The laser fuse additive manufacturing parameters have an important influence on the solidification structure

especially the grain size

which affects the properties of the formed parts. Based on the finite element method

the thermal history of 316L stainless steel was simulated

and the effects of different additive manufacturing processes on grain size were studied. The results show that that the size of the molten pool obtained by simulation is consistent with the reality

and the energy transfer is vertical to the scanning direction and the thickness direction. With the increase of scanning speed

the maximum temperature of forming process decreases. The bottom region of the monolayer microstructure is cellular crystal

the middle region is large columnar dendritic crystal

and the top region is fine equiaxed crystal. The primary dendrite spacing of columnar dendrites reduces as the scanning speed increases.