Experimental Research Of Electrolytic-Abrasive Edge Passivation Process For Carbide Tool

The carbide materials are widely used in the field of cutting tools for its excellent properties of high wear resistance and high hardness.However,carbide materials belongs to brittle material,there are lots of micro-gaps in different size on the cutting edge of carbide tool even the tool has been sharpened carefully.These micro-gaps can be easily expended in the cutting process,which will directly accelerate the tool wear rate.With the increasing emphasis on the tool edge passivation technology,a variety of edge passivation methods emerged,which usually containing mechanical contact passivation and hand passivation.However,there are existing problems in carbide tool passivation such as low efficiency,inconsistent quality,seriously tool wear.In view of current situation mentioned above,Electrolytic-abrasive process was used to carbide tool edge passivation in this paper.Experimental program and laboratory equipment are designed to explore the feasibility of this passivation process.Firstly,the results of experiment indicate that it is feasible to use electrolytic-abrasive process for carbide tool edge passivation.Cutting edge have been significantly improved and the shape of the edge have been changed into a smooth arc-shaped edge,meanwhile,the surface near cutting edge has been polished,its roughness has been reduced from Ra0.312 to Ra0.141.Secondly,Electrolysis gap has been picked as control factor for edge radius,the test shows the edge radius can be adjusted by controlling the electrolysis gap,it can be ranged from 0.014 mm to 0.036 mm,the scope mentioned above is useful for finishing and Semi-finishing.Thirdly,diversification of the edge was showed by conducting SEM and EDS for the tool which has been processed by electrolytic-abrasive,experiment indicate that the consequent of passivation was affected by the initial state of edge when comes to brush passivation,but electrolytic-abrasive passivation is on the contrary.Meanwhile,SEM shows that whether the edge is processed by brush or electrolytic-abrasive,there are plenty of “micro-pits” on the tool surface,and the diameter of most “micro-pits” is less than 1 micron.The EDS indicate cobalt-rich region are ionized fast than other region,these “micro-pits” are formed for the reason mentioned above.