Sensitivity Analysis in the Modelling of a High Speed Steel Thin-Wall Produced by Directed Energy Deposition

This paper reports the sensitivity of the thermal and the displacement histories predicted
by a finite element analysis to material properties and boundary conditions of a directed-energy
deposition of a M4 high speed steel thin-wall part additively manufactured on a 42CrMo4 steel
substrate. The model accuracy was assessed by comparing the simulation results with the experimental
measurements such as evolving local temperatures and distortion of the substrate. The numerical
results of thermal history were successfully correlated with the solidified microstructures measured by
scanning electron microscope technique, explaining the non-uniform, cellular-type grains depending
on the deposit layers. Laser power, thermal conductivity, and thermal capacity of deposit and
substrate were considered in the sensitivity analysis in order to quantify the e ect of their variations
on the local thermal history, while Young’s modulus and yield stress variation e ects were evaluated
on the distortion response of the sample. The laser power showed the highest impact on the thermal
history, then came the thermal capacity, then the conductivity. Considering distortion, variations of
the Young’s modulus had a higher impact than the yield stress.