Plastic Deformation Behavior Of S32760 Duplex Stainless Steel In Sawtooth Chip Formation Process

S32760 duplex stainless steel is a super stainless steel whose ferrite phase and austenite phase account for almost equal proportions under solution annealing conditions.It has excellent mechanical properties and corrosion resistance.Therefore,it is used in complex marine engineering and marine engineering.And it has a wide range of applications in corrosive working environment.Due to the small thermal conductivity,Young’s modulus,and specific heat capacity of S32760 duplex stainless steel,the temperature rises quickly and is not easy to spread during the cutting process,the workpiece material is deformed,and it is easy to produce serrated chips,and the tool is easy to wear.It is difficult to effectively guarantee the quality of the processed surface of the workpiece,and the high-efficiency processing of S32760 duplex stainless steel has become an urgent problem to be solved.Since the metal cutting process is essentially the elasto-plastic deformation process caused by the chips,this article focuses on the S32760 duplex stainless steel,starting from the microscopic mechanism of plastic deformation,based on its mechanical properties under high temperature and high strain rate,through cutting experiments and Through simulation,the plastic deformation characteristics of chips during the cutting of S32760 duplex stainless steel were studied.Firstly,based on dislocation dynamics,it explains the plastic deformation of materials in the metal cutting process from a microscopic point of view.The microscopic control mechanism of material plastic deformation during machining and its transformation law with cutting speed are analyzed,and a theoretical model of stress-strain rate relationship is established,which provides a theoretical basis for later analysis of plastic deformation of chips during cutting.Secondly,the high-temperature dynamic mechanical properties of S32760 duplex stainless steel were studied through mechanical experiments combined with professional material performance simulation software JMat Pro.The results show that the thermal softening effect and strain rate strengthening effect of S32760 duplex stainless steel are relatively obvious,and its sensitivity to temperature has a critical temperature threshold.After the threshold is exceeded,the plastic deformation mechanism of S32760 changes from dislocation slip to dislocation climbing.Then,a right-angle free cutting test of S32760 duplex stainless steel was designed and carried out.The chips under different cutting parameters were collected and made into metallographic observation samples,and the influence of cutting parameters on the geometric characteristics of the chips was analyzed.The microstructure characteristics of the material in the zigzag chip adiabatic shear zone were observed with an electron metallurgical microscope,and the influence of cutting parameters on the zigzag chip adiabatic shear zone was analyzed.Finally,using the stress-strain data of S32760 duplex stainless steel,the J-C constitutive equation was fitted.The two-dimensional cutting simulation model was established,and the reliability of the model was verified by the geometric characterization parameters of sawtooth chips.Using Abaqus software,the characteristics of force and heat in the chip formation process are analyzed.The results show that the cutting force and cutting heat of S32760 sawtooth chips change periodically and there is a certain connection.Then,by analyzing the relationship between stress,strain and temperature in the adiabatic shear zone at different cutting speeds,it lays the foundation for revealing the formation mechanism of sawtooth chips in S32760 duplex stainless steel.