| Electro-spark deposition is a kind of surface repair and strengthening of special processing process method,can really realize the matrix and sediment layer between high strength of metallurgy,is widely used in mechanical parts failure surface remanufacturing field,especially suitable for service in some high temperature,loss and other extreme environment of mechanical parts failure surface repair and reinforcement,etc.In the deposition process,due to the existence of single control measures and difficulty in regulating the micro-process of fusion of heterogeneous materials(electrodes and substrates),the quality and repair reliability of the EDM deposition layer are unstable.Therefore,the research method of magnetic field regulation of EDM deposition is carried out in this paper,in order to improve and reduce the adverse effects of electrode material sputtering and insufficient fusion of molten heterogeneous materials in the deposition process,improve the utilization rate of electrode materials,accelerate the fusion speed of heterogeneous materials,and improve the surface quality and binding strength of the deposited layer.The specific research content is as follows:(1)The overall scheme design of the electric spark deposition device controlled by magnetic field is carried out,including the overall structure of the device,the gap control system and the scheme design of the magnetic field control device.According to the principle and design requirements of EDM deposition process,the overall structure of the device is designed and developed.Using the root gap average voltage detection method,a gap state detection and regulation system controlled by single chip microcomputer is designed.According to the detection results of gap state between electrodes,the feed and retreat of stepping motor are controlled,and the real-time automatic control of gap state is completed.(2)According to the principle of electric spark deposition controlled by magnetic field and the basic theory of electromagnetic field,a magnetic field control device with permanent magnets as magnetic field source is designed.The magnetic field intensity can be controlled by adjusting the relative distance between permanent magnets,and the magnetic field frequency can be controlled by adjusting the rotating speed of permanent magnets.Through The simulation and analysis of the magnetic field generated by the magnetic field control device on the surface of the workpiece was simulated and analyzed by Ansoft Maxwell,and the magnetic induction intensity and distribution under the static magnetic field and the dynamic magnetic field were obtained,respectively,and the magnetic induction intensity and distribution state of the theoretical calculation and simulation analysis were consistent.(3)The developed electric spark deposition device with magnetic field control and ferromagnetic electrodes and matrix materials were used for deposition experiments.Investigate the influence of magnetic field strength and magnetic field frequency on the microscopic morphology,cross-sectional micromorphology,surface roughness,thickness and microhardness of the deposition layer.The results of the comparison with the deposition conditions without magnetic field show that the microscopic morphology of the surface and cross-sectional micromorphology of the prepared sedimentary layer are significantly improved with the increase of magnetic field strength and magnetic field frequency,respectively;When the magnetic field strength is 700 m T and the magnetic field frequency is10 Hz,the surface roughness value is reduced by 44.3%,the thickness is increased by 13.39%,and the microhardness is increased by 5.32%,which proves that the magnetic field regulation of EDM deposition can effectively improve the quality of the deposition layer and the reliability of the bond.The magnetic field control electric spark deposition device developed in this paper has low cost and high stability,which is of great significance to the basic research of failure surface remanufacturing of mechanical parts. |
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