Study On The Electrochemical Grinding Process Of Tungsten Carbide

Cemented carbide is a kind of sintered material with high strength,abrasion resistance and heat resistance.With the development of science and technology,cemented carbide materials are widely used in many field.However,due to its excellent material properties,it is difficult to process.Therefore,new machining methods for hard materials such as cemented carbide were developed.Electrochemical Grinding?ECG?is a compound machining method combining electrochemical machining and mechanical grinding.For hard working materials,electrochemical grinding method can improve machining efficiency and get better surface quality.However,the electrochemical corrosion mechanism of hard alloy in electrochemical grinding is not clear.In this paper,the electrochemical corrosion test and mechanism of YG15 cemented carbide were investigated by experimental study and theoretical analysis.The results show that the structure of the corrosion layer is loose and the thickness of the corrosion layer can be controlled by controlling the electrochemical parameters.According to the research results,the optimized electrochemical parameters were selected for the electrochemical grinding process test,and the better machining quality was obtained.In addition,compared with the mechanical machining method,the electrochemical grinding of cemented carbide can significantly reduce the grinding force,providing a certain theoretical basis for its application.The specific research content of this paper is as follows:firstly,the anodic polarization curves of three cemented carbides YG8,YG15 and YG20 in common electrolytes were measured through a three-electrode test system,and the polarization characteristics of these three carbides in electrolytes are compared.Through the test curve and corrosion phenomena,NaNO₃ electrolyte with a concentration of 3 mol/L was finally selected as the electrolyte for processing.Secondly,the electrochemical corrosion process of YG15 cemented carbide in 3mol/L NaNO₃ electrolyte was analyzed by combining potentiodynamic test and potentiostatic test.The experimental results show that the Co element in the alloy dissolves first at high potential,leading to the destruction of the surface integrity of the matrix material and the formation of loose structure.The test results show that the corrosion product on the surface of the material is W oxide,and the main component is WO₃.When the potential is too high,the gas will cause the corrosion products to fall off and intensify the surface corrosion.Again,for the actual processing by two electrode system,electrochemical parameters such as machining voltage,time,interelectrode gap experiments were conducted to explore the influence of composition and thickness of the corrosion layer,and its morphology and composition were observed by scanning electronic microscope and energy spectrometer,the most suitable processing of electrochemical parameters were obtained by contrasting,and the cause of surface topography were analyzed.Finally,with the optimization of the electrochemical parameters,the method of orthogonal experiment was used to study the influence of mechanical processing parameters such as spindle speed,feed speed,grinding depth,so as to optimize process parameters and determine the degree of the influence of different parameters on the grinding quality and priority level,optimize the YG15 electrochemical grinding process parameters,and obtained good processing quality.Compared with the grinding force of mechanical grinding,it shows that the machining of electrochemical corrosion layer of hard alloy can significantly reduce the grinding force and ensure the machining stability.