Simulation And Prediction Of 316L Stainless Steel Selective Laser Melting Deformation Based On In-Situ Test

Selective laser melting(SLM)additive manufacturing technology has the advantages of no mold,saving raw materials,short manufacturing cycle,high near net forming accuracy and simple process.316 L stainless steel powder molded parts can be used in aerospace,medical devices,automobile and other military and civil industries.In recent years,the near no allowance additive manufacturing of 316 L stainless steel has become one of the important research problems of part forming.316 L stainless steel components prepared by SLM usually have high residual internal stress,which is easy to reduce the forming accuracy of SLM prepared parts,and even lead to serious deformation such as warpage and cracking of SLM prepared parts.Therefore,it is urgent to explore the evolution law and modeling simulation of residual stress-induced deformation of316 L stainless steel during SLM preparation,and realize the effective control of SLM parts.It is of great significance to optimize the process parameters of SLM forming and improve the properties of formed parts.The specific work and results of this thesis are as follows:(1)The in-situ deformation detection device is set up,and the real-time deformation data of 20 layers of deformation samples deposited under different laser scanning strategies are measured in-situ,and the in-situ deformation laws of different scanning strategies are studied.When the first layer is deposited,the residual stress induced deformation of parallel melt passages is significantly higher than that of vertical melt passages;The residual stress-induced deformation of parallel melt passages is slightly lower than that of vertical melt passages in the subsequent deposition process;The in-situ deformation corresponding to 45° interlaminar rotation scanning is slightly lower than that corresponding to 90° interlaminar rotation scanning,which is consistent with the law of engineering practice.(2)Based on the traditional inherent strain method and in-situ deformation law,the inherent strain modeling of 316 L stainless steel fabricated by SLM is developed,and the inherent strains of the first layer and other layers of the parts fabricated by SLM are obtained.The deformation simulation of 316 L stainless steel fabricated by SLM is realized by using finite element method,and the error between the simulation prediction results and the actual deformation experimental results is about 15%.(3)The deformation simulation and compensation control of 316 L stainless steel parts fabricated by SLM based on finite element method are carried out.Through reverse compensation,the effective compensation control of 316 L stainless steel parts fabricated by SLM is realized.After compensation for typical structural components,the shape and position deformation of components can be reduced from ±200μm to ±55μm,which shows that the deformation compensation control in this study can effectively improve the shape and position accuracy of components prepared by SLM,and is expected to provide effective technical support for deformation control of metal components prepared by SLM.Through the above research results,the in-situ deformation law can be used as a means to optimize the process parameters(scanning strategy),and provide a reasonable and scientific reference for determining the scanning strategy.Based on in-situ deformation,the inherent strain finite element method can get the deformation prediction results of SLM forming parts simply and quickly.Through the technical means of antideformation compensation,the precision of forming parts can be improved,and the deformation value of parts can be effectively reduced.It provides a means for deformation control in the process of additive manufacturing,and has certain research and practical value.