Numerical Simulation And Performance Research Of Selective Laser Melting Process Of 316L Pipeline

With the development of the aerospace field,the aviation EHA,as a highly integrated hydraulic device,has an increasing demand for high-quality,multi-directional,complex and special-shaped pipeline components.The traditional subtractive manufacturing technology can no longer solve the problem of component manufacturing,and the additive manufacturing technology represented by SLM technology makes it possible.SLM technology is also faced with problems such as easy warping of the upper surface of largediameter circular pipelines and poor uniformity of pipeline wall roughness.Therefore,this paper studies the problem of integrated forming of pipe workpieces by laser melting technology in selected areas.The research content mainly includes the following aspects:First,the physical process of laser melting forming in selected areas is studied,the thermal physical parameters of 316 L stainless steel are analyzed and calculated,the characteristic forms of temperature field and stress field in the SLM process are explored,and the basic theoretical formulas are derived.Secondly,the finite element model of the characteristic pipeline is established,and the stress field of the forming process is numerically simulated and analyzed to obtain the evolution law of the stress field during the forming process,the corresponding relationship between the maximum equivalent stress after forming and different process parameters.The aging treatment way is used to reduce the residual stress of the pipeline model.Thirdly,the deformation field during the forming process of the characteristic pipe model is numerically simulated and analyzed to obtain the evolution law of the accumulation of deformation during the forming process,and the corresponding relationship between the largest deformation variable after forming and different process parameters.and the cumulative deformation of pipes of different sizes is analyzed.Aiming at the problem of integrated forming of special-shaped pipelines,the aviation EHA lowpressure valve block pipeline model is extracted.Distortion simulation analysis is carried out,and supporting structure is added for the low-pressure valve block pipeline to reduce the distortion of the low-pressure valve block pipeline.Finally,the experimental method is used to analyze the molding quality,size,morphology,surface quality,Vickers hardness and microstructure of the characteristic pipeline samples under different process parameters.The analysis of morphology,size and Vickers hardness will verify the law of numerical simulation results from the side..