Research On Electrochemical Machining And Key Technology Of Titanium Alloy Cascade

With the rapid development of aerospace technology,higher requirements are put forward for the application and processing of high-performance materials and components with complex structures.Titanium alloy materials are widely used in the construction of major national infrastructure projects such as manned spaceflight and deep space exploration due to their excellent physical properties.Electrochemical machining plays an important role in the processing of key titanium alloy products for aerospace engines due to its excellent process characteristics.In this paper,titanium alloy cascade of the new generation liquid oxygen kerosene engine turbine pump is taken as the object.Pitting corrosion control technology of titanium alloy electrochemical machining is carried out.Surface quality and machining accuracy of electrochemical machining of titanium alloy products are improved through the research of key technologies such as the composition and processing characteristics of the electrolyte,electrode simulation and optimization,and post-processing of electrochemical machining.Thereby,the quality and reliability of aerospace products are improved.The specific research contents are as follows:(1)The reasons for the formation of pitting morphology in the electrochemical machining of titanium alloy cascades were analyzed.Electrode structure design and internal surface design were completed by using three-dimensional auxiliary design software,and the cascade electrochemical machining gap was established with the help of fluid dynamics simulation software.Flow field simulation model and flow field simulation analysis were carried out.Finally,combined with the simulation analysis results,the structure of the cascade electrochemical machining cathode system was optimized,and the optimized cathode system structure was obtained.The superiority of the structure of the cathode system with the liquid inlet on both sides was verified through experiments.(2)The electrochemical anodic polarization characteristics of titanium alloy materials are analyzed.The electrolyte composition matching test shows that the electrolyte composed of Na Cl and saturated EDTA-2Na is the preferred electrolyte for the electrochemical machining of titanium alloy cascades.Influences of electrolyte composition,temperature,pressure and metal ion completing agent EDTA-2Na on the electrochemical machining of titanium alloy cascades are analyzed.Then,process envelope of the key parameters of the electrolytic machining of titanium alloy cascades is obtained,which 10%Na Cl+saturated EDTA-2Na,electrolyte temperature38-40? and electrolyte pressure 2.6MPa-3.2MPa.(3)Comparison test of the electrochemical machining of titanium alloy under the DC power supply and the pulse power is supplied.It is clear that the pulse power supply is more suitable for the electrolytic machining of titanium alloy.At the same time,the key technology is the surface roughness of the electrochemical machining of titanium alloy cascade blades and the maximum deviation of the blade profile.The influence of important parameters of electrochemical machining of titanium alloys on key technical indicators has been studied,and the key technological parameter envelope of electrochemical machining of titanium alloy cascades has been obtained: power supply voltage17V-20 V,power supply frequency?400Hz,and duty cycle50%-60%,the cathode feed speed3.0mm/min-3.5mm/min.The validity of the processing parameter envelope is verified by the process test.(4)Fluid dynamics simulation analysis is used to optimize the abrasive flow processing tooling of titanium alloy cascade blades.Orthogonal experimental analysis method was used to study the impact of key abrasive flow parameters such as abrasive material,abrasive particle size and carrier viscosity on the pitting corrosion of titanium alloy surface.The influence of pit removal is obtained.The post-treatment process parameters of the abrasive flow of the titanium alloy blade cascade electrolytic machining blade are: boron carbide abrasive particles,800 mesh abrasive particle size,abrasive particle flow rate2-3m/min,and processing pressure23-26.9Bar,8-10 times cycles.Post-treatment processing of the titanium alloy cascade blades after electrolytic machining is carried out with the optimized abrasive flow post-processing processing parameters,and the surface roughness of the titanium alloy cascade blades after processing is less than or equal to Ra0.65?m,and there are no pitting pits on the root and surface of the blade,indicating that the abrasive flow machining technology can effectively realize the pitting pits on the surface of the titanium alloy cascade after electro-processing.Research shows that with appropriate electrochemical machining parameters and abrasive flow post-processing technology,the surface pitting corrosion of the electrochemical machining of titanium alloy material scan be effectively controlled,which provides technical reference for the extensive application of titanium alloy material electrochemical machining technology in the manufacture of aerospace liquid power system.