Microstructure Study Of Dry-cut 304 Stainless Steel

With the development of science and technology,the requirements for the surface quality of parts are getting higher and higher.The difficult-to-process material AISI 304 stainless steel is widely used in various fields due to its excellent mechanical properties and chemical properties.However,its serious work hardening phenomenon and difficult processing quality limit the further widespread use of AISI 304 stainless steel.The essence of work hardening is the change of metal microstructure,that is,the process in which the resistance of dislocation movement increases with processing deformation.Therefore,the change of the metal microstructure has a very important influence on the work hardening of the metal.Therefore,from the microstructure level,it is particularly important to study the influence of cutting parameters and tool structure on the surface quality of AISI 304 stainless steel machined.In this paper,AISI 304 stainless steel is used as the research object.Based on the theory of dislocation density,the influence of cutting parameters and tool structure on the dislocation density,grain size and microhardness of the machined surface of AISI 304 stainless steel is studied.First,based on the ABAQUS/Explicit finite element simulation software,according to the material properties of AISI 304 stainless steel,select appropriate parameters,and establish a three-dimensional bevel cutting finite element model of AISI 304 stainless steel.Through the comparison of the experimental value and the simulation value of the cutting force,the credibility of the finite element simulation model is verified.The distribution of stress field,strain field and cutting temperature in the simulation results,as well as the influence of cutting parameters and tool parameters on the equivalent plastic deformation are analyzed.Secondly,based on the dislocation density theory,compile a user subroutine and import it into the established AISI 304 stainless steel three-dimensional bevel cutting finite element model.The finite element model analyzes the dislocation density and grain size of the machined surface based on the dislocation density theory.Calculation,thus realizing the prediction of the microstructure of the machined surface.Through the comparison of the experimental and simulated values of the cutting force and the microstructure of the machined surface,the credibility of the model is verified.And through the point extraction function,the influence of cutting parameters and tool structure on dislocation density and grain size is analyzed.Thirdly,based on the experimental data,the influence of cutting parameters on the microhardness and the average depth of the slip line from the machined surface was analyzed,and a regression model of the microhardness and the average depth of the slip line from the machined surface was established.Finally,on the basis of the microstructure prediction model,the microhardness prediction model was further established,and the reliability of the model was verified by comparing the experimental and simulated values of microhardness under different feed rates.And analyzed the influence of tool structure parameters on the microhardness of the machined surface.