• 제목/요약/키워드: hot deformation

검색결과 460건 처리시간 0.027초

열간분말단조 공정의 열탄소성 유한요소해석 (Thermo-Elasto-Plastic Finite Element Analysis of Powder Hot Forging)

  • 김형섭
    • 한국분말재료학회지
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    • 제4권2호
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    • pp.83-89
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    • 1997
  • A finite element analysis to solve the coupled thermomechanical problem in the plane strain upsetting of the porous metals was performed. The analysis was formulated using the yield function advanced by Lee and kim and developed using the thermo-elasto-plastic time integration procedure. The density and temperature dependent thermal and mechanical properties of porous metals were considered. The internal heat generation by the plastic deformation and the changing thermal boundary conditions corresponding to the geometry were incorporated in the program. The distributions of the stress, strain, pressure, density and temperature were predicted during the free resting period, deformation period and dwelling period of the forging process.

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상변태를 고려한 핫프레스포밍 공정의 유한요소해석 (FE Analysis of Hot Press Forming Process considering the Phase Transformation)

  • 강경필;이경훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.226-229
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    • 2008
  • Hot press forming is an advanced forming technology fur manufacturing of complex and crash-resistant automotive parts using ultra high strength steels. The 3-dimensional FE analysis of hot press forming process, in which process the deformation, heat transfer and phase transformation behavior are fully coupled, is carried out. The vast amount of material properties for the FE analysis is obtained from material properties calculation software which is based on thermodynamic calculations. The overall methodology for the FE analysis of HPF process and the analysis results are discussed here.

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열간 등가압 소결에 의한 Ti-6Al-4V 분말의 치밀화 거동 (Densification Behavior of Ti-6Al-4V Power Compacts by Hot Isostatic Pressing)

  • 양훈철;김기태
    • 대한기계학회논문집A
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    • 제24권2호
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    • pp.394-402
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    • 2000
  • Densification behavior of titanium alloy powder was investigated under hot isostatic pressing at various pressures and temperatures. Uniaxial creep responses of a dense specimen were also obtained at high temperatures. The densification model of Abouaf and co-workers was implemented into a Finite element program (ABAQUS) to compare with experimental data for titanium alloy powder. The agreements between finite element calculations and experimental data for deformation and densification of titanium alloy powder were good during hot isostatic pressing.

핫 엠보싱 공정을 이용한 플라스틱 CE(capillary electrophoresis) 마이크로 칩의 제작 (Fabrication of plastic CE (capillary electrophoresis) microchip by hot embossing process)

  • 차남구;박창화;임현우;박진구
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1140-1144
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    • 2005
  • A plastic-based CE (capillary electrophoresis) microchip was fabricated by hot embossing process. A Si mold was made by wet etching process and a PMMA wafer was cut off from 1mm thick PMMA sheet. A micro-channel structure on PMMA substrate was produced by hot embossing process using the Si mold and the PMMA wafer. A vacuum assisted thermal bonding procedure was employed to seal an imprinted PMMA wafer and a blank PMMA wafer. The results of microscopic cross sectional images showed dimensions of channels were well preserved during thermal bonding process. In our procedure, the deformation amount of bonding process was below 1%. The entire fabrication process may be very useful for plastic based microchip systems.

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Inhomogeneity of Hot Rolling Texture in Cu/Nb Added Ultra Low Carbon Steels

  • Jiang, Ying-Hua;Park, Young-Koo;Lee, Oh-Yeon
    • 한국재료학회지
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    • 제17권12호
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    • pp.634-636
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    • 2007
  • The texture and microstructure in Cu/Nb added ultra low carbon steels through the different thickness layer were studied after hot rolling. It was found that the two ultra low carbon steels all show the inhomogeneity of hot rolling texture and the Cu-added ultra low carbon steel was far more inhomogeneous than Nb-added one. In the center layer, the strong ${\alpha}\;fibre,\;{\gamma}\;fibre$ textures and the shear textures including 001<110>, 111<112> were founded. Near the surface, the ${\alpha}\;fibre$ texture and the orientation texture caused by a typical plane-strain deformation condition of bcc metals were observed.