Influence of processing parameters on the density of 316L stainless steel parts manufactured through laser powder bed fusion

Abstract

Additive manufacturing technologies are becoming more popular, as they allow the fabrication of specific parts with complex geometries not achievable by conventional manufacturing. In metal additive manufacturing, one of the most widely used technologies is laser powder bed fusion. This work focuses on the influence of different processing parameters on the density of AISI 316L stainless parts obtained through this technology. The article presents a review of published works on the deposition of AISI 316L stainless steel using laser powder bed fusion to define an optimal range of parameters to produce parts with densities above 99%, complemented by density measurements for new sets of laser powder bed fusion processing parameters within the defined optimal range. The investigation provides a further insight on the effect of operating parameters such as vector size and gas atmosphere (Nitrogen and Argon) on the part density. The density measurements were performed using two techniques: micrograph analysis and Archimedes method. Results reveal that an increase in vector size has a negative influence on part density. With the Archimedes method, a maximum relative density of 99.87% was achieved using Nitrogen atmosphere, showing that it is possible to produce near fully dense parts by laser powder bed fusion without post-processing by laser re-melting.

Hybrid Additive Manufacturing of Collector Coins

“…The average density of the wrought AISI 316L stainless steel allowed determining the average relative densities R that are included in Table 2. The obtained values are very close to unity and are typical of material deposition by laser powder bed fusion [22]. The flow curve of the deposited material was determined by means of compression tests.…”

“…The deposition strategy is schematically illustrated in Figure 3 and consisted of a parallel bidirection sectorial scanning with 5 mm width, rotated by 63.5° between layers to avoid repetition until several layers are added. This deposition strategy is similar to another with rotation angles of 67° that was recently used by the authors for a different application [22]. Wire electro-discharge machining (wire-EDM) using a (Charmilles Robofil 190) with a wire diameter of 0.25 mm to slice the deposited cylinders into individual blanks.…”

Synergy between topology optimization and additive manufacturing in the automotive field

“…L-PBF accomplished in the recent years a notable increase in the quality and mechanical properties of parts and is now widely used for automotive and aerospace applications. 46,47 In order to ground the FE model on a solid experimental base, values for the material card have been retrieved through a two-step testing process. First, the combination of machine, powder and process parameters has been tuned and then frozen by building a validation job that included:…”

Investigation of mechanical properties and microstructures of GH536 fabricated by laser powder bed fusion additive manufacturing

“…During fabrication, many processing parameters of L-PBF—such as laser power, hatch space, scanning speed and layer thickness—have significant impact on the mechanical properties and microstructures of formed parts. 4,5 Song et al 6 found that the increase of laser power and the decrease of scanning speed will result in size increase of crystal grains and molten pool. Tonelli et al 7 studied the effect of laser energy density on the microstructure, surface morphology and hardness of Co-28Cr-6Mo alloy.…”