Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Study on the optimization of additive manufacturing process parameters to fabricate high density STS316L alloy and its tensile properties

고밀도 STS316L 합금 적층 성형체의 제조공정 최적화 및 인장 특성 연구

  • Yeonghwan Song (Functional Materials and Components R&D Group, Korea Institute of Industrial Technology)
  • 송영환 (한국생산기술연구원 강원본부 기능성소재부품연구그룹)
  • Received : 2023.12.07
  • Accepted : 2023.12.14
  • Published : 2023.12.31
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Abstract

To optimize the process parameters of laser powder bed fusion process to fabricate the high density STS316L alloy, the effect of laser power, scanning speed and hatching distance on the relative density was studied. Tensile properties of additively manufactured STS316L alloy using optimized parameters was also evaluated according to the build direction. As a result of additive manufacturing process under the energy density of 55.6 J/mm3, 83.3 J/mm3 and 111.1 J/mm3, high density STS316L specimens was suitably fabricated when the energy density, power and scan speed were 83.3 J/mm3, 225 W and 1000 mm/s, respectively. The yield strength, ultimate tensile strength, and elongation of STS316L specimens in direction perpendicular to the build direction, show the most competitive values. Anisotropic shape of the pores and the lack of fusion defects probably caused strain localization which result in deterioration of tensile properties.

STS316L 합금의 Laser powder bed fusion 공정 최적화를 위하여 Laser power, Scan speed 및 Hatching distance의 공정조건을 제어하면서 투입 레이저 에너지 밀도와 조형체의 상대밀도와의 상관관계를 연구했고, 최적조건으로 제작된 조형체의 적층 방향에 따른 인장특성 변화를 분석했다. STS316L 분말을 에너지밀도가 55.6 J/mm3, 83.3 J/mm3 및 111.1 J/mm3인 조건에서 적층 성형한 결과, 투입 레이저 에너지밀도가 83.3 J/mm3이며, Power 및 Scan speed 각각 225 W, 1000 mm/s인 조건에서 가장 안정적으로 고밀도 STS316L 샘플을 제작할 수 있었다. 최적공정조건을 이용해 적층 방향과 인장방향이 각각 0°, 45°, 90°인 인장시험편을 제작하여 인장특성을 비교한 결과 적층 방향과 인장방향이 수직인 시험편의 항복강도, 인장강도 및 연신율이 가장 우수한 것이 확인되었다. 적층 방향과 수직 방향으로의 이방성을 가지는 기공 및 Lack of fusion 결함이 응력집중을 야기하여 인장특성을 열화 시키기 때문인 것으로 추정된다.

Keywords

Acknowledgement

본 연구는 한국생산기술연구원의 기업수요기반생산기술실용화사업(JA-23-0014)의 지원으로 수행되었습니다.

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