Experimental Study On Magnetic Abrasive Finishing Of The Inner Surface Of Titanium Alloy Tube Assisted By Alternating Magnetic Field

In recent years,with the rapid development of China's high-tech field,many mechanical manufacturing industries are increasingly demanding parts materials and their surface quality.As a special metal material,titanium alloy is favored by many manufacturing industries due to its high specific strength,strong corrosion resistance and low temperature performance,and its use range is also expanding.In the fields of military industry,petrochemical industry,etc.,titanium alloy materials are used as pipe parts for high-pressure transportation of liquids and gases due to their corrosion-resistant and high-pressure-resistant materials.As a part of high-pressure transportation,the uneven and tiny cracks on the inner surface of titanium alloy pipe easily cause the gas and liquid in high-pressure transportation to cause a certain internal pressure on titanium alloy pipe and affect the uniformity of flow velocity,thus forming surging and other phenomena,destroying the stability of transportation and reducing work efficiency.Therefore,it is of great significance for finishing the inner surface of titanium alloy tube.This experiment is based on the processing principle of magnetic grinding,and through the force analysis of the magnetic abrasive particles that change in the alternating magnetic field,it is concluded that the abrasive particles are mainly affected by magnetic field force,centrifugal force and own gravity during processing.By comparing the motion trajectories of magnetic grits under alternating magnetic field and ordinary rotating magnetic field,it is concluded that ordinary rotating magnetic field is more stable,the motion mode of internal magnetic grits is too single,and the machining track is monotonous and easy to coincide.However,in the alternating magnetic field,the track of the magnetic abrasive is interlaced with each other,and the grinding track presents a network structure,with a wide coverage of the processing area,which can effectively improve the processing efficiency.Through the analysis of the material removal mechanism in the process of magnetic particle grinding assisted by alternating magnetic field,it is concluded that the grinding polishing is mainly completed by the joint action of chemical action,oxidation,corrosion and mechanical friction,and mechanical friction plays the main role in the grinding process.On the basis of reading a large number of literatures at home and abroad,this paper independently developed a set of polishing device for alternating magnetic field to assist the magnetic particle grinding of the inner surface of titanium alloy tube.The electromagnetic field analysis in Ansys Maxwell finite element software theoretically verifies the feasibility of increasing the auxiliary magnetic poleto improve the polishing efficiency,and provides a reasonable theoretical basis for the experiment.Experiments were carried out on the influencing factors such as the current frequency,the number of turns of the external magnetic field generator and the shape of the auxiliary magnetic pole.The optimal experimental device process parameters were obtained: During the grinding process,the current frequency is selected to be 50 Hz,the number of turns of the motor winding coil is 80,and the shape of the auxiliary magnetic pole is spherical.The Box-Behnken experiment was designed by response surface methodology.The influence of the interaction between the external magnetic field generator feed rate,the magnetic abrasive particle size and the amount of slurry on the grinding quality was analyzed.The optimal process parameters were found to verify the alternating rotating magnetic field.Feasibility of Magnetic Particle Grinding for Finishing of Inner Surface of Titanium Alloy Tube.The above research work overcomes the problem of low efficiency in grinding titanium alloy tubes with general magnetic field and avoids chemical pollution in electrochemical or electrochemical composite magnetic grinding process.By means of alternating rotating magnetic field formed by electromagnetic field,the auxiliary magnetic pole can rotate and move in multiple directions in space,which can improve the machining efficiency and the surface quality of the workpiece.