316H Stainless Steel Laser Powder Bed Forming Process And Tissue Properties Study

316H is mostly used in the reactor and power station pressure vessel,and its parts are complex and difficult to process.At present,the traditional manufacturing method cannot fully meet the process requirements of parts,and additive manufacturing technology provides a new solution to this problem.Laser powder bed melting technology can obtain complex shape and excellent performance parts.LPBF formed 316H stainless steel is in the initial stage,so it is necessary to study the process parameters and microstructure properties of 316H stainless steel by laser powder bed melting.It provides basic reference for laser powder bed melting 316H stainless steel.The main research contents are as follows:(1)Based on laser powder bed fusion melting and solidification,process parameters and common forming defects,the fundamentals of laser powder bed fusion forming were analyzed to provide a theoretical basis for experimental research.To study the process parameters of laser powder bed fusion formed 316H stainless steel and analyze the effects of parameters on forming quality,microstructure morphology and Vickers hardness value.The optimal forming parameters were selected according to the forming quality,the effect of different positions on the forming quality was tested,and the grain morphology of the optimal specimens was analyzed.(2)To study the organization and mechanical properties of 316H stainless steel under different placement forming directions.The optimum process parameters were used to print the specimens for testing,and the results showed that the microstructure morphology of transverse forming and vertical forming specimens is different,and the Vickers hardness,tensile properties at the room temperature and high temperature of transverse forming specimens are better than those of vertical forming specimens.(3)To study the effect of substrate preheating and heat treatment on defects and tissue properties of 316H stainless steel.Substrate preheating and heat treatment were used to improve the forming quality of the specimens,count the porosity and observe the metallurgy.The results show that:the generation of defects can be reduced when the substrate preheating temperature is high,the cracks of the specimen at the heat treatment temperature of 1050℃are reduced significantly,the microstructure morphology changed significantly,and the changes of the physical phase,Vickers hardness and tensile properties after heat treatment were analyzed,which provides a basic reference for the study of laser powder bed fusion forming 316H stainless steel.