• Title/Summary/Keyword: Casting materials

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Optimization of Casting Design for Automobile Transmission Gear Housing by 3D Filling and Solidification Simulation in Local Squeeze Diecasting Process (국부가압 다이캐스팅 공정에서 3차원 유동 및 응고해석을 통한 자동차 변속기 Gear Housing의 주조방안 설계 최적화)

  • Park, Jin-Young;Kim, Eok-Soo;Park, Yong-Ho;Park, Ik-Min
    • Korean Journal of Materials Research
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    • 제16권11호
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    • pp.668-675
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    • 2006
  • In the partial squeeze casting process, the filling behavior of liquid metal and solidification pattern in thick area have significant influence on the quality of casting products and die life. For the optimal casting design of automobile transmission gear housing, various analyses were performed in this study by using computer simulation code, MAGMAsoft and the simulation results were compared and analyzed with experimental results. By air pressure criteria, internal porosities caused by air entrap during the mold filling were predicted and reduced remarkably by modification of gating system. Also, optimal squeeze-time lag to apply partial squeeze pin in thick area was calculated and the castings was free from shrinkage defects with the result of solidification analysis. Consequently, casting design for automobile transmission gear housing was optimized and approved by Computer Tomography.

A Study of the Development of a High-Strength Al-Zn Based Alloy for Die Casting I (고강도 Al-Zn기 다이캐스팅 합금개발에 관한 연구 I)

  • Shin, Sang-Soo;Yeom, Gil-Yong;Kim, Eok-Soo;Lim, Kyung-Mook
    • Korean Journal of Metals and Materials
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    • 제48권10호
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    • pp.936-941
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    • 2010
  • Al-Zn based alloys are the most common types of wrought Al alloys. Although Al-Zn alloys have high strength, they cannot be applied to a conventional casting process. In this study, Al-Zn-based alloys applicable to a die casting process were developed successfully. The developed Al-45 wt% Zn-based alloys showed a fine equiaxed grain structure and high strength. A fine equiaxed grain having an average size of $25{\mu}m$ was obtained by the die casting process. The UTS and elongation of the new alloy are 475 MPa and ~3.5%, respectively. In addition, we elucidate the effect of a Zn addition on variations in different mechanical properties and the microstructure characteristics of (Al96.3-xZnxCu3Si0.4Fe0.3) x=20, 30, 40, and 45 wt% alloys fabricated by a die casting process.

A Study of Iron Pot Casting and Bellows Technology (토제 거푸집 무쇠솥 주조와 불미기술 연구)

  • Yun, Yonghyun;Doh, Jungmann;Jeong, Yeongsang
    • Korean Journal of Heritage: History & Science
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    • 제53권2호
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    • pp.4-23
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    • 2020
  • The purpose of this study was to explore the diversity of Korea's iron casting technology and to examine various casting methods. The study involved a literature review, analysis of artifacts, local investigation of production tools and technology, and scientific analysis of casting and cast materials. Bellows technology, or Bulmi technology, is a form of iron casting technology that uses bellows to melt cast iron before the molten iron is poured into a clay cast. This technology, handed down only in Jeju Island, relies on use of a clay cast instead of the sand cast that is more common in mainland Korea. Casting methods for cast iron pots can be broadly divided into two: sand mold casting and porcelain casting. The former uses a sand cast made from mixing seokbire (clay mixed with soft stones), sand and clay, while the latter uses a clay cast, formed by mixing clay with rice straw and reed. The five steps in the sand mold casting method for iron pot are cast making, filling, melting iron into molten iron, pouring the molten iron into the cast mold, and refining the final product. The six steps in the porcelain clay casting method are cast making, cast firing, spreading jilmeok, melting iron into molten iron, pouring the molten iron, and refining the final product. The two casting methods differ in terms of materials, cast firing, and spreading of jilmeok. This study provided insight into Korea's unique iron casting technology by examining the scientific principles behind the materials and tools used in each stage of iron pot casting: collecting and kneading mud, producing a cast, biscuit firing, hwajeokmosal (building sand on the heated cast) and spreading jilmeok, drying and biyaljil (spreading jilmeok evenly on the cast), hapjang (combining two half-sized casts to make one complete cast), producing a smelting furnace, roasting twice, smelting, pouring molten iron into a cast, and refining the final product. Scientific analysis of the final product and materials involved in porcelain clay casting showed that the main components were mud and sand (SiO2, Al2O3, and Fe2O3). The release agent was found to be graphite, containing SiO2, Al2O3, Fe2O3, and K2O. The completed cast iron pot had the structure of white cast iron, comprised of cementite (Fe3C) and pearlite (a layered structure of ferrite and cementite).

Failure and Phase Transformation Mechanism of Multi-Layered Nitride Coating for Liquid Metal Injection Casting Mold

  • Jeon, Changwoo;Lee, Juho;Park, Eun Soo
    • Korean Journal of Materials Research
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    • 제31권6호
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    • pp.331-338
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    • 2021
  • Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three ㎛-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 ℃ molten metallic glass.

Characterization of the Ceramic Reinforced AC4C Matrix Composites Processed by Squeeze Casting (용탕단조법으로 제조된 AC4C 합금기 세라믹강화 복합재료의 특성연구)

  • Kim, Eok-Soo
    • Journal of Korea Foundry Society
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    • 제25권2호
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    • pp.88-94
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    • 2005
  • The microstructure and mechanical property of the ceramic reinforced AC4C matrix composites processed by squeeze casting were investigated. In this study Kaowool and Saffil fiber which are ceramic reinforcements are used as preform materials. As a matrix material, Al-7wt.%Si-0.3wt.%Mg(AC4C) has been used. In case of Kaowool and Saffil/AC4C composites, 7.5 MPa squeezing pressure and minimum 7.0% binder amount are needed to produce sound composite materials. The tensile strength of Kaowool/ AC4C composite is lower than the matrix metal and this can be explained by the melt unfilling due to formed cluster of Kaowool reinforcements. But the mechanical properties of hardness, wear resistance and thermal expansion are better than the matrix materials due to the strengthening effect of ceramic reinforcements.

Fabrication of Textured $Al_2O_3-Mullite-SiC$ Nano-composite by Slip Casting in a High Magnetic Field and Reaction Sintering

  • Sakka, Yoshio;Saito, Sho;Honda, Atsushi;Suzuki, Tohru S.;Moriyoshi, Yusuke
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.327-328
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    • 2006
  • We have demonstrated that textured $Al_2O_3-mullite-SiC$ nanocomposites can be fabricated by slip casting followed by partial oxidation - reaction sintering of mixed suspensions of $Al_2O_3$ and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that alumina-oriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.

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Fabrication of Textured $Al_2O_3-Mullite-SiC$ Nano-composite by Slip Casting in a High Magnetic Field and Reaction Sintering

  • Sakka, Yoshio;Saito, Sho;Honda, Atsushi;Suzuki, Tohru S.;Moriyoshi, Yusuke
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.455-456
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    • 2006
  • We have demonstrated that textured $Al_2O_3-mullite-SiC$ nanocomposites can be fabricated by slip casting followed by partial oxidation. reaction sintering of mixed suspensions of $Al_2O_3$ and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that aluminaoriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.

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Inverse Heat Transfer Analysis at the Mold/Casting Interface in the Aluminum Alloy Casting Process with Precision Metal Mold (정밀금형 알루미늄 합금주조공정시 주물/금형 접촉면에서의 Inverse 열전달해석에 관한 연구)

  • Moon, Su-Dong;Kang, Shin-Ill
    • Journal of Korea Foundry Society
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    • 제18권3호
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    • pp.246-253
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    • 1998
  • Precision metal mold casting process is a casting method manufacturing mechanical elements with high precision, having heavy/light alloys as casting materials and using permanent mold. To improve dimensional accuracy and the final mechanical properties of the castings, the solidification speed and the cooling rate of the casting should be controlled with the optimum mold cooling system, and moreover, to obtain more accurate control of the whole process interfacial heat transfer characteristic at the mold/casting interface must be studied in advance. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling system was designed and the temperature histories at points inside the metal mold were measured during the casting process. The heat transfer phenomena at the mold/casting interface was characterized by the heat flux between solidifying casting metal and metal mold, and the heat flux history was obtained using inverse heat conduction method. The effect of mold cooling condition upon the heat flux profile was examined, and the analysis shows that the heat flux value has its maximum at the beginning of the process.

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