• Title/Summary/Keyword: Extrusion

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COMBINED FORWARD-BACKWARD EXTRUSION WITH REVERSE RAM MOTION -APPLICATION TO FORMING OF GEAR-

  • Otsu M.;Hayashida D.;Osakada K.;Hanami S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10b
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    • pp.158-161
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    • 2003
  • Extrusion of forward-gear and backward-rod by combined extrusion with controlling the extrusion velocity using a counter tool is studied. In the combined forward-backward extrusion with controlling extrusion velocity, only parts with short gear can be formed. To obtain longer gear parts, extrusion with reverse ram motion is carried out after the combined forward-backward extrusion process. In this method, combined forward-backward extrusion is carried out until excessive extrusion length is attained and then, the motion of the punch is stopped and the counter tool is moved in the inverse direction and returned to the position for obtaining the desired extrusion length. The experiment is carried out by using lead for billets as a model material. With reverse ram motion, longer gear teeth without under-filling defect can be formed than that by only combined extrusion with controlling extrusion velocity.

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Analysis of microstructure and texture evolution in AZ31Mg alloy fabricated by direct/indirect extrusion process (직/간접 압출공정에 의해 제조된 AZ31Mg 합금의 미세조직 및 집합조직 변화 분석)

  • Kim, D.H.;You, B.S.;Park, S.S.;Yoon, D.J.;Choi, S.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.38-41
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    • 2008
  • To investigate the evolution of microstructure and texture in AZ31 Mg alloy, direct/indirect extrusion process was carried out at $300^{\circ}C$ with various extrusion speeds. The distribution of grain size depends on extrusion method and extrusion speed. More homogeneous grain site can be obtained at higher extrusion speed of indirect extrusion process. Extrusion speed does not affect significantly texture evolution during extrusion process regardless of extrusion method. ODF section is more useful to understand texture evolution during extrusion process compared with pole figure.

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Effect of Extrusion Conditions on Microstructures and Mechanical Properties of AM80 Magnesium Alloys (AM80 마그네슘 합금의 미세조직 및 기계적 특성에 대한 압출조건의 영향)

  • Lee, S.K.;Kim, D.H.;Kim, D.H.;Lim, S.G.
    • Transactions of Materials Processing
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    • v.27 no.6
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    • pp.379-385
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    • 2018
  • This study investigated the effect of extrusion conditions on microstructures and mechanical properties of AM80 magnesium alloys. The billets of magnesium alloy used for hot extrusion were prepared by permanent mold casting method, and its extrusion was hot direct extrusion with different extrusion conditions. The results of microstructural analysis showed that the main phases in the as-casted alloys were ${\alpha}-Mg$, ${\beta}-Mg_{17}Al_{12}$, and lamella $Mg_{17}Al_{12}$. Hot extrusion results, The tensile strength of the most soundly manufactured extruded bars (extrusion temp: $350^{\circ}C$, extrusion ratio: 27:1, ram speed: 2mm/s) was approximately 327MPa at room temperature. The increase in the mechanical properties of hot-extruded alloys was as a result of grain refinement by dynamical recrystallization during hot extrusion.

Effect of the Design Parameter for Internal Spline Forming Using the Tube (중공축 내접 스플라인 성형을 위한 설계변수의 영향)

  • Wang, C.B.;Lim, S.J.;Park, Y.B.
    • Transactions of Materials Processing
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    • v.15 no.7 s.88
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    • pp.512-517
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    • 2006
  • In this paper, the cold extrusion process for internal spline forming using a thin and long tube has been analyzed by using a rigid plastic finite element code. The internal spline consists of 10 tooths. The cold extrusion process has been focused on the comparisions of load-stroke relation and filling states of the teeth according to design parameters. The design parameters involve extrusion ratio, extrusion angle and friction factor. The internal spline forming can cause the buckling and folding during the cold extrusion process because of using a thin and long tube. The optimum design parameters have been obtained through rigid-plastic finite elements analysis. The extrusion ratio and extrusion angle have great effects on the deformation characteristics of the cold extrusion process.

An Experimental Anlysis in Non-Circular Tube Extrusion Using the Effective Extrusion Ratio (비원형 중공 압출의 유효 압출비를 이용한 실험적 해석)

  • 한철호;김상화
    • Transactions of Materials Processing
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    • v.8 no.5
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    • pp.520-526
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    • 1999
  • In this study a practical formula based on the experime수 랙 the estimation of load in the non-circular tube extrusion with the mandrel is proposed by using the effective extrusion ratio. Through some experiments for the several shaped sections, the coefficients of the empirical equation are determined by ticine as a model material at room temperature. The proposed empirical formula for the estimation of extrusion load will be applicable to the non-steady state as well as steady state for the extrusion of various shaped tubes from hollow billets.

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Thixo-extrusion of Semi Solid 7075 Aluminum Alloys and Mechanical Properties of The Extrudates (반응고 7075 알루미늄 합금의 반용융 압출 및 압출재의 기계적 특성)

  • Choi, Tae-Young;Kim, Dae-Hwan;Kim, Soo-Bae;Shim, Sung-Young;Lim, Su-Gun
    • Journal of Korea Foundry Society
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    • v.34 no.3
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    • pp.87-93
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    • 2014
  • Thixo-extrusion of semi-solid 7075 aluminum alloy and the mechanical properties of its extrudates were investigated. The semisolid alloy was prepared by a cooling slope cast. In other to perform thixo-extrusion, semi-solid 7075 aluminum alloy billets were reheated at the reheating conditions reported in a previous study. The maximum extrusion pressure in thixo-extrusion was 615MPa. This was lower than that of conventional hot extrusion ($P_{max}=940MPa$) at the same extrusion conditions due to the increased fluidity of the alloy billet in the semi-solid state. The values of Rockwell hardness (scale B) at the extrusion direction of the as thixoextruded bar were 48~53HRB and the difference in Rockwell hardness between the transverse direction and the extrusion direction was 5HRB or less. The results show that thxio-extrusion of semi-solid 7075 Al alloy improves the workability and anisotropic with the extrusion direction compared with hot extrusion of the conventional alloy.

Extrusion Die Development of Interior & Exterior Parts for High Speed Train on Aluminum Alloys and Controls of Extrusion Conditions (고속전철 내·외장재용 알루미늄 합금의 압출 금형 개발 및 압출 조건의 제어)

  • Kim, Kee Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.50-55
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    • 2018
  • The important thing in extrusion technology is the design and production of molds. Appropriate design of the molds is essential for achieving the desired extrusion of molds at the same time to maximize the life of the molds and increase their efficiency. The extrusion temperature and extrusion speed are the main parameters at the time of extrusion. Different extrusion conditions should be added depending on the extrusion ratio, physical properties of the material, and type of extrusion. In this study, the extrusion process of various 6xxx series aluminum cast alloys for high speed train interior or exterior parts were investigated. The extruded die design was performed for the 6063, 6061, 6N01, 6005, 5083 and 6060 alloy profiles and an extrusion test was conducted. In addition, the extrusion conditions, such as extrusion pressure following as the billet temperature, extrusion temperature, and materials change, were analyzed. Although the 6063 aluminum alloy can be extruded at the lowest temperature and pressure, the 6061 alloy can be extruded at the highest temperature and pressure. From these results, the successful extruded products were manufactured from these established conditions.

The Characteristics of Hot Hydrostatic Extrusion of AZ Magnesium Alloy (AZ계 마그네슘 합금의 열간 정수압 압출특성 연구)

  • Yoon, D.J.;You, B.S.;Lim, S.J.;Kim, E.Z.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.62-65
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    • 2008
  • Extrusion characteristics of Mg alloys were studied experimentally. The Al-Zn-Mg alloys, AZ31, AZ6l, AZ80, and AZ91 were extruded with hot hydrostatic extrusion process. The hydrostatic process was efficient to reduce surface friction and extend steady state region in extrusion which made it more convenient to examine deformation behavior of the alloys avoiding the disturbance caused by temporary contact state between billet and die, and billet and container. High pressure was cooperative to expand forming limit of the alloys which were applied on the billet during the extrusion process. Extrusion limits were traced in temperature and extrusion speed domain with changing composition of the alloying elements. Effects of process parameters on extrusion load and microstructure evolution were investigated also.

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Unsteady State Analysis of Al Tube Hot Extrusion by A Porthole Die (포트홀 다이에 의한 Al 튜브의 비정상상태 열간 압출 공정 해석)

  • 조형호;이상곤;박종남;김병민
    • Transactions of Materials Processing
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    • v.10 no.4
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    • pp.311-318
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    • 2001
  • Porthole die extrusion has a great advantage in the forming of long hollow section tubes. It is difficult to produce long hollow section tubes with complicated section by the conventional extrusion process with a mandrel on the stem Because of the limit of the length of mandrel and the complexity of cross section. Porthole die extrusion is affected by many parameters, such as extrusion ratio, extrusion speed, die geometry, porthole number, bearing length etc. Up to now, most of studies about porthole die extrusion have been investigated by experiments or steady state FE-analysis. However, in this paper, porthole die extrusion is analysed by the unsteady state 3D FE-simulation. And the result of unsteady state analysis is compared with the experimental result. Also, the surface state of extruded tubes are examined for the various process conditions.

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A Study on the Con-focal Microscope for the Surface Measurements (공초점 현미경을 이용한 물체표면 형상측정에 관한 연구)

  • 강영준;송대호;유원재;백성훈
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.5
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    • pp.73-81
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    • 2003
  • In case of hollow cylinder extrusion using porthole die, the effects of extrusion parameters-temperature, the speed of extrusion, the shape of the die and mandrel-on metal flow in porthole die extrusion of aluminum have been investigated. However, there have been few studies about condenser tube extruded by porthole die. Original metal flow of condenser tube by porthole die extrusion is similar to hollow cylinder extrusion but the estimation of metal flow for extrusion parameters is different. For example, variation of chamber length in hollow extrusion only affects the welding pressure, however, the welding chamber length in condenser tube extrusion influences to the welding pressure as well as the deflection of mandrel. This study was designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection according to angular variation in the bottom of chamber in porthole die. Estimation was carried out using finite element method in as non-steady state. Analytical results can provide useful information the optimal design of porthole die.