Effect Of Deposition Efficiency On Microstructure And Property Of 316L Stainless Steel Fabricated By Laser Engineered Net Shaping

316L stainless steel is ultra-low carbon austenitic stainless steel with good mechanical properties and excellent intercrystalline corrosion resistance.It is used widely in high and new technology fields such as aeronautics and astronautics,medical instruments,energy power and marine chemical industry.The preparation of traditional 316 L stainless steel parts often needs to be forged and machined.For some special structural parts,there are problems such as large removal quantity or tool interference.With the appearance of material increasing technology,the Laser Engineered Net Shaping technology has been applied early to the direct preparation of 316 L stainless steel parts.However,there are still some contradictions in the shaping quality and deposition efficiency.High efficiency and low energy consumption always are the goal of the scientific and technological personnel.Deposition efficiency,a key index related to manufacturing cycle and cost,can be achieved within a large range.It is important and practical to shorten the manufacturing cycle and reduce laser energy consumption as much as possible to improve the deposition efficiency.In this paper,a series of research on the deposition efficiency of 316 L stainless steel fabricated by Laser Engineered Net Shaping are carried out.The main research work is as follows:(1)This experiment is designed and implemented by single factor method.The formation of different deposition efficiencies can be achieved by changing the powder feeding rate and adjusting the lift between layers.The influence of process parameters on the surface quality,effective width,laser energy consumption and density of single channel samples was studied.The effect of different deposition efficiencies on transverse and longitudinal microstructure of samples was studied.The dendrite segregation in the samples of different deposition efficiency was analyzed by using the Energy Spectrum Analyzer(EDS).(2)The tensile test specimens were designed according to the requirements of the national standard,and then the tensile test was carried out at room temperature.Scanning electron microscope(SEM)was used to observe the fracture surface.Judging the inclusion types in fractography by using energy spectrum analyzer.The hardness of the sample along the direction of deposition was measured by Vivtorinox hardness tester.(3)The samples were subjected to electrochemical corrosion experiments under neutral,acidic and alkaline conditions.The corrosion resistance of the samples under different deposition efficiency was analyzed by polarization curve.The surface morphology of samples after corrosion was observed by optical microscope.Different deposition efficiency was realized by adjusting process parameters.We can achieve synergistic optimization of deposition efficiency and performance,and achieve the goal of low energy consumption and efficient manufacturing of high-performance parts.