Experimental Study Of The Cutting Performance Of Titanium Alloy With Polished & Coated Carbide Inserts

Titanium alloy is widely used in the fields of aerospace,automobile and ship for its excellent properties,such as high temperature resistance,corrosion resistance and impact resistance.At the same time,titanium alloy is a typical difficult-to-machine materials with small thermal conductivity,high temperature and high chemical activity,low elastic modulus,friction coefficient and other characteristics,and it can easily lead to the poor processing performance.The coated cemented carbide inserts have the advantages of high hardness,high wear resistance and stable chemical stability,and it is the main tool for machining titanium alloy.However,the coated carbide inserts substrate are mainly made of the grinding process,and the surface of the cemented carbide inserts have some defects,such as deterioration,irregular scratch and residual stress.These defects greatly reduce the cutting performance and working durability of coated carbide inserts.In view of chemical mechanical polishing(CMP),it has the advantages of good surface quality,no surface or subsurface damage,low surface defect density,high material removal rate,low cost and so on.Therefore,CMP is an important way to realize the precision and ultra precision machining of cemented carbide inserts in the future.The research on the cutting performance of cemented carbide inserts,which were made by chemical mechanical polishing has important engineering application value and theoretical significance.For this reason,the YG8 cemented carbide inserts were studied in this paper.At First,the surface of carbide inserts were pretreated by chemical mechanical polishing,and then PVD and CVD were used to prepare the coated cemented carbide inserts.The influence of cutting parameters on cutting force and inserts durability were studied by the comparison experiment of turning titanium alloy.The cutting performance of cemented carbide inserts were analyzed by means of force measuring instrument,ultra deep field microscope,scanning electron microscope and energy dispersive spectrometer.The specific work is as follows:1)The Polishing pretreatment of YG8 cemented carbide inserts were carried out.The multi-step processes were adopted,which is rough polishing,semi-fine polishing and fine polishing and the surface morphology of cemented carbide inserts were observed by using ultra deep field microscope.2)The preparation of polished and coated cemented carbide inserts were implemented.The CVD and PVD coating technologies were used to coat the cemented carbide inserts base,which laid the foundation for the subsequent cutting experiment.3)The experiment on cutting force of machining titanium alloy by polished and coated carbide inserts was carried out.The influence of cutting parameters on the cutting force of cemented carbide inserts was revealed by turning TC4 titanium alloy with orthogonal test method.4)The experiment of durability of titanium alloy processed by polished and coated carbide inserts was carried out.The experiment of turning TC4 titanium alloy was carried out by single factor test method.The effects of different cutting parameters on the durability of the inserts were revealed by means of using ultra deep field microscopy,field emission scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS),and the wear mechanism of the inserts were analyzed.In summary,the research results of this paper provide a scientific basis for further improving the cutting performance and optimizing the coating technology.