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The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (II) - Laser Weldability of Hot Stamping Steel with Ultra-High Strength - (레이저 열원을 이용한 보론강 및 핫스탬핑강의 용접특성에 관한 연구 (II) - 초고강도 핫스탬핑강의 레이저 용접특성 -)

  • Kim, Jong Do;Choi, So Young;Park, In Duck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1373-1377
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    • 2014

  • Hot-stamping is a method of obtaining ultrahigh-strength steel by simultaneously forming and cooling boron steel in a press die after it has been heated at $900^{\circ}C$ or above. After heat treatment, boron steel has a strength of 1500 MPa or more. This material ensures a high level of quality because it overcomes the spring-back phenomenon, which is a problem associated with high-strength steel materials, and the degree of dimensional precision is improved by 90 or more because of the good formability compared with existing types of steel. In this study, the welding characteristics were identified through the butt and lap welding of hot-stamped steel using a disk laser. Full penetration was obtained at a faster speed with butt welding compared to lap welding, and a white band was observed in every specimen.

  • https://doi.org/10.3795/KSME-A.2014.38.12.1373 인용 PDF KSCI

Effect of carbon and boron addition on sintering behavior and mechanical properties of hot-pressed SiC (카본 및 보론 첨가가 탄화규소 열간 가압 소결거동 및 기계적 특성에 미치는 영향)

  • Ahn, Jong-Pil;Chae, Jae-Hong;Kim, Kyoung-Hun;Park, Joo-Seok;Kim, Dae-Gean;Kim, Hyoung-Sun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.1
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    • pp.15-21
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    • 2008

  • SiC has an excellent resistance to oxidation and corrosion, high temperature strength and good thermal conductivity. However, it is difficult to density because of its highly covalent bonding characteristics. Hot-press sintering process was applied to fabricate fully densified SiC ceramics with carbon and boron addition as a sintering additive. The addition of carbon improved the mechanical properties of SiC because it could induce a fine and homogeneous microstructure by the suppression of abnormal growth of SiC grain. Also, the addition of carbon could control the phase transformation of SiC. The phase transformation of 6H to 4H increased with sintering temperature but the addition of carbon decreased that kind of phase transformation.

  • PDF KSCI