Study On Temperature Field Of Selective Laser Melting 316L

As an extremely promising technology,laser additive manufacturing has attracted great attention and is developing rapidly.The control of shape and performance in additive manufacturing process is an important research problem.The temperature field is a very important research content about the control of shape and performance.This article takes the temperature field during selective laser melting(SLM)316L as the research object.It uses the DFLUX subroutine to compile the mobile double ellipsoid heat source,and the USDFLD subroutine to realize the material property transition,and uses the model change function to realize powder accumulation layer by layer.This article also takes into account the influence of thermal properties and latent heat of material.In this paper,a finite element model of temperature field during selective laser melting is established by the combination of experimental and numerical simulation.The main research contents and conclusions are as follows:(1)The selective laser melting 316L experiment is carried out and the corresponding specimens are obtained.The molten pool dimension of specimens is observed by SEM.The comparison with the dimension obtained by ABAQUS simulation results confirme the correctness of the simulation.Finally,the heat source parameters are determined to be a=b=90 μm,c=20 μm,and η=0.35.(2)The temperature field under certain process conditions during selective laser melting is analyzed.As the scan track increases,the peak temperature of midpoint at scan track,lifetime of molten pool,heating rate and molten pool dimension increase,cooling rate decreases gradually.When laser scan the layer 2,the peak temperature of midpoint at scan track,lifetime of molten pool,heating rate and molten pool dimension are higher than layer 1,and the cooling rate is lower than layer 1.(3)Finally,the influence of different process parameters on the temperature field is analyzed,including laser power,scan speed,scan spacing and powder depth.It is found that the effect of laser power and scan speed are significant,and the scan spcaing and powder depth are relatively small.