Study On Bonding Damage Broken Experimental Of Discontinuous Cutting Tube Materials And Establishment Of Free Energy Model

Tube material 2.25 Crl Mo0.25 V is an important material for the manufacture of nuclear reactors and other large reaction vessels.It has the advantages of high heat resistance,high strength and good thermal toughness and it is a kind of difficult-to-process plastic metal material.This material is easy to bond with cemented carbide tools in the process of machining,resulted in bond damage to the tool,thus affecting the production efficiency and production costs.For this reason,supported by the National Natural Science Foundation of China(Grant No.51575146)"Research on the damage mechanism of the bonding layer on the rake face of carbide cutting tools in heavy cutting",this paper aims at the hard material of cutting tube material of 2.25 Crl Mo0.25 V.The rake face of the alloy tool is damaged and bonded,and experimental research on the bond damage is established.The theory of thermodynamic free energy is established,and the theoretical research on the bonding and fracture of the cemented carbide tool rake face is carried out.Firstly,single-factor and orthogonal turning test of 2.25 Crl Mo0.25 V steel is carried out through experimental study of bond damage single factor and orthogonal.Through the experiments,the cutting force and the cutting temperature variation during the cutting process are obtained.The high-speed camera is used to observe the process of chip breakage and the superficial depth microscope is used to obtain the data of cutting rake face damage.The volume of bond failure,the depth of damage,and the area of ? ? damage,provide the data for the study based on the change of free energy of bond damage.Secondly,the cutting simulation model is established by Deform-3D finite element software.The cutting force,temperature and stress of the contact area between the chip contact area and the rake surface are obtained.It gets the effects ofthe cutting force,cutting temperature and stress on the tool rake grain size changes,and it also provides a theoretical basis for the study on the chip breakage damage.Thirdly,the theoretical model of free energy of rake contact zone is established.Based on the study of the contact relationship between tool and workpiece,the mechanics theory model,shear work theory model,friction theory theory model and contact area model are established,and the generation,distribution and conduction of cutting heat in the contact area of ? ? razor chip are analyzed.On the basis of thermodynamic theory model and thermodynamics theory model,the theoretical model of free energy entropy of rake face is established.The model of free energy enthalpy is established based on internal energy,pressure and volume in cutting process.Based on entropy model,enthalpy model and temperature,a free energy model is established,which provides a theoretical basis for further research on the free energy damage to the tool.Finally,the variation of free energy is analyzed based on experimental and simulation data.The free energy under different cutting parameters is studied,and the influence of free energy on the bond damage depth,bond breakage volume and bond fracture area in the contact area of ? ? the chip sawdust is analyzed.At the same time,the variation of free energy on the grain size is studied.The corresponding free energy parameters are substituted into the free energy model to analyze the effect of free energy on the grain size variation.