• Title/Summary/Keyword: rolling

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Study of the Effect of Loading Path on the Strain and Mechanical Properties of Aluminum with Flat and Groove Rolling Experiment (순수 알루미늄의 판재압연 및 공형압연시 가공경로에 따른 변형분포와 기계적 성질의 예측)

  • Kim, S.I.;Byon, S.M.
    • Transactions of Materials Processing
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    • v.17 no.6
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    • pp.420-428
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    • 2008
  • The effect of loading path changes on the strain and mechanical properties of a commercial pure aluminum was studied using flat rolling and groove rolling. Material during flat rolling undergoes a continuous monotonic compressive loading, while one during groove rolling experiences a series of cross compressive loading. Four-pass flat rolling and groove rolling experiment are designed such that the aluminum undergoes the same amount of the strain at each pass. The rolling experiment was performed at room temperatures. Specimens for tensile test are fabricated from the plate and bar rolled. In addition, the strain distribution for the plate and bar cold rolled specimens is also calculated by finite element method. The results reveal that differences of loading path attributed by monotonic loading(flat rolling) and cross loading(groove rolling) significantly influence the mechanical properties such as yield stress, ultimate tensile stress, strain hardening and elongation. It is clear that the different loading path can give raise to change the deformation history, although it is deformed with same amount of strain for same material.

Effect of friction between roll and sample on residual shear strains in AA1050 sheet during asymmetrical rolling (비대칭 압연한 AA1100 판재에서 잔류전단변형에 미치는 롤과 재료간의 마찰의 영향)

  • 지영규;정효태;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.156-158
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    • 2003
  • Sheets of aluminum alloy 1050 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The variation of the shear strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced residual shear strain gradients throughout the thickness layers.

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Development of 3-dimensional strip rolling analysis

  • Jiang, Zheng-Lian;Park, Hae-Doo;Chung, Jin-Hwan
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.253-256
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    • 1997
  • Through right deduction of theoretical equations and some disposal technique, a 3-dimensional strip rolling coupled analysis software has been successfully developed in this paper, which considers strip plastic deformation and roll elastic deformation simultaneously. The calculated examples with different kinds of rolling conditions all conform to the reality, and results show that the developed 3-dimensional program is applicable to the wide strip.

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Tension Estimation of Interstand Strip in Looperless Hot Rolling Process Using SVR (SVR을 이용한 Looperless 열연 공정에서의 스텐드간 장력 추정)

  • Han, Dong-Chang;Shim, Jun-Hong;Park, Cheol-Jae;Park, Hae-Doo;Lee, Suk-Gyu
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.10
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    • pp.1007-1011
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    • 2007
  • This paper proposes a novel tension estimation of interstand strip in looperless hot rolling process using SVR(Support Vector Regression). The quality of hot coil which is final product of hot rolling process is substantially decided by tension control of finishing rolling in hot rolling process. The fluctuation of the strip tension in conventional hot rolling process is controlled by the strip tension measured by an inter-stand looper. However, the looper can cause a motor trip and tension hunting in hot rolling process, therefore, alternative method is essential to replace it. In this paper, the mathematical modeling of tension mechanism is implemented to estimate the tension using the proposed SVR algorithm without looper in hot rolling process. The simulation results show a reliable estimation performance and a possibility of tension control using SVR technique.

Development of Texture in Aluminum 1100 Sheets during Asymmetrical Rolling. (비대칭 압연시 알루미늄 1100 판재에서 집합조직 형성)

  • 지영규;정효태;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.105-108
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    • 2003
  • Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

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Mathematical Model for Cold Rolling and Temper Rolling Process of Thin Steel Strip

  • Lee, Won-Ho
    • Journal of Mechanical Science and Technology
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    • v.16 no.10
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    • pp.1296-1302
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    • 2002
  • A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in tile setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.

Relationship between Rolling Motion and Microstructural Change in Rolling Element (구름계의 미소조직 변화와 구름운동의 상호관계)

  • 차금환;김대은
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1996.10a
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    • pp.163-167
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    • 1996
  • The life of rolling elements depends on various factors such as operating conditions and material properties. In this work, the effect of microstructure on the rolling behavior is investigated. Specially, the deformations in the substrate regions before and after rolling are compared. It is found that rolling action causes severe flow of material in the direction opposite to the rolling direction in the case of dry rolling direction. With lubrication, the deformation is more severe at the subsurface region rather than at the surface.

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Development of Deformation Texture in Aluminum Sheets during Asymmetrical Rolling with a Roll Speed Ratio of 1.5/l.0 (롤속도 비 1.5/l.0 비대칭 압연 시 알루미늄 판재에서 변형집합조직의 형성)

  • 지영규;정효태;허무영
    • Transactions of Materials Processing
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    • v.12 no.3
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    • pp.244-250
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    • 2003
  • Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed with a roll speed ratio of 1.5/l.0. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

A Study of Rolling Characterization on Mg Alloy Sheet (마그네슘 합금 판재의 압연특성연구)

  • Jeong, Y.G.;Lee, J.B.;Kim, W.J.;Lee, G.A.;Choi, S.;Jeong, H.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.53-56
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    • 2006
  • Magnesium alloy AZ31, which processed by conventional rolling or extrusion, has high anisotropy of mechanical properties in its strength and elongation at room temperature. We compared the influence of differential speed rolling with conventional rolling process on microstructure and mechanical properties of commercial AZ31 sheet. Commercial AZ31 alloy sheets were processed with conventional and differential speed rolling with thickness reduction ratio of 30% at a various temperature. The elongation of AZ31 alloy, warm-rolled by differential speed rolling is larger than those rolled by conventional rolling. Besides, grain size and distribution on microstructure of the conventional rolled materials were coarse and inhomogeneous, on the contrary, those of the differential speed rolled were fine and homogeneous.

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Prediction for Rolling Force in Hot-rolling Mill Using On-line learning Neural Network (On-line 학습 신경회로망을 이용한 열간 압연하중 예측)

  • Son Joon-Sik;Lee Duk-Man;Kim Ill-Soo;Choi Seung-Gap
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.1
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    • pp.52-57
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    • 2005
  • In the foe of global competition, the requirements for the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a mai or change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved. In this paper, an on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.