Research On Abrasive Cut-off Processing Parameters And Surface Quality Of Titanium Alloys

Titanium alloys is widely used in aerospace,energy and other fields because its material properties of high strength,high temperature resistance and corrosion resistance,among which titanium castings take up a large portion.However titanium alloys is a difficult material to be processed and the cleaning of titanium castings in our country need multi-process machining artificially.So the productivity effect and quality of product are all hard to be guaranteed.Abrasive cut-off operation which belongs to grinding has the advantages of fast speed,high precision and low cost,no smoke or heat,is easy to realize automation.In order to find optimum process parameters,the paper conducted experiments of abrasive cut off TC4 bars and studied the machined surface quality.The main research contents are as follows:1)To determine critical parameters,the geometry characteristics of Abrasive cut-off operation are analyzed.Besidesv_s or_wv,the workpiece position H affects the contacting arc length between the wheel and workpiece,the productivity effect as also and is divided into four types:transition-cut position,full-state-cut middle position,no-transition-cut position and full-state-cut edge position.2)Analyze the influence factors of surface quality.It's found that the peripheral abrasive grains are the main cutting part and play the role of shaping.The formulas of the equivalent chip thickness and contact arc length are derived,then analyze the influence rules of the research process parameters?grinding wheel spindle speed,feed speed of workpiece,workpiece position?on equivalent chip thickness and contact arc length.3)From single factor experiments,it's found that asv_s increases,the surface groove marks get lighter and thinner so_aR decreases,but when_sv?58.88m/s,many coatings appear and_aR increases;as_wv increases,the surface coatings reduce and groove marks get clear so_aR decreases,but whenv_w=35mm/min,the grooves get thicker and coatings appear so_aR increases;the transition zone is prone to get burned because of long contacting arc;full-state-cut edge position gets smallest_aR,but there exists a dividing line on the surface below which surface quality is obviously worse.4)The formation mechanism of the dividing line in full-state-cut edge position is analyzed theoretically.The surface is formed after the grinding of the circumferential edge and the friction of the transverse plane.Single grit cutting depth decide material final removal way anda_gmaxof the surface below the dividing line is smaller which results material removing mode turn into fatigue fracture from plastic grinding,which cause the difference of surface morphology;In addition,the difference between the friction time of the transverse plane on workpiece causes a concave valley forming the dividing line,the optimal location H=59 is found through Matlab simulation in which the dividing line can be eliminated.5)The control technology of the dividing line is studied.By orthogonal tests,the optimal processing parameters are H=59mm,_sv=47.1m/s,_wv=25mm/minand the surface roughness Ra=0.926um,no burn,burr,dividing line appear.The influence rule of each factor on Ra is consistent with the single factor test results,and the main minor order is H>v_s>_wv.This paper analyzes the processing parameters?v_s,v_w,H?influence on the cutting surface roughness and surface morphology,and the surface quality is good under the optimizing processing parameters.which can reduce the machining allowance in next working procedure or reduce working procedure.This can improve the produce efficiency of titanium alloys and has certain reference significance for realizing automatic controlled cutting.