Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Electron Beam Weld ability of Alloy 718 Nozzle for Jet Propulsion Component

고속 추진체용 Alloy 718 노즐 단조품의 전자빔 용접성 평가

  • 이채훈 (동의대학교 신소재공학과) ;
  • 김정한 (한국기계연구원 부설 재료연구소) ;
  • 홍재근 (한국기계연구원 부설 재료연구소) ;
  • 염종택 (한국기계연구원 부설 재료연구소) ;
  • 윤종원 (동의대학교 신소재공학과) ;
  • 박노광 (한국기계연구원 부설 재료연구소)
  • Published : 2008.11.01
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Abstract

In this study, mechanical properties of Alloy 718 welded after forgings for jet propulsion component was investigated. Hot-forged and machined work-pieces($230mm\times70mm\times15mm$) which have different grain sizes are welded by electron beam welding technique. After welding, the components were solution heat-treated and aged. Samples were sectioned to analyze the microstructural evolution and formation of micro-crack. It was found that HAZ grain boundary liquation crack generally initiates in the coarse grains rather than the fine grains. Needle-like phases with high Nb contents were found at the outer part near the base metal. Vickers hardness and tensile tests were carried out at room temperature and at $649^{\circ}C$. The tensile properties of electron beam welding specimens exhibited around 100MPa and 10% decrease in strength and elongation, respectively.

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References

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