• Title/Summary/Keyword: Forming effects

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A Study on Forming of Al-Zn-Mg-Sc Aluminum Alloy Bolts (Al-Zn-Mg-Sc 알루미늄 합금 볼트 성형에 관한 연구)

  • Yoon, D.J.;Hahm, S.Y.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.21 no.7
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    • pp.447-452
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    • 2012
  • This paper is concerned with forming of Al-Zn-Mg-Sc aluminum alloy bolts, focusing on the effects of heat treatment and age-hardening on the formability and ductile damage evolution. Both experimental and finite element studies were performed. From the experiments, it is observed that the heat treatment or the normalization of Al-Zn-Mg-Sc aluminum alloy increases its formability dramatically resulting in successful bolt forming, while the effects of age-hardening at room temperature on the stress-strain relationship and formability are not very critical. Deformation characteristics such as distribution of effective stress and strain, material flow, and ductile damage evolution during bolt forming are examined using a commercial finite element package, Deform-2D. It should be noted that the extrusion load predicted by the finite element method matches well the experiment results. The finite element predictions on the deformation characteristics support the experimental observations such as fracture of bolt head flange, material flow, and distribution of hardness.

Development of FE Analysis Scheme for Milli-Part Forming Using Grain and Grain Boundary Element (입자요소를 이용한 미세 박판 부품의 유한요소 해석 기법 개발)

  • 구태완;김동진;강범수
    • Transactions of Materials Processing
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    • v.11 no.5
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    • pp.439-446
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    • 2002
  • This study presents a new computational model to analyze the grain deformation in a polycrystalline aggregate in a discrete manner and based directly in the underlying physical micro-mechanisms. When scaling down a metal forming process, the dimensions of the workpiece decrease but the microstructure of the workpiece remains the similar. Since the dimensions of the workpiece are very small, the microstructure especially the grain size will play an important role in micro forming, which is called size effects. As a result, specific characteristics have to be considered for the numerical analysis. The grains and grain boundary elements are introduced to model individual grains and grain boundary facets, respectively, to consider the size effects in the micro forming. The constitutive description of the grain elements accounts for the rigid-plastic and the grain boundary elements for visco-elastic relationships. The capability of the proposed approach is demonstrated through application of grain element and grain boundary element in the micro forming.

Analysis of effects of the roll forming process parameters of side sill (롤 포밍용 차체 부품 공정 변수 영향도 해석)

  • Kim, D.K.;Sohn, S.M.;Lee, K.H.;Lee, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.310-313
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    • 2007
  • In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. In this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal roll flower model and proper roll-pass sequence can be suggested by analyzing courcenter strain and longitudinal strain according to the roll-pass with FEM simulation. And also effects of the process parameters on the final shape formed by roll forming defects a evaluated.

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Comparison of Forming force on forward and Backward Flow Forming for Combustion Chamber (연소기를 위한 전후방 유동성형에서의 성형력 비교)

  • Nam, Kyoun-Go;Cho, Cheon-Hwey;Hong, Sung-In
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.4
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    • pp.34-39
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    • 2006
  • The flow forming has been used to produce long thin walled tube parts, with reduced forming force and enhanced mechanical for a good finished part, compared with other method formed parts. Especially, the flow forming is suitable for making high precision thin walled cylinders, such as rocket motor cases, combustion chamber, hydraulic cylinders and high-pressure vessels and so on. In this paper, finite element analysis of three-roller forward and backward flow forming for combustion chamber is carried out to study effects of forming depth and feed rate on forming force. The axial and radial forming forces of forward flow forming on several forming depth and feed rate conditions are compared with those of backward flow forming.

Effects of Erythrosine on Murine Immune Functions and Methemoglobin Formation (식품 첨가물의 면역독성 및 혈액독성 - Erythrosine이 마우스의 면역기능과 Methemoglobin형성에 미치는 영향 -)

  • 황미경;윤혜정;유충규;문창규
    • Journal of Food Hygiene and Safety
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    • v.2 no.4
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    • pp.191-196
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    • 1987
  • Erythrosine used as a colouring agent in drugs, cosmetics and foods in Korea, was examined for its effects on murine immune system and methemoglobin formation. As immunotoxicologic assay parameters, we adopted circulating leukocytes and immunoorgan weights for pathotoxicology, IgM plaque forming cells and arthus reaction for humoral immunity, delayed hypersensitivity reaction of cell mediated immunity and carbon clearacnce for macrophage function. Erythrosine's effects were observed as follows; 1. Ery throsine showed no significant effects on circulating leulocyte counts and relative immunoorgan weight. 2. Erythrosine diminished IgM plaque forming cells. 3. Erythrosine decreased arthus reaction, in the dose dependent manner. 4. Erythrosine had no significant effect on delayed hypersensitivity. 5. Phagocytic and corrected phagocytic index were not affected. 6. Methemoglobin content was similar in the test and control groups.

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Effects of sheet and stamping process variables on side wall curl (딥 드로잉 벽면 만곡에 미치는 소재 및 가공조건의 영향)

  • 박기철;한수식;조태현;황상무
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.53-57
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    • 1998
  • In order to investigate the effects of the variables during the stamping process upon the side wall curl behavior, experiments and finite element analyses were done using a 90 degree draw-bending test. The variables considered were the die radius, the forming speed, the restraint force, the lubrication and the sheet grade. The experiments and simulation conditions were selected according to the design of experiment (DOE) approach. The effects of the restraint force, the lubrication and the forming speed were the same for both high strength and mild steels, but the effects of the die radius on the side wall curl were dependent on the magnitude of the die radius and the sheet grade. A straight side wall was observed for both high strength and mild steels when the die radius was about 2∼3 times of the sheet thickness. It was recommended that the restraint force, the forming speed and the friction be increased in order to reduce the side wall curl.

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Effects of Jiyutang with Fructus Immaturus Ponciri on the immune response in the Mouse (지유탕가(地楡湯加) 지실(枳實)이 생쥐의 면역반응(免疫反應)에 미치는 영향(影響))

  • Song Chae-Seok;Park Eun-Jeong;Jeong Gyu-Man
    • The Journal of Pediatrics of Korean Medicine
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    • v.6 no.1
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    • pp.15-32
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    • 1992
  • This study was done to know the effect of Giyuetang on the inflammatory response, contact hypersensitivity (CH), and rosette forming capacity of spleen cells. The effects of Jiyutang with Fructus Immaturus Ponciri on the inflammatory response were evaluated by measuring the production of such reactive oxygen intermediate(ROI) as $O_2^-$ and $H_{2}O_2$ in the peritoneal neutrophils and macrophages. The effects of Jiyutang with Fructus Immaturus Ponciri on the CH were evaluated by checking the ear swelling response against dinitrofluorobenzene(DNFB). The administration of Jiyutang with Fructus Immaturus Ponciri on the mouse decreased the amount of ROI in both neutrophils and macrophages. Jiyutang with Fructus Immaturus Ponciri depressed CH without affecting the rosette forming capacity of spleen cells. The results of this study showed that Jiyutang with Fructus Immaturus Ponciri might have anti-inflammatory effects by decreasing the amounts of ROI in the phagocytes and suppressing the CH, without affecting the rosette-forming capacity of spleen cells.

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Development of Tube End-forming Process using Roll Die (롤다이를 이용한 튜브 축관공정 개발)

  • Kim, Yeong-Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.121-126
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    • 2011
  • An accumulator placed on the refrigerant cycle pipe lines is a part to relax fluctuations of pressure within the pipe lines and stabilize refrigerants flowed into pipe. The accumulator has been mainly manufactured by the process of tube spinning using CNC(Computer Numerical Control) lathe. However, this process has the defects which are low productivity per hour and high cost. For that reason, tube end-forming using roll die is actively being developed, recently. The purpose of this study is to develope the tube end-forming process using roll die in order to manufacture the accumulator for the refrigeration pipe lines. First, the process design of tube end-forming was performed based on specification of product, and then was verified with FE analysis. Also, the effects of friction coefficient and revolution speed of roll die on forming load were investigated. The analytical results were applied in the final process design of tube end-forming. Finally, tube end-forming test was carried out to verify the validity of the FE analysis and the process design.

Development of Manufacturing Technology for SILL SIDE with Roll Forming Process (롤 포밍 공법을 이용한 고강도 차체 SILL SIDE제작 기술 개발)

  • Kim, D.K.;Sohn, S.M.;Lee, K.H.;Lee, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.357-360
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    • 2008
  • In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. In this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal SILL SIDE manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

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Effect of Friction on Springback in Channel Forming (채널 성형에서 마찰이 탄성복원에 미치는 영향)

  • 한영호;송윤준
    • Transactions of Materials Processing
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    • v.12 no.3
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    • pp.236-243
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    • 2003
  • Maintaining the required dimensional accuracy after springback becomes the main concern of sheet-forming die designers when formability is secured through beforehand tryouts. As a part to build guidelines for springback control in automobile frame forming, experiments are carried out to show the effects of process parameters, such as holding force, blank size, and lubrication, on corner angles of channels formed by U-bending or by square-cup drawing and trimming. The results predicted by a commercial FE package were compared with the experiment and the current limitations on springback evaluation were closely discussed.