SLM Simulation And Forming Quality Control Of Multi-pass Lap Jointing And Remelting Of Stainless Steel Metal Powder

As a kind of additive manufacturing technology that has been widely used in aerospace,automobile transportation,biomedicine and life,selective laser melting has the advantages of short production cycle,strong innovation,environmental protection,and processing line compared with the processing of traditional manufacturing.High flexibility,flexible design does not need to be bound by the new development advantages of the manufacturing process of the parts.However,the porosity control and surface roughness reduction of its formed parts still need further research to meet the requirements of finishing and special porosity.In this paper,single-layer double-melting channels,unremelted cubes,and remelted upper surface cubes are formed experimentally,and the surface morphology and roughness of the obtained samples are measured.The experimental material is 316 L stainless steel metal powder.Combined with numerical simulation of melt channel overlap and remelting process,the relationship between single-layer melt channel overlap quality and process parameters is studied,the law of mutual influence in the process of melt channel forming,and the relationship between layer overlap and process parameters are analyzed.,from the single-layer fusion channel lap to the interlayer lap,analyze the variation law between process parameters and pores,as well as the relationship between the remelting quality of the upper surface and the process parameters,the remelting technology reduces the roughness of the upper surface of the sample.The research work of this paper includes:(1)Use fluid dynamics simulation to simulate the lap relationship between single-layer melt channels and the influence of thermal effects,and analyze physical properties such as recoil pressure and Marangoni flow in the melt pool under the action of different laser powers,scanning speeds,and scanning distances.The effect of the phenomenon on the evolution of the melt channel in the molten pool was obtained,and the effect of the process parameters on the lap morphology of the single-layer molten channel was obtained.(2)Use fluid dynamics simulation to simulate the overlapping relationship between layers of melt channels and the influence of thermal effects,and analyze the physical phenomena such as recoil pressure and Marangoni flow in the melt pool under the action of different laser powers and scanning speeds.The influence of the formed melt channel is obtained,and the influence law of the overlapping shape of the interlayer melt channel is obtained.(3)Use fluid dynamics simulation to simulate the remelting of the upper surface of the sample,and analyze the improvement mechanism of surface defects such as sticky powder,spheroidization,holes,etc.under the action of different laser powers,scanning speeds,and scanning strategies,and the melting after remelting.The height of the track is reduced,the contour valley of the overlap area is reduced,and the influence of the roughness is reduced.(4)Through experiments,single-layer double-melting channels,cubes,and cubes on the upper surface of remelting were completed,and electron microscopy was used to observe the microscopic morphology of the surface,and analyze the relationship between process parameters and fusion channel overlap and remelting quality.association.(5)Using a three-dimensional topography instrument,measure the roughness of the upper surface of the cube,analyze the relationship between process parameters,microscopic topography,and surface roughness,as well as the law of change,and measure the reduction of surface roughness by remelting technology.efficient.It lays a foundation for exploring how to further reduce the roughness by changing the process parameters during the remelting process.