally, experimental verification was completed and the coordinates of the machined workpiece solids and outer wall contours before and after optimisation were compared and analysed. The experimental results show that the use of the optimised electrolyte and cathode structure can effectively improve the pitting phenomenon, significantly improve the machining accuracy and surface quality, and meet the actual production requirements, providing a technical reference for the wide application of ECM technology for titanium alloy materials in the manufacture of aerospace liquid power systems.