• Title/Summary/Keyword: casting

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Corrosion Behavior of Dental Alloys Cast by Various Casting Methods (치과용 주조합금의 주조방법에 따른 부식거동)

  • Choe Han-Cheol;Ko Yeong-Mu
    • Journal of the Korean institute of surface engineering
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    • v.37 no.5
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    • pp.296-300
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    • 2004
  • The defects of partial denture frameworks are mainly shrinkage porosity, inclusions, micro-crack, particles from investment, and dendritic structure. In order to investigate a good casting condition of partial denture frameworks, the three casting alloys and casting methods were used and detected casting defects were analyzed by using electrochemical methods. Three casting alloys (63Co-27Cr-5.5Mo, 63Ni-16Cr, 63Co-30Cr-5Mo) were prepared for fabricating partial denture frameworks with various casting methods; centrifugal casting (Kerr, USA), high frequency induction casting (Jelenko Eagle, USA), vacuum pressure casting (Bego, Germany). The casting temperature was $1,380^{\circ}C$ (63Co-27Cr-5.5Mo and 63Ni-16Cr) and $1,420^{\circ}C$ (63Co-30Cr-5Mo). The casting morphologies were analyzed using FE-SEM and EDX. The corrosion test of the dendritic structure was performed through potentiodynamic method in 0.9% NaCl solutions at $36.5^{\circ}C$ and corrosion surface was observed using SEM. The defects of partial denture frameworks improved in the order of centrifugal casting, high frequency induction casting, and vacuum pressure casting method, especially, pore defects were found at part of clasp in the case of centrifugal casting method. The structure of casting showed dendritic structure for three casting alloys. In the 63Co-27Cr-5.5Mo and 63Co-30Cr-5Mo, $\alpha$-Co and $\varepsilon$-Co phases were identified at matrix and $${\gamma}$-Ni_2$Cr second phase were shown in 63Ni-16Cr. Also, the corrosion resistance of cast structure increased in the order of vacuum pressure casting, high frequency induction casting, and centrifugal casting method.

Effect of Casting Processes on the Microstructures and Mechanical Properties of B390 Aluminium Alloy (주조용 B390 알루미늄합금의 조직과 기계적 성질에 대한 각종 주조법의 영향)

  • Han, Yo-Sub;Lee, Ho-In;Kim, Sung-Su;Kim, Jung-Sik
    • Journal of Korea Foundry Society
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    • v.13 no.3
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    • pp.259-267
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    • 1993
  • The effects of casting processes-direct and indirect squeeze casting, permanent mold casting and die casting on the microstructure and mechanical properties were studied for the hypereutectic B390 aluminium alloy. The effects of T5 and T6 heat treatment were also examined. The direct and indirect squeeze casting showed no casting defects such as porosity and shrinkage were observed in permanent mold castings and die castings. The primary silicon phase was refined and homogeneously distributed in the order of indirect squeeze casting, diecasting, direct squeeze casting and permanent mold casting. Depletion of primary silicon phase in die casting surface was disappeared in indirect squeeze casting. Tensile strength of cast and heat treated specimens were increased in the order of direct squeeze casting, permanent mold casting, indirect squeeze casting and die casting. Hardness of indirect squeeze castings was larger than that of other castings. As indirect squeeze casting of B390 aluminium alloy, the time of T6 heat treatment to achieve high strength can be reduced.

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A Study on the Direct Casting of Photo-polymer (포토 폴리머의 직접 주조에 관한 연구)

  • Kim, Woo-Soon;Kim, Dong-Hyun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.6
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    • pp.127-133
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    • 2006
  • Rapid prototyping technologies have been widely used to reduce the development cost of new products. Manufacturing industries are nowadays characterized by the flexibility and complexity of products. This to due to the rapid development of manufacturing technology and diverse needs of customers. In this paper, the best homing out and casting condition for getting casting product of resin pattern(photopolymer) have been examined experimentally. In generally, the burning out and casting conditions have effect on the casting products. Using the direct casting. we directly Producted the Jewelry. And in this paper, we used only gypsum. Many study of casting for resin have been used to dental investment. A dental investment is good for resin casting. but dental investment is too hard and not useful on the jewelry casting. Therefore we need to find the way of resin casting by gypsum.

A Study on The Effect of Air-Vent Utilized to Dental Precision Casting (치과정밀주조에 활용되는 Air-Vent의 효과에 관한 연구)

  • Kim, Bu-Sob
    • Journal of Technologic Dentistry
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    • v.16 no.1
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    • pp.5-11
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    • 1994
  • On purpose of relative comparison of between air-vent attached pattern and non attached one, casting tests were accomplished by castability analysis unrig wax screen mesh pattern. Experimental specimens are divided Into 4groups. 1) Air-vent attached pattern with high casting pressure(coil spring type centrifugal casting machine 2.5turn). 2) Air-vent attached pattern with low casting pressure(coil spring type centrifugal casting machine 1.5turn). 3) Air vent non attached pattern with high casting pressure(coil spring type centrifugal casting machine 2.5turn). 4) Air-vent non attached pattern with low casting pressure(coil spring type centrifrgal casting machine 1.5turn). The main results are as follows : 1) The condition of high casting pressure no.1, no.3 were showed perfect castability. 2) The condition of low-casting pressure, there is a wide difference between no.2, no.4 group. Castability of no.2 group preferable to no.4 group(p<0.001). 3) Low casting pressure and complex shape cause the low-castability. So it is recommanded that use of air-vent in case of complex shaped wax pattern with low easting pressure.

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A study on the Horizontal Continuous Casting by Horizontal Continuous Casting Machine of Al-xSi(x=10-15%) Aluminum Alloy (수평식 연속주조 시스템을 이용한 Al-xSi(x=10-15%)합금 수평연주에 관한 연구)

  • Seo, Heesik;Ha, Sangbaek
    • Journal of the Korean Society of Industry Convergence
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    • v.17 no.3
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    • pp.122-135
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    • 2014
  • This paper was studied on the horizontal continuous casting of Al-xSi(x=10~15%) aluminum alloy. The experiments of the horizontal continuous casting was carried out by the horizontal continuous casting machine for various casting conditions and investigated on fracture types and mechanisms. Surface defect types for the horizontal continuous casting is also investigated. And the study was carried out that the horizontal continuous casting conditions such as casting temperature, cooling rate, and drawing speed affect the hardness and primary silicon size of Al-xSi(x=10~15%) aluminum rod bar. Casting temperature within this experiment conditions don't affect on the hardness of rod bar but the higher casting temperature is the smaller primary silicon size. The higher cooling rate and drawing speed have the higher hardness and the smaller primary silicon size.

Development of the Simulated Die Casting Process by using Rapid Prototyping (쾌속 조형 공정을 이용한 다이캐스팅 제품의 시작 공정 개발)

  • Kim K. D.;Yang D. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.180-186
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    • 2002
  • The simulated die-casting process in which the traditional plaster casting process is combined with Rapid Prototyping technology is being used to produce Al, Mg, and Zn die-casting prototypes. Unlike in the die-casting process, molten metal in the conventional plaster casting process is fed via a gravity pour into a mold and the mold does not cool as quickly as a die-casting mold. The plaster castings have much larger and grosser grain structure as compared as the die-castings and the thin walls of the plaster mold cavity may not be completely fillet Because of lower mechanical properties induced by the large grain structure and incomplete Idling, the conventional plaster casting process is not suitable for the trial die-casting Process. In this work, an enhanced trial die-casting process has been developed in which molten metal in the plaster mold cavity is vibrated and pressurized simultaneously. Patterns for the casting are made by Rapid Prototyping technologies and then plaster molds, which have runner system, are made using these patterns. Imparted pressurized vibration to molten metal has made grain structure of castings much finer and improved fluidity of the molten metal enough to obtain complete filling at thin walls which can not be filled in the conventional plaster casting process.

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Numerical Simulationof Plaster Casting with Pressurized Vibration (진동을 부가한 저압의 석고주조 공정 해석)

  • Kim, Gi-Don;Yang, Dong-Yeol;Jeong, Jun-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.9
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    • pp.101-109
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    • 2001
  • The simulated die casting process in which the traditional plaster casting process is combined with rapid prototyping technology is being used to produce Al, Mg and Zn die casting prototypes. Because of lower mechanical properties induced by the large grain structure and incomplete filling, conventional plaster casting is not suitable for the simulated die casting process. A plaster casting process with pressurized vibration was developed for the simulated die casting process[5]. In this paper, numerical simulation for the filling stage of the process has been performed to show the effect of the pressurized vibration for complete filling. Treatment of boundary condition based on the finite element method has been proposed for imparted pressurized vibration in the plaster casting process.

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Decision-Making of Casting Process using Expert System (전문가 시스템을 이용한 주조법 결정)

  • Kim, Jong-Do;Yoon, Moon-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.6
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    • pp.54-60
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    • 2014
  • In industry, several casting process are widely used to manufacture complex and accurate blank part of hard materials such as aluminum, casting steels, bronze and magnesium alloys which are difficult to manufacture in a blank shape. Even if the casting process does not high accuracy superior surface characteristics other machining process, the casting process is widely used in manufacturing blank part. Furthermore, it is difficult to select appropriate casting process a part among several casting process. for effective selection different process, a careful decision given casting application is necessary. An appropriate casting for a given material and shape condition must be selected for novice engineers in industry. In this paper, an expert system based on an analytic network process(ANP) is suggested for best selection of casting considering a prior interdependency effect among various factors such as material, geometry, process capability, economy and equipment.

Development of Rapid Tooling Technology for Shoe Mold and Its Applications (신발 금형의 쾌속제작기술 개발 및 그 적용에 관한 연구)

  • Chung, Sung-Il;Im, Yong-Gwan;Jeong, Hae-Do;Jeong, Du-Su;Bae, Tae-Yong;Lee, Seok-Woo;Choi, Han-Zong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.8
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    • pp.1371-1379
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    • 2003
  • RP&M (Rapid Prototyping and Manufacturing) is the most appropriate technology for the small-lot production system, because the production cycle is getting shorter owing to various needs of the consumer. In this paper, rapid tooling technology is applied to the casting process. The casting process has the ability to reflect complicated shapes in one process. But it has not been widely used to make a die and mold because of the poor surface quality caused by air bubbles on the surface of the casting product. In this study, the porous casting mold is fabricated from a mixture of plaster and water-soluble binder. The porous casting mold can improve the characteristics of casting products with the help of the vacuum sealed casting process. The vacuum sealed casting process is an advanced technology that removes the air bubbles between the porous casting mould and the liquid metal, thus making the surface of the casting product finer. The purpose of this paper is to develop a high quality shoe mold using porous casting mold and to apply the RP&M technology to the shoe industry.

Effect of Casting Speed on Microstructure and Mechanical Properties of Al-Mg-Si/Al Hybrid Material by Duo-Casting

  • Park, Sung Jin;Suh, Jun-Young;Lee, Hee-Kwon;Chang, Si Young
    • Korean Journal of Materials Research
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    • v.30 no.3
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    • pp.111-116
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    • 2020
  • Two different casting speeds of 60 and 80mm/min are adopted to determine the effect of casting speed on the microstructure and mechanical properties of Al-Mg-Si/Al hybrid material prepared by duo-casting. The obtained hybrid material has a uniform and straight macro-interface between the pure Al side and the Al-Mg-Si alloy side at both casting speeds. When the casting speed is increased to 80mm/min, the size of primary α phases in Al-Mg-Si alloy decreases, without change of shape. Although the Al-Mg-Si alloy produced at higher casting speed of 80mm/min shows much higher ultimate tensile strength (UTS) and 0.2 % proof stress and lower elongation, along with higher bending strength compared to the case of the 60mm/min in casting speed, the tensile properties and bending strength of the hybrid material, which are similar to those of pure Al, are the same regardless of the increase of casting speed. Despite the different casting speeds, deformation and fracturing in hybrid materials are observed only on the pure Al side. This indicates that the macro-interface is well-bonded, allowing it to endure tensile and bending deformation in all hybrid materials.