Research On The Cohesive Strength And Cutting Performance Of The CMP Pretreated Coating Cemented Carbide Inserts

Carbide inserts have the characteristics of high wear resistance,high hardness and high heat resistance,and are widely used as the base material of coated tools.Especially with the rapid development of high-speed machining in China,the application market of domestic coated hard alloy inserts will be more and more extensive.At present,the substrate of domestic coated carbide blades is often prepared by grinding process.The surface of the substrate has defects such as micro cracks,scratches and metamorphic layers,resulting in low cohesive strength of the substrate and the coating and poor coating surface quality.The middle coating is easy to fall off prematurely,and it generates a large cutting force and chip adhesion,which seriously affects the service life of the tool and reduces the processing quality.How to effectively improve the surface quality of the substrate and increase the cohesive strength to further improve the cutting performance is an important bottleneck problem that needs to be urgently solved in the preparation of domestic coated cemented carbide blades.Therefore,this article takes traditional YG10 cemented carbide as the research object,and proposes the chemical mechanical polishing(chemical mechanical polishing)pretreatment technology to pretreat its surface,and then uses the PVD method to prepare the coated tool,and passes the scratch test 1.Theoretical calculation of cohesive strength,turning austenitic stainless steel,and exploring the influence of polishing pretreatment on the cohesive strength and cutting performance of coated blades.The specific research contents are as follows:1)Preparation of CMP polishing pretreatment YG10 cemented carbide blade.Based on the multi-process flow,the oxidant concentration,abrasive grain size and abrasive grain hardness in the pretreatment polishing liquid are taken as the base point,the substrate blade is subjected to polishing pretreatment,and the super depth of field microscope and scanning electron microscope are used to compare and analyze the surface of the cemented carbide blade before and after pretreatment quality.2)Study of the effect of polishing pretreatment on the coating surface quality.The surface morphology of the coated blade was observed using a super-depth microscope,the factors affecting the surface morphology of the coated tool were analyzed,and the influence of the surface quality of the substrate on the surface quality of the PVD coated blade was discussed.3)Establish a theoretical model of cohesive strength to discuss the effect of polishing pretreatment on the coating-substrate cohesive strength of coated blades.For the simplification and assumption of the true morphology of the polished and pretreated surface of the cemented carbide base surface,based on the compressive stress micro-deformation model of the PVD coating,the stress model of the coating-substrate interface is established,and the mechanical model of scratch is used in the slip field.Based on the principle,the theoretical model of interface cohesive strength is determined,and the effectiveness of the model is verified by the scratch test.Using the scratch test to measure the cohesive strength of the coating blade,reveal the influence of the polishing pretreatment of the base surface on the cohesive strength of the coating-substrate,and use scanning electron microscopy to observe and analyze the coating scratch damage morphology,and discuss the pretreatment on the coating-influence of the bonding mechanism of the matrix interface.4)Research on the influence of polishing pretreatment on the cutting performance of coated inserts.The experiment of turning austenitic stainless steel with coated tools to explore the influence of the basal surface state on the cutting force and durability of the austenitic stainless steel;borrow scanning electron microscope and energy spectrometer to observe the surface morphology of the coated blade and the element composition of the damaged area.Reveal the wear mechanism and initial material transfer of coated tools.In summary,the research in this paper uses CMP pretreatment to coat the cemented carbide base surface to improve the surface quality of the tool matrix and the cohesive strength of the coating,improve the cutting performance of the tool,and is expected to expand the preparation methods and applications of domestic coated cemented carbide tools.