Research On Surface And Pore Control Of Selective Laser Melting Of Stainless Steel Metal Powder

Selective laser melting technology is based on the basic principle of material accumulation molding.First,the slicing is completed according to the three-dimensional model of the component,and then the laser processing trajectory is generated.Finally,the laser is used to scan layer by layer to complete the forming of the component.Selective laser melting technology can achieve rapid,mold-free,near-net shaping of complex metal parts.It has unique advantages such as short production cycle,high material utilization rate,low production cost,high density and high precision in the production of metal parts with complex structure and expensive materials,personalized and small batch customized production.Therefore,it is widely used in aerospace,industrial manufacturing,medical and other fields.In this paper,the effects of laser process parameters on the forming quality of the single melt channel are studied by a combination of experiments and numerical simulations.On this basis,the influence of process parameters on the surface roughness and porosity of the regular hexahedron was studied,the influence of the single melt channel forming quality on the surface roughness and porosity of the regular hexahedron formed,and the formation mechanism of the surface roughness and pores was explored.The main research contents and results of this thesis are as follows:Firstly,the micro-morphology of the single melt channel was observed,and the width and height of the single melt channel were measured and analyzed through the single melt channel experiment of selective laser melting and the single melt channel morphology observation experiment.Combined with numerical simulation,the influence of laser power and scanning speed on the forming quality of single melt channel is studied.It is concluded that when the laser power is about 200 W and the scanning speed is about 1.0m/s,it can form a single melt channel with uniform width,small height fluctuation and good bonding effect with the substrate.Secondly,based on the single melt channel with better forming quality in the experiment,the mathematical model of the overlap of the melt channel was established,and the regular hexahedron forming experiment,the micro-morphology observation experiment,and the roughness measurement experiment were completed.The formation mechanism of the surface roughness on the regular hexahedron by selective laser melting was explored,and the effects of the forming quality of a single melt channel and the scanning distance on the surface roughness of the regular hexahedron were studied.Similarly,based on the single melt channel with better molding quality in the experiment,the formation mechanism of internal pores in the regular hexahedron formed by selective laser melting was explored through porosity measurement experiments and metallographic experiments.The effects of laser power,scanning speed and scanning distance on different types of pores in the regular hexahedron were studied.Finally,it is concluded that when the laser power is 200 W,the scanning speed is 1.0m/s,and the scanning distance is 80μm,the formed regular hexahedron can obtain a lower roughness upper surface and a smaller porosity.At this time,the upper surface roughness was 11.88 μm,and the porosity was 2.87%.