• Title/Summary/Keyword: Casting/Forging

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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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Development of intermediate roll which has a long life for cold rolling mills (냉간압연용 장수명 중간롤 개발)

  • Park Y. C.;Kim B. H.;Kim I. B.;Kim J. T.;KIM H. M.;Lee W. D.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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    • pp.207-215
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    • 2004
  • There are various characteristics called for in work roll and intermediate rolls for cold rolling mills. Among these characteristics, the two main requirements are to ensure the quality of the rolled products and to reduce roll cost. To achieve these needs, resistance to wear, to thermal shock and to contact fatigue are especially important. This paper describes that new material(named DSR1) for intermediate rolls which greatly increases rolling campaign and improves resistance to wear has been developed. DSR1 was successfully manufactured and has been used in the cold rolling mill. It showed that Trial product was homogenous in hardness distribution and sufficient usable diameter. Also in service test, trial product is much more excellent rolling performance than conventional $5\%Cr$.

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Thixoforging Process of Rheology Materials Fabricated by Spiral Mechanical Stirring Equipment (나선형 기계 교반 장비로 제조된 레오로지 소재의 Thixoforging 공정)

  • Jung, I.K.;Han, S.H.;Bae, J.W.;Kang, C.G.
    • Transactions of Materials Processing
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    • v.17 no.1
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    • pp.5-8
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    • 2008
  • As the semi-solid forming technology has a lot of advantages compared to the die casting, squeeze casting and hot/cold forging, it has been studied actively. This paper focuses on the thixoforging of the rheological materials fabricated by the spiral mechanical stirring equipment with A356 casting aluminum alloy and A6061 wrought aluminum alloy. Formability tests of rheological materials fabricated by spiral mechanical stirring were carried out and the microstructures of forged sample were observed. After thixoforging experiment, the heat-treated conditions of forged samples are investigated to improve the mechanical properties. These results are able to suggest the possibility of commercialization for rheological materials fabricated by spiral mechanical stirring.

Determination of Solid Solution Treatment Condition of Mg-6Al-xZn(x=0,1,2) Alloys Fabricated by Squeeze Casting Method (용탕단조법에 의해 제조된 Mg-6Al-xZn(x=0,1,2) 합금의 용체화처리조건 규명)

  • Kang, Min-Cheol;Yoon, Il-Sung;Kim, In-Bae
    • Journal of the Korean Society for Heat Treatment
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    • v.9 no.4
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    • pp.281-288
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    • 1996
  • This study has been investigated the influence of solid solution treatment on the microstructure of Mg-6Al-xZn(x=0,1,2) alloys fabricated by squeeze casting process. The products having clean surface and fine microstructure are fabricated by adopting the liquid metal forging method. The microstructures of as-fabricated state show ${\beta}(Mg_{17}Al_{12})$ precipitates between the dendrite boundaries. It is found that the hardness of the alloys is increased with increasing amount of zinc due to the solid solution hardening effect of zinc. In the changes of microstructure upon solid solution treatment time at $405^{\circ}C$, ${\beta}$ phases are dissolved in ${\alpha}$ matrix up to 1hr and the microstructure are coarsened rapidly after 2hrs. The microhardness are decreased rapidly until 1hr of solution treatment time and then stabilized. From the above results, it is concluded that the optimum solid solution treatment condition for Mg-6Al-xZn alloys is at $405^{\circ}C$ for 1hr. The solution treatment time is greatly reduced comparing to conventional casting(at $385{\sim}418^{\circ}C$ for 10~14hrs) due to the formation of the super-saturated solid solution by liquid metal forging.

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A Study on Terminology of Metal Handles in Traditional Korean Furniture - Focusing on Korean and Western Furniture - (한국전통가구의 금속 손잡이 영문표기 연구 - 한국 및 서구를 중심으로 -)

  • Moon, Sun-Ok
    • Journal of the Korea Furniture Society
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    • v.23 no.4
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    • pp.449-459
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    • 2012
  • The article aims to making a comparison between traditional Korean and Western furniture metal handles to give the detail information of the handle terms by analyzing the related literature including internet and interviews. In terms of that, the Korean and Western metal handles are compared in the types, components, materials, methods, and terms affecting the development made by the craftsmen before the Industrial Revolution about the mid or late 18th century. As a result, first, ring and drop pull handles were mostly and wooden knobs were a little used to open the furniture doors and drawers. The Korean drop pulls, Deulswae, came out after the ring pulls, Gori, while the Western drops called loop or bail handles as well, came out before the ring pulls. Second, the components were composed by ring, Gori, loop or bail, Deulswae, Post, Baemok, washer, Baemokbatchim, and backplate, Deulswaebatchim. Most of the Western handles were fastened by the bolt and nut, while the post of two strips, Baemok, fastened the Korean metal handles. Third, the metal handles were created of brass and iron mostly, gilded gold and silver. Forth, the method were largely used by casting, engraving, forging, plating, and hammering in the Korean handles, and by casting, molding, engraving, and stamped in the Western handles. Finally, the terms such as "knobs, pulls, drops, ring and drop pulls, loop or bail handles, posts, washers, backplate, casting, molding, engraving, forging, plating, and stamped" were clarified by the two comparison in Korean and English.

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Effect of Process Conditions on the Microstructure and Mechanical Properties of 7175Al Ring Roll Forgings (7175Al 링롤단조재의 미세조직과 기계적 성질에 미치는 공정조건의 영향)

  • Lee, I.G.;Kang, R.K.;Lee, O.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.1
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    • pp.10-16
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    • 2004
  • The aim of this study is to investigate the process conditions on the microstructual changes and mechanical properties of large 7175 aluminum ring roll forgings. The billets range from 370 mm to 720 mm in diameter were homogenized and ring roll forged after direct chill casting. The tensile properties of ring roll forged specimen manufactured with ${\Phi}370mm$ billets were superior to those of ${\Phi}720mm$ billets under $T_6$ condition. Also, these properties showed better than those of military specification under $T_{74}$ treatment. The impact value of ring roll forged specimen under $T_{74}$ treatment increased up to 20% than that of $T_6$ condition. The fracture toughness of ring roll forged specimen manufactured with ${\Phi}370mm$ cast billet showed nearly same level of ${\Phi}720mm$ billet which was processed using MF or Cog free forging followed by ring roll forging.

An Experimental Study on Void Closure Behavior with respect to Reductions in Height (압하율에 따른 기공압착 거동에 관한 실험적 연구)

  • Choi, I.J.;Choi, H.J.;Park, H.J.;Choi, S.;Jung, T.W.;Park, D.K.;Choi, S.K.;Lim, S.J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.114-117
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    • 2009
  • In this work, closing behavior of the voids generated in a casting process was investigated for various parameters such as reductions in height void size and billet rotation during hot open die forging process. The reduction in height and path schedule including the number of paths and billet rotation were chosen as key process variables to express the change of geometrical void shape and void closing behavior. On the other hand, values of die overlapping and die width ratio were set to be constant. Extend of void closure was observed and evaluated using tensile test and microscope. Based on the experimental result, it is ensured that void closure do not occur at 15% and 30% reduction in height as well as one or two rotations of a billet. The useful datum obtained from this study could be utilized to establish an optimum path schedule in the open die forging process.

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주조/단조 공정에서 $A\ell$6061의 단조효과에 관한 연구

  • 권오혁;김형진;배원병;조종래
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.05a
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    • pp.251-251
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    • 2004
  • 이 연구에서는 주단조 공정을 자동차 부품인 low control arm 제조에 적용하였다. Al6061에 주단조 공정을 적용함므로써 재료비 감소와 기존의 스틸제품보다 경량화 효과를 얻을 수 있다는 것을 증명하기 위함이다. 첫째로 단조 재료인 A16061의 최적 주조조건을 찾기 위하여, 주조 실험은 알루미늄의 주입온도, 금형온도, 주입시간을 조절함으로써 수행되어졌다. 최적주조조건은 주입온도 $700^{\circ}C$, 금형온도 30$0^{\circ}C$, 주입시간 10초로 정하여졌다. 각각의 미세조직을 관찰하고 응력-변형률곡선을 구하기 위하여 열가단조실험은 빌렛온도, 변형률속도와 감소율을 기초로 하여 수행되어졌다.(중략)

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Study on Manufacturing Process of Hollow Main Shaft by Open Die Forging (자유단조공법을 통한 중공형 메인샤프트 제조공정에 관한 연구)

  • Kwon, Yong Chul;Kang, Jong Hun;Kim, Sang Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.2
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    • pp.221-227
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    • 2016
  • The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts.

Analysis of A356 alloys filling behavior considering Two-Phase flow (Two-Phase Flow를 이용한 A356 합금의 충전거동 해석)

  • Seol, D.E.;Kang, C.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.425-428
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    • 2006
  • A semi-solid forming technology has some advantages compared with conventional forming processes such as die casting, squeeze casting and hot/cold forging. In this study, the numerical analysis of semi-solid filling has been studied with solid fraction fs = 30% of A356 aluminum alloys. The finite difference program of two-phase flow model of Navier Stokes' equation coupled with heat transfer and solidification has been developed to predict a filling pattern, liquid segregation and temperature distribution of semi-solid metals. It gives die filling patterns and final solidification area. It can predict mechanical properties of semi-solid forming processes.

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