Process Evaluation of AISI 4340 Steel Manufactured by Laser Powder Bed Fusion

Document Type

Article

Publication Date

1-1-2018

Abstract

Laser powder bed fusion (L-PBF) involves the consolidation of metal powder, layer by layer, through laser melting and solidification. In this study, process parameters are optimized for AISI 4340 steel to produce dense and homogeneous structures. The optimized process parameters produce mechanical properties at the center of the build plate that are comparable to wrought in the vertical and horizontal orientations after heat treatment and machining. Four subsequent builds are filled with specimens to evaluate the mechanical behavior as a function of location and orientation. Variations in the mechanical properties are likely due to recoater blade interactions with the powder and uneven gas flow. The results obtained in this study are analyzed to assess the reliability and reproducibility of the process. A different build evaluates the performance of near-net-shaped tensile specimens angled 35°-90° from the build plate surface (horizontal). Ductility measurements and surface roughness vary significantly as a function of the build angle. In the stress-relieved and as-built conditions, the mechanical behavior of vertically oriented specimens exhibits somewhat lower and more variable ductility than horizontally oriented specimens. Therefore, several process variables affect the mechanical properties of parts produced by the L-PBF process.

Identifier

85030870940 (Scopus)

Publication Title

Journal of Materials Engineering and Performance

External Full Text Location

https://doi.org/10.1007/s11665-017-2989-8

e-ISSN

15441024

ISSN

10599495

First Page

63

Last Page

71

Issue

1

Volume

27

Fund Ref

U.S. Department of Defense

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