• Title/Summary/Keyword: Solidification

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Filling and Solidification Analysis for the Casting Process of Cylinder Liner (실린더 라이너 주조공정에 대한 충전 및 응고해석)

  • Kim, Jung-Hoon;Kim, Chang-Hee
    • Journal of Korea Foundry Society
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    • v.24 no.4
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    • pp.225-230
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    • 2004
  • Computer simulation of mold filling and solidification has been performed in order to analyze the flow and solidification phenomena for the casting process of cylinder liner. The simulation result of mold filling shows that the molten metal flows into the mold in stable without scattering. The simulation results of solidification indicate that the last solidified area is located in the feeder. The temperature variation in casting is measured in actual casting and the result is compared with calculation result.

A Study on the Turbulent Flow and Solidification in a Continuous Casting Process with Electromagnetic Brake (EMBR을 이용한 연주공정에서의 난류유동 및 응고에 대한 연구)

  • Kim, Deok-Soo;Kim, Woo-Seung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.3
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    • pp.374-387
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    • 1999
  • Two-dimensional turbulent fluid flow and solidification were investigated in a continuous casting process of a steel slab with electromagnetic field. The electromagnetic field was described by the Maxwell equations. The enthalpy-porosity relation was employed to suppress the velocity within a mushy region. A revised low-Reynolds number $k-{\varepsilon}$ turbulence model was used to consider the turbulent effects. It is shown that the temperature gradient in the casting direction in the case with EMBR becomes very weak compared to that of the case without EMBR. The results also show that the velocity profiles of the case with solidification are quite different from those of the case without solidification.

A Study on the Filling and Solidification Process During Gravity Casting Using Implicit VOF Method (암시적 VOF법을 이용한 중력주조에서의 충전 및 응고과정에 대한 연구)

  • Im, Ik-Tae;Kim, Woo-Seung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.1
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    • pp.102-113
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    • 2000
  • In this study, a three-dimensional gravity casting problem has been examined to investigate a coupled phenomenon of the filling and solidification process. This work simultaneously considers the two key phenomena of metal casting : the fluid flow during mold filling, and solidification process. The VOF method is used to analyze the free surface flow during filling and the equivalent specific heat method is employed to model the latent heat release during solidification. The time-implicit filling algorithm is applied to save the computational time for analyzing the mold filling process. The three-dimensional benchmark problem used in the MCWASP VII has been solved using both the implicit and explicit algorithm, and the present results are compared with the benchmark experimental results and the other numerical results.

Finite Element Analysis of Compression Holding step Considering Solidification for Semi-Solid Forging (반용융 단조에서 응고 현상을 고려한 가압유지 단계의 유한요소해석)

  • Park, J.C.;Park, H.J.;Cho, H.Y.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.10
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    • pp.102-108
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    • 1997
  • The technology of Semi-Solid Forging (SSF) has been actively developed to fabricate near-net- shape products using light and hardly formable materials. Generally, the SSF process is composed of slug heating, forming, compression holding and ejecting step. After forming step in SSF, the slug is compressed during a certain holding time in order to be completely filled in the die cavity and be accelerated in solidification rate. This paper presents the analysis of temperature, solid fraction and shrinkage at compression holding step for a cylindrical slug, then predicts the solidification time to obtain the final shaped part. Enthalpy-based finite element analysis is performed to solve the heat transfer problem considering phase change in solidification.

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A study on the formation of surface solidification layer in compacted/vermicular graphite cast iron (CV흑연주철(黑鉛鑄鐵)에서의 표면응고층(表面凝固層) 생성(生成)에 관(關)한 연구(硏究))

  • Park, K.S.;Lee, S.I.;Kim, S.Y.
    • Journal of Korea Foundry Society
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    • v.6 no.1
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    • pp.20-26
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    • 1986
  • In order to investigate the solidification characteristics of CV. graphite cast iron, decantation technique and thermal analysis test were used. Solidification characteristics were studied in the specimens with various compositions and graphite shape. The results were as follows; 1. The first surface solidifcation layer is formed along the mold wall by the growth of austenite dendrites in hypoeutectic composition and thin solid film in hypereutectic composition. 2. The mushy degree of solidifcation of hypereutiectic composition is higher than that of hypoeutectic. 3. In hypoeutectic, the effect of change of the mushy degree of solidification on the graphite shape is small, however, in hypereutectic the mushy degree of solidification becomes higher in order of flake, CV, and spheroidal graphite cast iron.

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Solidification Structure of Al-2.7wt%Li Alloys by Cooling Rate Controlled (냉각속도에 따른 Al-2.7wt%Li 합금계의 응고조직)

  • Shim, Deung-Seub;Choe, Jeong-Cheol;Cho, Hyung-Ho;Kwon, Hae-Wook
    • Journal of Korea Foundry Society
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    • v.11 no.5
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    • pp.398-405
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    • 1991
  • Al-Li alloy has a high strength with low density. Practically this alloy should use by the material which made from the rapid solidification. Therefore we examine the solidification structures of alloy with cooling rate. According to cooling rate increased, grain size and secondary dendrite arm spacing were smaller. Also grain size was further smaller by Zr added. To obtain more fine solidification structure, rapid solidification by single roll melt spinning was performed. According to higher wheel speed, cooling rate increased and cell size was smaller. Because of locally different cooling rate, different cell size was obtained in same specimen. More than cooling rate $10^6^{\circ}C$ /sec, zone A(insensible zone to corrosion)was obtained.

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On Compositional Convection in Near-Eutectic Solidification System Cooled from a Bottom Boundary

  • Hwang, In Gook
    • Korean Chemical Engineering Research
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    • v.55 no.6
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    • pp.868-873
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    • 2017
  • Natural convection is driven by the compositional buoyancy in solidification of a binary melt. The stabilities of convection in a growing mushy layer were analyzed here in the time-dependent solidification system of a near-eutectic melt cooled impulsively from below. The linear stability equations were transformed to self-similar forms by using the depth of the mushy layer as a length scale. In the liquid layer the stability equations are based on the propagation theory and the thermal buoyancy is neglected. The critical Rayleigh number for the mushy layer increases with decreasing the Stefan number and the Prandtl number. The critical conditions for solidification of aqueous ammonium chloride solution are discussed and compared with the results of the previous model for the liquid layer.

Change of Secondary Dendrite Arm Spacing of Hypoeutectic Al-Si Alloys according to Si Content and Cooling Rate (아공정 Al-Si 합금에서 Si 함량과 냉각속도에 따른 제이차수지상간격의 변화)

  • Park, Kyeong-Seob;Kim, Hee-Soo
    • Journal of Korea Foundry Society
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    • v.37 no.4
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    • pp.108-114
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    • 2017
  • In this study, we investigated the effect of the Si content on the secondary dendrite arm spacing (SDAS) of hypoeutectic Al-Si binary alloys in the range of 4~10 wt% Si. Cooling curves were measured during the solidification of the alloy cast in a step-wise mold. We compared two kinds of solidification time: the first is the total solidification time for both dendritic and eutectic growth, and the second is the solidification time for only dendritic growth. The proportional constant in the relationship between SDAS and cooling rate was estimated, as this constant represents the stability of the cast microstructure. The proportional constant decreased with the Si contents from 4 wt% to 8 wt%, and it remains relatively uniform with up to 10 wt% of Si.

Control of Contaminants Elution by Solidification of Contaminated Soil (오염토양의 고형화에 따른 오염물질 용출제어)

  • Chung, Ha-Ik;Cho, Jin-Woo;Yu, Jun;Lee, Yong-Su
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.739-742
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    • 2002
  • Immobilization of contaminants in contaminated soils by solidification processes is an attractive potential remediation process. In this study, the treatability of lead, copper, toluene, and COD was investigated by leaching test. Industrial sand was adopted as the test material and was contaminated with lead copper, and toluene to 100mg/kg, 500mg/kg, 200mg/kg respectively. P solidifying agent was used as the binder(20% by weight of contaminated soil) in the solidification treatment. The leachability of contaminants leached from the solidified soil was evaluated using column test. The percentage of contaminants leached from the solidified soil was significantly reduced by reaction of waste species with cement components and encapsulation reaction of binder. Based on the tests, it is ascertained solidification process can be a very effective method to control the elution of contaminants from the contaminated soil.

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Visualization of double-diffusive convection during solidification processes of a binary mixture (이성분혼합물의 응고과정중 이중확산대류의 가시화)

  • Jeong, U-Ho;Jeong, Jae-Dong;Yu, Ho-Seon;Lee, Jun-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.4
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    • pp.440-451
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    • 1998
  • An experimental study has been conducted to investigate solidification of NH$_{4}$CI-H$_{2}$0 mixtures inside a vertical rectangular enclosure. Solidification process is visualized by the shadowgraph method. Emphasis is placed on the effect of solidification parameters such as the aspect ratio, cooling wall temperature and initial composition. The aspect ratio shows a dominant effect on the number and developing time of the double diffusive layers which reveals the relative strength of solutal convection to thermal convection. Similar flow pattern is observed when the concentration difference between interdendritic liquid and the pure liquid which drives solutal convection is the same regardless of the different cooling wall temperature and initial concentration.