• 제목/요약/키워드: Strain States

검색결과 230건 처리시간 0.019초

FCC 금속에서 압연 전단집합조직의 형성에 미치는 변형상태의 효과 (Effect of Strain Slates on the Formation of Shear Textures during Rolling in fcc Metals)

  • 강춘구;최웅규;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 춘계학술대회 논문집
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    • pp.483-486
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    • 2005
  • In order to study the effect of strain states on the formation of shear textures during rolling in fcc metals, the evolution of textures was simulated by the full constrain model using various ideal strain states. Considering rolling as a two-dimensional problem, i.e., $\varepsilon_{22}\;=\;\varepsilon_{12}\;=\;\varepsilon_{23}\;=\;0$, the deviation from the plane-strain state manifest itself as nonzero contribution of $\varepsilon_{13}$. With increasing variations of $\varepsilon_{13}$, shear textures develop. The sign of ell hardly affects the evolution of textures. The texture simulation with various idealized strain states indicates that the ratio $\mid\varepsilon_{13}\mid/\mid\varepsilon_{11}\mid$ in each time interval in a roll gap plays a dominant role in the evolution of textures during rolling.

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SUS/AL/SUS 판재의 cladding시 변형상태 고찰 (Study on the strain state during cladding of SUS/AL/SUS sheets)

  • 김종국;지광구;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 춘계학술대회논문집
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    • pp.136-138
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    • 2003
  • Strain states of clad sheets consisted of AL3003 and SUS430 were studied by FEM simulation. Main simulation parameters include roll size, reduction, material properties, material temperature, and friction between roll and material (or friction between materials). To investigate the effect of friction on the evolution of strain states, the friction coefficient between roll and material (or fraction coefficients between materials) was varied. Components of strain rate, strain were compared according to the variation of friction coefficients. And strain states during cladding were compared with those induced by simple rolling process.

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5겹 복합판재 시료의 압연시 각 판재 층의 변형상태 및 집합조직의 형성 (Deformation behavior, evolution of strain states and textures during roll cladding of five ply composite sheets)

  • 김종국;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.413-416
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    • 2006
  • Two clad composites of five ply sheets comprising STS430/AA3003/AA3003/AA3003/STS430 and STS430/AA3003/STS430/AA3003/STS430 were produced by roll cladding at $350^{\circ}C$. In order to clarify the deformation behavior and strain states in the composites during roll cladding, the variation of individual sheet thickness and the evolution of through thickness textures and microstructures of the composites were investigated. The thickness reduction of each sheet depended on the location of the sheet and on the strength of each sheet in the composites. In order to elucidate the evolution of textures and microstructures in AA3003 sheets, the strain states in AA3003 sheets during roll cladding were calculated by FEM. The formation of shear textures and fine grains in AA3003 sheet was discussed in terms of the strain states in each sheet layer. Finally, the strain states extracted from the FEM were verified by texture simulations

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Three-roll Screw Rolling 공정 시 동봉재의 변형상태와 미세조직의 발달 (Evolution of Strain States and Microstructures During Three-roll Screw Rolling of Copper Rods)

  • 김상현;박은수;김휘준;배정찬;허무영
    • 소성∙가공
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    • 제17권1호
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    • pp.68-72
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    • 2008
  • In order to investigate the evolution of strain states during screw rolling, the samples of copper rod were rolled in a three-roll screw rolling mill. Microstructure observations and hardness measurements were carried out for examining the deformation history during screw rolling. The finite element method(FEM) was employed to calculate the evolution of strain states during screw rolling. The strain state in the roll gap is quite inhomogeneous through the rod thickness layers. It turned out that shear strain gradients through the thickness layers are reduced by applying a higher reduction.

알루미늄 5052 합금 판재의 이형 압연 시 변형률 상태에 미치는 윤활의 영향 (Effect of lubrication on the evolution of strain states in AA 5052 sheet during shape rolling)

  • 박은수;황규철;허무영;김휘준;배정찬
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2009년도 춘계학술대회 논문집
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    • pp.256-259
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    • 2009
  • In order to investigate the effect of strain states attributed to the lubrication during shape rolling, shape rolling for V-sectioned sheets was carried out with and without lubrication. The evolution of strain states during shape rolling was studied by three-dimensional finite element method (FEM). Shape rolling with and without lubrication produces shape-rolled samples in fairly similar outer shapes, since the distribution of normal strain components is nearly independent of the lubrication condition. In contrast, the distribution of shear strain components strongly depends on the lubrication condition.

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스테인리스강과 알루미늄 롤-클래드 시 변형상태 연구 (Study on Strain States during Roll-Cladding of Stainless Steel and Aluminum)

  • 김종국;허무영;지광구
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 춘계학술대회 논문집
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    • pp.221-224
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    • 2004
  • The clad samples of five plies of sheets comprising ferritic stainless steel (STS) and aluminum (Al) were prepared by roll-cladding at $350^{\circ}C$. The evolution of strain states and textures during roll-cladding of STS430/AA3003/AA3003/AA3 003/STS430 and STS430/AA3003/STS430/AA3003/STS430 was investigated by measurements of crystallographic textures and by simulations with the finite element method (FEM). Because the deformation mainly occurs in the Al layer during roll-cladding, the present investigation was focused on the Al layers located. The stacking sequence of sheet materials in the clad samples played an important role in the evolution of strain states during roll-cladding.

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AA1050 판재의 비대칭 압연 시 변형률 상태와 집합조직 발달에 미치는 압연변형 형상의 영향 (Effect of Roll Gap Geometry on the Evolution of Strain States and Textures during Asymmetrical Rolling in AA1050)

  • 강형구;나정준;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.219-221
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    • 2006
  • Asymmetrical rolling was performed by rolling AA 1050 sheets with different velocities of upper and lower rolls. In order to study the effect of roll gap geometry on the evolution of strain states and textures during asymmetrical rolling, the reduction per rolling pass was varied. After asymmetrical rolling, the outer thickness layers depicted shear textures and the center thickness layers displayed a random texture. With decreasing reduction per an asymmetrical rolling pass, the thickness layers depicting shear textures increases. The strain states associated with asymmetrical rolling were investigated by simulations with the finite element method (FEM).

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Cu rod의 three-roll screw rolling 공정 시 미세조직 및 변형상태 해석 (Evolution of strain states and microstructures during three-roll screw rolling of copper rods)

  • 김상현;박은수;허무영;김휘준;배정찬
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.158-161
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    • 2007
  • In order to investigate the evolution of strain states during screw rolling, the samples of pure copper rod were rolled in a three-roll screw rolling mill. Microstructure observations and hardness measurements were carried out for examining the deformation during screw rolling. In addition, the finite element method (FEM) was employed to calculate. The strain states reveal that the shear strain plays a dominant role in the deformation during screw rolling.

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알루미늄 판재에서 두께층에 따른 변형율 상태와 집합조직의 발달에 미치는 다양한 공정의 영향 (Effect of various processes on the evolution of through thickness strain states and textures in aluminum sheets)

  • 나정준;강형구;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.87-90
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    • 2007
  • The evolution of texture and microstructure was tracked for a number of differently cold rolled aluminum sheet and through-thickness layers which were differentiated by different strain states upon preceding deformation. The results substantiate a correlation of deformation texture with the amount of shear applied during cold rolling.

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냉간 대칭/비대칭 압연시 압연변형율 상태와 집합조직의 형성 (Evolution of Strain States and Textures During Symmetrical/Asymmetrical Cold Rolling)

  • 허무영;이재필;이재협
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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    • pp.19-24
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    • 2004
  • Symmetrical and asymmetrical rolling was performed in AA 1050 sheets. Asymmetrical rolling was carried out by using different roll velocities of upper and lower rolls. The effect of the reduction per rolling pass on the formation of textures and microstructures during symmetrical and asymmetrical rolling was studied. In order to intensify the shear deformation, symmetrical and asymmetrical rolling was carried out without lubrication. The strain states associated with rolling were investigated by simulations with the finite element method (FEM). A fairly homogeneous residual shear strain throughout the sheet thickness was observed after asymmetrical rolling. Symmetrical rolling with a high friction gave rise to a strong net shear strain gradient in the sheet thickness.

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