Blade Passivation Hss Tap Tapping Research

Threaded connection is widely used in machinery and equipment, andthread processing precision influence pre-tightening force and the strength ofthreaded connection, so the study of thread processing is necessary.As atypical internal thread cutting tools, tap is widely used in the productionprocess. The progress of the tool cutting edge can make the edge formingsmall rounded process is called cutting edge passivation. Existing studiesconfirm that the tap is dealt with by proper cutting edge passivation process,which can effectively increase its durability, effectively improve machiningefficiency,and significantly reduce machining costs, so the study involvingcutting edge passivation radius of taps will have therotical and practicalsignificance. In today’s processing production, clearing edge passivationvalues under certain conditions, not only needs to do a lot of test research,but also does not have operability for the existing industrial power. So, if wecan find a scientific and effective method to predict law which involves tapcutting edge passivation radius influences cutting process and tool life, andthus optimize tap passivation value, it will be useful in broadcasting of thistechnology.This paper primarily did a numerical and simulative study on tappingprocess of cutting edge passivation high speed steel tap to obtain optimizetap passivation value, which was based on the element theory and largecommercial finite element software of DEFORM-3D. This paper establisheda three-dimensional model of the edge passivation tap by using Pro/E; builtTapping rigid visco-plastic fem model on three-dimensional coupled thermo-mechanical in DEFORM-3D through analysing tapping process, anddetermined constitutive model of workpiece material, chip separation criteria,adaptive meshing, chip cone friction model, the coupled thermo-mechanicalfinite element theory and boundary constraints, etc; this paper simulatedM24tap’s（material: W9Mo3Cr₄V） complete tapping40Cr process and gotaxial force, torque, temperature changes with the cutting parameter; finally, this paper analysed process which involved edge passivation HSS tapprocessed40Cr and TC4titanium alloy.Studies find that simulation results and cutting life tap test results in theprocessing of40cr be in high accordance, verified the correction ofconstructived model and feasibility of finite element analysis. Besides, edgepassivation has different influence on the change rule of axial force, torque,temperature when tapping different materials， which means better edgepassivation radius of the tool trend different range. Better edge passivationradius is0.02-0.03mm when tapping40cr;and it can predict that edgepassivation radius is0.03-0.04mm and close to0.04mm in tapping TC4.