| The superalloy GH4169 has good properties under high-temperature conditions,including high yield strength,high mechanical properties,fatigue resistance,oxidation resistance,thermal corrosion resistance,thermal stability.So it is widely used in aviation,aerospace,petroleum,and nuclear energy,Chemical industry,and shipbuilding,especially for hot section components such as various gas turbines and aerospace turbine engines.These parts have various types of micro-holes,deep-holes,and group-hole structures.The general diameter of these holes is small,the number is large,and the machining accuracy is high.As a typical difficult-to-machine material,the high-temperature alloy GH4169 is difficult to process traditionally.Realize this kind of hole processing.Electrochemical machining(ECM)of tube electrodes is one of the important methods of traditional electrochemical machining.Hollow tube electrodes are used to supply the electrolyte,and voltage is applied to the workpiece and the tube electrodes.At the same time,the tube electrode is fed to finish the material removal of the workpiece anode and realize the processing of different structures.As an important hole structure processing method,tube electrode electrochemical machining is widely used in the processing of small holes of difficult-to-machine materials.The processing aperture is generally between 0.3mm and 5mm.However,there are also a series of problems in the electrochemical machining of the tube electrode,including the problem of the hole inlet and outlet and hole wall machining accuracy,the stability of the machining process,and the discharge of the product during deep small hole machining.To solve the series of problems in the electrochemical machining of tube electrodes,scholars at home and abroad have proposed a suction tool electrochemical machining method,which uses the electrolyte suction tool to realize the supply and recovery of electrolyte and ensure the machining accuracy of the geometric structure.In this paper,COMSOL Multiphysics is used to establish a multi-physics coupling model for the electrochemical machining with electrolyte suction tool,and the finite element analysis of the electrochemical machining with electrolyte suction tool is carried out,and the electric field distribution,flow field distribution,and geometric structure field distribution of each parameter during the machining process are analyzed.At the same time,the simulation results were verified by experiments,and the experimental parameters were corrected by the simulation results,and an experimental device for electrochemical machining with an electrolyte suction tool was built,and the appropriate processing parameters were selected.The experimental results were compared with the simulation results,and the influence of various processing parameters on the orifice morphology was studied.At the same time,the ability of electrochemical machining of deep holes with electrolyte suction tool was studied.The specific research work is as follows:(1)This paper discusses the development status of micro-hole machining technology,compares the advantages and disadvantages of various micro-hole machining methods,selects the suitable micro-hole machining method of superalloy GH4169,and expounds on the principle and the related theory of electrochemical machining with electrolyte suction tool.The experimental platform of electrochemical machining with electrolyte suction tool was designed and built.The components of the experimental system were introduced in detail.The electrolyte circulation mode of the suction tool,the composition of the suction tool components,and the insulation mode of the electrode were analyzed.Through the finite element simulation method,the distribution of each physical field during the electrochemical machining with electrolyte suction tool was analyzed,and the axisymmetric two-dimensional model was established.The multi-physics coupling of the electric field,flow field,and geometric structure field was completed.Simultaneously,using the established simulation analysis model,the influence of the supply flow and suction pressure on the flow field and electric field distribution results is studied.(2)It can be seen from the flow field distribution of the simulation results that,compared with the ordinary tube electrode,the suction tool can confine the electrolyte under the electrode,which is the processing area,and improve the localization of processing;The electric field distribution shows that the electrolyte current density distribution on the anode surface of the electrochemical machining with electrolyte suction tool is relatively concentrated,and the low current density area is small,and there is no low current density transition area,so better processing accuracy can be obtained,and for the processing of the pore structure,the low current density will cause the generation of stray corrosion defects around the orifice,which will lead to the reduction of the surface roughness of the anode of the workpiece.From the simulation parameter research of the simulation results,the supply flow rate and the suction pressure have a very significant impact on the machining localization.A relatively small electrolyte flow rate and a suitable suction pressure can achieve a good electrolysis circulation flow field and a relatively concentrated electrolyte current density distribution.(3)Experiments were carried out to verify the influence law of the parameters in the simulation model,and the influence of the supply flow rate and the suction pressure of the two important parameters of the suction tool on the machining accuracy was studied.By comparing the distribution of the results of the electrochemical machining with electrolyte suction tool under different parameters,it can be obtained: with the gradual increase of the supply flow,the inlet aperture gradually increases,and the degree of stray corrosion is gradually serious.The inlet morphology obtained at 1.5 m L/min is the best Good;with the gradual increase of the recovery flow rate,the inlet aperture gradually decreases,and the degree of stray corrosion gradually decreases.The inlet morphology obtained at the recovery flow rate of 27 m L/min is the best,without stray corrosion and a short circuit.(4)The feasibility of machining deep holes of superalloy GH4169 by the electrochemical machining with electrolyte suction tool is studied,and the simulation and experiment of the electrochemical machining with electrolyte suction tool of the deep hole are carried out.The simulation results show that the electrochemical machining of the deep hole of the suction electrode has certain advantages.In the experiment,acid electrolyte and high-durability casing insulation layers are used to obtain better processing stability.The processing results show that the use of more durable casing insulation can ensure that the insulating layer is not damaged during the processing,and the current and flow field during the processing is stable.The deep hole processing is completed,and the hole depth is 50 mm.,A deep hole with a depth-to-diameter ratio of about 36.2. |
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