Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Transactions of Materials Processing
Journal Basic Information
Journal DOI :
The Korean Society for Technology of Plasticity
Editor in Chief :
Volume & Issues
Volume 15, Issue 9 - Dec 2006
Volume 15, Issue 8 - Nov 2006
Volume 15, Issue 7 - Oct 2006
Volume 15, Issue 6 - Sep 2006
Volume 15, Issue 5 - Aug 2006
Volume 15, Issue 4 - Jun 2006
Volume 15, Issue 3 - Apr 2006
Volume 15, Issue 2 - Mar 2006
Volume 15, Issue 1 - Feb 2006
Selecting the target year
Contact Heat Transfer Coefficient for Finite Element Analysis in Warm Forging Processes
Kang J.H. ; Ko B.H. ; Jae J.S. ; Kang S.S. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 183~188
DOI : 10.5228/KSPP.2006.15.3.183
Heat transfer coefficients have great influence on finite element analysis results in elevated temperature forging processes. Experimentally calculated contact heat transfer coefficient is not suitable for one-time finite element analysis because analyzed temperature will be appeared to be too low. To get contact heat transfer coefficient for one-time finite element analysis, tool temperature in operation was measured with thermocouple and repeated finite element analysis was performed with experimentally calculated contact and cooling heat transfer coefficient. Surface temperature of active tool was obtained comparing measurement and analysis results. Contact heat transfer coefficient for one-time finite element analysis was achieved analyzing surface temperature between repeated finite element analysis and one-time finite element analysis results.
Automated Adaptive Tetrahedral Element Generation for Three-Dimensional Metal Forming Simulation
Lee M.C. ; Joun M.S. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 189~194
DOI : 10.5228/KSPP.2006.15.3.189
In this paper, an automated adaptive mesh generation scheme, based on an advancing-front-Delaunay method, is presented fur finite element simulation of three dimensional bulk metal farming processes. Basic approach is introduced in detail, including a surface meshing and volume meshing technique and a mesh density control scheme. The presented approach is applied to automatic forging simulation in order to evaluate the effect of the developed schemes. Comparison shows a good agreement between required mesh density and generated mesh density, implying that the presented approach is appropriate for automatic mesh generation in metal forming simulation.
A Study on Rheology Forming Process of Al-7%Si Alloy with Electromagnetic Application
Ko J.H. ; Seo P.K. ; Kang C.G. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 195~205
DOI : 10.5228/KSPP.2006.15.3.195
This paper focuses on a rheo-forming of am part fabricated by electromagnetic stirring system (EMS). This forming process take place under high pressure of high pressure die casting and thin walled casting is possible. Furthermore, the productivity is better than low pressure die casting because of shorter cycle time. The advantages of rheo-forming are performed in the semi solid state with laminar flow and the gas content is low, which makes welding possible. Therefore this research applies for arm part with EMS and has investigated the mechanical properties after T6 and T5 heat-treatment.
Development of Design-Program of Fixed Type Tube-Sheet for Heat Exchanger
Kong J.S. ; Lee K.J. ; Han J.Y. ; Cho J.R. ; Bae W.B. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 206~212
DOI : 10.5228/KSPP.2006.15.3.206
Design programs of tube-sheet for heat exchanger based on the related engineering society codes have been widely used. But it is not easy fer beginners to use the design programs. So we need to develop an easy program for design of tube-sheet for heat exchanger. This paper describes a developed design-program of tube-sheet fur heat exchanger. The developed program was coded on boiler theory and pressure vessel codes, provided by TEMA(Tubular Exchanger Manufactures Association) and ASME(American Society of Mechanical Engineers). Visual Basic, which is convenient for beginners to deal with, was used in the programming. Also a finite element analysis of tube-sheet for heat exchanger was carried to verify this developed program by using a commercial software, ANSYS. In the finite element analysis, tube and tube-sheet of heat exchanger were substituted by solid plate having equivalent properties for convenience of calculation. The thickness of tube-sheet obtained by the developed design-program was in good agreement with that of tube-sheet by FEA.
The Study of Glass Crystallization Mechanism Using Femtosecond Laser Pulse
Moon P.Y. ; Yoon D.K. ; Lee K.T. ; Shin S.B. ; Cho S.H. ; Ryu B.K. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 213~219
DOI : 10.5228/KSPP.2006.15.3.213
To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous phase inside glass. In this study, Ag-doped
glasses were irradiated to strengthen by crystallization using femto-second laser pulse. XRD, Nano-indenter and SEM etc., irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value(
) of elastic modulus which related with strength of glass than values heat-treated samples and these are
times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.
Finite Element Analysis of the Hydro-mechanical Punching Process
Yoon J.H. ; Kim S.S. ; Kim E.J. ; Park H.J. ; Choi T.H. ; Lee H.J. ; Huh H. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 220~225
DOI : 10.5228/KSPP.2006.15.3.220
This paper investigates the characteristics of a hydro-mechanical punching process. The hydro-mechanical punching process is divided into two stages: the first stage is the mechanical half piercing in which an upper punch goes down before the initial crack is occurred; the second stage is the hydro punching in which a lower punch goes up until the final fracture is occurred. Ductile fracture criteria such as the Cockcroft, Brozzo and Oyane are adopted to predict the fracture of sheet material. The index values of ductile fracture criteria are calculated with a user material subroutine, VUMAT in the ABAQUS Explicit. The hydrostatic pressure retards the initiation of a crack in the upper region of the blank and induces another crack in the lower region of the blank during the punching process. The final fracture zone is placed at the middle surface of the blank to the thickness direction. The result demonstrates that the hydro-mechanical punching process makes a finer shearing surface than the conventional one as hydrostatic pressure increases.
Evaluation of the Forging Process by the Application of Optimization Technology
Yeo H.T. ; Park K.H. ; Hur K.D. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 226~231
DOI : 10.5228/KSPP.2006.15.3.226
The fuel injector is a pa.1 that controls the fuel supply of automotive engine. The housing of the fuel injector supports the rod, the needle valve and the solenoid. In this study, the rigid-plastic FE-analysis by using the design of experiments (DOE) and the response surface methodology (RSM) has been performed to produce the product reducing the under-fill and the maximum effective strain. From the results of DOE, the stem of counter punch and the face angle of punch at the
process, and the stem of punch at the
process were determined as the significant design variables far each response such as the upper under-fill, lower under-fill and the maximum effective strain. From the results of RSM, the optimal values of the design variables have been also determined by simultaneously considering the responses.
Finite-Element Analysis of Warm Square Cup Deep Drawing Process of Magnesium Alloy AZ31 Sheet
Kim H.K. ; Lee W.R. ; Hong S.K. ; Kim J.D. ; Han B.K. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 232~240
DOI : 10.5228/KSPP.2006.15.3.232
Magnesium alloys are expected to be widely used fur the parts of structural and electronic appliances due to their lightweight and EMI shielding characteristics. While the die casting has been mainly used to manufacture the parts from the magnesium alloys, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. However, the magnesium alloy has low formability at room temperature and therefore, in many cases, forming at elevated temperatures is necessary to obtain the required material flow without failure. In the present study, square cup deep drawing tests using the magnesium alloy AZ31 sheet were experimentally conducted at various elevated temperatures as well as room temperature, and the corresponding finite-element simulations, which calculated the damage evolution based on the Oyane`s criterion, were conducted using the stress-strain relations from the tensile tests at various temperatures. The formability predictability by the finite-element analysis was investigated by comparing the predicted damage distributions over the deformed AZ31 sheet at elevated temperatures with the corresponding experimental deformations with failures.
FE Analysis for Application of Isotropic Steel Sheet on Auto-Roof Panel
Han S.S. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 241~246
DOI : 10.5228/KSPP.2006.15.3.241
The isotropic steel sheet was developed and started to apply on the auto-body outer panel, however the characteristics of application on auto-body were not well known. In this paper the FE analysis of outer panel of auto-body was carried out to investigate the characteristics of isotropic steel sheet. For the FE analysis of the roof panel of ULSAB body the isotropic steel sheet and the bake hardening steel sheet were used. The Isotropic steel sheet shows more deformation at punch bottom area of roof panel than the bake hardening steel sheet that is most required forming properties far outer panel to obtain the shape likability of forming parts. It is shown that the isotropic steel sheet has suitable material properties far outer panels of auto-body.
Measurement of Material Properties for Miniature Stamping
Kim Y.S. ; Shim H.B. ;
Transactions of Materials Processing, volume 15, issue 3, 2006, Pages 247~254
DOI : 10.5228/KSPP.2006.15.3.247
Rather than traditional manufacturing processes, miniature manufacturing processes usually require sophisticated equipments and characteristics of the processes of high cost and of low productivity. Contrarily, miniature stamping process can be realized in a low cost high productivity with relatively inexpensive equipments. In the meso scale, mechanical properties, especially work hardening characteristics, are discovered to be statically scattered and size dependent by intensive experimental and numerical investigations, which make the stamping process hard to apply to the miniature manufacturing. In this study, dual purpose experimental device that can be used for both miniature scale tensile test and miniature scale stamping by simple change of attachment has been developed. For the tensile test, the elongation has been measured with a combined use of a CCD camera and a linear encoder in order to account for the possibility of slippage between specimen and the grip and to ensure the accuracy of the measurement, while load has been measured with a load cell. To satisfy the required material properties for stamping, optimal annealing condition has been found by examining the microstructure of annealed specimen.