Effect Of Cryogenic Treatment On Microstructure And Cutting Performance Of Cemented Carbide Tools

With the development of the world economy,people have put forward higher requirements and expectations for industrial production innovation,environmental protection,and product quality.As an important part of industrial production,the advantages and disadvantages of the tool are related to the development of the entire industry.Cryogenic treatment,also called ultra-low temperature treatment,is an extension of the traditional heat treatment technology.It can effectively improve the hardness and service life of carbide tools.At present,domestic and foreign scholars have many deficiencies in the research about the mechanism and process parameters of cryogenic treatment on cryogenic carbide tools.With the extensive application of carbide tools,the research about cryogenic treatment on carbide tools is really significance.The research is supported by National Natural Science Foundation of China,studies the effect of cryogenic treatment process on microstructure,mechanical properties and cutting performance of coated carbide tools,also studies the mechanism of cryogenic treatment.The main contents of this paper are as follow:Carry out cryogenic treatment of coated carbide by computer controlled cryogenic equipment.Using SEM,EDS,XED and some other equipments to see tool's microstructure changes in morphology,phase and grain size.The experimental result shows that,after cryogenic treatment,the polygonal,gray-white WC-phase is refined,the black Co-phase is more evenly distributed,and the dark gray ?-phase comes more;the ?-Co convert to ?-Co,which is more stable.The orthogonal experiment based on four factors such as cryogenic temperature,cooling rate,holding time and tempering temperature.The effect of cryogenic treatment on the hardness of coated cemented carbide tools was studied by using range analysis,and build empirical model of tool hardness.The result shows that after cryogenic treatment,the tool hardness is significantly improved,cryogenic treatment process has a significant degree of impact on tool hardness,the degree of influence from high to low is cryogenic temperature,cooling rate,soaking time,tempering temperature.Scratch method was used to study the effect of cryogenic treatment on membrane-based binding force of coated tools.The results show that cryogenic treatment enhance the membrane-based binding force.In this paper,cutting experiment was investigated under constant material removal volume(MRV)condition.Studied about the influence of cryogenic treatment process on the tool flank wear and the surface roughness,then compare the change of cutting force with the untreated tools.The result shows the tool flank wear is reduced by cryogenic treatment,the cutting force and surface roughness are reduced too.lt indicated that by using can get better mechanical processing quality.