Pulsed-mode Selective Laser Melting of 17-4 PH stainless steel: Effect of laser parameters on density and mechanical properties


Ozsoy A., YASA E., Keles M., Tureyen E. B.

Journal of Manufacturing Processes, vol.68, pp.910-922, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 68
  • Publication Date: 2021
  • Doi Number: 10.1016/j.jmapro.2021.06.017
  • Title of Journal : Journal of Manufacturing Processes
  • Page Numbers: pp.910-922
  • Keywords: Metal additive manufacturing, Precipitation hardening, Stainless steel, 17-4 PH, Pulsed-wave Selective Laser Melting, Powder bed fusion, MICROSTRUCTURE, PARTS

Abstract

© 2021 The Society of Manufacturing EngineersThis study involves SLM process parameters development with a pulsed laser to manufacture parts from 17-4 PH stainless steel with high density and good mechanical properties using a design of experiments approach. Unique factors of the pulsed laser processing such as point distance and exposure time have been taken into account in addition to other process parameters and their interactions to clarify the most influential process variables on the outputs. Although it has been confirmed that the volumetric energy density is an important and effective tool for process parameters development, it is shown that it should not be the only consideration. Consideration of linear energy density has also been found beneficial for the Selective Laser Melting process development, yet, incomplete for pulsed-wave lasers. It is found that the energy density distribution should be evaluated to understand the delivery of energy by the pulsed laser to the powder material in order to select the optimal parameters correctly. In addition, phase constitution has been found to be an important factor for parameters development of multi-phase materials, affecting the maximum theoretical density which is used to calculate % relative density using Archimedes' Method. Finally, the resulting mechanical properties of the parts with high density have shown to be affected by the energy density distribution governed by the pulsed nature of the laser.