Numerical and experimental investigation of the thermal behavior and microstructure of wire arc additive manufactured 316L stainless steel straight wall part

The heat transfer behavior during wire arc additive manufacturing is closely related to the dimensional accuracy and performance of the formed part. To investigate the thermal behavior of stainless steel 316L straight wall part fabricated by the wire arc additive manufacturing process, a three-dimensional transient finite element model is established based on the double elliptic heat source model. At the same time, the temperature measurement experiment on the characteristic position of the substrate is carried out. The thermal cycle curve obtained by the finite element model is in good agreement with the measured result. By analyzing the simulation results, the finite element model established can effectively reveal the thermal behaviors such as melting, solidification, heat accumulation and remelting during the forming process of the straight wall part. In addition, the solidification parameters obtained by the model are correlated with the microstructure. High G/R induces the production of cellular crystals and columnar dendrites, on the contrary, the formation of equiaxial crystals, which provide guidance for the prediction of the morphology of the microstructure.