• Title/Summary/Keyword: Aluminum Die-Casting

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Reheating Process of Semi-Solid Aluminum Alloy (반융용알루미늄재료의 재가열공정)

  • 강성수;도영진;강충길
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.06a
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    • pp.16-27
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    • 1997
  • A semi-solid forming has a lot of advantages compared to the die casting, squeeze costing and convenctional forging, therefore, semi-solid forming process are now becoming of industial interest for the production of metal components and metal matrix composites. However, the material behaviour in the semi-solid temperature range is not sufficiently known although it controls the whole process through forces and geometry evolutions bcause the behaviour of metal slurries is complex. The semi-solid materials(SSM) fabricated under electric-magnetic stirring condition is necessary to be applicate in forming process. A reheating conditions were studied with the reheating time, holing time and reheating temperatures. The microstructure of SSM (which specimen size:d 40${\times}$i60) on condition of heating time 10min and heating temperature 590$^{\circ}C$ is most globular and finest one. The microstructure of SSM(specimen size:d75${\times}$i60) reheated under the three step reheating conditions is most globular and finest.

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Study on the improvement of productivity and quality on the Aluminum wheel by low pressure die casting (저압주조 알루미늄 휠 생산성 향상 및 품질개선에 관한 연구)

  • 이영철;최정길
    • Proceedings of the KAIS Fall Conference
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    • 2001.05a
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    • pp.224-228
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    • 2001
  • 자동차용 Al Wheel의 반복 금형 주조 공정에 있어서의 적정 냉각조건 확립 및 수축공 등의 주조결함을 제어하기 위하여 3차원 응고, 유동, 응력 해석 프로그램 연동 기술과 자동 금형온도 조절장치를 실제 현장에 적용하여 생산되는 Al Wheel 제품의 최적 주조조건 및 냉각조건을 확립하였다. 주조과정 중의 금형의 온도 변화 및 주물의 응고, 유동 거동은 수치해석 결과와 잘 일치하는 경향을 나타내었다. 또한 금형온도 자동 조절 장치를 사용함으로서 금형 작업온도의 가열 및 유지가 정량적으로 제어 가능하며, 제품 품질의 유지 및 Cycle Time 최적화를 이룰 수 있으며 궁극적으로는 금형 수명 연장 및 생산성 향상 등을 이룰 수 있었다.

A Study on the Surface Characterization of Fe-17wt.%Cr Steel for Cast-bonding of Al and Stainless Steel (Al과 스텐레스강의 주조접합을 위한 STS430(Fe-17wt.%Cr)강의 표면처리 특성연구)

  • Kim, Eok-Soo
    • Journal of Korea Foundry Society
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    • v.25 no.3
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    • pp.134-141
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    • 2005
  • To overcome the undesirable deformation, peeling off and geometrical restrictions which were mainly caused by differences in thermal expansion coefficients during the cladding of aluminum strip and stainless strip, new processing method based on vacuum die casting is designed and implemented in fabricating Al/Fe-17wt%Cr steel(stainless steel). To increase cast-bonding ability, the surface of Fe-17wt%Cr steel is electrochemically etched to have optimum pit size and density. The optimum conditions to generate best pit are as follows: Solution: 1 M $Fecl_{3}$+1 M Nacl, Addition: $CuCl_{2}+HCl$, Current density: 80 $mA/cm^{2}$, Total current: 400 $coulomb/cm^{2}$, AC frequency :60 Hz.

Corrosion Behavior of High Pressure Die Cast Al-Ni and Al-Ni-Ca Alloys in 3.5% NaCl Solution

  • Arthanari, Srinivasan;Jang, Jae Cheol;Shin, Kwang Seon
    • Corrosion Science and Technology
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    • v.16 no.3
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    • pp.100-108
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    • 2017
  • In this investigation corrosion behavior of newly developed high-pressure die cast Al-Ni (N15) and Al-Ni-Ca (NX1503) alloys was studied in 3.5% NaCl solution. The electrochemical corrosion behavior was evaluated using open circuit potential (OCP) measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization results validated that NX1503 alloy exhibited lower corrosion current density ($i_{corr}$) value ($5.969{\mu}A/cm^2$) compared to N15 ($7.387{\mu}A/cm^2$). EIS-Bode plots revealed a higher impedance (${\mid}Z{\mid}$) value and maximum phase angle value for NX1503 than N15 alloy. Equivalent circuit curve fitting analysis revealed that surface layer ($R_1$) and charge transfer resistance ($R_{ct}$) values of NX1503 alloy was higher compared to N15 alloy. Immersion corrosion studies were also conducted for alloys using fishing line specimen arrangement to simultaneously measure corrosion rates from weight loss ($P_W$) and hydrogen volume ($P_H$) after 72 hours and NX1503 alloy had lower corrosion rate compared to N15 alloy. The addition of Ca to N15 alloy significantly reduced the Al3Ni intermetallic phase and further grain refinement may be attributed for reduction in the corrosion rate.

Numerical Analysis on Semi-Solid Forging and Casting Process of Aluminum Alloys (알루미늄합금의 반용융 단조 및 주조공정에 관한 수치해석)

  • 강충길;임미동
    • Transactions of Materials Processing
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    • v.6 no.3
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    • pp.239-249
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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 vary from dendritic to globular. To optimal net shape forging of semi-solid materials, it is important to investigate for filling phenomena in forging process of arbitrarily shaped dies. To produce a automotive part which has good mechanical property, the filling pattern according to die velocity and solid fraction distribution has to be estimated for arbitrarily shaped dies. Therefore, the estimation of filling characteristic in the forging simulation with arbitrarily shaped dies of semi-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for arbitrarily shaped dies is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process with arbitrarily shaped dies is performed to the isothermal conditions of two dimensional problems. To analysis of forging process by using semi-solid materials, a new stress-strain relationship is described, and forging analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for forging force and filling limitations will be compared to experimental data. The filling simulation of simple products performed with the uniform billet temperature(584$^{\circ}C$) from the induction heating by the commercial package MAGMAsoft. The initial step of computation is the touching of semi-solid material with the end of die gate and the initial concept of proposed system just fit with the capability of MAGMAsoft.

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Importance of Fundamental Manufacturing Technology in the Automotive Industry and the State of the Art Welding and Joining Technology (자동차 산업에서 뿌리기술의 중요성 및 최신 용접/접합 기술)

  • Chang, InSung;Cho, YongJoon;Park, HyunSung;So, DeugYoung
    • Journal of Welding and Joining
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    • v.34 no.1
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    • pp.21-25
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    • 2016
  • The automotive vehicle is made through the following processes such as press shop, welding shop, paint shop, and general assembly. Among them, the most important process to determine the quality of the car body is the welding process. Generally, more than 400 pressed panels are welded to make BIW (Body In White) by using the RSW (Resistance Spot Welding) and GMAW (Gas Metal Arc Welding). Recently, as the needs of light-weight material due to the $CO_2$ emission issue and fuel efficiency, new joining technologies for aluminum, CFRP (Carbon Fiber Reinforced Plastic) and etc. are needed. Aluminum parts are assembled by the spot welding, clinching, and SPR (Self Piercing Rivet) and friction stir welding process. Structural adhesive boning is another main joining method for light-weight materials. For example, one piece aluminum shock absorber housing part is made by die casting process and is assembled with conventional steel part by SPR and adhesive bond. Another way to reduce the amount of the car body weight is to use AHSS (Advanced High Strength Steel) panel including hot stamping boron alloyed steel. As the new materials are introduced to car body joining, productivity and quality have become more critical. Productivity improvement technology and adaptive welding control are essential technology for the future manufacturing environment.

Effects of Iron and Silicon Additions on the Microstructures and Mechanical Properties of Aluminium Bronze (알루미늄 청동의 미세조직과 기계적 성질에 미치는 Fe 및 Si 첨가의 영향)

  • Kim, Jee-Hwan;Kim, Ji-Tae;Kim, Jin-Han;Park, Heung-Il;Kim, Sung-Gyoo
    • Journal of Korea Foundry Society
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    • v.36 no.6
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    • pp.202-207
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    • 2016
  • The effects of Fe and Si additions on the microstructures and mechanical properties of aluminum bronze have been investigated. In a bar-type specimen cast in a die mold, the addition of Fe promoted the dendritic solidification of the ${\alpha}$ phase. The hardness values increased slightly in the Fe-added specimen with heat treatment, while these values was increased significantly in the specimens with Si or with combined additions of Fe and Si. When a centrifugal casting bush with combined addition of Fe and Si was heat treated, the FeSi compound within the matrix was finely dispersed, and was observed to be the origin of cup-cone type conical dimple failure in the tensile fracture surface. The mechanical properties of the heat treated centrifugal casting bushes, whose nominal alloy compositions were (Cu-7.0Al-0.8Fe-3.0Si)wt%, exhibited tensile strength of $703-781N/mm^2$, elongation of 6.6-11.7% and hardness of Hv 222.6-249.2. These high values of strength and elongation were attributed to the strengthening of the matrix due to the combined addition of Fe and Si, and to precipitation of fine the FeSi compound.

An Experimental Study on the Fabrication and the Compression Behavior of Semi-Solid Aluminum Material (반응용 알루미늄재료의 제조 및 압축거동에 관한 실험적 연구)

  • Gang, Chung-Gil;Yun, Jong-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.3
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    • pp.796-805
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    • 1996
  • A fabrication process using Semi-Solid Material(SSM) for casting alloy has been studied to demonstrate the possibility for mass production with controlled solid fraction. The SSM was fabricated under the various solid fractions and preheating temperatures of mold. The behaviour of a semi-solid global microstructure has been investigated under the various heating and die temperatures for solid fraction. The effect of reheating time on the globularization of SSM microstructure has been investigated in detail. And the behavior of SSM which has the solid fraction 0.5 was observed under compression. The stress strain relationship was also obtained for the compression test of semi-solid materials. The rheological behaviour of semi-solid with globule microstructure was investigated as a function of the compression velocity under isothermal holing conditions.

The Development of Aluminum Alloy Piston for Two-Stroke Cycle Engine by Powder Forging

  • Park, Chul-Woo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.1
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    • pp.173-177
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    • 2013
  • The purpose of this paper is to investigate the influences on mechanical properties of two-stroke cycle motor pistons manufactured by casting, conventional forging and powder forging, through the comparison of characteristics, merits and disadvantages of each forming technology. For each forming technology, the optimal process parameters were determined through the experiments for several conditions, and microstructure, hardness, tensile strength and elongation of pistons are compared and analyzed. In conventional forging process, material temperature was $460^{\circ}C$ and the die temperature was $210^{\circ}C$ for the Al 4032. The optimal condition was found as solution treatment under $520^{\circ}C$ for 5 hours, quenching with $23^{\circ}C$ water, and aging under $190^{\circ}C$ for 5 hours. In powder forging process, the proper composition of material was determined and optimal sintering conditions were examined. From the experiment, 1.5% of Si contents on the total weight, $580^{\circ}C$ of sintering temperature, and 25 minutes of sintering time were determined as the optimal process condition. For the optimal condition, the pistons had 76.4~78.3 [HRB] of hardness, and 500 [MPa] of tensile strength after T6 heat treatment.

Thermal Insulation Improvement by Laminated Adiabatic Structure Change in Holding Furnace with Molten Aluminum Alloy (알루미늄 용탕 보온용기의 단열재 적층구조 변경을 통한 보온성 향상)

  • Hwang, June-Sun;Kang, Chung-Gil
    • Journal of Korea Foundry Society
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    • v.31 no.6
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    • pp.336-341
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    • 2011
  • Recently, aluminium usage in the automobile industry has been increased cause of its lightweight. The aluminium has a melting-solidification process in producing line and another melting process was needed in manufacturing process. Two times of melting process for making ingot and casting not only makes the loss of time and money but contaminates the air with Sox, Nox. For this reason, the holding furnace with laminated adiabatic material was developed. This holding furnace can deliver the molten aluminium directly to the industry needing molten aluminium. Recent holding furnace has above $15^{\circ}C/h$ of cooling rate and that causes solidification of molten aluminium. The ANSYS software was used to analysis the heat transfer. The adiabatic materials were laminated with optimized arrangement and holding furnace shape was changed with optimized modelling by ANSYS analysis for reducing the cooling rate of molten aluminium in holding furnace.