Experimental Study On Magnetic Abrasive Finishing Of Titanium Alloy Tube Inner Surface Based On Electromagnetic Field

With the rapid development of China ’s high-tech industry,higher requirements are put forward for the materials and properties of parts.Titanium alloy materials are widely used in the field of parts manufacturing because of their high strength,good corrosion resistance and stable low temperature performance.Titanium alloy material is often made into pipe parts,which are used to transport high-pressure substances such as liquid and gas,which puts forward strict requirements on the surface quality of the pipeline.If the inner wall of the pipeline is uneven,it is easy to affect the uniformity of flow velocity,and even cause surge phenomenon.If there are defects such as microcracks in the inner wall of the pipe,the corrosion resistance of the pipe will be reduced and the pipe fracture accident will be caused.Therefore,it is imperative to finish the inner surface of titanium alloy pipeline.As a new finishing technology,magnetic abrasive finishing has the advantages of adaptability,flexibility and profiling,which are not possessed by traditional processing technology.It has a good application prospect in the field of surface finishing of pipe parts.In this thesis,aiming at the difficulty of machining the inner surface of titanium alloy tube,TC4 titanium alloy tube is taken as the research object,and the inner surface is polished by electromagnetic magnetic abrasive finishing method.The specific research contents are as follows :(1)The electromagnetic phenomenon and the generation form of dynamic magnetic field are analyzed.Based on the principle of magnetic abrasive finishing,a low frequency alternating magnetic field generator is designed.The force condition of single magnetic abrasive particle is revealed,and the motion state of magnetic abrasive particle is simulated by EDEM software.The cutting mechanism and material removal form of magnetic abrasive particles are described.(2)The problems of structure selection and material selection in the design process of electromagnetic device are expounded,and the distribution of electromagnetic winding and the way of energization are designed.The magnetic field of the processing area is simulated and analyzed by ANSYS Maxwell,and the optimal coil excitation form is determined by magnetic abrasive finishing test.(3)Considering the magnetic flux leakage phenomenon of the electromagnetic device,the magnetic pole head is designed and the profiled magnetic pole head is proposed.The ANSYS Maxwell software was used to simulate the magnetic field morphology of the machining area under different taper profiled magnetic poles in time and space.The EDEM software was used to simulate the morphology of the magnetic abrasive particles and the movement of the magnetic abrasive particles under different parameters of the magnetic poles.Finally,the best taper parameters of the profiled magnetic poles were determined by the magnetic abrasive finishing test.(4)Magnetic abrasive finishing was carried out by permanent magnet assisted electromagnet,and the magnetic field morphology inside the pipe was analyzed.The heating principle of electromagnet is explored.The electromagnetic loss law of electromagnet is simulated and summarized by ANSYS Maxwell software.According to the simulation results and heat dissipation theory,a reasonable heat dissipation device is designed for electromagnet.The air cooling effect of the heat dissipation device is simulated by ANSYS Maxwell and Fluent software,and the optimal heat dissipation angle is obtained.Then the coil current parameters were discussed,and the heating and heat dissipation effects of the electromagnet under different current parameters were simulated.The optimal processing current was determined by magnetic abrasive finishing test.(5)The response surface method was used to optimize the grinding parameters of the magnetic abrasive finishing test based on low-frequency alternating magnetic field.The optimization variables include : pipe speed,magnetic abrasive mesh,and magnetic pole feed speed.Box-Behnken experiment was designed and verified by experiments.The most suitable magnetic abrasive finishing process for titanium alloy tube was obtained.