Effects of laser spot size on the mechanical properties of aisi 420 stainless steel fabricated by selective laser melting

Xi Huai Yang, Chong Ming Jiang, Jeng Rong Ho, Pi Cheng Tung, Chih Kuang Lin

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The purpose of this study is to investigate the effects of laser spot size on the mechanical properties of AISI 420 stainless steel, fabricated by selective laser melting (SLM), process. Tensile specimens were built directly via the SLM process, using various laser spot diameters, namely 0.1, 0.2, 0.3, and 0.4 mm. The corresponding volumetric energy density (EV ) is 80, 40, 26.7, and 20 J/mm3, respectively. Experimental results indicates that laser spot size is an important process parameter and has significant effects on the surface roughness, hardness, density, tensile strength, and microstructure of the SLM AISI 420 builds. A large laser spot with low volumetric energy density results in balling, un-overlapped defects, a large re-heated zone, and a large sub-grain size. As a result, SLM specimens fabricated by the largest laser spot diameter of 0.4 mm exhibit the roughest surface, lowest densi-fication, and lowest ultimate tensile strength. To ensure complete melting of the powder and melt pool stability, EV of 80 J/mm3 proves to be a suitable laser energy density value for the given SLM processing and material system.

Original languageEnglish
Article number4593
JournalMaterials
Volume14
Issue number16
DOIs
StatePublished - Aug 2021

Keywords

  • AISI 420 stainless steel
  • Laser spot size
  • Mechanical properties
  • Selective laser melting

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