Research On The Key Technology Of High Efficiency And Precision Electrochemical Machining Of Aluminum Alloy Thin-walled Barrel Rifling

Something widely used aluminum alloys in aerospace,medical devices,and military weapons due to their lightweight,high strength,high specific hardness,and corrosion resistance.In order to achieve lightweight weapons and give full play to the mobility and flexibility of modern individual weapons and equipment,aluminum alloy materials have broad application prospects in barrel light weapons and equipment.However,the existing thin-walled barrel rifling processing has defects such as easy deformation,low production efficiency,poor production surface quality,and low safety,which cannot meet the actual production needs.This paper proposes an efficient and precise machining method for aluminum alloy thin-walled barrel rifling using electrochemical machining,which has an important theoretical research significance and practical application value.Based on the analysis of the current research situation at home and abroad,this paper investigates the anodic dissolution law of aluminum alloy electrochemical machining,reveals the formation mechanism of pitting corrosion,conducts polarization curve measurement experiments,and obtains the electrolyte parameters of aluminum alloy electrochemical machining,aiming at the problems of easy formation of passivation layers on the surface,low processing efficiency,poor surface quality,and poor forming accuracy during anodic dissolution of aluminum alloy in electrochemical machining.The cathode structure design and gap flow field simulation were carried out,and the cathode liquid supply hole layout was optimized.They conducted single factor and orthogonal experiments to obtain a set of optimal process parameters.High efficiency and precision electrochemical machining of aluminum alloy thin-walled barrel rifles has been achieved.Firstly,the law of anodic dissolution of aluminum alloy was investigated,the formation mechanism of pitting corrosion in anodic dissolution of aluminum alloy and the methods for inhibiting pitting corrosion were analyzed,and the anodic polarization curves of aluminum alloy in different types,concentrations,and temperatures were analyzed.It was obtained that in a 10%Na Cl+9%Na NO₃ composite electrolyte,when the electrolyte temperature was 30℃,the passivation zone was stable,the over passivation zone rose smoothly,and the rising speed was significantly accelerated,The current density becomes significantly higher,the processing efficiency is relatively improved,and the processing quality reaches a good level.Secondly,in view of the different flow directions of the electrolyte that will produce different flow field effects,this paper adopts a pull-type downstream cathode structure and a pull-type counter current cathode structure.Through simulation and analysis of the gap flow field of different cathode structures,it is found that the flow fields distribution of the pull-type downstream cathode structure is more uniform.The arrangement angles of the pull type downstream feed hole was optimized.When the dip angles of the feed hole was 40°,the electrolyte pressure was higher,the flow field distribution was more uniform,and it could decompose the processing products and temperature in a timely manner.Finally,a single factor influence experiment was conducted to study the effects of processing voltage,processing current,and electrolyte flow rate on the work piece forming accuracy and surface quality,and the approximate range of process parameters was obtained;Then,an orthogonal experiment of aluminum alloy barrel rifling was conducted to obtain a set of optimal processing parameters.Under the conditions of parameter combination:voltage of 7.5V,current of 1850 A,electrolyte flow rate of 6.0L/h,composite electrolyte of 10%Na Cl+9%Na NO₃,electrolyte temperature of 30℃,electrolyte inlet pressure of 1.2MPa,cathode structure of pull-type downstream cathode,arrangement angle of liquid supply holes of 40°,cathode feed speed of 100 mm/min,electrolytic machining test of aluminum alloy thin-walled barrel rifling was conducted,and the surface roughness of the processed sample was Ra0.741μm.The forming accuracy value is 0.035 mm.