• 제목/요약/키워드: Thixoforming technology

검색결과 31건 처리시간 0.022초

Thixoforming을 위한 재가열용 유도코일 설계의 최적화 (Optimization of Induction Coil Design for Reheating in Thixoforming Process)

  • 김남석
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 1999년도 춘계학술대회논문집
    • /
    • pp.165-168
    • /
    • 1999
  • The coil design of induction heating systems and their optimization are of paramount importance for semi-solid processing(SSP) The authors of this paper present the coil design and optimization of a 60 Hz induction heating system for ALTHIX 86S (Al-6%_Si-3%Cu-0.3%Mg) alloy. An objective function on the basis of the optimization process for the coil design is proposed by introducing an optimization technique. Finally the results of the optimal coil design are also applied to the induction heating process to obtain a fine globular microstructure. The proposed new objective function based on the computational techniques would contribute to obtaining the thixoformed components with good mechanical properties and reducing lead time.

  • PDF

반용융 단조공정에 있어서 제조 조건이 성형성과 기계적 성질에 미치는 영향 (The Effects of Fabrication Conditions on Forging Limitation and Mechanical Property in Semi-Solid Forming Process)

  • 정경득;강충길
    • 소성∙가공
    • /
    • 제10권3호
    • /
    • pp.214-222
    • /
    • 2001
  • The homogeneous distribution of solid region without liquid segregation is important in terms of high quality component during thixoforming process. In closed die semi-solid forging process, liquid segregation is strongly affected by injection velocity than solid fraction because the material has to travel relatively long distance to fill the cavity through a narrow gate. The designed die by computer simulation data was used to thixoforging process. The thixoforming velocity to prediction the liquid segregation had been determined with strain rate associated with multistage velocity control during compression test of semi-solid material. The optimal forging velocity and die temperature were investigated to produce the near-net-shape compressor component. The mechanical properties of thixoformed component were tested with various die and material temperatures before and after heat treatment.

  • PDF

반용융 성형공정에 있어서 액상편석제어를 위한 압축 D/B 및 응용 (Compression D/B for Liquid Segregation Control in Semi-Solid Forming Process and Its Application)

  • 정경득
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 1999년도 고액공존금속의 성형기술 심포지엄(III) SYMPOSIUM ON SEMISOLID FORMING TECHNOLOGY(III)
    • /
    • pp.15-32
    • /
    • 1999
  • A relationship between stress and stain is very important to design a die to avoid defects of products during semi-solid forming process. Since the liquid will be of eutectic composition in alloys liquid segregation will result in significant or undesirable situation. The materials used in this experiment are A 357. A390, Al2024 alloys that is fabricated by the electro-magnetic stirring process from Pechiney in France. The compression test was performed by induction heating equipment and MTS. In order to prevent the liquid segregation these measured temperature would be useful to control of strain rate during compression test. The liquid segregation is controlled as change of the strain rate and solid fraction during the compression process, The characteristics of flow between solid and liquid phase considering liquid segregation is examined through the above experiments. In the case of medium and high volume fractions of solid the distribution of strain rate is calculated by using compression test data of semi-solid materials (SSM). The thixoforming experiments with the designed die are carried out successfully. The die filling patterns of SSM for variation of die temperature and pressing force have been investigated. The hardness of the thixoformed scroll products is evaluated in terms of the microstructure for each position.

  • PDF

경량화 소재의 반용융 및 주조/단조기술 (Semi-Solid Forming, Casting and Forging Technologies of Lightweight Materials)

  • 강충길;최재찬;배원병
    • 한국정밀공학회지
    • /
    • 제17권4호
    • /
    • pp.7-21
    • /
    • 2000
  • This paper describes an overview of the thixoforming and thixomolding processes. Semi-solid metalworking (SSM), which is called the thixoforming process of aluminium materials, incorporates the elements of both casting and for the manufacture of near net shape parts. The SSM has some advantages such as net shape or near net shape manufacturing, the ability to form thin walls, excellent surface finish, tight tolerance, and excellent dimensional precision. The thixomolding process of Mg alloy (AZ9l) is a combination of two technologies both conventional die casting and plastic injection molding. The feed material used is a machined chip with a geometry of approximately 1 mm square and a length of 2~3 mm. The semi-solid forming (SSF) of high quality aluminium and magnesium parts will be established in the automotive and electronic industry, in the future. The hybrid method of casting/forging has been caused attention. This process uses a preformed material made by casting instead of the wrought material and finishes it by a single forging process. This process is expected to lower costs without sacrificing the mechanical and finishes it by a single forging process. The process is expected to lower costs without sacrificing the mechanical properties. The authors, intending that the casting/forging process contributes to a reduction in production cost of aluminum automotive parts in Korea, describes the feature of the casting/forging process, aluminum alloys suitable for the cast preform, microstructure and mechanical properties of the cast preform, application examples of cast/forging, and further study.

  • PDF

나선형 기계 교반 레오로지 소재의 이용한 Thixoforging 공정 (Thixoforging Process of Rheology Materials fabricated by Spiral Mechanical Stirring)

  • 한수훈;정일갑;배정운;강충길
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2007년도 춘계학술대회 논문집
    • /
    • pp.131-134
    • /
    • 2007
  • A semi-solid forming technology has a lot of advantages compared to the die casting, squeeze casting and hot/cold forging, so semi-solid forming has been studied actively. Semi-solid forming has two methods. One is thixoforming with reheating of prepared billet, the other is rheoforming with cooled melt until semi-solid state. Thixoforging technology can produce non-dendritic alloys for semi-solid forming complex shaped parts in metal alloys. In this study, the thixoforging was experimented with made rheology materials by the spiral stirrer equipment. Rheology materials for forging were made by A356 casting aluminum alloy and A6061 wrought aluminum alloy. After experiment, forged samples were measured microstructure and were heat treated for high mechanical properties.

  • PDF

전기자동차용 알루미늄 서스펜션 반응고 성형품의 기계적 특성 (Mechanical Properties of Thixoformed Aluminum Suspension Parts for Electric Vehicles)

  • 강병무;박범석;이상용
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2001년도 추계학술대회 논문집
    • /
    • pp.240-243
    • /
    • 2001
  • Recently, many automobile parts produced by semi-solid forming(SSF) process has been applied for improved weight reduction, better environmental protection and energy savings. SSF process was well developed for high volume production of light weight aluminum components. In this paper, knuckle has been manufactured with A357 by SSF and thor investigated for microstructures and mechanical properties followed by various heat-treatment conditions. It was found that the examined microstructure was equiaxed at the whole cross-section area and as a result, the mechanical properties were satisfied by 100MPa YS, 260MPa UTS and $14\%$ elongation.

  • PDF

반응고 성형법에 의해 제조된 고효율 전동기용 Cu-Rotor의 미세조직 및 결함 분석 (Analysis of Microstructures and Defects of the Thixoformed Cu rotor for High Efficiency Electrical Motors)

  • 강병무;서동우;손근용;이상용
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2003년도 추계학술대회논문집
    • /
    • pp.55-59
    • /
    • 2003
  • Rotor in small-medium induction motor has been usually manufactured by aluminum diecasting. In order to improve efficiency of induction motors, however, it is desirable that pure aluminum is replaced by high electrical conductivity copper alloy. For this purpose, a rotor is thixoformed with Cu-Ca alloy. Thermomechanical processing(TMP) is carried out to modify the semi-solid microstructure of the alloy and final microstructures and filling defects of thixoformed Cu- rotors are investigated. The characteristics of thixoformed Cu-rotor such as motor efficiency and torque are compared with those of Al rotor.

  • PDF

반용융 단조금형의 Gate 형상이 성형성에 미치는 영향 (The Effect of Gate Shape for Semi-Solid Forging Die on the Filling Limitation)

  • 손영익;강충길
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2000년도 추계학술대회 논문집
    • /
    • pp.178-184
    • /
    • 2000
  • To obtain high quality component with thixoforming process, it is important that the homegeneous distribution of solid particles without liquid segregation. In closed-die semi-solid forging process, liquid segregation is strongly affected by injection velocity than any other process variables because the material has to travel relatively long distance to fill the cavity through a narrow gate before solidification begins. The optimal injection velocity and die temperature were investigated to fabricate near-net-shape compressor component called Al frame.

  • PDF

회전식 바렐 장치에 의한 레올로지 소재의 연속 제조 공정 (Continuous Fabrication Process of Rheology Material by Rotational Barrel Equipment)

  • 서판기;정용식;강충길
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2004년도 추계학술대회논문집
    • /
    • pp.103-106
    • /
    • 2004
  • The new rheology fabrication process has been developed to rheo die casting and rheo forming process. Thixoforming process has disadvantages in terms of induction reheating process, scrap recycling, loss of raw material and cycle time. Therefore, to reduce the number of process, new rheology fabrication process with specially designed the rotational barrel type equipment has been proposed to apply in various part productions. The barrel type equipment, which could continuously fabricate the rheology materil, was specially designed to have a function to control cooling rate, shear rate and temperature. During the continuous rotation of barrel with a constant temperature, the shear rate is controlled with the rotation speed. The barrel surface has both the induction heating system and the cooling system to control the temperature of molten metal. By using this system, the effect of the rotation speed and the rotation time on the microstructure was widely examined. The possibility for the rheoforming process was investigated with microstructural characteristic.

  • PDF

전자기 교반한 알루미늄합금 빌렛의 재가열시 고액공존구역에서의 조직변화 (Microstructural Evolution of Electromagnetically Stirred Al alloy Billet During Isothermal Reheating at the Solid-liquid State)

  • 이덕영
    • 한국주조공학회지
    • /
    • 제28권3호
    • /
    • pp.129-135
    • /
    • 2008
  • The reheating stage of electromagnetically stirred Al billet is a critical factor in the thixoforming process. When reheated to the solid-liquid state, the microstructure evolves to a more globular and more homogeneous structure by a coarsening mechanism, the kinetics depending on the initial microstructure. Microstructural evolution has been characterized by conventional parameters (mean size of particle and shape factor) as a function of holding time in the solid-liquid state. The aim of this study is to report experimental results concerning microstructural evolution in the solid-liquid state of electromagnetically stirred Al billet. The material was elaborated in the form of continuously cast bars solidified with electromagnetic stirring to degenerate the dendritic structure. The choice of the reheating conditions is determined by a dendritic ripening and coalescence mechanism, involving variations of both the shape and size of the particles. The reheating time has to be long enough to allow a minimum degree of spheroidizing, but has to be limited as much as possible in order to avoid excessive ripening. The optimum microstructure was obtained at the reheating temperature of near $584^{\circ}C$ and the holding time of 5 min. The only means of combining high productivity with good casting quality was to use feedstock billets whose microstructure showed rapid transformation characteristics.