Numerical Simulation Research On Electron Beam Cladding Of NiCoCrAlY On Inconel 617 Alloy Surface

Inconel617 alloys are widely used in aerospace industry because of their good mechanical properties.Most of the failure of material properties starts from the material surface,the electron beam cladding technology can effectively improve the material surface quality.But the energy is concentrated in the process of electron beam cladding,which will quickly produce a large temperature gradient on the material surface,and the residual stress of uneven distribution will be formed inside after the material is cooled.these residual stresses will lead to cracks on the cladding layer and the alloy substrate surface,which seriously affects the mechanical properties of the components.Therefore,the research of temperature field and stress field can clearly understand the nature and distribution regular of residual stress has important reference significance in engineering optimization.This paper selects Inconel617 alloy as Material and NiCoCrAlY as cladding powder to prepare corresponding experimental materials.Based on the finite element analysis software ANSYS,to established the finite element model of temperature field and stress field of electron beam cladding process.By using APDL to write the relevant program,analyzed the different process parameters: electron beam,beam spot diameter,scanning speed Impact temperature field,stress field distribution regular,analysis of the optimal selection of reasonable process parameters,carry out the corresponding electron beam cladding experiment comparative numerical simulation results.The results show that: The temperature field peak of cladding is approximately positively linear with electron beam power;with the diameter of beam spots D increased,the temperature field peak become more smaller,with the scanning speed V increased,the temperature field peak become more smaller;The temperature field of cladding process is divided into three stages: rapid heating stage,stable stage and cooling stage;the temperature field peak is about half of the previous peak at the same distance falling along the thickness direction;The better cladding parameter obtained is V=8mm/s,D=4mm,I=20m A.During the cladding process,some stress concentration phenomena will occur at the top of the bottom material surface of the metal around the molten pool;When the process parameter is V=8mm/s,D=4mm,I=20m A,the residual stress is mainly distributed at the junction of the edge of the cladding track and the Material,the maximum value is 401 MPa;the tensile stress is ?sz>?sy>?sx;the compressive stress is-?sx>-?sz>-?sy;the cracks in the cladding are mainly caused by longitudinal tensile stress ?sz.Electron beam cladding is carried out according to the selected process parameters of numerical simulation,the morphology quality of cladding layer is better.In some large-scale practical projects,the electron beam shifts the theoretical focus point under the influence of residual magnetic field,the method is to add deflection magnetic field is used to “relocate the focus point of the electron beam trajectory”,The CST numerical simulation is compared with the experiment.The results show that when the magnetic field at the theoretical focus is 72 Gs,Number of turns of external magnetic field is 100 turns,the current along the direction of the electron beam scanning path is 538 m A,the scanning path distance of the electron beam focus offset the theoretical position is reduced from 14.4 mm to 1.6 mm,the external magnetic field is more effective to the electron beam trajectory "re-restraint ".