• Title/Summary/Keyword: Semi-Solid process

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The Effect of Plunger Tip Shape on the Formability in Semi-Solid Die Casting Process (반용융 다이캐스팅 공정에 있어서 플런저 팁의 형상이 성형성에 미치는 영향)

  • 서판기;손영익;강충길
    • Transactions of Materials Processing
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    • v.11 no.4
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    • pp.312-322
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    • 2002
  • In this study, an innovative semi-solid die casting technology to replace heavier cast iron compressor parts with lightweight aluminum castings was proposed, and the application possibility for home-appliance component was investigated. The most important factors regarding the semi-solid die casting process are the reheating process of the raw materials to the semi-solid state, specifications of the forming machine, the optimal injection conditions and die design. Materials used in this study were A3S7 and hSn alloys fabricated by the electromagnetic stirring process. The optimal injection conditions for semi-solid die casting process were Presented with the reheating conditions of the semi-solid materials. To investigate the effect of plunger tip shape on the formability and mechanical properties in semi-solid die casting process for complicated shape part, two kinds of plunger tip shape with long and short plunger tip taper are proposed.

Development of Image Analysis Program for Microstructure in Semi-solid Forming Product (반용융 성형 제품의 미세조직 영상분석을 위한 프로그램 개발)

  • Kwon, Soon-Goo;Park, Joon-Hong
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.1
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    • pp.3-9
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    • 2001
  • Many products related to automobile and airplane have been manufactured by semi-solid process. There are many parameters in semi-solid process such as punch velocity, die temperature, and solid fraction of material. Among these parameters, solid fraction of material is one of the most important factors to determine quality of product. To obtain solid fraction of a certain semi-solid product is very necessary and useful for inspecting and analyzing the product. In this paper, image analysis program for microstructure by semi-solid forming process has been developed with the simple apparatus such as a personal computer and scanner, instead of expensive image analyzer.

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Finite Element Analysis for Forming Process of Semi-Solid Material Considering Induction Heating (유도가열을 고려한 반용융 재료의 성형공정에 관한 유한요소 해석)

  • Park, W.D.;Ko, D.C.;Kim, B.M.;Park, J.C.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.8
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    • pp.82-91
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    • 1997
  • The major objective of this study is to establish analytical technique in order to analyze the behaviour of semi-solid material considering induction heating of the billet. Induction heating process is analyzed by using commerical finite element software. ANSYS. The finite element program, SFAC2D, for the simulation of deformation in semi-solid state is developed in the present study. The semi-solid behaviour is described by a viscoplastic model for the solid phase, and by the Darcy's law for the liquid flow. Simple compression and closed-die compression process considering induction heating are analyzed, and also it is found that the distribution of initial solid fraction of the billet has an important effect on deformation behaviour of semi-solid material. In order to verify the effectiveness of proposed analytical technique the simulation result is compared with experimental result.

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Assessment of mechanical Properties of Thixotropic Al-Si Materials in Semi-Solid Forming Process (반용융 성형공정에서 Thixotropic Al-Si 소재의 기계적 성질 평가)

  • 허재찬
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.56-62
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    • 2000
  • Semi-solid forming process has some advantages such as successful manufacturing of high quality components with less inner defects suitable for less machining high productivity and energy-saving effect. the thixotropic behavior(solid-like in the unperturbed state and liquid-like during shearing) has been the basis for the semi-solid forming process. The main focus of this article is the investigation of the effect of T6 heat treatment and alloying elements on the mechanical properties in the semi-solid formed products using thixotropic hypoeutectic (A357 and ALTHIX 86S) and hypereutectic(A390) materials. The new methods to produce semi-solid formed components with high quality are also proposed and discussed in terms of a die design and the development of a lubricant.

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Semi-Solid Forming Process of Thin Products (박막 성형품의 반응고 성형공정)

  • 서판기;정용식;강충길
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.60-63
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    • 2003
  • Semi-solid forming is the process of stirring alloy during solidification, making the mixture of liquid and solid, solidifying it, reheating it to the solid-liquid coexistent temperature, and then injecting this semi solid slurry into dies. In the semi-solid die casting process, it is very important to find out the correlation of injection condition, microstructure and mechanical properties. Especially, an improper injection condition is the main cause of liquid segregation and non-homogeneous mechanical properties due to the difference of solid fraction according to the position of the products. To ensure the database requisite to the semi-solid die casting product, it is essential to acquire the mechanical properties considering liquid segregation to the injection condition. In this study, the effect of injection condition on liquid segregation, formability, microstructure and mechanical properties in a thin product was investigated.

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Finite Element Analysis of Extrusion Process in Semi-Solid State (반용융 재료의 압출공정에 관한 유한요소 해석)

  • Hwang, Jae-Ho;Go, Dae-Cheol;Min, Gyu-Sik;Kim, Byeong-Min;Choe, Jae-Chan
    • Transactions of Materials Processing
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    • v.7 no.4
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    • pp.364-374
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    • 1998
  • It is the objective of this study to analyze the effect of various process variables on the quality of extruded product and extrusion force for semi-solid extrusion of Al2024 with solid phase structure of globular type by the finite element method. Process variables are initial solid fraction, ram speed, semi-angle of die, and reduction in area. The results of experiment are compared with those of simulation in order to verify the usefulness of the developed finite element program. The flow and deformation of semi-solid alloy are analyzed by coupling by coupling the deformation of porous skeleton and the flow of liquid phase. It is also assumed that initial solid fraction is homogeneous.

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A Study on Induction Heating with Forced Surface Cooling in Semi-Solid Forming Process (반용융 성형에서 강제 표면 냉각에 의한 유도 가열 방법에 관한 연구)

  • Park Joon Hong;Choi Young
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.1
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    • pp.97-102
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    • 2005
  • The procedure of semi-solid forming is composed of heating a billet, forming, compression holding and ejecting step. There are several methods to heat a billet during semi-solid forming process such as electric heating and induction heating. Usually in semi-solid forming process, induction heating has been adopted to achieve more uniform temperature of semi-solid material. Although induction heating is better method than any others, however, there is still difference of temperature between internal part and surface part of semi-solid material. Worse yet, in case of high liquid fraction of semi-solid material, liquid of the billet will flow down though solid of the billet still remains, which is very difficult to handle. In the present study, induction heating of semi-solid material with compulsive surface cooling has been performed to obtain uniform distribution of temperature. Distribution of temperature of the billets was measured and compared with that of conventional distribution of temperature. By this new induction heating method, not only temperature over the whole billet become uniform, but also control of temperature is possible.

A Study on Induction Heating with Compulsive Surface Cooling in Semi-Solid Forming Process (반용융 성형에서 간제 표면 냉각에 의한 유도 가열 방법에 관한 연구)

  • Choi, J. C.;Kim, B. M.;Choi, Y.;Park, J. H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.465-468
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    • 2000
  • The procedure of semi-solid forming is composed of heating a billet, forming, compression holding and ejecting step. There are several methods to heat a billet during semi-solid forming process such as electric heating and induction heating. Usually in semi-solid forming process, induction heating has been adopted to achieve more uniform temperature of semi-solid material. Although induction heating is better method than any others, however, there is still difference of temperature between internal part and surface part of semi-solid material. Worse yet, in case of high liquid fraction of semi-solid material, liquid of the billet will flow down though solid of the billet still remains, which is very difficult to handle. In the present study, induction heating of semi-solid material with compulsive surface cooling has been performed to obtain uniform distribution of temperature. Distribution of temperature of the billets was measured and compared with that of conventional distribution of temperature. By this new induction heating method, not only temperature over the whole billet become uniform, but also control of temperature is possible.

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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.

Deformation Analysis of Semi-Solid Aluminum Material Considering Seperation Phenomena of Solid Particles (고상입자의 분리현상을 고려한 Semi-Solid 알루미늄재료의 변형해석)

  • 최진석;강충길;김기훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.98-105
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    • 1997
  • The behaviour of alloys in the semi-solid state strongly depends on the imposed stress state and on the morphology of the phase which can very from dendritic to globular. The estimation of behaviour characteristic in the compression simulation with seim-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for compression process is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process considering soldification phenomena is performed to the isothermal conditions of two dimensional problems. To analysis of compression process by using semi-solid materials, a new stress-strain relationship is described, and compression analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for compression force and ram displacement will be compared to experimental data.

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