• Title, Summary, Keyword: Aluminum Tube

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Loading Path Optimization in Aluminum Tube Hydroforming using Response Surface Method (반응표면법을 이용한 알루미늄 튜브 하이드로포밍의 하중경로 최적화)

  • Lim, H.T.;Kim, H.J.;Kim, H.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.314-317
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    • 2007
  • Automotive rear subframe of aluminum tube was developed by using hydroforming process, based on the numerical analysis and physical tryouts. In the previous study, the effect of prebending was evaluated on the basis of forming limit diagram which had been obtained from free bulging, T-shape forming and cross-shape forming, using the developed tube hydroformability testing system. In order to get the sound products, appropriate internal pressure is to be imposed corresponding to the axial feeding. In this study, the loading path, the combination of internal pressure and axial feeding during the process, was optimized to ensure minimum thickness variation and dimensional accuracy, by using response surface method.

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A study on the deformation characteristic of heat-treated 6061,7075 aluminum alloy with changes of elevated temperature and strain rate for warm hydroforming (열처리된 알루미늄 6061, 7075 합금의 온간 액압 성형 적용을 위한 온도 및 변형 속도 변화에 따른 변형 특성 연구)

  • Yi H. K.;Moon Y. H.;Sohn S. M.;Lee M. Y.;Suh D. W.;Lee S. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.23-26
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    • 2004
  • The deformation behaviors of fully annealed or T6-treated 6061 and 7075 aluminum tubes are investigated at elevated temperature using uniaxial tensile test. Fully annealed 6061 and 7075 tube, and T6-treated 7075 tube do not show sharp local necking with an elongation of $50\%$ at tensile temperature of $300^{\circ}C$, accordingly, it is expected that warm hydroforming process can be applied. The increase of tensile temperature does not significantly affect the total elongation of T6-treated 6061 tube.

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Forming Limit Diagram of an Aluminum Tube Through Hydroforming Tests (액압성형 시험을 통한 알루미늄 튜브 재료의 성형한계도)

  • Kim J. S.;Lee J. K.;Park J. Y.;Lee D. J.;Kim H. Y.;Kim H. J.
    • Transactions of Materials Processing
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    • v.14 no.6
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    • pp.514-519
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    • 2005
  • A tube hydroformability testing system was designed and fabricated enabling to apply the forming condition along arbitrarily pre-programmed internal pressure-axial feed path. The free-bulging and T-forming tests were carried out on the extruded aluminum (A6063) tube specimens with 40.6 mm outer diameter and 2.25 mm thickness. Nine different combinations of internal pressure and axial feed, yielding different strain paths from one another, were taken into consideration in order to induce bursting at various deformation modes. Major and minor strains were automatically measured from deformed grids around the fracture using a stereo-vision-based surface strain measurement system, named ASIAS. The forming limit diagram of the A6063 tube material was successfully obtained. Most of the data points acquired from free bulging and T-forming tests appeared in the range of negative minor strain on the FLD and are mostly located near the strain paths calculated from explicit finite element simulations. The forming limit obtained from tests after pre-tension was considerably lower than that from tests without pre-tension, which showed the strain path-dependency of the forming limit as well known in the sheet forming fold.

A Study on Roundness Improvement of Heat-treated Large Diameter Aluminum Tube-turning with Collet Type Jig (열처리된 대직경 알루미늄 튜브선삭에서 콜릿지그를 통한 진원도 향상에 관한 연구)

  • Kim, Pyeong-Ho;Lim, Hak-Jin;Lee, Jung-Min;Lee, Jong-Hwan;Kim, Jung-Suk
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.21 no.5
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    • pp.824-829
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    • 2012
  • The purpose of this study is to evaluate the proposed jig for turning process of large-scale aluminum tube of D500mm through Finite Element Analysis (FEA). Also, a machining evaluation is conducted with general heat-treated and cryogenic heat-treated tubes. Dimensions of the specimens are determined to be suitable for collet appearance. The characteristics of equivalent stress and strain according to the expansion of the collet are evaluated by FEA. The aluminum tubes which are heat-treated by T4/T6 condition and cryogenic condition are machined by using a large-scale lathe machine and the roundness of machined tube is evaluated by using a 3D measuring machine. Through the results of this study, effects of each heat treatment and residual stress on the roundness are established.

Effect of Heat Treatments on the Hydroformability of Aluminum Tubes (알루미늄 관재의 액압성형성에 미치는 열처리의 영향)

  • Lee, M.Y.;Kang, C.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.3
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    • pp.146-150
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    • 2004
  • Because of the social needs for energy saving and the rigid environmental regulation, the development of light materials and new economical manufacturing technologies have been actively investigated. Recently, the hydroforming of high strength aluminum tube has attracted great interest due to its good strength-to-weight ratio, which could play an important role in lightweighting of automobile. However, the limited formability of high strength aluminum alloys is considered to hinder the active application of the hydroforming process. In this paper, the hydroformability of aluminum tubes with different heat treatments was investigated as the basic research of the hydroforming process for the high strength aluminum tubes.

Comparison of Heat Transfer Performance and Pressure Drop of Fin-Tube and Aluminum Heat Exchangers (핀-튜브 열교환기와 알루미늄 열교환기의 전열성능과 압력강하 특성비교)

  • Chang, Keun-Sun;Lee, Hyun-Su;Kim, Jae-Duck
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.2
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    • pp.222-229
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    • 2009
  • This study presents comparison of heat transfer and air side friction characteristics in a condenser condition of air conditioner between Louver fin-tube heat exchangers and aluminum parallel heat exchangers. All experiments are performed using an air-enthalpy type calorimeter, which is designed based on the method described in ASHRAE standards. The air velocities crossing the heat exchanger tubes are varied from 0.7 to 1.6 m/s with 0.3 m/s interval, maintaining air dry temperature and relative humidity at $20^{\circ}C$ and 60% respectively. Water temperature and flow rate inside the tube are $70^{\circ}C$ and 10 LPM, respectively. Experimental results show that the heat transfer performances of aluminum heat exchangers are 17-163% higher than those of Louver fin-tube heat exchangers based on the data per unit volume, mass, and heat transfer area, whereas air side pressure drops of aluminum heat exchangers are 19-81% lower.

Evaluation of Elastic Properties of Anisotropic Cylindrical Tubes Using an Ultrasonic Resonance Scattering Spectroscopy

  • Kim, Jin-Yeon;Li, Zheng
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.6
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    • pp.548-557
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    • 2010
  • An ultrasonic resonance scattering spectroscopy technique is developed and applied for reconstructing elastic constants of a transversely isotropic cylindrical component. Immersion ultrasonic measurements are performed on tube samples made from a boron/aluminum composite material to obtain resonance frequencies and dispersion curves of different guided wave modes propagating in the tube. Theoretical analysis on the acoustic resonance scattering from a transversely isotropic cylindrical tube is also performed, from which complete backscattering and resonance scattering spectra and theoretical dispersion curves are calculated. A sensitive change of the dispersion curves to the elastic properties of the composite tube is observed for both normal and oblique incidences; this is exploited for a systematic evaluation of damage and elastic constants of the composite tube samples. The elastic constants of two boron/aluminum composite tube samples manufactured under different conditions are reconstructed through an optimization procedure in which the residual between the experimental and theoretical phase velocities (dispersion curves) is minimized.

Effects of Heat Treatment on Hydroformability of Aluminum Tubes (알루미늄 튜브의 열처리 조건에 따른 액압 성형성 연구)

  • Lee M. Y.;Sohn S. M.;Jo Y. J.;Lee S. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.364-367
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    • 2001
  • Recently social demands of fuel economy and environmental regulation require the development of light materials and new manufacturing technologies. In this point, aluminum tube hydroforming, which is satisfied with good strength-to-weight ratio and recyclability, is new innovative concept. but, up to now the level of that is relatively low. In this paper, we studied formability of different aluminum tubes in different heat treatments under internal pressure and axial feeding, and mechanical properties of aluminum tubes before and after hydroforming.

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Bending Performances and Collapse Mechanisms of Light-weight Aluminum-GERP Hybrid Square Tube Beams (경량화 알루미늄-GFRP 혼성 사각관 보의 굽힘성능 및 붕괴 메커니즘)

  • Lee, Sung-Hyuk;Kim, Hyung-Jin;Chang, Young-Wook;Choi, Nak-Sam
    • Composites Research
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    • v.20 no.3
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    • pp.8-16
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    • 2007
  • Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.