• Title/Summary/Keyword: Electro-magnetic stirring

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Fabrication of Particulates Reinforced Metal Matrix Composites by Electro-Magnetic Stirring and Reheating Process for Thixoforming (전자기식 교반법을 이용한 입자강화형 금속복합재료의 제조 및 Thixoforming을 위한 재가열 공정)

  • 임해정;강충길;조형호
    • Transactions of Materials Processing
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    • v.9 no.5
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    • pp.494-503
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    • 2000
  • The electro-magnetic stirring and mechanical process were applied to fabricate particulate metal matrix composites(PMMCs) with various particle size. The mechanical test on PMMCs was carried out in order to clarify the effect of 76 heat treatment on tensile behaviors. In order to study the thixoforming of PMMCs, fabricated billet are reheated by using the coil designed as a function of length between PMMC billet and coil surface, coil diameter and billet length. The effect of reinforcement distribution on billet temperature variation has been investigated with the calculated solid fraction theory based on a function of matrix alloy and volume fraction of reinforcement.

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Multi-Step Reheating Process of Metal Matrix Composites for Thixoforming (Thixoforming을 위한 금속 복합재료의 다단 재가열 공정)

  • 허재찬;강충길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.180-183
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    • 1997
  • The forming process of metal matrix composites by the die casting and squeeze casting process are limited in size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting, squeeze casting and compocasting. The characteristics of thixoforming process can decrease the liquid segregation because of he improvement in fluidity in a globular microstructure state and utilizes flow without air entrapment. Therefore, in order to obtain the sound parts of metal matrix composites by using thixoforming process which as co-existing solidus-liquidus pahse, it si very important to obtain reheating condition. However, for he thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

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The effect of forging process conditions of semi-solid aluminum material on mechanical properties (반용융 알루미늄재료의 단조공정조건이 기계적 성질에 미치는 영향)

  • Gang, Chung-Gil;Gang, Dong-U
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.9
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    • pp.1400-1413
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    • 1997
  • Semi-solid forging(SSF) process of A356 aluminium alloy has been studied to assess the effect of process variables on the component integrity. Semi-solid material(SSM) was fabricated by mechanical and electro-magnetic stirring process. The fabricated SSM by using mechanical stirring process has been carried out on cooling rate of 0.022.deg. C/sec 0.0094.deg. C/sec and stirring speed n=600, 1000 rpm, respectively. The fabricated SSM by using electro-magnetic stirring process is supplied by Pechiney. The holding time and temperature in the semi-solid state before forging also affects the globular microstructure of alloy. Therefore, the influence of these two parameters is discussed in terms of the microstructure of alloy. The SSF process has been conducted with three different die temperatures($T_{die}$=250.deg. C, 300.deg. C, 350.deg. C) and two kinds of gate types(straight gate and orifice gate). This paper is to investigate the influence of gate shapes of die on filling phenomena in SSF process more deeply. The mechanical properties of forged components were also investigated for variation of process conditions such as die temperature, gate shape and SSM.

Reheating Process of Particulates Reinforced Metal Matrix Composites for Thixoforming (Thixoforming을 위한 입자강화형 금속복합재료의 Reheating 공정)

  • 이동건;안성수;강충길
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.218-223
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    • 2000
  • A both mixing process of electro-magnetic stirring and mechanical process technique were used to fabricate particulate metal matrix composites(PMMCs) for variation of particle size. The PMMCs were tested for their tensile test for with and without heat treatment with T6. PMMCs fabrication processing conditions for both electrical and mechanical process are also suggested. In order to thixoforming of PMMCs, fabricated billet are reheated by using the optimal coil designed as a function of length between PMMC billet and coil surface, coil diameter and billet length. The effect of reinforcement distribution on billet temperature variation are investigated with calculated solid fraction theory proposed as a function of matrix alloy and volume fraction of reinforcement.

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The Grain Size Control of A356 Aluminum Alloy by Electromagnetic Stirring (수평식 전자교반을 이용한 A356 합금의 결정립 제어)

  • Ko J. H.;Seo P. K.;Choi W. S.;Kang C. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.111-114
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    • 2004
  • It is many devices to obtain the globular structure because the globularity of the structure is the key to the low apparent viscosity and also to good rheological properties. In this study, the morphology of the change of primary Al phase in A356 alloy by electro magnetic stirrer was investigated to obtain the globular structure. The parameters are the current, stirring time, pouring temperature individually. The greater current and longer stirring time was to get the finer the primary however in case of over the 80A of current and 60sec of stirring time, the primary Al was merged together and was increased. The effect of pouring temperature has an important effect on the size of primary phase. About the $675^{\circ}C$, the primary Al was very fined.

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The effect of the primary particle of the A356 Alloy according to different wall thickness of the sleeve of die-casting by electromagnetic stirrer (전자교반시스템에서 Sleeve 의 크기가 유동특성과 미세조직에 미치는 영향)

  • 고재홍;서판기;강충길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.660-663
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    • 2004
  • Recently in the automotive industries, light and high quality material is strongly required because of emissions regulation issues. In the electromagnetic stirring process, it has many merits that are the exact control ability about material processing and a good point of the protection of environment. In this paper, the morphology of the change of primary Al phase in A356 alloy by electro magnetic stirrer was investigated to obtain the globular structure. The parameters are the current, stirring time, pouring temperature and cooling rate of different wall thickness; 5mm, 15mm, 25mm respectively. By proper selection of the processing parameters, globular primary particles can be obtained by electromagnetic stirrer.

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Continuous Combined Process for Homogeneous Dispersion of Ceramic Particle and Aluminum Materials (세라믹 입자/알루미늄 소재의 연속복합 균일분산)

  • 이동건;이승후;강충길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.381-384
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    • 2001
  • The combined stirring method to uniform distribution of particle is consisted of two strring force both electro-magnetic stirring generated from induction heating and mechanical stirring with graphite stirrer. PMMC billets were fabricated with the volume fractions ranged from 0% to 20% and particle sizes ranged from 14$\mu\textrm{m}$ to 25$\mu\textrm{m}$. It is important to control the size of primary ${\alpha}$-AI solid particles because it could become the cause of the particle pushing or capture phenomena from the fact that secondary dendrite arm spacing size depends on the cooling rate during the solidification in hypoeutectic AI-Si alloy.

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Induction Heating of Vertical Type for Semi-Solid Forging with Metal Matrix Composites (반용융 단조를 위한 복합재료의 수직형 고주파 유도가열)

  • 이동건;허재찬;강충길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.385-388
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    • 2001
  • In part forming process of metal matrix composites, the die casting and squeeze casting process are limited the size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting squeeze casting and compocasting. However, for the thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

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The Effect of Electromagnetic Stirring on the Microstructure of A356 Al Alloy by the Continuous Casting Process (A356 합금의 연속주조시 전자기 교반에 따른 미세조직 변화)

  • Kim, Won-Bae;Kwon, Tae-Woo;Kim, Jong-Chul;Park, Tae-Ho;Ye, Byung-Joon
    • Journal of Korea Foundry Society
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    • v.25 no.4
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    • pp.156-160
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    • 2005
  • There are many factors that influence solidification behavior during continuous casting, e.g. include superheat, casting speed, cooling rate and holding time. However, when melt is stirred by electromagnetic force, there would be some changes in its solidification behavior compared to that of the ordinary casting process. In this study, the billets of A356 alloy with a diameter of 3 inch were fabricated with electromagnetic stirring under various conditions of superheat, casting speed and input voltage of electro magnetic stirring (EMS) device. The microstructure was also investigated under the various casting conditions and electromagnetic input voltages. When increase in input voltage, the microstructure was changed from dendritic to rosette type and finally to spheroidal. With pouring temperature, casting speed and electromagnetic input voltage were $650^{\circ}C$, 100 mm/min and 140 V, respectively, the billet with a diameter of 3 inch, which has a uniform dispersed spheroidal particles in the whole area of billet except for the surface area, was manufactured.