• 제목/요약/키워드: cold rolling textures

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알루미늄 1050계 판재에서 결정립 성장 집합조직에 미치는 재결정 집합조직의 영향 (Effect of Primary Recrystallization Texture on the Formation of Grain Growth Texture in Aluminum 1050 Sheet)

  • 김현철;강형구;허무영
    • 대한금속재료학회지
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    • 제47권6호
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    • pp.356-362
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    • 2009
  • In order to vary the primary recrystallization textures, AA 1050 sheets were cold rolled in two different manners. Differences in cold rolling schedule gave rise to the formation of different cold rolling textures also leading to the formation of different primary recrystallization textures. Upon annealing for grain growth, changes in microstructure and texture hardly occurred in the sample depicting Cube recrystallization texture, while grain growth was accompanied with the development {001}<100> Cube texture in the sample displaying a recrystallization texture comprising of weak rolling texture components. The selective growth of Cube oriented grains is attributed to the high mobility of their grain boundaries.

AA5052 판재의 비대칭 냉간압연 시 압연 패스당 압하율 제어에 의한 전단 변형 향상 (Improvement of shear deformation by controlling reduction per a rolling pass during asymmetrical cold rolling in AA 5052)

  • 강형구;한용희;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.226-228
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    • 2007
  • During asymmetrical cold rolling in AA 5052 sheet a reduction per a rolling pass was varied to investigate the effect of the ratio of the contact length between the roll and sample ($l_c$) to the sheet thickness (d) on the formation of shear textures. In order to intensify the shear deformation during asymmetrical rolling, AA 5052 sheet was asymmetrically cold rolled without lubrication by using different roll velocities of upper and lower rolls. Asymmetrical rolling with $l_c$/d=1.8 led to the formation of texture gradients throughout the sheet thickness in which the outer thickness layers depicted shear textures and the center thickness layers displayed a rolling texture. Asymmetrical rolling with $l_c$/d=3.1 gave rise to the formation of shear textures in the whole through-thickness layer. The strain states associated with asymmetrical rolling were investigated by the finite element method (FEM) simulation. FEM results indicated that the evolution of deformation texture in a thickness layer is strongly governed by integrated values of strain rates and along the streamline in the roll gap.

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교차롤로 냉간 압연한 IF 강에서 압연 집합조직과 재결정 집합조직의 형성 (Formation of Rolling and Recrystallization Textures in IF Steel Cold-rolled by Cross-Roll Rolling Mill)

  • 이계만;김상현;허무영
    • 대한금속재료학회지
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    • 제48권7호
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    • pp.644-650
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    • 2010
  • Interstitial free (IF) steel sheets were cold rolled by the cross-roll rolling mill in which the roll axes are tilted by ${\pm}7.5^{\circ}$ away from the transverse direction of the rolled sample. After cross-roll rolling of IF steel sheets, the cold rolling and the recrystallization textures were distinguished from those observed after rolling in a normal rolling mill. The three-dimensional finite element method (FEM) simulation revealed that the operation of a large shear strain ${\varepsilon}_{23}$ during cross-roll rolling leads to the formation of a distinct cold rolling texture. During recrystallization annealing, a pronounced change in texture components was not observed, which is attributed to the lack of either selective growth or oriented nucleation during the recrystallization process. Cold cross-roll rolling led to the formation of finer recrystallized grains in IF steel sheets.

페라이트계 스테인리스 강의 열간압연 시 표면 층의 집합조직 발달에 미치는 윤활의 영향 (Effect of Lubrication during Hot Rolling on the Evolution of Textures at the surface of 18%Cr Ferritic Stainless Steel Sheet)

  • 편영범;강형구;허무영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 춘계학술대회 논문집
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    • pp.411-414
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    • 2008
  • In order to study the effect of lubrication during hot rolling, ferritic stainless steel (FSS) sheet were hot-rolled with and without application of lubrication. The effect of two hot rolling processes on the evolution of texture and microstructure after hot rolling, cold rolling and subsequent recrystallization annealing was studied by means of macro-texture analysis and microstructure observations. After hot rolling, the specimen rolled with lubrication showed rolling textures at the sheet surface, while the specimen rolled without lubrication displayed shear textures in the outer layers of the sheet. Hot rolling with lubrication was beneficial to the formation of strong recrystallization textures at sheet surface. However, hot rolling with lubrication led to the formation of orientation colonies in outer thickness layers of the recrystallized sheet.

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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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압연조건에 따른 변형률 상태의 변화와 집합조직의 형성 (Evolution of Strain States and Textures During Rolling with Various Conditions)

  • 강형구;허무영
    • 소성∙가공
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    • 제15권7호
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    • pp.479-484
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    • 2006
  • The evolution of strain states and textures during rolling with various conditions was investigated by finite element method (FEM) simulations and measurements of rolling textures. Symmetrical rolling with a high friction gives rise to a strong variation of shear strains in rolled sample leading to the formation of texture gradients throughout the thickness layers. A small variation of shear strains during rolling with a well lubrication condition leads to the formation of a fairly homogeneous rolling texture throughout the sheet thickness. During asymmetrical rolling, a proper control of rolling parameters provides the evolution of a fairly homogeneous shear texture throughout the whole sheet thickness.

탄탈륨 판재의 어닐링 집합조직과 결정립 크기 (Annealing Textures and Grain Size of Tantalum Sheet)

  • 강전연;박성원;박준영;박성준;송이화;박성택;김광련;오경원
    • 소성∙가공
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    • 제28권5호
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    • pp.247-256
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    • 2019
  • In this study, the development of annealing textures in cold rolled and annealed tantalum sheets was analyzed using electron backscatter diffraction. At $900^{\circ}C$, the textures of the recrystallized grains in the partially and completely recrystallized microstructures displayed significant similarities. The average diameter of the recrystallized grains with ${\gamma}-fiber$ orientations exceeded that of grains with different orientations, and the average growth rates were unrelated to the orientations after an initial stage of recrystallization. Additional cold rolling and annealing was done for controlled initial microstructures and textures inherited from various processes of prior cold rolling and annealing. This second cycle of the process resulted in stronger textures with major ${\gamma}-fiber$ orientations as a result of the enhanced ${\gamma}-fiber$ orientations in the preceding textures. A coarse-grained prior microstructure resulted in a weaker annealing texture than a fine grained one regardless of the stronger previous texture, which was occasioned by the sub-structures of the minor orientations at local deformation inhomogeneities such as sharp in-grain shear bands.

알루미늄 5182 압연 판재의 어닐링 집합조직 (Textures Evolution of Rolled AA5182 Alloy Sheets after Annealing)

  • 김기주;신광선;정효태;백영남
    • 한국자동차공학회논문집
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    • 제13권6호
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    • pp.128-134
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    • 2005
  • In order to fabricate the aluminum alloys with good drawability, the textures evolution of the AA5182 sheets after rolling and annealing was studied. The measurement of the deformation textures was carried out for the sheets which were cold rolled with high reduction ratio by using the symmetric roll. In addition, the change of the recrystallization texture was investigated after heat-treatments of the rolled sheets with various heat treatment conditions. Rolling without lubrication and subsequent annealing led to the formation of favorable $rot-C_{ND}\;\{001\}<110>\;and\;{\gamma}-fiber ND//<111>$ textures in AA5182 sheets. From the results, the ${\gamma}$-fiber ND//<111> component well evolved during rolling at highest reduction ratio (over $90\%$, l/d parameter of 6.77). Among shear deformation textures, the ${\gamma}$-fiber ND//<111> was not rotated in holding time of $180\~7,200$ seconds at $350^{\circ}C$. The Monte-Carlo technique was used and could be representatively simulated these textures evolution during recrystallization.

Sandwich 판재 시료의 냉간압연 시 각 판재 층의 변형상태 및 집합조직의 형성 (Evolution of strain states and textures in sandwich sheet samples during cold rolling)

  • 김종국;허무영;지광구
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 추계학술대회논문집
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    • pp.138-139
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    • 2003
  • Sandwich sheet samples comprising AA1050/AA1050/AA1050, AA3003/AA1050/AA3003, AA3003 AA3003 AA3003. AA1050/AA3003/AA1050, SUS430/AA3003/SUS430, AA3003/SUS430/AA3003 and SUS430/SUS430/SUS430 were cold rolled in order to clarify the evolution of strain states md textures in the sandwich samples. To investigate the effect of stacking sequences of the samples on strain and texture, the relative contribution of each layer to the total reduction was measured and textures of the mid-layer sheet of sandwich samples were determined.

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430 스테인리스강의 미세조직 및 집합조직 형성에 미치는 냉간압연 및 소둔조건의 영향 (Effect of Cold Rolling and Annealing Conditions on the Microstructure and Texture Evolution)

  • 김광육
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.202-205
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    • 2000
  • The effect of two step cold rolling and intermediate annealing conditions on the microstructure and texture evolution in type 430 stainless steel has been investigated tin order to improve ridging characteristic and deep drawability. The rolling and recrystallization textures were examined by orientation distributionfunction(ODF) and electron backscattered diffraction(EBSD). The observation showed that the intensity of ${\gamma}$-fiber was increased with two-step cold rolling process and so ridging characteristic and deep drawability were considerably improved. The relation between these properties an texture evolution has been discussed.

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