Experimental Study On Electrolytic-magnetic Complex Finishing Of TC4 Titanium Alloy

Titanium alloy is an important structural metal.Compared with other superalloys,it has high strength,good corrosion resistance,high thermal strength and high chemical activity.It can also maintain good mechanical properties at low temperature and ultra-low temperature.Therefore,it is widely used in precision instruments,aerospace,medical devices and important ships and ships.In the military field,it is used to make some key components,such as turbine shaft,blade disc,engine blade and so on.Due to the comprehensive material properties of titanium alloys,titanium alloys play an increasingly important role in the strategic development of the country.The parts made of titanium alloy are very important to the normal operation of spacecraft and the use of ships.The surface of these parts will directly or indirectly affect the service life of the machine.Because of the poor grinding performance of titanium alloy,the traditional grinding of titanium alloy parts surface is difficult to meet the requirements of precision parts and aerospace.Therefore,this paper intends to use the special processing method of electrolytic-magnetic composite grinding to process the surface of titanium alloy,which can combine the characteristics of flexible grinding of magnetic grinding with the advantages of non-material hardness in electrochemical-electrolytic process,so as to build the experimental platform of electrolytic-magnetic composite grinding.As an experimental workpiece,the mechanism of electrolytic processing and the electrolytic characteristics of titanium alloy are analyzed.The effects of electrolytic voltage,current and processing time on the formation of passive film are analyzed.The electrolyte sodium nitrate is selected as the experimental electrolyte through the comparison of electrolytes.Considering three factors and three levels,including electrolyte temperature(level 20 ?,30 ?,40 ?),number of magnetic abrasive particles(60 #,80 #,100 #)and spindle speed(500 r/min,750 r/min,1000 r/min),the experimental design of titanium alloy workpiece is carried out by response surface methodology,and the surface roughness and material removal amount are taken as the response surface.Seventeen groups of experiments are designed and the interaction between the two factors on the response value is analyzed.The regression equation is obtained through the design and the data of variance are analyzed.The optimum experimental parameters are obtained,so that the surface of the processed titanium alloy could meet the practical requirements and ensure the accuracy of the position and shape of the processed titanium alloy.The optimum parameters of the experiment are electrolyte temperature of 30 ?,number of magnetic abrasive particles of 80 #,spindle speed of 1000 r/min.Secondly,the optimum level of parameters is verified by experiments.The surface hardness,three-dimensional morphology,two-dimensional morphology,surface roughness,material removal,composition change and surface residual stress of the titanium alloy workpiece are measured.After processing,the surface is polished,the surface texture is basically removed,and the machined surface is rough.The surface roughness has reached 0.12 ?m from the original 1.13 ?m,and it can satisfy the application requirements of titanium alloy in aerospace very well.