• Title/Summary/Keyword: Powder forming

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Near-Net-Shape Forming and Finite Element Analysis for Ceramic Powder Under Cold Combination Pressing and Pressureless Sintering (냉간 조합압축과 상압소결에 의한 세라믹 분말의 정밀정형과 유한요소해석)

  • Kim, Hong-Gi;Lee, Hyeong-Man;Kim, Gi-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.2 s.173
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    • pp.526-534
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    • 2000
  • Near-net-shape forming of zirconia powder was investigated under the combination of cold die and isostatic pressing and pressureless sintering. A novel combination pressing technique, i.e., die com paction under cold isostatic pressing, allowed to produce a complex shaped ceramic powder compact with the controlled dimensions and relatively uniform density distributions. The constitutive models proposed by Kim and co-workers for densification of ceramic powder under cold compaction and high temperature were implemented into a finite element program (ABAQUS). Experimental data for relative density distributions and deformations of zirconia powder compacts produced by cold combination pressing and pressureless sintering were compared with finite element results. Finite element results agreed well with experimental data.

A Finite Element Analysis for Near-net-shape Forming of A16061 Powder under Warm Pressing (온간 성형 하에서 A1 합금 분말의 정밀정형에 대한 유한요소해석)

  • Kim, Jong-Kwang;Yang, Hoon-Chul;Kim, Ki-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.11
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    • pp.1897-1906
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    • 2003
  • A finite element analysis for near-net-shape forming of A16061 powder was performed under warm rubber isostatic pressing and warm die pressing. The advantages of warm compaction by rubber isostatic pressing were discussed to obtain a part with better density distributions. The shape of rubber mold was designed by determining a cavity shape that provides a desired shape of the final powder compact. To simulate densification and deformed shape of a powder compact during pressing, the elastoplastic constitutive equation based on yield function of Shima-Oyane was implemented into a finite element program(ABAQUS). The hyperelastic constitutive equation based on the Ogden strain energy Potential was employed to analyze nonlinear elastic response of rubber. Finite element results were compared with experimental data for Al6061 powder compacts under warm die pressing and warm isostatic pressing.

Influence of Binders on the Structure and Properties of High Speed-steel HS6-5-2 Type Fabricated Using Pressureless Forming and PIM Methods

  • Matula, G.;Dobrzanski, L.A.;Kloc, A.;Herranz, G.;Varez, A.;Levenfeld, B.;Torralba, J.M.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.589-590
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    • 2006
  • Based on the comparison of structures and properties of the HS6-5-2 high speed steels made with the powder injection moulding method, pressureless forming, compacting and sintering, and commercial steels made with the ASEA-STORA method, fine carbides spread evenly in the steel matrix were found in the structure of all tested high-speed steels in the sintered state. The steels made with the pressureless forming method are characteristic of the lowest sintering temperature and the highest density, resulting from the high carbon concentration coming from the binding agent degradation.

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Pulse response characteristics and preparation of piezoelectic composite materials with 1-3 connectivity (1-3형 압전복합재료의 제조 및 펄스응답특성)

  • 김진수;김용혁;김호기;이덕출
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1989.06a
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    • pp.77-80
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    • 1989
  • The aim of the study is to develope the processing technique of PZT-Polymer piezoelectric composite materials for ultrasonic transducer application such as biomedical probe and hydrophone. Piezoelectric composite of PZT and polymer with 1-3 connectivity patterns have been fabricated by dicing-filling method and extrusion forming method. In this study processing forming method. In the study processing steps by extrusion forming method in the preperation of PZT/polymer piezoelectric composites are described. The PZT powder used in the study is commercial powder which is prepared by mixing PbO, TiO$_2$ and ZrO$_2$. The binder, water and plasticizer are mixed with the PZT powder to form a slip. It is necessary to adjust the viescosity of slip according on the PZT rod diameters to be extruded. The electromechanical properties of the piezoelectric composites are characterized in terms of the thickness resonance mode. The pulse response characteristics by the ultrasonic transducer analyzer and osciloscope are evaluated.

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Characteristics of HTS tube fabricated by centrifugal forming process (원심성형법으로 제조한 고온초전도 튜브의 특성 분석)

  • Jang, Gun-Eik;Park, Yong-Min
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.211-215
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    • 2000
  • Bi-2212 HTS tube was fabricated by CFP(Centrifugal Forming Process). Slury was prepared in the mixing ratio of 8:2 between powder and binder and ball-milled for 24 hrs. Slurry was initially charged into the rotating mold with 300${\sim}$450 rpm and heated at the temperature ranges of 840${\sim}$860$^{\circ}$C for partial melting to finally obtain a uniformly textured tube shape. It was observed the plate-like grains with more than 20 ${\mu}$m were well oriented along the rotating axis and the measured T$_c$ was around 67K. In this paper we will discuss and analyze the tube characteristics depending on many different processing parameters such as, powder composition, binder mixing ratio between powder and binder, motor speed, heating temperature and etc.

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A Study on the Properties of Cold Forging P/M Products by Incremetal Forming Process (회전 성형법에 의한 분말단조 제품특성에 관한 연구)

  • 윤덕재;나경환;김영은
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.03a
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    • pp.31-40
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    • 1995
  • Powder metallurgy process has many advantages such as hight efficientyof material, mass productivity and complex shape production with good mechanical properties. Among the powder forming processes, incremental forging allows the consolidation to be achieved with amaller force then those required by conventional forging. In particular the proces known as rotary forging is an unique and prodominant process known as rotary forging is an unique and prodominant process in which the working constraints approximate to those in normal closed die forging. This study is concerned with the powder compaction by rotary forging process. An experimental rotary forging press with 500kN load capacity has been developed, which is equippe dwith the rotational conicla die inclined to the central axis of the press at arbitrary angle. It is found that the highly densified P/M parts can be obtained by rotary forging process and the material properties are superior to those of the conventrional sintered parts. The detailedcomparision of the mechanical properties by rotary forging process with those by conventional process are given.

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