Multiphysics Simulation of Thermal-Fluid Behavior in Laser Powder Bed Fusion of H13 Steel: Influence of Layer Thickness and Energy Input.

In this research, the multiphysics modelling was implemented for laser powder bed fusion (L-PBF) process simulation to study the influence of layer thickness on thermo-fluid behavior, and single tracks formation during L-PBF process of AISI H13 steel. The influence of energy input adjustment on forming characteristics of single tracks in various layer thickness were examined and predicted in this work. The discrete element method and the computational fluid dynamic model were implemented to simulate the temperature distribution, and molten metal flow behavior during L-PBF process. The results indicated that the layer thickness has more effect on the depth of single track than width of single track. Due to high thermal conductivity between solid substrate and powder bed at the lowest layer thickness of 30 µm, the shallowest single tracks penetration depth was formed. The adjustment of energy input including laser power and scanning speed is an effective method to obtain the sufficient depth of penetration at 30 µm, 70 µm, and 100 µm layer thicknesses. The single track depth with the layer thicknesses of 30 µm reduced around 27 µm when laser power was decreased from 200 to 125 W and 28 µm and the scanning speed was increased from 1000 to 1600 mm/s. At 70 µm layer thickness the depth of single track was increased around 20 µm when the laser power was elevated from 200 to 250 W, and 19 µm when scanning speed was reduced from 1000 to 800 mm/s. Moreover, from this study the numerical simulation result revealed the layer thickness adjustment range between 50 and 70 µm with particle sizes used in this research provided the single track with continuous, regular sizes and sufficient penetration depth when medium energy density is used. [ABSTRACT FROM AUTHOR]